Anas Final Internship Report.pdf

INTERNSHIP REPORT

IBRAHIM FIBRES LIMITED 38KM, Faisalabad Sheikhupura Road, Faisalabad

September 11, 2014

INTERNSHIP REPORT | IFL | 2014

SUBMITTED TO Mr. Raza Ali Alvi (Manager Training & Development)

SUBMITTED BY Anas Bin Ashraf BS Chemical Engineering, Third Year National University of Sciences and Technology (NUST), Islamabad

Zaid Ashraf Rana BS Chemical Engineering, Graduate National University of Sciences and Technology (NUST), Islamabad

Imran Rasheed BS Chemical Engineering, Final Year University of The Punjab (PU), Lahore

Amina Mehmood BS Chemical Engineering, Final Year National University of Sciences and Technology (NUST), Islamabad

Aqsa Khalid BS Polymer Engineering, Final Year University of Engineering and Technology (UET), Lahore

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“ In The Name of Allah; The Most Beneficent, and The Most Merciful”

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“ Knock, And He'll open the door Vanish, And He'll make you shine like the sun Fall, And He'll raise you to the heavens Become nothing, And He'll turn you into everything.” ( Rumi )

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Table of Contents Acknoledgments………………………………………………………………………………………10 Preface…….................................................................................................................... ............11 Safety Precautions…..………………………………………..……………………………………….12 Company Profile……………………………………………………………………………………….13 Polymer Section……………………………………………………………………………………… ..17 Product (PET) Introduction......................................................................................................... 18 Process Summary for PET Production ....................................................................................... 18 Mass Balance for PET Process ................................................................................................... 20 What is PTA? ................................................................................................................................ 21 PTA Uses ....................................................................................................................................... 22 PTA Section Division .................................................................................................................... 22 Storage and Handling Charging of PTA

............................................................................................................. 22

........................................................................................................................ 23

Conveying of PTA

..................................................................................................................... 23

Process Flow Diagram ................................................................................................................ 25 Main Equipment Used ................................................................................................................ 25 Filter

.................................................................................................................................. 25

Compressor Cooler

................................................................................................................... 26

............................................................................................................................. 26

Rotary Feeder

............................................................................................................... 26

Equipment Interlocks .................................................................................................................. 27 Ethylene Glycol ........................................................................................................................... 27 Process Description .................................................................................................................... 27 MEG Sampling............................................................................................................................. 28 MEG Unloading and pumping to Process line ....................................................................... 28 MEG Uses ..................................................................................................................................... 29 Process Flow Diagram ................................................................................................................ 29 Equipment Interlocks .................................................................................................................. 30

EGR……………………………………………………………………………………………………….29 Process Description .................................................................................................................... 30 Main Equipment Used ................................................................................................................ 31 Kettle type Evaporator

............................................................................................... 31

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INTERNSHIP REPORT | IFL | 2014 Distillation Column

....................................................................................................... 32

Equipment Interlocks .................................................................................................................. 32 Process Flow Diagram ................................................................................................................ 33

HTM……………………………………………………………………………………………………….33 Process Description .................................................................................................................... 34 BCO Cycle ................................................................................................................................... 36 HTM Cycle .................................................................................................................................... 36 Process Flow Diagram ................................................................................................................ 37 Main Equipment Used ................................................................................................................ 37 Furnace

.......................................................................................................................... 37

Conduction

...................................................................................................... 38

Convection

...................................................................................................... 38

Radiation Stack

........................................................................................................... 38

................................................................................................................................ 38

Pre-Heater (HFO).......................................................................................................... Atomizer Blower

38

......................................................................................................................... 38

.............................................................................................................................. 39

Economizer

.................................................................................................................... 39

.......................................................................................................................... 39

Damper Equipment Interlocks .................................................................................................................. 39 TDO……………………………………………………………………………………………………….40 Process Description .................................................................................................................... 40 Process Flow Diagram ................................................................................................................ 41 TDO Uses ...................................................................................................................................... 42

Catalyst Systems……………………………………………………………………………………….42 Process Description .................................................................................................................... 42 Process Flow Diagram ................................................................................................................ 43

Paste Preparation……………………………………………………………………………………..44 Process Description .................................................................................................................... 44 Process Flow Diagram ................................................................................................................ 45 Main Equipment Used ................................................................................................................ 46 Shank System

................................................................................................................ 46

Paste Mixer.....................................................................................................................

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INTERNSHIP REPORT | IFL | 2014 Esterfication……………………………………………………………………………………………..46 Process Description .................................................................................................................... 46 Temperature and Pressure ........................................................................................................ 47 Residence Time ........................................................................................................................... 47 Acid Number ............................................................................................................................... 47 Process Flow Diagram ................................................................................................................ 48 ES-1

................................................................................................................................... 48 ................................................................................................................................... 49

ES-2 Polycondensation……………………………………………………………………………………..50 Process Description .................................................................................................................... 50 Process Flow Diagram ................................................................................................................ 52 PP-1 and PP-2 DRR

................................................................................................................ 52

................................................................................................................................... 52

Main Equipment Used ................................................................................................................ 53 Scrapper Condenser Ejector System

............................................................................................................... 53

Vacuum Pump Fume Arrestor

.................................................................................................. 53

............................................................................................................. 53

................................................................................................................ 53

MEG Safety .................................................................................................................................. 54 Emergency Overview Inhalation Ingestion

................................................................................................. 54

....................................................................................................................... 54

......................................................................................................................... 54

Skin Contact

.................................................................................................................. 54

Eye Contact

.................................................................................................................. 54

Chronic Exposure

......................................................................................................... 54

Aggravation of Pre-existing Conditions ................................................................. 54 First Aid Measures Inhalation Ingestion

......................................................................................................... 55

....................................................................................................................... 55

......................................................................................................................... 55

Skin Contact

.................................................................................................................. 55

Eye Contact

.................................................................................................................. 55

Note to Physician

......................................................................................................... 55

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INTERNSHIP REPORT | IFL | 2014 PTA Safety .................................................................................................................................... 55 Emergency Overview Skin contact Inhalation Ingestion

.................................................................................................................. 55

....................................................................................................................... 55

......................................................................................................................... 55

Eye contact

................................................................................................................... 56

First Aid Measures Eye Skin

................................................................................................. 55

......................................................................................................... 56

................................................................................................................................... 56 ................................................................................................................................... 56

Inhalation Ingestion

....................................................................................................................... 56

......................................................................................................................... 56

PET Safety ..................................................................................................................................... 56 Emergency Overview Inhalation Skin

....................................................................................................................... 56

................................................................................................................................... 56

Absorption Ingestion Eyes

................................................................................................. 56

..................................................................................................................... 56

......................................................................................................................... 57

.................................................................................................................................. 57

Target Organs ............................................................................................................... 57 Primary Routes of Entry (Exposure) .......................................................................... 57 First Aid Measures Inhalation Skin

....................................................................................................................... 57

................................................................................................................................... 57

Ingestion Eyes

......................................................................................................... 57

......................................................................................................................... 57

.................................................................................................................................. 57

Utilities……………………………………………………………………………………………………58 Boiler.…………………………………………………………………………………………………….58 Types............................................................................................................................................. 58 Components ............................................................................................................................... 59 Process Description .................................................................................................................... 60 Process Flow Diagram ................................................................................................................ 61 Capacities ................................................................................................................................... 62

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INTERNSHIP REPORT | IFL | 2014 Equipment Interlocks .................................................................................................................. 62 Why Nitrogen is Important? ....................................................................................................... 63 Production

..................................................................................................................... 63

Process Description .................................................................................................................... 64 Technical Nitrogen Pure Nitrogen

...................................................................................................... 64

................................................................................................................ 64

Pressure Swing Adsorption.........................................................................................

64

Process Flow Diagram ................................................................................................................ 67 Applications ................................................................................................................................ 67 Cooling Towers…………………………………………………………………………………………68 Basics ............................................................................................................................................ 68 Process Description .................................................................................................................... 69 Process Diagram ......................................................................................................................... 70 Water Treatment Plant………………………………………………………………………………..71 Water required: ........................................................................................................................... 71 Equipments .................................................................................................................................. 72 Process Description .................................................................................................................... 73 Process Flow Diagram ................................................................................................................ 74 Chillers……………………………………………………………………………………………………75 Electric Chiller .............................................................................................................................. 75 Process Description .................................................................................................................... 77 Compressor Drive...................................................................................................................... Compressor

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................................................................................................................................ 77

Condenser

.................................................................................................................................. 77

Evaporator

.................................................................................................................................. 77

Process Flow Diagram ................................................................................................................ 78 Steam Absorption Chiller ........................................................................................................... 78 Process Description .................................................................................................................... 79 High Temperature Generator (HTG) .................................................................................... 79 Low Temperature Generator (LTG)

..................................................................................... 79

Condenser

.................................................................................................................................. 79

Evaporator

.................................................................................................................................. 80

Absorber

...................................................................................................................................... 80

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INTERNSHIP REPORT | IFL | 2014 Process Flow Diagram ................................................................................................................ 80 Spinning & Fibre Line………………………………………………………………………………….81 Heat Exchanger .............................................................................................................. 81 Spin Pumps ...................................................................................................................... 81 Spin Pack ......................................................................................................................... 81 Quench Air ...................................................................................................................... 82 Air Discharge ................................................................................................................... 82 Spin Wall ........................................................................................................................... 83 Disassembling.................................................................................................................. 85 Assembling ...................................................................................................................... 86 Creel Area ....................................................................................................................... 88 Finger Guides and Guiding Rollers ............................................................................... 88 Dipping Bath (YO4) ........................................................................................................ 89 Draw Frame-I (YO5) ........................................................................................................ 89 Draw Bath (YO6) ............................................................................................................. 89 Effect of Glass Transition Temperature on Drawing .............................. 89 Draw Frame-II (YO7) ....................................................................................................... 90 Steam Box (YO8) ............................................................................................................. 90 Draw Frame-III (YO9) ...................................................................................................... 90 Thermosetting Unit (Y10) ................................................................................................ 91 TOW Cooler (Y11) ........................................................................................................... 91 Draw Frame-IV (Y12) ...................................................................................................... 92 TOW Converger and Three Roller Frame (Y13 & Y14) ............................................... 92 Tension Roller (Y15) ......................................................................................................... 92 Pre-Steam Chamber (Steam Box Y16) ........................................................................ 92 Crimper Unit (Y17) ........................................................................................................... 92 Traversing Unit ................................................................................................................. 93 Tow Drier .......................................................................................................................... 93 Fibre Cutter Unit (7458-Y23) ........................................................................................... 93 Baler .................................................................................................................................. 94 Procedure: ........................................................................................................... 95 Process Flow Diagram ........................................................................................ 96 Textile Lab ........................................................................................................................ 97

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INTERNSHIP REPORT | IFL | 2014 UDY/SPUN TOW ................................................................................................... 97 PSF ......................................................................................................................... 99

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ACKNOWLEDGMENTS We are thankful to, Almighty Allah for His unlimited blessings and bounties; for keeping us sane, sound and successful, our Parents for all their support and trust in us, Ibrahim Fibres Limited for providing us with this great opportunity which not only give exposure to industry but also enhanced our technical and professional skills. Our Instructors Mr. Muhammad Saeed (Area Manager Polymer), Mr. Haseeb (Deputy Manager Polymer),Mr. Mirza Faqeer (Area Manager Utilities), Mr. Nouman (Deputy Manager Utilities), Mr. Alam (Deputy Manager Utilities),Mr. Khalid Ejaz (Senior Deputy Manager Spinning), Mr. Abaid Ullah (Senior Deputy Manager Textile Lab), Mr. Jamshaid Yaqub (Senior Assistant Manager Utilities), Mr. Irfan Aziz (HR Officer), Mr. Salman Qazim (Shift Engineer), Mr. Iftikhar (Shift Engineer), Mr. Khalid (Shift Engineer), Mr. Bilal (Shift Engineer), Mr. Zafar Niazi (Shift Engineer), Mr. Umer Mehboob (Shift Engineer), Mr. Umar Faraz (Shift Engineer), Mr. Ahsan (Shift Engineer), Mr. Hamza Abbas (Trainee Engineer),Mr. Afnan Amjad (Trainee Engineer) and Mr. Zain Ul Abideen (Trainee Engineer) in Ibrahim Fibres Limited for all their guidance and help. We are also thankful to all the Supervisors, Operators and every Individual who has helped us even a bit for the completion of this report.

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PREFACE This report produces a peer based review and learning outcome about the working and processes of polyester fiber at a plant. In this report we have tried to mention all those things which we have learned during our internship. In the first section of this report, Polymer Section is briefly explained. Basically all the chemical processes needed in the production of polymer melt occur in this section. Second section of this report is based on Utilities. Utilities are those things which are necessary to run a plant. e.g. steam, N 2 & compressed air etc. This section is considered as the Heart of the Plant. Third section of this report deals with Spinning and Fibre line Process. This section is totally based on physical operations. Spinning is the formation of filaments by the use of spinnerets. Fibre Line is the area where all of the drawing of fibres is done. Fibres acquire most of their physical properties in this area. Last section is relevant to testing and characterization of different materials in the whole plant, Textile Lab. Safety Precautions about the plant are also discussed in this report.

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SAFETY PRECAUTIONS In order to avoid the hazards on the plant, company train its employees for the safe handling and operation of materials and units installed on plant. Even a small mistake on the plant can cause a serious damage so man, machine & material is very important. 

Personal Protection Equipments (PPEs) must worn in the plant premises.



Smoking is strongly prohibited on all areas of the plant because at different places different flammable materials are under process and some leakages may occur and so serious damage can occur.



Over speeding is prohibited on the roads because staff is always crossing the roads and also tanks with explosive materials are present at different places and anything hitting them may cause a serious danger.

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Mobile phone is not allowed in plant area because electromagnetic waves



may disturb the sensitive control system. For the training of internees, schedules are issued that means that for every unit some guide is provided for the specific period of time and we are not allowed to go in any area according to our desire.

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Yellow marks are there on the steps that are odd as compared to other to prevent injury of workers.

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Yellow borders are also provided in front of computer control systems to prevent the tripping of systems as they are very sensitive.



MSDS (material safety data sheets) are provided with every material for the safe handling and storage of the materials.



Different water, gas and sand exhaust systems are provided for overcoming fire.

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COMPANY PROFILE Ibrahim Fibres Limited Company was established in 1947 in Faisalabad, Pakistan as a cloth trading business. In 1980, Ibrahim Textile Mills Limited was established under the form of a manufacturing blended yarn. In 1982 and 1987 two more companies were established (A.A. Textiles Limited and Zainab Textile Mills Limited). In order to improve the efficiency and quality of its manufacturing units that require a continuous uninterrupted supply of electricity, the Ibrahim Group has established its Power Generation plant and now it is being expanded to cater for the expansion of its manufacturing units. Power generating capacity of the project is 31.8 MW based on heavy fuel oil. The plant and machinery of the project comprises of 6 furnace oil generating sets, each having a capacity to produce 5.3 MW, supplied by Nigata Engineering Company, Japan. All these manufacturing companies have now been merged into Ibrahim Fibres Limited. Ibrahim Fibres Limited is incorporated in Pakistan as a public limited company under the Companies Ordinance, 1984 and is listed on Karachi and Lahore Stock Exchanges in Pakistan. The principal business of the Company is manufacture and sale of Polyester Staple Fibre and Yarn. The registered office of the Company is located at 1-Ahmed Block, New Garden Town, Lahore. The manufacturing units are located at Faisalabad- Sheikhupura Road, in the Province of Punjab. Allied Bank Limited The consortium of Ibrahim Leasing Limited and Ibrahim Group assumed the control of the Allied bank in August 2004 by injecting Rs 14.2 billion into the capital of Allied bank for acquiring 325 million additional shares. Today Allied Bank's paid up Capital & Reserves amount to Rs. 10.5 billion, deposit exceeded Rs. 143 billion and total assets equal Rs. 170 billion.

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The Allied Bank's story is one of dedication, commitment to professionalism, adaptation to changing environmental challenges resulting into all round growth and stability, envied and aspired by many.

Polyester Fibre Project The Polyester Fibre Project is based on the engineering and technology supplied by Zimmer AG Germany, who are market leaders in the Polyester Polymer capacities supplied worldwide representing nearly 30% share in the world market. The plant is equipped with Provox plus Distributed Control System (DCS) using SRX process controllers providing a foundation for real time, effeicient and accurate control and monitoring of the process of entire plant through Computer Integrated Manufacturing (CIM). The Provox plus data provides access to historical process data for monitoring and analyzing process conditions. Intelligent alarming techniques help enhanced operator control capability to evaluate changing conditions and to respond quickly to any process changes. The plant has one to one redundancy starting from process control units up to all input/output modules enabling smooth and consistent operation of the plant. The designed capacity of the project, consumption of raw materials, utilities and quality of finished products are guaranteed by German supplier. Polyester Fibre Project IFL-l Initiated in 1994 and operational since December 1996, Plant I has a capacity to produce 200 tons/day of PSF in two lines of 100 tons/day each. Based on 24 hours/day operations of the poly condensation and spinning plant and on 20 hours/day operation of fiber lines, the installed annual manufacturing capacity of the plant 70,000 tons of PSF.

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Polyester Fibre Project IFL-ll This plant has a single polymer line of 410 tons/day and three spinning and staple fibre processing lines, each having capacity of 132 tons/day. The installed annual manufacturing capacity of the plant is 138,600 tons of PSF per annum. The plant supplier opted to start operations of spinning and staple fibre processing lines one after other and the commercial production was started in October 2002. Polyester Fibre Project IFL-lll The Company has successfully implemented the balancing, modernization and expansion of Polyester plant with a new project IFL-ll having a production capacity of 600 tons per day. The commercial production of this plant has been started in the month of April 2013. The Polyester Fibre Division of the company produces wide range of the PSF of different lusters and varieties including semi dull, bright, optical bright, anti pilling, flame retardant and tri lobal with cut length of 32, 38, 44, 51 and 64 mm and fineness of 0.8, 1.0, 1.2, 1.5, 1.7, 2.0, 3.0 and 6.0 denier. The project is the first in Pakistan to start the production of dyed fibre and hollow fibre in siloconised and non-siliconised varieties. Some of the specifications of the products produced are:

Sr #

Parameters

Unit

Specification

Max Tolerance +/-

1 2 3 4 5 6 7 8

Denier Cut lengths Tenacity Elongation Crimp No Crimp Removal Crimp Stability Shrinkage

d mm g/d % No./inch % % %

0.8 38 6.8 21 13 Min 15 Min 60 5.0

0.04 4% 0.2 3 1 1.0

9 10 11 12

Elec.Resistence Moisture Color L Color b

Ω x 10 11Max 1.0 % -

Max 0.4 Min 92 Max 3.0

-

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Ibrahim Fibres is situated at the integrated site of Ibrahim Group close to Faisalabad, where nearly 50% of Pakistan's spinning capacity is located. The site orientation allows for just in time delivery for over 80% of the customers. The textile plants of group are also users of polyester staple fibre and this allows in house quality tests. The group today derives its strength from a unique blend of entrepreneurial ownership added with unparalleled skill of professionals. Keeping up with the ever increasing awareness of quality and high standards, the principle of continually improving the products and production techniques is followed. A well-trained quality control department is responsible for ensuring that the quality of all the products of the Company meets the most stringent international standards. The people in this important activity are supported by complete and modern chemical and textile laboratories. A further step to strengthen the manufacturing efficiency, process and products was achieved when the Company received ISO 9002 Quality Certification for its manufacturing process. The Company achieved net sales of Rs. 38,839 million during the year under review as compared to Rs. 35,853 million during the previous year. The gross profit earned during the year was Rs. 2,725 million as against Rs. 2,622 million earned during previous year. Today, the Group is managed by highly qualified team of professionals with vast experience in their respective fields. Every department is headed by a professional, qualified and experienced executive. At present Ibrahim Group has total employment of 2958 individuals comprising of 1727 skilled persons, 879 semiskilled persons, 87 senior technical executives and 265 officers and managerial staff.

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Product (PET) Introduction The main product in this process is the Polyethylene terephthalate. However, water is produced as a polycondensation by-product with no important economic value. Polyethylene terephthalate (PET) is a polycondensation polymer. It is most commonly produced from a reaction of ethylene glycol (EG) with either purified terephthalic acid (PTA) or dimethyl terephthalate (DMT), using a continuous meltphase polymerization process. In many cases, melt phase polymerization is followed by solid-state polymerization. This polymer is the most common thermoplastic polyester. It is often called just

“polyester”, which often causes confusion. PET is a hard, stiff, strong, dimensionally stable material that absorbs very little water. It has good gas barrier properties and good chemical resistance except to alkalis (which hydrolyze it). Its crystallinity varies from amorphous to fairly high crystalline. It can be highly transparent and colorless but thicker sections are usually opaque and off-white. PET is widely known in the form of thermally stabilized films used for capacitors, graphics, film base and recording tapes etc. It is also used for fibres for a very wide range of textile and industrial uses. Other applications include bottles and electrical components.

Process Summary for PET Production In Ibrahim Fibres Limited, PET is generally produced direct esterification of purified terephthalic acid (PTA) with EG. The first stage is to produce a mixture of ethylene glycol ester ofterephthalic acid. This mixture of linear oligomers (mainly bishydroxyethyl terephthalate BHET) is subjected to a further stage known as

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polycondensation that produces polyethylene terephthalate of fiber-forming molecular weight. Solid-state polymerization is required only for the production of bottles.

The first stage in the polymer synthesis is esterification, which results from the reaction of carboxylic group with an alcoholic group. Since these groups occur at the ends of bifunctional compounds, PET with a linear structure is produced. However, it is necessary during esterification for the compound that is eliminated (water or methanol) to be rapidly removed from the reaction mixture so that the equilibrium shifts preferentially in favor of the polycondensation product. With the rising worldwide demand for polyethylene terephthalate, prospective PET producers are faced with a lot of decision; whether to use purified terephthalic acid or dimethyl terephthalate as the raw material, batch or continuous process, and whether to use the conventional process or to add some modifications to reduce the costs and increase the productivity.

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Mass Balance for PET Process

Following assumptions are made for calculations: 1. No impurities are present in the reactants 2. 100% conversion of reactants 3. 100% solubility of PTA in EG 4. By-products other than water are neglected 5. No loss of expensive materials E/T=1.03/1 Components

In (kg/kg PET)

Out (kg/kg PET)

MEG

0.33

-

PTA

0.86

-

PET

-

1.00

Water

-

0.19

Total

1.19

1.19

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E/T = 2/1 Components

In (kg/kg PET)

Out (kg/kg PET)

MEG

0.64

-

PTA

0.86

-

PET

-

1.32

Water

-

0.18

Total

1.5

1.5

PTA SECTION What is PTA? It is 1, 4-Benzenedicarboxylic Acid with a chemical name of Pure Terephthalic Acid - C6H4 (COOH) 2 . It is commonly produced by the oxidation of p-xylene by the oxygen in air. Some properties of PTA are listed in the following table: Color

White Crystalline Powder

Auto-ignition Temperature

495oC

Flash Point (Open Cup)

260 oC

Products of Combustion

Carbon Oxides (CO, CO2)

Specific Gravity (15

oC)

1.51

Vapor Pressure (25

oC)

0.00158 Pa

Particle Size

70-160 microns

Impurities

Acetic acid, Mo, Cr, Ni, Fe

pH

2.16

Molecular weight, g/mol

166.14

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Melting point, oC

427

PTA (Pure Terephthalic Acid) is the basic raw material for the production of Polyester. Polyester fibers based on PTA provide easy fabric care, both alone and in blends with natural and other synthetic fibers. Polyester films are used widely in audio and video recording tapes, data storage tapes, photographic films, labels and other sheet material requiring both dimensional stability and toughness.

PTA Uses 1. PTA, a white solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. 2. PTA is also used in the pharmaceutical industry as a raw material for certain drugs. 3. It is further used as filler in some military smoke grenades. 4. PTA is also used in the paint as a carrier.

PTA Section Division The whole PTA section deals with the storage, handling, charging and conveying of this raw material.

Storage and Handling PTA is supplied to IFL by the following two companies. 1. Lotte Pakistan PTA Ltd. 2. Siam Mitushi PTA Co. Ltd Siam Mitushi provide PTA in containers with 22 tons each (container casing weighs 1.2 ton). The container charging crane in PTA section has a capacity to handle a maximum load of 25 tons.

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Daily consumption of PTA depends on the daily production of polyester plant. Storage warehouse of PTA section can store a stock of one month.

Charging of PTA In this process, PTA is charged into Buffer Silos with the help of rotary feeders. The charging process is of two types: 1. Bag Charging System 2. Container Charging System In Bag Charging system, PTA bags are taken on the top of charging station with use of hoist system. The bags are then opened on a pan with a vibrating screen beneath it. A vent pipe is also there to remove extra fine particles. This screen removes any coarse particles present in the feed. This feed is then transferred to a rotary feeder equipped with a bag filter to trap any fine particles that may rise in the feeder. This feed further moves to a buffer silo. This silo opens up in a rotary feeder. This feeder prepares batch to be moved for compression and finally to a large storage silo. The Container Charging system uses large containers to prepare batch for IFL-2 (can also be used for IFL-1). Containers are first loaded on a charging station that is inclined to an angle of 25-30 degrees. The maximum elevation provided is 45 degrees. The container is opened and PTA is loaded in a rotary feeder after passing through vibrating screens. Initial mechanism for both types of charging systems is different while the remaining steps are essentially same. PTA section has two bag charging systems (new and old).

Conveying of PTA In this process PTA is conveyed to the storage silos of second stage with the help of compressed nitrogen gas. It is then conveyed, from the storage silos, to the respective plants.

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N2 is separated from air in UTY section. The gas is compressed to ~4.2 barg in Screw compressors. There are total 8 compressors; 3 for IFL-1, 2 for IFL-2 and 3 for IFL-3. Each compressor section maintains different outlet pressure, however, the suction pressure (70-80 mbarg) is same for all the compressor sections. Capacities of compressors are listed in the following table: Compressor Name

Capacity

Discharge Temp.

1204-K01

13.5 m3/min

165 oC

1204-K02

13.5

m3/min

165 oC

1204-K05

13.5 m3/min

165 oC

1204-K11

29.5 m3/min

135 oC

1204-K12

29.5 m3/min

135 oC

1214-K11

40 m3/min

230 oC

1214-K12

40 m3/min

230 oC

1214-K13

40 m3/min

230 oC

Each compressor has a filter at its inlet and outlet position, except the standby compressor of IFL-3. A cooler is present at the discharge of each compressor. Temperature of discharged gas depends on the outlet pressure of respective compressor and that is why outlet temperatures of exit N 2 varies for all the three compressor sections and that is why different water flow rates are maintained in the coolers to obtain sufficient cooling. After cooling, the gas passes through bag filters and then through the storage silos to fluidize N 2 to different plants. PTA is not allowed to come in contact with air because if it comes in contact with 10% air, it forms an explosive mixture. That is why N2 is used as a conveying medium.

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Process Flow Diagram

Main Equipment Used Filter There is a bucket type filter where nitrogen is filtered with the polythene type filter medium that removes all the powdered and undersize particles from the recovered nitrogen. The purpose of this filter is that no PTA will pass from the compressor as it can damage the capital property of the compressor.

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Compressor Here In case of PTA Conveying and Storage we need a compressed inert gas. As PTA is one of the explosive materials, so for the sake of convenience we have selected compressed Nitrogen as a driving source of PTA due to its unique property that it remains inert even at very high temperature. The Compressors are rotary type screw compressors that compress the nitrogen up to 2.4-3.2 bars pressure at nearly 250 °C. In screw type compressors the gas is compressed between the threads of screws that generates very high pressure i-e ranging from 2.4-3.2 bars. The pressure of nitrogen in the conveying and storage lines is nearly 65-80 mbar that is responsible for the fluidization of PTA during the storage and conveying operations.

Cooler Compressed nitrogen from compressor contains a high temperature of nearly 250oC, which needs to be cooled to 40-60 oC to avoid the auto-ignition with PTA. For this purpose we cool the temperature of nitrogen to desired range with the help of Shell and Tube heat Exchanger, where water after passing through the strainer, installed to remove the suspended solid particles from water, is inserted into the shell side of cooler where nitrogen is in tube. Both the fluids move in cocurrent manner and water is collected into the drain vessel. The cooled nitrogen is sent to the silos for fluidization of PTA.

Rotary Feeder Rotary feeder is responsible for the transfer of required PTA at IFL-1, IFL-2 and IFL3. Rotary feeder provide the specific mass to a bed of nitrogen depending upon the capacity of that bed. We have adjusted the Rpm or frequency of Rotary feeder from the DCR depending upon the requirement of raw material at IFL-1, IFL-2 and IFL-3 and pressure of nitrogen.

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Equipment Interlocks Compressors (1204-K01, 1204-K02, 1204-K05) interlocks depend on these variables: 1. 2. 3. 4. 5.

Discharge Pressure Discharge Temperature Oil Pressure Oil Temperature Suction Pressure

MEG TANK YARD Ethylene Glycol Ethylene glycol is produced industrially by the reaction of ethylene oxide with excess water. The typical product distribution between the products of this reaction, which are ethylene glycol, diethylene glycol, and triethylene glycol, is a mass relation of 30:4:1 respectively. The glycols are separated by purification under vacuum in distillation columns connected in series.

Process Description The second important raw material for the production of Polyester (Mono Ethylene Glycol) is imported from Saudi Arabia and Kuwait. The tankers which are used for the transportation of MEG have a capacity of 20 tons each. These tankers are then discharged in the MEG storage section in Ibrahim Fibres Limited. Following companies export MEG to IFL: 1. SABIC – KSA 2. Equate – Kuwait 3. Mobil – KSA

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MEG Sampling Samples are taken from the tankers before discharging them to IFL main tanks. Color, viscosity and moisture content is tested. MEG should contain less than 1% moisture content to pass the quality test.

MEG Unloading and pumping to Process line Unloading is carried out with the help of a centrifugal pump. A strainer is present at pump suction and a flow meter (micro meter motion sensor) followed by a filter at pump discharge. The purpose of strainer (bucket type) and filter is to trap unwanted objects from the flow. MEG then enters a 3 way valve. The valve directs it to one of the two MEG storage tanks, 1107-T01, and 1107-T02 for IFL-1. One tank is filled at one time. The total capacity of the tanks is 2000 tons each. Each tank is equipped with level transmitters which generate the low level alarm and high level alarm if MEG level in tanks reaches the fixed set-points. The tanks are filled up to a maximum level of 90%. Level transmitters are used to keep a check on the level. MEG is transported with the help of centrifugal pumps at 8-9 bar pressure to participate in the reaction for the production of polyester. Each pump has a strainer at its suction, to separate unwanted objects, and each pump has a recirculation for safety purpose. Some properties of MEG are mentioned in the following table: Chemical Formula

OH-CH2-CH2-OH

Molecular weight

62.03 g/mol

Boiling Point

197oC

Auto-ignition temperature

398 oC

Flash Point (closed cup)

111 oC

Specific gravity

1.116

Color

Colorless

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Odor

Odorless

Taste

Mild sweet

Purity

99.9%

MEG Uses 1. MEG is primarily used as a raw material in the manufacture of polyester fibers and fabric industry. 2. It is also used as an additive to prevent corrosion in liquid cooling systems for PCs. 3. One major use of MEG is as a medium for convective heat transfer. 4. MEG also acts as a Dewatering agent.


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Equipment Interlocks Storage Vessels (1107-T01/T02, 1110-T01/T02, 1111-T01/T02) have following interlocks: 1. Level Alarm

EGR (Area Code – 3101) Process Description The EGR unit is basically a recycling plant to enhance the purity of spent ethylene glycol which is obtained from different plants of poly process plant. Basic chemical reactions for the preparation of polyester are as follows:

The reaction shows that MEG is obtained as a by-product during the process. This spent MEG is a contaminated by-product with monomers, aldehydes and moisture. The recovery process starts from 3101-V01 Vessel which holds spent glycol from different parts of process plant. It is transported to a kettle-type evaporator which maintains a pressure of ~260 mbarg vacuum and temperature of ~167 oC. At this vacuum condition SEG converts to vapor form while it has a boiling point of 197 oC at atmospheric pressure. SEG vapors are added to the 6 th plate of vacuum distillation column. Top of rectifying section has a temperature of ~60 oC while the bottom of stripping section has ~160 oC. Temperature is maintained with the help of hot HTM coils in the bottom of column. ~99.5% pure ethylene glycol is obtained at the bottom of 3101-C01. 70% level of fluid is maintained in the bottom of column for the safety of HTM coils. The bottom product, REG, passes through a

30


plate and frame cooler (3101-E03); it exchanges heat with cooling water and then enters to REG storage vessel (3101-V04). Samples of REG are taken to check the quality. The MEG collected at the bottom is 25% of the total being used at the plant. This is then forwarded to 1117-T01. The remaining sludge which contains impurities is collected in the barrels and is sold as fuel. Top product from 3101-C01, which consists of ~0.5% EG and remaining water vapors, enters into a partial condensation vessel that is actually a heat exchanger (3101-E02). Condensate, water, goes to the reflux drum (3101-V02) which supplies a controlled amount of reflux at the top plate to maintain appropriate temperature conditions. Also, the reflux is used enhance the purity of top product. Vapors and any overflow from the partial condenser go to a drain vessel (3101V03). Vacuum pump (liquid ring) is attached with partial condenser, evaporator and reflux drum to maintain vacuum conditions within the whole system. A knock out drum is attached at the discharge of vacuum pump. The distillation column is also equipped with temperature sensing elements, control valves and controllers. The temperature is sensed by the thermocouples and is converted into current amperes. A set point is given to each controller. Whenever there is a change in the set point, a signal is generated in the feedback system which is attached to Distribution Control System (DCS). The DCS responds to the controller to set the flow rate of HTM to regulate temperature.

Main Equipment Used Kettle type Evaporator Kettle type evaporator is special type of evaporator designed especially for the evaporation under evacuated conditions. It contains a kettle type structure where heating coils are present. In this evaporator the SEG (Spent Ethylene Glycol) is heated with the HTM in the coil at 169 C and 260 mbar pressure. SEG contains MEG, water vapors and

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aldehyde groups. The Boiling Point of MEG is 197 C. Under Vacuum water vapors and MEG gets boiled at 169 C and collected at the Distillation Column and

sludge is discharged to waste column. It’s necessary to maintain 50% level of this evaporator to avoid any damage of coils.

Distillation Column Distillation Column is at 260 mbar pressure. It consists of 16 plates and feed is provided at the 6th plate. It is bubble and cap type evaporator. The purpose of bubble and cap is to provide maximum hurdles for the MEG vapors having low latent heat that they lose their latent heat and condensed at the base. Only water vapors are at the top of column that are condensed and partly returned as a reflux and partly stored at the vessel. Reflux has two major benefits: 1. It gives us maximum purity of MEG. 2. It utilized the latent heat of MEG vapors and gets evaporated again without disturbing our economy. 3. In other words, heat required to evaporate Reflux water (Heat of Vaporization) =Heat Released by the MEG vapors (Heat of Condensation).

Equipment Interlocks Distillation Column Unit (3101-CO1) have the following interlocks: 1. Column Differential Pressure 2. Pressure of Column 3. Level of SEG storage vessel

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HTM Section (Area Code– 3007) Process Description HTM stands for “Heat Transfer Media”. HTM is used as a source of heat for different units of plant. Santotherm is used as HTM. HTM is heated in the furnaces. Partially hydrogenated terephenyl (HTM) liquid circulates in coils where the combusted natural gas or BC oil heats it in furnace. The trade name of HTM (Santotherm) is

“Therminol 66.” Therminol 66 fluid is designed for use in non-pressurized/lowpressure, indirect heating systems. It delivers efficient, dependable, uniform process heat with no need for high pressures. The high boiling point of Therminol 66 helps reduce thevolatility and fluid leakage problems associated with other fluids. Some properties of HTM (Santotherm) are as follows: Color

Clear, Pale yellow liquid

Maximum moisture content

150 ppm

Flash point

184oC

Fire point

212 oC

Auto-ignition temperature

374 oC

Specific gravity

1.012

Density at 25 oC

1005 kg/m3

Optimum use range

0-345 oC

Dowtherm is another heating media which is used in vapor form. It is used to heat reaction vessels (ES-1, ES-2, PP-1, PP-2, DRR etc.) by staying in the jacket of these vessels. It has a low boiling point. Santotherm is used to exchange heat with this heating media to convert it into vapor state. Some of its properties are listed as follows:

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Freezing point

2.3oC

Boiling point

243 oC

For heating of HTM, three furnaces are used. In IFL-1, there are two furnaces. One of them is in operation while the other furnace is at standby position. The most important thing is the flow in and out of furnace. There are steam lines (25 bar, 6 bar) coming from boiler house to HTM area to different places such as 1. Pre heaters (Steam heaters) 2. BC oil vessel 3. HTM drain and make up vessel in HTM area 4. Economizer LPG gas (Liquefied petroleum gas) is used to provide initial spark for ignition and BC oil or Natural gas is used as a fuel. Air for combustion comes to the intake of the fan from atmosphere and stoichiometric requirement of air for furnace is 20 % excess air for burning. Process used for sending air by fan to top of furnace is actually known as Force and Draft Mechanism. Discharge from FD fan goes to economizer having shell and tube arrangement. The air freshly enters into the economizer at 49 oC approximately. it is in the shell side and in tube side there are flue gases at ~330 oC. There is shell and tube arrangement in economizer. The air discharge from economizer at approximately 180 oC because flue gases coming at 330 oC and they exchange heat with air after exchanging heat gases retain the temperature of about ~220-225 oC.

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BCO Cycle From V03 vessel, BCO is pumped towards the furnace with the help of low pressure pumps. V03 has a heating system in its shell which pre-heats BCO to ~100oC before being pumped by low pressure pumps which increase its pressure to ~9 barg. It than goes to the suction of high pressure pumps which increase the pressure energy to ~35 barg. The discharge passes through a pre-heater which uses 25 bar steam as a heating medium. BCO then enters the furnace and it is atomized with the help of an atomizer. BC oil which is used for burning and is given a set point of 130 oC. For BC oil transportation from vessel to furnace high pressure pumps (Gear pumps) are used. The flame of gas burning in furnace is blue while the flame of oil burning is yellow (Blue flame is stronger than yellow). It is important to pre-heat the BCO, otherwise, cool BCO will disturb the temperature profile of the furnace. Thus disturbing the whole process.

HTM Cycle HTM is built up in a3007-V01 vessel. Its level is checked with the help of a Magnetic Level Indicator. It is then moved to 3007-V02 vessel at 25 m. If the level of 3007V01 falls, then barrels of HTM are charged each weighing 230 kg. The level of 3007V02 is maintained at 50%. If there are any leakages in the HTM system, then they are directed to 3007-V04 at 0 m. HTM is used as two systems. In coils as liquid and in vessel boundaries as vapors. Santotherm is used in the primary cycle where it is heated in the furnace. This Santo therm then moves in coils to a secondary cycle where it is used to convert Dowtherm into vapor state in an evaporator. This Dowtherm is used in the linings of the vessel to maintain the temperature of the mixture and to make sure efficient heat transfer throughout.

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Main Equipment Used Furnace Furnace is there to heat the santotherm which is our HTM to a temperature of 325 oC

from 292 oC. The Furnace is operated with Heavy Furnace Oil (HFO), after pre-

heating the HFO at pre-heater is sprayed at the top of furnace with the help of an Atomizer. Atomizer Creates a fine spray of HFO for easy and complete combustion. Another source of fuel for the Furnace is natural Gas, Natural Gas is being provided by Utility Department at the required temperature and Pressure. Air is taken from atmosphere, pre-heated in economizer and then provided to the

37


damper with the help of blower and then injected both natural gas and air in a required ratio to the Furnace. It is then started and the HTM is heated with Conduction, Convection and Radiation mode of heat transfer.

Conduction This Mode of heat transfer is effective in those coils which are in direct contact with the burner.

Convection This mode is effective when the flue gases moves in bulk due to density and momentum difference.

Radiation This mode is effective in the whole body of furnace.

Stack Stack is for the emission of flue gases after passing through the economizer. Stack have a variable area to reduce the emissions of solid contents and increase the kinetic head of gases.

Pre-Heater (HFO) Pre-Heater is available for HFO which pre-heats the HFO using 6 bar steam followed by 25 bars steam at two different stages. The Purpose of this pre-heater to save our fuel for maximum heat economy. This step economizes our process by providing us maximum efficiency.

Atomizer Atomizer is a device which is used to convert the jet of any fuel or liquid into fine spray in order to increase the effective surfaces throughout the reactor or furnaces.

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Blower Blower is an instrument that is used to convert pressure head of air to its kinetic head and increases the flow rate for effective combustion.

Economizer Economizer is also a pre-heater that uses the flue gases and pre-heat the air coming from blower before providing to the furnace in order to have the maximum utilization of waste heat.

Damper We provide natural gas and warm air to damper that maintains a specific air to fuel ratio for maximum oxidizing flame. As the reducing flame will cause more toxic emissions that needs to be processed before emitting into the air.

Ignition Fuel LPG is the ignition fuel of Furnace in order to have effective start up.

Equipment Interlocks Furnace Unit (3007-F01/F02) has the following interlocks: 1. HTM Flow Pressure 2. Air Inlet Pressure 3. FD Fan (Blower) Load 4. Fuel Gas Pressure 5. Ignition Gas Pressure 6. Fuel Oil Temperature 7. Fuel Oil Pressure 8. Discharge Pressure Pump Load 9. Blocking Tightness Control 10. Flame Eye Intensity

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TDO Section Process Description TDO or Titanium dioxide is a white powdered solid (mol. wt. 79.9 g/mol). In fiber making process, it is used as dulling agent in the second stage of esterification process. It is used to make products of different brightness. For making a semi-dull product, the concentration of TDO in the solution is 10% and 0.3% by weight of PET in the final product. On the other hand, a bright product must have 3% concentration of TDO in solution and 0.03% by weight of PET in the final product. It also has following advantages for the final product, 1. TDO provides matt finish to the final product. 2. It increases the durability of the product. 3. TDO Anatase has high refractive index close to diamond, which causes glitter-ness. 4. TDO also gives hardness to the product i.e. on a scale of 0-10, where talc has zero hardness and diamond has maximum of 10, TDO has hardness of 5.5 – 6.5 Mohs. A 500 kg bag of TDO is added into 1307-V01 vessel via a hopper assembly. Now, 500 kg of fresh MEG is added to this vessel to make a 50% concentration mixture. Then the mixture is agitated for 4 hours. This mixture then moves to 1307-V07 where 1610 L of EG are added to reduce the concentration of solute to 20%. It is again mixed for 1 hour before moving it to centrifuge (1307-A02). The centrifuge undergoes through three steps during its operation: 1. Classifying – Fine and oversized particles are classified and this process lasts for 50 minutes. 2. Dispersing – Dispersion of Oversized particles with MEG and this step lasts for ~20 minutes.

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3. Discharging – Discharging of oversized particles by MEG to Pearl Mill and this step lasts for ~5 minutes. Undersized particles are separated and moved to 1307-V02 in which 1800L of EG are added to make the mixture concentration to 10%. Pearl Mill grinds the oversize particles by using a Muller which has fine particles of Zirconium dioxide of diameter 0.8 micron. Ground particles form pearl mill are again moved to 1307V01 vessel. Mixture from 1307-V02 is now separated into two lines for making products of different properties i.e. semi-dull and bright. 1307-V03 is used for making semi-dull product of 10% TDO concentration. Bright product is made up in 1307-V04 vessel from where it enters 1307-V05 vessel in which 4363 L of EG are added to reduce the concentration of TDO up to 3%.


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TDO Uses 1. TDO is used as a pigment in fibers, paints, varnishes, paper, plastics, and cosmetics. 2. TDO also acts as a photo catalyst under ultraviolet (UV) light. 3. It is also used as a tattoo ink and in styptic pencils.

–

Catalyst System (Area Code 1402) Process Description It is important to add catalyst into the reaction chamber to decrease the activation energy. Catalyst helps to achieve required results in lower residence time. Polyester fiber is made through an endothermic reaction, therefore, the energy required to start the reaction is high. The catalyst lowers this amount of energy, thus, making the process economical. Antimony triacetate Sb(CH3COO)3 is used as a catalyst. It occurs in the form of granules and its active part is only 40%. Catalyst is prepared in the form of solution before feeding into the Paste Preparation Vessel. Catalyst solution is prepared according to the following recipe:

The whole procedure is carried out at 75-80oC. The mixture is constantly agitated for 4 hours and 1 hour is provided as settling time. An analysis of the solution is done after 5 hours and it is ensured that the concentration of catalyst is 2% in the solution. Out of this 2%, only 0.8% is the active catalyst that actually takes part in the reaction. The quantity of catalyst in the melt is 185 ppm by weight. The standard concentration is 175 ppm by weight.

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The true solution prepared in the 2nd equation contains 3250 Liters of MEG along with 75 kg of catalyst. This solution is charged into the catalyst feed hopper from where it moves to the 1402-V01 batch preparation tank. This vessel can be operated at a maximum of level of 95% and minimum of 35%. Flow counters are attached which send the measured quantity of EG in the catalyst vessel. The batch in the 1402-V01 is then sent to a filter in which batch is filtered for any suspended solids. Clear solution is now ready for the paste preparation tank.


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Paste Preparation Section Process Description In this stage all the essential components are mixed in specific amounts. A paste is formed which is then sent to main reaction vessels. Following ingredients are added into this vessel: 1. MEG 2. PTA 3. Catalyst PTA and MEG are charged in a specific mole ratio here we call it E/T ratio. Normally two moles of MEG require one mole of PTA to react. In the paste chamber the E/T ratio is set as:

    = = 1.12    

Essentially no serious reaction is occurring in the paste preparation chamber that is why the ratio is set as 1.12. The ratio highly depends on the production rate of plant. Addition of 0.86 mol of MEG is carried out in the later reaction stages to meet the required mole ratio. In the paste preparation vessel mostly Recovered MEG from EGR and Column MEG are added to run the process economically. However, fresh MEG is also added to maintain a certain purity level. Fresh MEG is 99.9% pure. Flowmeters carefully control the flow rates of EG entering the vessel. PTA is added into the paste preparation vessel from the day silo. A rotary feeder directs PTA to the Shank System, a motor operated assembly. Shank System is an

44


arrangement to carefully control the flow rate of PTA in order to achieve a specified mole ratio. The catalyst in the 1402-V01 vessel is directed towards paste tank. The capacity of the tank is 29m3 and is operated at 90% level. The temperature in this tank is around 45oC which is way lower than the actual process condition. The paste is constantly agitated with the help of a fix speed agitator. The paste in the tank is provided a residence time of 3 hours and is then moved to the first esterification tank. The density of the final paste is 1.393 g/cm3. Due to the addition of catalyst some amount of product (i-e monomers and oligomers) start forming in this stage. Thus in later stages reaction completion will require less time.


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Main Equipment Used Shank System Shank System contains an inclined plate that rotates at a specific speed to maintain mole ratio between PTA and MEG. It is situated at the base of Rotary Feeder of Day Silo.

Paste Mixer Paste mixer receives the raw material from shank system and it has three lines of MEG. First is fresh MEG, 2nd is REG and 3 rd is recovered MEG. We have maintained the mole ratio of PTA and MEG is 1:1.12 at the paste mixer. Agitator is present at the top of paste mixer in order to mix the catalyst and raw material for a specific time.

Esterification (ES-I and ES-II) Process Description Two reactions are involved in the preparation of polyester from raw materials. The first one is esterification, which takes place in ES-I and ES-II, and the second is polycondensation which takes place in PP-I, PP-II and DRR.

The main reaction takes place in a large esterification reactor 1424-R01 (ES-I) which has a capacity of 50m3. It is a Continuous Stirred-Tank Reactor (CSTR) which is maintained at a level of 55%. The tank is heated internally with the help of 9 spiral Santo therm coils. An external jacket contains Dow therm vapors which do

46


not let any solid deposition on the walls of the reactor. An agitator with blades having angle of 38o provides agitation for complete mixing and efficient heat transfer. Product from ES-I goes to ES-II (10 m3). ES-II is also heated by an external jacket, which contains Dowtherm vapors, and internally by santotherm which is present in the coils. Following are some factors which affect the reaction rate:

Temperature and Pressure The temperature and pressure inside the reactor (ES-I) is maintained at 254oC and 0.35 bar while in ES-II; 256 oC and 0.14 bar.

Residence Time Residence time in ES-I is 3.2 hr and in ES-II, 1.18 hr.

Acid Number Samples are withdrawn from ES-I and ES-II to check reaction completion and product quality. The acid number is a factor to judge the reaction completion; it tells us how much KOH will be required to neutralize all the acid in the sample. For ES-I its value is ~55-60 mg KOH/mg Sample and for ES-II its value is 20 mg KOH/mg Sample. In ES-I, the reaction is 92-93% complete and in ES-II the reaction is 7-8% complete. EG which evaporates in each reactor vessel, ES-1 & ES-2, is moved to an internal distillation column 1424-C01 where it is fed at the sump of the column. The sump is maintained at a level of 85%. The whole column is heated with the help of HTM to which a steam tracing is provided so that the temperature of the HTM does not fall down. The temperature at the bottom of column is ~180 0C; middle 1420C; top 1000C. A safety pressure valve is also available which automatically open when the column pressure reaches 3.5 bar. Normally, the column operates at nearly atmospheric pressure. Column MEG from the top of 1424-C01 is used during paste preparation and in other reactors.

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ES-1

48


ES-2

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Polycondensation Process Description The second reaction of polycondensation takes place in following three reactors: 1. PP1 2. PP2 3. DRR

In

these

reactors,

monomers

and

oligomers

undergo

condensation

polymerization with elimination of MEG. Value of degree of polymerization that is achieved in these stages is ~104. The produced monomer has two functional groups; carboxl group (COOH) and hydroxyl group (OH). It goes through stepgrowth polymerization, where the growth of the molecules occurs through the reaction of the two functional groups PP1 is the first reactor of this operation. It does not contain any stirrer. The reactor is operated at 256oC and 0.12 bar vacuum pressure. Residence time in PP1 is ~1 hour. The EG vapors that evaporate from the top are captured in a scrapper condenser. This system consists of a liquid EG shower at the top which is used to condense the vapor. Vapors and liquid are in direct contact with each other. At the bottom, a scrapper shaft is attached which scraps any solids that may deposit in the condenser walls. The level of the tank is measured with the help of capacitor type level indicator. This consists of a 2 rods, one has reference current passing through it whereas the second rod senses current from the tank. The change in the current with respect to the reference rod is calibrated as the level indication.

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The product from PP1 is conveyed to PP2 via HTM jacketed lines. PP2 is equipped with an agitator which continuously cuts the viscous solution and generates new surfaces. Residence time in PP2 is ~0.85 hour and it operates at ~273 oC and 0.02 bar vacuum pressure. Moisture content of the tank is ~10%. Rate of evaporation from this reactor is higher because it operates at high temperature and low pressure. Vapors are, partially, condensed in the scrapper condenser. The level of the solution in the PP-2 is measured by not only capacitor system but also a radioactive level measuring system. Radioactive system uses radioactive Cobalt60 at the bottom of the tank. A detector is installed at the top which measures the radioactive intensity. When the level of the tank rises, the intensity at the top reduces. This reduction in intensity is calibrated against the level measurement. One of the main reasons to use radioactive elements for level measurement is

that the fluid in PP2 becomes highly viscous and other sensors can’t measure the level accurately. DRR (Disc Ring Reactor) is a horizontal reactor whose primary purpose is to achieve a specific value of intrinsic viscosity (0.6). There is a shaft across the length of DRR which continuously cuts the material with the help of rings. The material is exposed to high temperature (~280oC) and very low pressure. EG and moisture evaporates from DRR and pass through a scrapper condenser. Uncondensed vapors passes through a jet system. The jet system entertains the vapors from PP2 and DRR. Vapors after passing through the jet system (I, II & III) undergo sudden expansion which produces vacuum and condenses the vapors. Uncondensed vapors from the jet system passes through a vacuum system which uses vacuum pumps. Here maximum portion of vapors is condensed, uncondensed part is vented into the atmosphere. That part mainly contains aldehydes and ketones due to which it is not condensed. Product from DRR is filtered through candle filters which have stainless steel candles and it is then transported to spinning section via gear pumps.

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Process Flow Diagram PP-1 and PP-2

DRR

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Main Equipment Used Scrapper Condenser Scrapper Condenser is used to condense the vapors of MEG and water at the top of PP-1,PP-2 and DRR.It contain inclined plates and hurdles for vapors so that they lose their latent heat .Vapor condensate is treated as SEG and the remaining is sent to Ejector System.

Ejector System In this system vapors are compressed in the form of jet and then expanded in a vessel that cause two fruitful effects. 1. It condensed the maximum vapors. 2. It generates the vacuum in the lines.

Vacuum Pump Vacuum Pump generates vacuum by ejecting the gases present in the line with its suction power and after condensing them in its casing discharge into the vent.

Fume Arrestor Fume Arrestor is present at the top of every storage vessel which contains the flame-able liquids. it catches the fumes present at the different temperature of vessel and reduce the internal vapor pressure that act as a safety for the system.

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Materials Safety Guide MEG Safety Emergency Overview Warning! Harmful or fatal if swallowed. Harmful if inhaled or absorbed through skin. May cause allergic skin reaction. May Cause irritation to skin, eyes, and respiratory tract. Affects Central nervous system.

Inhalation Vapor inhalation is generally not a problem unless heated or misted. Exposure to vapors over an extended time period has caused throat irritation and headache. May cause nausea, vomiting, dizziness and drowsiness. Pulmonary edema and central nervous system depression may also develop. When heated or misted, has produced rapid, involuntary eye movement and coma.

Ingestion Initial symptoms in massive dosage parallel alcohol intoxication, progressing to CNS depression, vomiting, headache, rapid respiratory and heart rate, lowered blood pressure, stupor, collapse, and unconsciousness with convulsions. Death from respiratory arrest or cardiovascular collapse may follow. Lethal dose in humans: 100 ml (3-4 ounces).

Skin Contact

Minor skin irritation and penetration may occur.

Eye Contact Splashes may cause irritation, pain, eye damage.

Chronic Exposure Repeated small exposures by any route can cause severe kidney problems. Brain damage may also occur. Skin allergy can develop. May damage the developing fetus.

Aggravation of Pre-existing Conditions Persons with pre-existing skin disorders, eye problems, or impaired liver, kidney, or respiratory function may be more susceptible to the effects of this substance.

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First Aid Measures Inhalation Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Call a physician.

Ingestion Induce vomiting immediately as directed by medical personnel. Never give anything by mouth to an unconscious person. Get medical attention.

Skin Contact

Remove any contaminated clothing. Wash skin with soap and water for at least 15 minutes. Get medical attention if irritation develops or persists.

Eye Contact Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Get medical attention immediately.

Note to Physician Give sodium bicarbonate intravenously to treat acidosis. Urinalysis may show low specific gravity, proteinuria, pyuria, cylindruria, hematuria, calcium oxide, and hippuric acid crystals. Ethanol can be used in antidotal treatment but monitor blood glucose when administering ethanol because it can cause hypoglycemia. Consider infusion of a diuretic such as mannitol to help prevent or control brain edema and hemodialysis to remove ethylene glycol from circulation.

PTA Safety Emergency Overview This product has been evaluated and does not require any hazard warning on the label under OSHA criteria. Handling and/or processing of this material may generate airborne fibers and particles which can cause mechanical irritation of the eyes, skin, nose and throat.

Skin contact No significant health hazards identified.

Inhalation No significant health hazards identified.

Ingestion No significant health hazards identified.

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Eye contact No significant health hazards identified. Particles or fibers may cause slight discomfort similar to getting dust in the eye.

First Aid Measures Eye Flush eyes with plenty of water.

Skin Wash exposed skin with soap and water.

Inhalation If adverse effects occur, remove to uncontaminated area. Get medical attention.

Ingestion If a large amount is swallowed, get medical attention.

PET Safety Emergency Overview Product form varies: chips, dice noodles or lace. Colors vary: milky white to black; several levels of translucence or luster. Under normal conditions of use, this product is not expected to create and unusual emergency hazards. Polyesters can burn if exposed to flame. Molten polymer generates small amounts of volatile degradation products (off-gases), one of which is acetaldehyde. Acetaldehyde vapors form explosive mixtures with air that can spontaneously ignite (auto-ignite) at temperatures above 347ºF (175ºC).Combustion products may include compounds of carbon, hydrogen, and oxygen; exact composition depends on conditions of combustion. In the event of fire, use normal firefighting procedures to prevent inhalation of smoke and gases.

Inhalation Irritation of the upper respiratory tract, coughing, and congestion may occur.

Skin Molten resin will cause thermal burns.

Absorption Not applicable

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Ingestion Not applicable

Eyes Temporary irritation (itching) or redness may occur.

Target Organs Upper respiratory passages, skin, and eyes.

Primary Routes of Entry (Exposure) Respiratory system, skin, and eye.

First Aid Measures Inhalation Remove to fresh air. Drink water to clear throat, and blow nose to remove dust.

Skin If contact with molten resin occurs the affected area should be flushed with plenty of water. Prompt medical attention is advised for burns.

Ingestion Not applicable

Eyes Flush eyes with large amounts of water for 5-15 minutes. If irritation develops, or persists, seek medical attention.

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Boiler (Area Code-3910) Boilers are pressure vessels designed to heat water or produce steam, which can then be used to provide water heating to a building. In most commercial building heating applications, the heating source in the boiler is a natural gas fired burner. The basic consumption of steam is in the fiber draw line, heavy furnace oil & polymerization section.

Types Boilers are classified into different types based on their working pressure and temperature, fuel type, size and capacity, and whether they condense the water vapor in the combustion gases. Two primary types of boilers include: 1. Fire Tube Boilers 2. Water Tube Boiler Both types of boilers are used in IFL.

Fire tube boilers Fire tube boilers consist of a series of straight tubes that are housed inside a waterfilled outer shell. The tubes are arranged so that hot combustion gases flow through the tubes. As the hot gases flow through the tubes, they heat the water surrounding the tubes. The water is confined by the outer shell of boiler. To avoid the need for a thick outer shell fire tube boilers are used for lower pressure applications.

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Water tube boilers Water tube boilers are designed to circulate hot combustion gases around the outside of a large number of water filled tubes. The tubes extend between an upper header, called a steam drum, and one or lower headers or drums. In the older designs, the tubes were either straight or bent into simple shapes. Newer boilers have tubes with complex and diverse bends. Because the pressure is confined inside the tubes, water tube boilers can be fabricated in larger sizes and used for higher-pressure applications.

Components Both gas and oil fired boilers use controlled combustion of the fuel to heat water. The key boiler components involved in this process are the burner, combustion chamber, heat exchanger, and controls.

Burner The burner mixes the fuel and oxygen together and, with the assistance of an ignition device, provides a platform for combustion.

Combustion chamber Combustion takes place in the combustion chamber and heat is generated.

Heat exchanger Generated heat is transferred to the water through the heat exchanger.

Controls Controls regulate the ignition, burner firing rate, fuel supply, air supply, exhaust draft, water temperature, steam pressure, and boiler pressure.

Deaerator A deaerator is used to reduce oxygen (O 2) and carbonic acid (CO 2) levels in boiler feed water to protect a boiler against corrosion. It is possible to reduce oxygen and carbonic acid levels to about < 0.02 mg/l of O 2 and 0 mg/l of CO2, depending on deaerator construction.

59


Condenser A condenser ensures that all steam is condensed before being pumped back into the deaerator and on into the boiler.

Damper A damper is used to make the mixture of air and fuel i.e. to set the air to fuel ratio.

Economizer An economizer is a heat exchanger that is placed in the exhaust from a boiler.

Fuel The source of heat for a boiler is combustion of any of several fuels. In IFL two sources are used: 1. Natural gas (mostly used) 2. Furnace oil (stand by)

Process Description The steam condensate (70%) returning from the plant comes to the condensate vessel (VO2), after that condensed steam is sent to the vessel (VO3) where two condensers are used to condense the steam of VO1, VO2 and VO3. Then by using low pressure pumps (PO4, PO5) condensate is sent to the boiler feed water tank where a deaerator is also attached to remove the air from the steam condensate. In this vessel chemicals are added to condensate. 1. Hydrazine - for removal of free oxygen 2. phosphate – anti corrosion agent After the feed water tank the condensate is pumped by boiler feed pumps (PO1, PO2 and PO3) to the boiler. The condensate along with 30% de-mineralized water enter the boiler on the shell side and converts to the vapors form by heat transfer from the fire entering from the tube side. The level of water in Boiler is 2/3 of total volume of boiler. The steam from the boiler then enters the super-heater at 25bar pressure and the steam from the super-heater exits at about 250°C. The

60


steam at 25 bar pressure is then divided in to 3 different pressures by steam header; 1. 25-bar 2. 10-bar 3. 6-bar


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Capacities Boiler Type

Quantity

Capacity

Fire tube boiler

2

10 ton/hr

Fire tube boiler

3

14 ton/hr

Water tube boiler

1

25 ton/hr

Pumps (Area code-3910) Boiler feed water pumps

Capacity PO1, PO2, PO3=18.40m 3/hr

Condensate pumps

PO4, PO5=36m3/hr

Condensate transfer pumps

PO6, PO7=36m3/hr

Oil circulation pumps

P21, P22=84.8lit/min

Vessels (Area

Capacity

Temperature

Pressure

VO1

2800 L

120°C

1.0 bar

VO2

5909 L

120°C

1.0 bar

VO3

1600 L

120°C

0.5 bar

code-3910)

Equipment Interlocks Super Heater Temperature

TAH: 285oC

Natural gas pressure

PAL: 100mbar, PAH: 350mbar

Oil Temperature

TAH: 160oC, TAL: 80 oC

Water Level Low

LAH: 12%, LAL: 90%

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Nitrogen Generation (Area Code–4400) Why Nitrogen is Important? Nitrogen is a chemical element with symbol N and atomic number 7. At room temperature, it is a gas of diatomic molecules and is colorless and odorless. Nitrogen is a common element in the universe, estimated at about seventh in total abundance in our galaxy and the Solar System. On Earth, the element is primarily found as the gas molecule; it forms about 78% of Earth's atmosphere. The element nitrogen

was

discovered

as

a

separable

component

of

air,

by Scottish physician Daniel Rutherford, in 1772. Many

industrial

compounds

such

as

ammonia,

nitric

acid,

organic nitrates (propellants and explosives), and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen dominates nitrogen chemistry, causing difficulty for both organisms and industry in converting the N2 into useful compounds, but at the same time causing release of large amounts of often useful energy when the compounds burn, explode, or decay back into nitrogen gas.

Production Nitrogen gas is an industrial gas produced by the fractional distillation of liquid air, or by mechanical means using gaseous air (i.e., pressurized reverse osmosis membrane or pressure swing adsorption). Commercial nitrogen is often a byproduct of air-processing for industrial concentration of oxygen for steelmaking and other purposes.

63


Process Description In Ibrahim Fibres Limited, nitrogen is separated from air by using Pressure Swing Adsorption technique. Primarily, nitrogen is classified into two types depending on its quality and nature of use; Technical Nitrogen and Pure Nitrogen. Nitrogen Generation Plant

Capacity

IFL 1,2

185 Nm3/hr

IFL 3

220 Nm3/hr

Technical Nitrogen Nitrogen grade which contains less than 2% oxygen. This grade is obtained, immediately, after the molecular sieves. Technical nitrogen is used to fluidize PTA for transferring it from one place to another. It is also used in some level indicating instruments and to transport materials by exerting a specific head.

Pure Nitrogen Nitrogen grade which contains less than 10 ppm oxygen concentration is called Pure Nitrogen. Pure nitrogen has limited applications in polyester plant. It is used in most critical places, such as reactors, which require inert atmosphere and proper nitrogen blanketing.

Pressure Swing Adsorption Pressure swing adsorption (PSA) is a technology used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an adsorbent material. It operates at near-ambient temperatures and differs significantly from cryogenic distillation techniques

of

gas

separation.

Specific

adsorptive

materials

(e.g., zeolites, activated carbon, molecular sieves, etc.) are used as a trap, preferentially adsorbing the target gas species at high pressure. The process then swings to low pressure to desorb the adsorbed material.

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Pressure swing adsorption processes rely on the fact that under high pressure, gases tend to be attracted to solid surfaces, or "adsorbed". The higher the pressure, the more gas is adsorbed; when the pressure is reduced, the gas is released, or desorbed. PSA processes can be used to separate gases in a mixture because different gases tend to be attracted to different solid surfaces more or less strongly. If a gas mixture such as air, for example, is passed under pressure through

a

vessel

containing

an

adsorbent

bed

of

zeolite

that

attracts oxygen more strongly than it does nitrogen, part or all of the oxygen will stay in the bed, and the gas coming out of the vessel will be enriched in nitrogen. When the bed reaches the end of its capacity to adsorb oxygen, it can be regenerated by reducing the pressure, thereby releasing the adsorbed oxygen. It is then ready for another cycle of producing nitrogen enriched air. Using two adsorbent vessels allows near-continuous production of the target gas. It also permits so-called pressure equalization, where the gas leaving the vessel being depressurized is used to partially pressurize the second vessel. This results in significant energy savings, and is common industrial practice.

65


The process starts with the compression of air (till 8 bar) in double-stage rotary screw type PD compressors. Compressed air has a temperature of 33-34 oC. It passes through dryers which use chilling effect, thus lowering the temperature to point where moisture disengages from the gas. Now, air temperature is reduced to 20oC and it is stored in storage vessels (4300-VO1, VO2). Air from storage vessels enter into a buffer vessel (4300-VO1). The function of this buffer vessel is to absorb sudden pressure surges. From 4300-VO1, air enters into a vessel which contains carbon molecular sieves. Air enters at high pressure. Oxygen gas is entrapped into the carbon molecular sieves due to its small molecular size while air, containing less than 2% Oxygen at 6.7 bar, exits through the vessels. This stream is called Technical nitrogen and it is stored in a vessel. Pure nitrogen is produced by passing technical nitrogen stream through a reactor (4300-RO1) which contains Palladium catalyst. Reactor is fed with controlled amount of hydrogen to reduce oxygen gas to water. Exothermic reaction occurs and a temperature of 185oC is produced. Outlet stream is cooled by enhancing the heat transfer area and through water. The gas passes through a desiccant chamber with absorbs moisture from the stream. Now, pure nitrogen stream is available for storage and use.

66



Applications One of the primary applications of PSA is in the removal of carbon dioxide (CO 2) as the final step in the large-scale commercial synthesis of hydrogen (H 2) for use in oil refineries and in the production of ammonia (NH3). Refineries often use PSA technology in the removal of hydrogen sulfide (H2S) from hydrogen feed and recycle streams of hydrotreating and hydrocracking units. Another application of PSA

is

the

separation

of

carbon

dioxide

from

biogas

to

increase

the methane (CH4) content. Through PSA the biogas can be upgraded to a quality similar to natural gas. PSA is also used in

67


1. Hypoxic air fire prevention systems to produce air with a low oxygen content. 2. On purpose propylene plants via propane dehydrogenation. They consist of a selective media for the preferred adsorption of methane and ethane over hydrogen. 3. Small-scale production of reasonable purity oxygen or nitrogen from air. PSA technology has a major use in the medical industry to produce oxygen, particularly in remote or inaccessible parts of the world where bulk cryogenic or compressed cylinder storage is not possible. 4. Nitrogen generator units which employ the PSA technique to produce high purity nitrogen gas (up to 99.9995%) from a supply of compressed air.

Cooling Towers

Basics The equipment which are used to cool water based on the difference between wet-bulb and dry-bulb temperature of air. There are two basic types of cooling towers: 1. Natural draft cooling towers 2. Mechanical cooling towers

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Natural draft cooling towers are of very large size and used for water circulation rates above 45,000 m 3/hr (used for normal power plants where condenser water requirements are high). Mechanical draft cooling towers are further classified into following types: 1. Forced draft cooling towers 2. Induced draft cooling towers Forced draft cooling towers employ fan at the bottom of cooling tower to direct the flow of air through the cooling tower. Induced draft cooling towers have a fan at their top which sucks the air through the cooling tower and directs it in the upward direction. Following are the parts of cooling tower: 1. Frame and casing 2. Fill 3. Cold water basin 4. Drift eliminator 5. Air inlet 6. Louvers 7. Nozzles and fans

Process Description In Ibrahim Fibres Limited, cooling towers are used to cool process water and chiller water. Process water is used in the main plant for different cooling purposes. Process water inlet temperature to cooling towers is about ~42oC and cooled process water exits at ~30 oC. Cooling water for chillers is supplied to the cooling towers at 39oC and exits at 34oC. High capacity centrifugal pumps are used to transport water from water sump to different locations.

69


Blow down time depends on the conductivity and pH of sump water. Cooling water is injected with biocides, anti-corrosion agents etc. to protect the cooling towers from fungal and corrosion attack. Corrosion inhibitors, such as sodium or zinc based are added in the water to reduce corrosion in the piping. The zinc reacts with access oxygen and a superficial layer of oxide is developed which prohibits rusting and corrosion.

Process Diagram

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Some specifications of cooling towers are mentioned as follows: Process Water Cooling Towers IFL-1 process water cooling tower

3

IFL-2 process water cooling tower

1

IFL-3 process water cooling tower

3

Cooling water supply

34oC

Cooling water return

42oC

Chiller Water Cooling Towers IFL-1 chiller water cooling tower

3

IFL-2 chiller water cooling tower

1

IFL-3 chiller water cooling tower

3

Chiller water supply

34oC

Chiller water return

39oC

WATER TREATMENT Water Treatment plant is a very important part of Utilities Section.

Water required: We need three type of water at IFL Plants: 1. Soft Water 2. Demineralized Water 3. Drinking water

Purpose Water treatment plant is responsible for the generation of the required water.

71


Equipments Some of the equipments used at the water treatment plant are:

Multilayer Filters: Multilayer Filter consist of layers of different materials which serve as filtration media, it consists of layers of sand, pebbles, and rocks. The arrangement of materials is in increasing order of particle size. Sand is at the top and coarse particles are at the base. The reason behind this arrangement is that multilayer filter has nozzles at the base and if we use sand at the base, it may choke the nozzles and can cause repeatedly back washing. It has a large assembly of pipe lines that is responsible for the back washing of filter after several days.

Bucket Filters Bucket Filter consist of polythene type filter medium for the filtration of filtrate. It is installed normally just after the main filter in order to remove grains from the filtrate that can affect the impeller of pumps (can cause capital damage).

RO Plant Reverse Osmosis is basically a purification technique. IFL has RO Plant that works on the reverse osmosis principle. It has two sections in horizontal direction separated by a permeable membrane. The feed water contains high quantity of ions and small quantity of water as compared to the soft water. The normal process of osmosis suggests that minerals should move towards inner section and water should move in outer section through the permeable membrane. But it’s not according to our requirement as we need minimum amount of ions in soft water. So In order to move maximum

72


ions to get separate from the raw water we provide osmotic pressure on the outer shell that helps us to separate the maximum ions on the membrane.

Degasser Degasser is equipment used to remove CO2 from soft water. It consists of a

vertical column that has packing’s (Rashing Rings). We provide feed from the top and air from the base that helps the CO2 to escape from the soft water.

Mixed Bed Ion Exchanger (Demineralization) Mixed bed Ion Exchanger consists of Cathodic and Anionic Resins, that removes maximum ions from the soft water and reduces the conductivity of water up to one micro Simons per centi meter. These resins become inactive after few days. We doze 5% by volume NaOH and HCl for the regeneration of these resins. HCl is effective for Anodic resins and NaOH is effective for Cathodic Resins.

Process Description Raw water from the source is pumped by centrifugal pumps to Multi Layer Filter. In Multilayer Filters we remove maximum suspended impurities. The capacity of Multilayer Filter is 4.5 m3/hr. Water just after the Multilayer Filter is dozed by HCl. HCl maintains a pH of 6.5 in the filtrate. After this the acidic water is filtered in Bucket Filters. The Purpose of HCl dozing is to convert CaCO3 into CaCl2. Calcium chloride has large particle size than the mesh no of Permeable Membrane of RO Section. The reaction that takes place at RO is given below: CaCO + 2HCl 3

CaCl

2+

CO2+H2O

RO plants reduce the conductivity of raw water from 3000 uS/cm to 65 uS/cm, which is our soft water. The Rejected water of the first RO assemblies is then passed to the next RO plants for further generation of soft water. After these plants the

73


rejected water whose conductance is 9000 uS/cm is rejected as drain. Capacity of Raw Water is 180 m 3 and 120 m 3 is soft water and 60 m 3 is rejected water. After this soft water is transferred to degasser to remove CO2 from soft water. The removal of soft water is necessary as it is an acidic gas that will cause corrosion. Soft water from the storage vessel is then utilized for different purposes at the plant site. The main use of soft water is in the DM Section. In DM Section maximum amount of Ions are removed by Cationic and Anionic Ion Exchange. The main Reaction taking place at this is given by Ca+2 + 2R-SO3H Mg+2 + 2R-SO3H

Ca(R-SO3)2 + 2H+ Mg(R-SO3)2 + 2H+

In Order to regenerate the Resins, We dozed 5% by Volume HCl and NaOH in the DM-Section that regenerates the Resins as given below Ca(R-SO3)2 + 2HCl

2R-SO3H + CaCl2

Mg(R-SO3)2 + 2HCl

2R-SO3H + MgCl2


74


CHILLERS A chiller is a machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. A chiller is usually factory assembled and shipped to the facility where final electrical and plumbing connections are made, but may be shipped in sections for field assembly. It has four primary components: the compressor, the compressor drive, the evaporator, and the condenser. Chillers can be categorized based on the type of compressor. Usually occurring types of chillers include: 

Electric Chiller



Steam Absorption Chiller

However, the choice of chiller is affected by the following decisions: 

First Cost



Operation Cost



Maintenance Cost



Life Cycle Cost

In Ibrahim Fibers Limited, Polyester plant we in total have 11 chillers at the utility section. These include both types of chillers. Chillers are used to chill (cool) the water. The chilled water circulates in the plant through a closed loop. Each chiller along with the phenomena is discussed further:

Electric Chiller Electrically driven chillers utilize electric motors to drive the compressor. These chillers can be further categorized according to the type of compressor which is used. Few of the types include 

Reciprocating Compressor Chillers use cylinders with pistons acting as pumps to increase refrigerant pressure. Compressors may have anywhere

75


from 1 to 12 piston-cylinder arrangements, which unload in pairs as load decreases. These compressors are well-suited for air-cooled condensers and low-temperature application, and dominate the market in small tonnage systems. 

Centrifugal Compressor Chillers are basically fans or blowers, building refrigerant pressure by forcing gas around a scroll and through a funnelshaped opening at high speed. They are generally quieter, require less maintenance, and have less vibration than reciprocating compressors. They are not suited for air-cooled chillers and must, therefore, be watercooled.



Screw Compressor Chillers The compressor consists of two matching helically grooved rotors which turn, compressing the refrigerant gas as it passes from one end of the screws to the other. Screw type systems are better suited for low temperature applications.



Scroll Compressor Chillers use two spirals, one within the other, to compress refrigerant. They are relatively new in commercial applications, very quiet, and efficient. Scroll compressors are available up to 60 tons.

In IFL we have 5 electric chillers i.e. 3 at IFL-1 and then 1 each at IFL-2 and IFL-3. Further specs of these chillers are described in the table below: Type

Centrifugal water cooled

Company

Trane

Capacity

1000/575 refrigerant tons/hr

WC In temp.

30˚C

WC Out temp.

35˚C

WCC In temp.

11-12˚C

WCC Out temp.

6˚C

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Process Description Electric Chiller follows exactly the refrigeration cycle in thermodynamics. The main components of this chiller are discussed individually:

Compressor Drive The compressor drive or pump is responsible for suction of refrigerant vapors from evaporator to the discharge in compressor.

Compressor The compressor receives the refrigerant vapors from pump and compresses it down to achieve high pressure. The vapors are then forwarded to condenser.

Condenser The condenser acts as a shell and tube heat exchanger and exchange of hest occurs between WC and refrigerant vapors causing vapors to condense to a liquid form.

Evaporator Here the l high pressure condensed refrigerant is atomized resulting in evaporation due to very low boiling temperature ultimately creating cooling effect. The condensate is prayed on the tubes carrying WCC. The chilled water exchanges heat and leaves the chiller at 6-7 ˚C. The cycle goes on and the vapors are sucked again by the pump.

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Steam Absorption Chiller The absorption cycle uses a heat-driven concentration difference to move refrigerant vapors (usually water) from the evaporator to the condenser. The high concentration side of the cycle absorbs refrigerant vapors (which, of course, dilute that material). Heat is then used to drive off these refrigerant vapors thereby increasing the concentration again. Lithium bromide is the most common absorbent used in commercial cooling equipment, with water used as the refrigerant. The steam absorption chiller can be of multistage, commonly found chillers are: 

Single Effect (Stage) Units



Double Effect (2-Stage) Units

In IFL we have total 6 steam absorption chillers which include 3 at IFL-2 and further 3 at IFL-3. The further specs of these chillers are stated in a table below.

78


Type

Centrifugal water cooled

Company

Trane

Refrigerant

LiBr Solution

Capacity

550 refrigerant tons/hr

WC In temp.

30˚C

WC Out temp.

35˚C

WCC In temp. WCC Out temp.

11-12˚C 6˚C

Process Description This chiller also follows the refrigeration cycle with the addition of few things. By being double stage chiller it is 30 % more efficient in providing cooling effect. The main components of this chiller are further discussed in detail individually:

High Temperature Generator (HTG) In HTG the 6 barg steam is running in the tubes causing the dilute LiBr solution to vaporize the water and become a saturated solution. The vaporized vapors are passed to LTG.

Low Temperature Generator (LTG) In LTG the water vapors from HTG cause further evaporation from the LiBr solution present already. The vapors altogether go right to the condenser.

Condenser The condenser is responsible for exchanging heat between WC and water vapors from generator. The WC carries away the heat of water vapors eventually causing the vapors to liquefy.

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Evaporator The condensed water vapors are then sprayed over the tubes carrying WCC. The water vapors are passed through atomizer which causes evaporation which in turn provides the cooling effect in this area. Water is chilled in here and the vapors are then attracted by the absorber. Here water serves as the refrigerant.

Absorber Absorber contains the rejected saturated LiBr solution from HTG and LTG. LiBr being hygroscopic attracts away the water vapors from evaporator and becomes diluted again. This cycle goes on like this. It is a closed loop cycle i.e.

refrigerant doesn’t leave the system.


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Spinning Section Some of the main parts of spinning section includes:

Heat Exchanger Heat Exchanger is at the 13M of IFL-1. It helps to attain the temperature of PET at 288 C. The HTM used in the Heat Exchanger is Santotherm. The line of PET is provided a continuous jacket of Dowtherm to maintain the temperature and specific flow rate. The Complex arrangement of lines of PET is for the generation of homogeneity mixture under some static mixers.

Spin Pumps IFL-1 has two lines of spin pumps. Each line contains 30 pumps called as positions. There are 5 assemblies of 6 positions. Each spin pump is provided a feed at 288 C and at 70 bars pressure. Each pump is screw type and has a throughput 2268 g/min.

Spin Pack Spin Pack has two types on the basis of number of holes at IFL. 1. 3750 Holes (Circular) 2. 2250 Holes (Trilobal) Filaments from the spin pack is drawn in a 50mm draw section. The spin pack is changed after 48 days for semi dull product and after 38 days for circular bright. After this we regenerate the spin pack in auxiliary workshop. So in the first step,

81


spin pack is removed out from specified spinning position with the help of pack manipulator. Then it is brought to auxiliary workshop by a trolley.

Polymer Melt

Fiber formation

Quench air

Ring oiler

Slub catcher

Drip Detecter

Cutter

Suction Nozzle

V-Guide

Thread oiler

Deflective Rollers

Finger Guider

Dia Blow Roller

Godet Roller

Sunflower Roller

Sub Tow

Quench Air Air coming from A/C Section is at 21 C and 85% Humid, known as Quench Air. This air is provided through the air filter just after the spinet. Air is provided to the filers in axial direction and filter supply that air to the filaments in radial direction, to avoid fusing of filaments. The flow rate of air is equal in all directions to cancel the opposite forces. The flow rate of this air is 1150 m3/hr. The purpose of humidification is to enhance the rate of heat transfer as the specific heat of water is greater than that of air.

Air Discharge Air from each position is discharged at the base through a suction line that leads the air at Scrabber.The temperature of this air is 60 C and flow rate is 1100 m 3/hr.

82


This air is processed in scrabber where water is shavered on air that contaminate the monomers and environment friendly air is discharged into the atmosphere.

Spin Wall Spin wall has following equipments with the stated functions: 

Slub Catcher

Slub Catcher catches the thread coming out from the spinet. 

Thread Oiler

Thread Oiler sprays the Spin Finish Oil on the threads coming from Slub Catcher. The function of SF Oil is to reduce the static charge and enhance the cohesive properties. 

V-Guide

There is a V shaped guide that collects the filaments from the thread oiler. The purpose of this is to create single tow of many filaments. 

Suction Nozzle

Suction nozzle is there to facilitate the cutter. It sucks the filaments near the effective part of cutter. 

Cutter

After closing the filaments to the cutter with the help of suction nozzle. Cutter cuts the filaments. 

Drip Ejector

Drip ejector consist of two slides. These slides have a defined path for the

filaments between them. If a drip gets into it, it doesn’t allow the drip to pass. So at the end filament gets break.

83

INTERNSHIP REPORT | IFL | 2014 

Deflecting Rollers

Deflecting Rollers deflect the filaments towards Dia Blow Rollers.



Finger Guider

Finger Guider has two functions at the Spin Wall. 1. It guides the filaments towards the Dia Blow Roller. 2. It facilitates the cutter to add the filaments into the sub tow during wiping. 

Dia Blow Roller

There are 6 Dia Blow Rollers that provide tension in the whole line. The Dia Blow Rollers has a difference of 0.25mm in their diameter. These Rollers have wrap detectors that detects the wrapping of filaments across the rollers. 

Godet Roller

Godet Roller provide feed to the sunflower rollers. 

Sunflower Rollers

Sunflower Rollers grips the sub tow and put it into the cans in the form of UDY (Undrawn Yarn)

Auxiliary Section Spin Pack is a costly auxiliary equipment, costs ~0.1 million for its preparation. Therefore it is essential to increase its life span by regenerating its different parts. It has specific, operational, life time of 40 days for good performance after which we have to change it. However, filter changing jobs are carried out after 20 days. On position spin pack cleaning is carried out after every 40 hours with the help of a spray.

84


Disassembling In the first step, spin pack is removed out from specified spinning position with the help of pack manipulator. Then it is brought to the auxiliary workshop by a trolley and placed on dis-assembling device. Here hydraulic machine disassemble immediately spin pack as it is removed. If this is not disassembled immediately,

spin pack would stuck and can’t be disassembled.

Washing and Cleaning Spin pack contain different parts which can’t be washed in same bath because of variable temperature sensitivity. Two different cleaning devices are used.

Vacuum Cleaning At vacuum of -0.4 to - 0.7 bars, spin pack’s parts are heated. Vacuum cleaning takes place in four stages. In the first stage, the polymer melt sticking on the parts will be melt down at 320oC. In the second stage, pyrolysis at 420oC takes place. In the third stage, oxidation of the polymer occurs at 450oC. Finally, cooling of spin packs to normal temperature. This process takes place in about 10.5 hours.

TEG Section The spinnerets are cleaned in TEG bath. In TEG bath, Tri-Ethylene Glycol is charged in TEG bath. A batch of five spinnerets is charged in TEG bath. The cleaning process continues at temperature of 270oC. Here residence time is 8 hours and 3 hours take to cool down the parts. After cleaning the spinnerets batch is removed out from the TEG bath and charged in 5% NAOH bath. After 5 no of batches used TEG is drained and fresh TEG is charged in TEG bath. 5 spinnerets can be charged in one batch of TEG bath.

85


Ultrasonic Bath TEG cleaning is charged into ultrasonic bath for 30 min. Also we clean the distributed plates and 5-fold filters for 15 min each. All these parts are charged individually.

Air Drying The spinnerets and other parts of the ultrasonic cleaning are dried in this device with the application of the process air. Then cover the dry spinnerets in polythene sheet and placed in store for inspection while 5-fold filter and ring distribution plate are placed in assembling room.

Inspection Room The dry spinneret is brought into spinneret inspection room. The holes are magnified inspected of individual hole is done. If any hole is choked, then the spinneret is recharged in TEG bath or in ultrasonic bath. Or dust is removed out from choked hole by compressed air or needle. The pack body or pack lousing, bolts & filling rings are cleaned with brass brush.

Assembling Some of the main parts used in the assembling of a Spin pack includes: 

One Fold Filter

The mesh size of single fold filter is 540. 

Sand

Sand of special type is added after the joint rings for the filtration purpose. The diameter of this sand particles are 1.2mm. Weight of sand per spin pack is 2.6kg. 

Joint Rings

Two Rings of different diameter is used.

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Four Fold Filter

These four fold filters have this arrangement on the basis of mesh size. 17000+4500+540+64 

Five Fold Filter

These fivefold filters have this arrangement on the basis of mesh size. 17000+4500+540+64+4500 

Ring Distribution Plate

Ring distribution plate is fitted just after the 5 fold filter. 

Five Fold Filter

These fivefold filters have this arrangement on the basis of mesh size. 17000+4500+540+64+4500 

Spinneret 1. 3750 holes(Circular) 2. 2250 holes(Trilobal)

87


Fiber Line Section Creel Area The fiber line starts from the Creel Area till Cutter and Bailer. UDY cans are placed in the creel area. Placement of the number of cans depend on the number of working positions at spinning line. Number of working spin pack positions and number of cans placed in the creel area are defined by over plant capacity; the capacity to process a certain band of denier, for IFL-1 its value is ~3.2 Md (Mega Denier). Mega Denier is defined by the width of crimper unit which, in fact, defines the whole capacity of a particular draw line. For IFL-1, the width of crimper unit for both the lines (71, 73) is 350 mm. UDY from cans passes through tension adjustment equipment in the creel area. UDY or sub-tow passes through following equipment during its journey:

1. Horn Guides 2. H-Guides 3. Knot Detector 4. Loose end detector (uses photovoltaic detectors) 5. Ring guides Non-adjustment of tension results in poor product quality.

Finger Guides and Guiding Rollers UDY enters into the fiber line draw zone after passing through finger guides which guide the sub-tow towards the rollers in the later stages. Tow guiding frame-1 (YO1) consists of seven rollers which adjusts the tension of sub-tow and make it uniform for each filament of UDY. It is basically a 3-4 arrangement of rollers. Rollers are driven by a variable speed motor which adjusts its revolutions according to the drawing speed.

88


Dipping Bath (YO4) Tow guiding rollers guide the tow towards the dipping bath which contains SF Oil at 0.3% concentration at 25oC. The purpose of dipping bath is to homogenize moisture content, temperature and oil content of Tow. SF Oil temperature is maintained with the help of chilled water which exchanges heat in a plate and frame type (counter-flow) heat exchanger. The purpose of SF Oil is to lubricate the tow to avoid entanglement, slippage and development of static charges due to resistance through multiple surfaces.

Draw Frame-I (YO5) UDY laboratory tests confirm an average elongation capacity of each filament as 470% at ~1.2 g/d tenacity. Thus, initial drawing starts at draw frame 1 which also consists of a set of 7 rollers of equal diameter and revolving at a uniform speed. Very first roller of Draw Frame-1 is in contact with a scavenging roller which drips off excess SF Oil from the tow.

Draw Bath (YO6) It is an intermediate stage between two draw frames where maximum elongation of the product takes place. In the draw bath, SF Oil is showered at ~79 oC to maintain glass transition of the polyester fiber. Steam at a pressure of 3 barg is used to heat SF Oil.

Effect of Glass Transition Temperature on Drawing Below the glass

transition

temperature, polymer

chains

are

rigid;

after

reaching the glass transition temperature, the chains become more flexible and are able to unfold under stress. If the temperature is above Tg and stretching is carried out, the randomly coiled and entangled chains begin to disentangle, unfold, and straighten and some of them even slide over their nearest neighbor chains.

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Draw Frame-II (YO7) Here, maximum drawing of TOW takes place which is around 85% of the desired elongation to meet quality standards. Draw Frame-II rollers (7 in number in 3-4 arrangement) roll at high speed to produce elongation up to the standards. Each Roller is supplied with a constant supply of 3 barg steam to maintain a desired amount of temperature. Each draw frame roller is provided with wrap detectors which detect the wrapping of tow and immediately trip the line. A slipping factor of 6-7% is exists during tow drawing in draw frame-II. Temperature is maintained with the help of soft water which is circulated inside individual rollers at a temperature of 80oC.

Steam Box (YO8) Steam box is an intermediate equipment between YO7 and YO9. It uses 3 barg steam to increase the temperature of process tow to 160oC. The function of steam box is to soften the tow for further stretching.

Draw Frame-III (YO9) It is the final stage of drawing process where final elongation of fiber takes place which is around 15-20% of the total elongation. YO9 rollers speed is different from the remaining set of rollers of previous draw frames. Steam is supplied at 10 barg pressure to the lines of YO9 which use PCVs to reduce the pressure upto 4.7 barg to achieve a specific amount of temperature. Each roller is supplied with an individual steam line to achieve a temperature of ~160oC. These rollers are also provided with wrap detectors. YO9 is also called master draw frame because the overall speed of fiber line is interlocked with the speed of YO9. Speed of YO9 is also called line speed because any change in its speed will affect the whole fiber line.

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Thermosetting Unit (Y10) Here the setting of all the thermal properties of polyester is carried out. Y10 has 12 rollers which revolve at variable speeds. There are actually three sets of rollers, four in each set. Y10 is provided with 25 barg steam while pressure adjustment is carried out in each set of rollers to achieve a specific temperature range to achieve thermosetting of properties. Rollers

Temperature

1st set

190OC

Second set

191 OC

Third set

204 OC

Setting of following properties takes place in Y10: 1. Tensile strength 2. Denier 3. Shrinkage 4. Elongation It is actually a thermal treatment process which does not infer any further elongation in the fiber but maintains a high temperature and provides large surface area for the properties to set.

TOW Cooler (Y11) It is a rapid cooling system which decreases the temperature from 205oC to 70oC with the help of SF Oil which is showered at 50 oC. Cooling results in the fixation of polymer structure which had been set in the thermosetting unit. Spin finish oil is sprinkled by 12 nozzles arranged at a 30 angle having 6 nozzles on both sides.

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Draw Frame-IV (Y12) The function of Y12 is to prevent shrinkages in tow. The frame has different arrangement of rollers, i-e 4-3 (four rollers at top and three rollers at the bottom). Unique roller arrangement facilitates tow converging and easy band formation.

TOW Converger and Three Roller Frame (Y13 & Y14) This unit overlaps the three tows used in the drawing & forms a single tow whose width is comparable to the width of the crimper intake.

Tension Roller (Y15) The unit maintains the tension of the roller & again sent to the steam unit to gain the cotton like property.

Pre-Steam Chamber (Steam Box Y16) This equipment finds its place before the crimper unit. It uses steam at 3 barg pressure to heat tow band. If heating is not done then the crimpers will not form permanently. Heating the tow will result in the formation of stable crimps.

Crimper Unit (Y17) Now tow is crossed through the crimper unit. This unit induces crimps on the fiber at a rate of 13 crimps per inch. The crimps are made for necessary fiber flexibility & cohesion with the natural fiber. Width of crimping section is 350mm. Crimper thumb rule

= 9350 denier/mm

Crimper width = 350 mm = 3.2 Md

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Traversing Unit The tow leaves via traversing unit where spin finish oil is sprayed on the crimp tow depending on the type of product. The traversing chute spreads the tow on the tow drier plate.

Tow Drier In this section the tow is dried & cooled. 10-bar steam is supplied for the heating zone. After being dried the tow is transported to the cutter vertically to free roller. Tow band temperature is reduced to ~52 oC, drying takes place in four sections.

Fibre Cutter Unit (7458-Y23) After braking rollers tow has already attained much tension and it is passed to the cutter. The cutter is a circular ring having blades of different sizes on edges. The tow is passed through the pressure plate which presses the tow to wind around the cutter ring. Due to winding the pressure on the inside increases and makes the tow cut down according to the blade size. Once the tow has been cut it passes down to the baler section. Creel Area

Tow guiding

Dipping path

Draw frame 1

Draw bath

Tow Cooler

Thermoset ting Unit

Draw frame 3

Steam Bath

Draw frame 2

Draw frame 4

Overlapp er

Three Frame Roller

Crimp unit

Traveser

Baler

Cutter

Drying Unit

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Baler Baler has different parts actively playing their roles in making bales. The average weight of a bale is 300kg. Parts of baler are described orderly: 

Pre-Bin As tow is cut down, the fiber will fall down on plate that is called pre-bin. This will be opened when plate below it will be closed.



Weigh-Bin The fiber falls on the weigh bin. Weigh bin weighs the fiber up to 50 kg and discharges by opening up. Similarly total six batches will be discharged to make a single bale.



Pusher The pusher pushes away the 50 kg fiber under the pre-press ram.



Pre-Press Ram It is a hydraulic press and it presses the single charge at 60 barg. In the same way it presses six charges into the revolving unit.



Revolving Unit The revolving unit consists of two rectangular shaped molds. At a time one mold is being charged by pre-press ram while the other mold is made ready by putting packing sheets on it. Once the charging is over, it revolves and comes under the main press and the other mold will go under the pre-press for charging.



Main Press Ram Main press applies pressure of 110 barg to the charged 300kg fiber in mold. The mold is removed and takes a shape of bale.



Packing Packing is done manually. It’s a man work. The operators pack the bale by joining the packing sheets on up and below the bale. The packing sheet is polypropylene. After the sheet covers the bale, ring binders are used to bind the sheet over bale to prevent its opening while carrying it to the customers.

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Cutter

Pre-Bin

Weigh-Bin

Revolving Unit

Pre-Press Ram

Pusher

MainRam

Packing

A/C Section A/C station is utilized for providing following types of air to the spinning and fiber line: 

Quench Air



Comfort Air

This station provides quench air to the spinning unit and comfort air for the ventilation/ atmospheric temperature maintenance purpose in spinning and fiber draw line plant.

Procedure: The fresh air from the atmosphere is sucked by K01 fan in the A/C station. Air while entering the station passes the back filters to remove any suspended particles. On the way to back filters the fresh air combines with the returned comfort air from

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plant, the returned comfort air is coming via K04 fan. Here the dampers are placed. The dampers are there to decide the fresh air to return air ratio. It is done in order to achieve the quench air temperature easily. After back filters is the steam showering unit which only works if air has low temperature than 19-20C usually in winters. The heat transfer coefficient of air is lesser than that of water. That’s why air is being made humid to achieve better heat transfer. For this reason there is showering of WC on air to make it humid. There is also a soft water filter there in A/C unit which filters the soft water before being showered at the air coming from back filters. Soft water showering is done to achieve 100% humid air. Then further this humid air is passed through WCC coolers. WCC does heat transfer with the humid air to achieve air at 19-20C. This quenched air is passed through the drift eliminators to remove excess water in order to achieve final 85% humid air for quenching. Next this air is taken up by fans named K02 and K05 for the quenching in spinning unit. Here one fan is stand by. And K03 takes away comfort air for venting to the whole plant.


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QUALITY CONTROL DEPARTMENT Quality control department keeps a check on the quality of the process starting from raw material to the final ready to dispatch product. The department includes the following labs responsible for this cross check. 

Chemical lab Chemical lab keeps a check on the chemical properties of the products in polymer section. Any problem encountered is being dealt there to achieve best product.



Textile lab Textile lab examines the physical properties of products in spinning and Dispatch section. In this spinning and fiber line process we’ll only be dealing with properties being checked in this textile lab.

Textile Lab In this lab, we check out our required properties of filament fiber by performing different tests on it. All the properties that are maintained during different operations are all customers dependent and are ensures at Textile lab. It covers two products i.e. from spinning section and fiber draw line section. The products are listed as following 

Undrawn Yarn/Spun tow



Polyester Staple Fiber

UDY/SPUN TOW UDY is the final product from spinning section. The properties of UDY that are examined in textile lab include:

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Single Filament Denier (d) Single filament denier is the denier of a mono filament. It is observed in an instrument called Vibroskop.



Position Denier (d) Position Denier is the total denier of the number of filaments at each position.

  = . .  ∗ .  ℎ   



Tenacity ( ⁄) Tenacity is defined as the ultimate (breaking) force of the yarn (in gram-force units) divided by the denier. It is measured with an instrument called Vibrodyn. We take one filament of UDY and place it in the machine. As the test starts, a stress vs. strain graph is also plotted on the computer. A tensile force is applied to the filament. The point just before which the filament breaks indicates the tensile strength of the filament. It is calculated as:

  =  

Moisture (%) Sample is weighed initially and then wrapped in a paper and placed in an

oven for 140˚C. After 30 minutes the sample is weighed again and the difference in weight gives away the percent moisture. 

OPU (%) Oil Pick Up is the amount of oil, fiber can retain after being finished with spin finish oil. In this test, we take 5g of UDY filaments in a burette and let 40g of methanol run through it. Methanol absorbs the oil present with UDY. A flask is placed below to collect the methanol and oil solution. It is heated to 100C,

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methanol evaporates away and the amount of oil remaining is measured and OPU is calculated. 

Elongation (%) The elongation at break is the increase of the length produced by stretching a yarn to its breaking point. It is expressed as a percentage of its initial length. It is examined via an instrument called Vibrodyn.

PSF 

Denier (d) Denier is defined as the 1 g per 9000meters fiber. It is examined using Vibroskop in textile lab. A single fiber is clamped and then put it in the Vibroskop. The vibroskop measures the denier and give digital results.





Tenacity ( ⁄) Tenacity is defined as the ultimate (breaking) force of the fiber (in gram-force units) divided by the denier. It is measured with an instrument called Vibrodyn. We take one filament fiber and place it in the machine. As the test starts, a stress vs. strain graph is also plotted on the computer. A tensile force is applied to the filament. The point just before which the filament breaks indicates the tensile strength of the filament. It is calculated as:

 = 

 



T-10 ( ⁄) It is the tenacity of fiber at 10% elongation. It is calculated graphically from the stress vs. strain graph obtained while measuring tenacity.

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Elongation (%) The elongation at break is the increase of the length produced by stretching a yarn to its breaking point. It is expressed as a percentage of its initial length. It is examined via an instrument called Vibrodyn.



Crimp Number (⁄) Mono fibers from different chips in sample are hanged via clamp one by one on device and crimps are counted manually.

Crimp No. =



    5.4 

Crimp Removal (%) Here one end of mono fiber from a chip in sample is stuck to a glass slab using transparent tape initially. The other end is stretched until all crimps disappear and stuck it too on the slab. Now the length is measured. Then via formula % no. of crimps removed will be calculated.

Crimps Removed =



− x 100 

Crimp Stability (%) Similarly % no. of crimps that stayed will also be calculated from this formula:

Crimps Stablized =



−3 x 100 −

Shrinkage (%) In this test, 6-8 filaments from different chips in sample are collectively loaded with a certain weight on shrinkage drum and readings are noted at shrinkage

100


tester. Then this drum is placed in oven at 180C for about 20 minutes. After being removed from oven the readings are noted again and the difference in the readings gives the percentage shrinkage of fiber.



OPU (%)

In this test, we take 5g of fiber filaments in a burette and let 40g of methanol run through it. Methanol absorbs the oil present with fibers. A flask is placed below to collect the methanol and oil solution. It is heated to 100C, methanol evaporates away and the amount of oil remaining is measured and OPU is calculated. 

Miscut (wt. %) It is a physical test, in which the person performing the experiment takes a bulk of fibers in his hands and stretches it. The fibers cut properly will be separated and if miscuts are present, they will be detected. So the bail containing miscuts will be categorized as B grade. If the miscut is more than 30 wt. % but less than 100 wt. % in length it is categorized as Over length and if it is more than 100 wt. % then it is categorized as Multiple length.



Fiber Length (mm) It is a test in which various chips from the sample are measured manually to examine the fiber length.



DDD (Deep Dyeing Defect) (%)

It’s a test to detect any fused fiber or overweight fiber or UDY. The sample fiber is dipped in a color for about 20 minutes and at 95C. The dyed fiber is then dried and examined manually by putting it on a bright plate. The UDY will pick up deep color and will be detected easily.

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Moisture (%) Sample is weighed initially and then wrapped in a paper and placed in an

oven for 140˚C. After ̴ 30 minutes the sample is weighed again and the difference in weight gives away the percent moisture. 

Color Value Color value of fiber is being checked by comparing it with a standard Cotton.

It’s a manual test. Two types of color values are checked, stated as follows





Color l – show whiteness



Color b – show yellowness

⁄ ) 

Bulk Density (

A can of measured volume is weighed initially W1. Then it is filled with sample fiber without any force or weight. It is weighed again W2 and bulk density is calculated as follows:

21   =   

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CONCLUSION On the whole, this internship was a useful experience. We have gained new knowledge, skills and met many new people. We achieved several of our learning goals. We got insight into professional practice. We learned the different facets of working in field. Related to our study we learned more about organic chemistry and physical processes. The internship was also good to find out our strengths and weaknesses. It helped us to define what skills and knowledge we have to improve in the coming time. One main thing that we have learned through this internship is time management skills as well as self-motivation. We learned that we needed to be organized and have questions ready for when it was the correct time to get feedback. From this internship and time management, we had to learn how to motivate ourselves through being in the office for many hours. Finally, this internship has given us new insights and motivation to pursue our careers in Polyester Field.

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“Intelligence plus character-that is the goal of true education.” (Martin Luther King Jr.)

THANK YOU ! 104

Anas Final Internship Report.pdf

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