MANUFACTURE OF PHENOL FORMALDEHYDE RESIN
A PROJE PROJECT CT REPORT Submitted by URMILA.K A.K (41 (41502203018) VARU VARUN N RATH ATHI (41502203019)
in partial fulfi fulfilllment for the award of the degree of BACHE BACHELOR LOR OF ENG EN GI NEERIN NE ERING G in CHEMICAL CHEMICAL ENGINEERING ENGINE ERING
S.R.M R.M ENGI E NGINE NEE ERING COLLEGE, COLLE GE, KANCH KANCHE EEPURAM EPURAM
ANNA ANNA UNI UNIVERS VERSITY:: Y:: CHE CHENNAI 600025
MAY 2006
i
ANNA NN A UNIV UNI VERSI ERSITY: CH CHENNAI EN NAI BONAF BO NAFIDE IDE CERTIFICA CERTI FICATE TE
Certified
that
this
project
“MANUFACTURE
report
OF
PHENOL
FORMA FOR MALDE LDEHYDE HYDE RESI RESIN” Is the bonafide work of “UR “URMILA.K A.K (41 (41502203018) and VARU VARUN RATH ATHI (41502203019)” who carried out the project work under my supervision. SIGNATURE
SIGNATURE
Dr.R.KARTHIKEYAN HEAD OF THE DEPARTME DE PARTMEN NT
Dr.R.KARTHIKEYAN Pro Professor and Head & Dr.B.S.M. KUMAR Professor
CHEMICA CHE MICAL L ENG EN GNEERI NE ERING NG
CHEMICA CHE MICAL L
ENGINEERING S.R.M. .R.M.E Engineering Colle ollege
S.R.M. .R.M.E Engineering College
Kattankulathur attankulathur--603203
Kattankul attankulathurathur-603203
KancheepuramDistrict strict
KancheepuramDistrict strict
ii
ANNA NN A UNIV UNI VERSI ERSITY: CH CHENNAI EN NAI BONAF BO NAFIDE IDE CERTIFICA CERTI FICATE TE
Certified
that
this
project
“MANUFACTURE
report
OF
PHENOL
FORMA FOR MALDE LDEHYDE HYDE RESI RESIN” Is the bonafide work of “UR “URMILA.K A.K (41 (41502203018) and VARU VARUN RATH ATHI (41502203019)” who carried out the project work under my supervision. SIGNATURE
SIGNATURE
Dr.R.KARTHIKEYAN HEAD OF THE DEPARTME DE PARTMEN NT
Dr.R.KARTHIKEYAN Pro Professor and Head & Dr.B.S.M. KUMAR Professor
CHEMICA CHE MICAL L ENG EN GNEERI NE ERING NG
CHEMICA CHE MICAL L
ENGINEERING S.R.M. .R.M.E Engineering Colle ollege
S.R.M. .R.M.E Engineering College
Kattankulathur attankulathur--603203
Kattankul attankulathurathur-603203
KancheepuramDistrict strict
KancheepuramDistrict strict
ii
ACKNOWLEDGEMENT
It is pleasure and privilege for us to present this project report, before which we would like to thank all those who supported and guided us at the various stages of this project.
R.R. Karthikeyan B.E., Ph.D, Professor and We express our sincere thanks to our ou r guides DR.R. Head of the Department of Chemical Engineering ,
and Dr.B.S.M.Kumar, M.sc.,
M.Tech.,Ph.D., Professor, Department of Chemical Engineering, S.R.M Engineering College, for their outstanding guidance, constant encouragement and support, apart from their ideas and approach which has helped us complete this project .
r.V.E .Annamalai, Dr.I.A. Dr.I.A.P.S P.SMur Murthy, of We would like to mention special thanks to Dr.V.E.Anna Carborundum Universal Ltd., For giving us opportunity in gaining practical knowledge in recent industry. We would like to thank all the staff members of our department for their endless suggestions and guidance towards the completion of this project.
ABSTRACT Phenol-formaldehyde resins belong to the class of thermo set resins. These are known for their outstanding heat resistance. PF resins are of two types-resoles and novolaks – depending on the phenol-formaldehyde ratio. They can be manufactured in both liquid and powder form. The raw materials which are charged in the reactor at room temperature undergo an exothermic reaction for two hours. Continuous vacuum distillation takes place for about 6 hours , till the required viscosity is attained. Thus the phenol formaldehyde resin, of resole type is manufactured, as proposed .
iii
TABLE TABLE OF CONTENTS CONTEN TS CHAPTE CHAPTERS RS
TITL TI TLE E
PAGE NO.
ABSTRACT
iv
LIST OF TABL ABLES
vii
LIST OF FIGURES FIGURES
viii
LIST OF SYMBOLS
ix
1
INTRODUCTION
1
2
PROPERTIES
3
2.1 PHYSICAL PROPERTIES
3
2.2 CHEMICAL PROPERTIES
4
3
APPLICATION
6
4
LITERATURE SURVEY 4.1 PROCESS SELECTION
5
PROCESS DESCRIPTION 5.1 EFFLUENT TREATMENT
8 10 12 16
6
MATERIAL BALANCE
7
ENERGY BALANCE
26
8
DESIGN
29
9
PROCESS CONTROL
40
10
PLANT LAYOUT
42
11
COST ESTIMATION
52
12
SAFETY
60
13
STORAGE AND TRANSPORTATION
64
14
CONCLUSION
65
BIBLOGRAPHY
66
iv
22
LIS LI ST OF TABLE TABLES S
TABLE
DES DESCRIPTION CRIPTI ON
PAGE PAGE NO.
NUMBER 2.1
Physical properties
3
5.1
Viscosity test
13
7.1
calculation of heat content
26
8.1
Heat transfer data
34
11.1
Delivered cost of equipments
52
11.2
Direct cost factor
53
11.3
Indirect cost factor
53
11.4
Auxillary cost factor
54
LIS LI ST OF FIGURE FIGURES FIGURE 5.1
FLOW SHEET
15
FIGURE 5.2
FLOW SHEET
21
FIGURE 6.1
REACTOR BALANCE
22
FIGURE 6.2
CONDENSER BALANCE
24
FIGURE 7.1
ENERGY BALANCE FOR
26
A REACTOR FIGURE 7.2
ENERGY BALANCE FOR
28
A CONDENSER FIGURE 10.1
PLANT LAYOUT
LIST OF SYMBOLS A
Area(m2 )
D,d
Diameter(m)
L
Length (m)
v
51
H
Height (m)
m
Mass (kg)
Nu
Nusselt number
n
Number of tubes
P
Pressure
Pr
Prandtle number
Re
Reynolds nymber
V
Volume
T
Temperature
U
Overall heat transfer Coefficient (W/m2ºC)
Cp
Specific heat capacity (KJ/KgK)
K
Thermal conductivity (W/Mk)
f tsk
Shear stress Skirt thickness (mm)
W
Weight of the reactor (N)
Cv
Correction factor
GREEK LETTERS
∆ T
Temperature difference(ºC)
µ
viscosity of liquid
λ
Latent heat of vapourisation (KJ/Kg)
ρ
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1.INTRODUCTION HISTORY Leo H.Bakeland applied for his famous “heat and pressure” patent for the processing of phenol formaldehyde resins. This technique made possible the worldwide application of the first wholly synthetic polymer material. Even from his first patent application of feb 18, 1907, it was clear that baekland , more than his predecessors was fully aware of the value of the phenolic resins. So that when bakelite started with phenolic resins the following were already know. Phenols and formaldehyde are converted to resinous products in the presence of acidic and alkaline catalysts. These may be permanently fusible and soluble in organic solvents or heat curable depending upon the preparation conditions. Phenolic resins were already being sold as substitutes for shellac, ebonite, horn and celluloid. These are colorable , can be mixed with fillers and under the influence of heart shaped in molds into solid parts. However , economic of molded parts are not yet possible. The “heat and pressure” patent became the turning point , indicating clearly the importance of economic processing techniques for market acceptance. Phenolic resins mixed with fillers could be hardened in a press or autoclave, which was called bakelistor, under pressure at temperature below 100 * c in a considerably short time and without the formation of blisters. According to the first bakelite patent phenol and formaldehyde, catalyst and fibrous cellulosic material were reacted at elevated temperature. The impregnation of the fibrous material can be improved by application of vacuum and pressure, infusible products being obtained only if the formaldehyde was used in excess. Soon afterwards he recommended the impregnation of the cellulosic fibers with liquid phenolic resins, acid catalyzed resins were being used at this stage. According to a patent application by lebach in February 1907 insoluble and infusible condensation products, useful as plastic materials, could be obtained if phenol is reacted with surplus formaldehyde using neutral or basic salts as catalysts. In the same year bakeland also patented a process for the preparation of phenolic resins using alkaline catalyst, preferably ammonia, NaOH and Na2CO3. Henschke granted a patent to him in the USA
vii
but not in Germany because of the lack of inventive steps considering previous publications. It was in this patent, however, that resin manufacture was described for the first time just as it is carried out today. ⇒ The reaction is performed in a closed vessel with a reflux condenser to prevent lo ss
of volatile material. ⇒ The reaction is interrupted when the desire viscosity i s obtained. ⇒ Distillation is performed in a vacuum and can be continued until a solid product,
which is still soluble in alcohols is obtained. Today, the most important fields of application are the wood industry, molding and insulation compounds. More than 2/3 of all phenolic resins are used in these three fields. But also all classic application established by bakeland could maintain their position.
2. PROPERTIES 2.1Physical properties Physical Properties
Metric
Density
1.39 - 1.51 g/cc
Apparent Bulk Density
0.64 - 0.68 g/cc
Water Absorption Linear Mold Shrinkage Hardness, Rockwell E Tensile Strength, Ultimate Elongation at Break Tensile Modulus Flexural Modulus Flexural Yield Strength Compressive Yield Strength Poisson's Ratio Charpy Impact, Notched
0.36 - 0.54 % 0.003 - 0.0065 cm/cm 75 - 83 50.5 - 59.7 MPa 0.7 - 0.9 % 7.22 - 9.13 GPa 7.07 - 8.3 GPa 80.1 - 95.6 MPa 187.2 - 198.5 MPa 0.36 0.19 - 0.2 J/cm² viii
Electrical Resistivity Dielectric Constant Dielectric Strength Dissipation Factor Arc Resistance Comparative Tracking Index CTE, linear 20°C Maximum Service Temperature, Air Flammability, UL94
4.14e+012 3.58139e+013 ohm-cm 5.2 - 5.9 10.2 - 13.7 kV/mm 0.032 - 0.054 80 - 150 sec 175 V 53 µm/m-°C 182 - 205 °C HB
Phenol formaldehyde resin is hard, scratch resistant, infusible, and water resistant. 2.2 Chemical Properties
1) Overview of PF Cure Cure behavior is one of the most important characteristics of thermosetting adhesives. Understanding adhesive cure behavior and its dependence on the temperature and chemical conversion is important for predicting processing windows and the properties of cured bond lines. Thermo set cure usually involves polymerization and cross linking, as it passes through two stages: gelation and vitrification. Gelation occurs when a three dimensional network structure with infinite viscosity is formed. It marks the transition between the liquid and gel state. Vitrification occurs when the glass transition temperature of the thermosetting (pf) material rises and equals the cure temperature. Vitrification marks the transition from a liquid or rubber to a glass. Before gelation, thermoset cure is a kinetically controlled process while after vitrification it is a diffusion-controlled process and the reaction rate decreases dramatically.
2)ACTION OF HEAT The base catalyzed reaction of phenol with formaldehyde produces Intermediates which condense into branched polymers (resoles) at temperatures of between 60 and 100 ‘C . An investigation of
ix
The degradation properties of PF resins was conducted by Cordey . He Concluded that the primary degradation pathway for PF resins is oxidative in nature even in an oxygen deficient atmosphere and that thermal processes only begin to compete at higher temperatures. The presence of CO is first detected at about 350 ‘C, while CH4 which is the major volatile product from the thermal degradation of the resin, is evident only at temperatures above 550° C.
3) Action of acids: Phenol formaldehyde is resistant to non-oxidizing acids, salts and many organic solvents.
4) Stability: Phenol formaldehyde is very stable. No decomposition at ordinary temperatures.
5) Toxicity: Oral LD50 : 9200 mg/kg (rat)
6) Ecological effects: Can be separated mechanically in water treatment plants.
7) Flammability: Phenol formaldehyde is generally un flammable. 3. APPLICATIONS
Phenolics are little used in general consumer products today due to the cost and complexity of production and their brittle nature. An exception to the overall decline is the use in small precision-shaped components where their specific properties are required, such as molded disc brake cylinders, saucepan handles, electrical plugs and switches, and electrical iron parts. Today, Bakelite is manufactured under various commercial brand names such as Micarta. Micarta is produced in sheets, rods and tubes for hundreds of industrial applications in the electronics, power generation and aerospace industries. Major use categories of phenolic resins are,
Molding materials. The discovery by bakeland that wood flour compounded with phenolic resins could be molded under heat and pressu re to give a strong
x
heat resistant part that would not crack or split apart on aging, was the start of phenolic resin industry.
Laminates. Liquid one step resins and solvent solutions of one step resins are used to make laminated structures. Two general classes are recognized: Industrial and decorative.
BONDING RESINS: This market area includes the use of phenolic resins to bond friction materials, abrasives, wood particles, and inorganic fibers for insulation.
Friction materials. Phenol Formaldehyde resins is the principal bonding agent for the asbestos used in friction materials. The major categories are automotive brake linings, clutch facings, and automatic –transmission discs, but a wide variety of other products are made, e.g. brakes for oil well drilling rigs, power derricks, and rail road cars.
Bonded abrasives. About half of oil grinding wheel tonnage is resin bonded, the phenolic resins being used almost exclusively. Resins have replaced the various ceramic bonds because resinoid wheels can withstand more mechanical and thermal shock.
Coated abrasives. Phenolic resins have replaced hide glue for industrial grades of “sand paper” where heat is generated in dry grinding or where water-cooling is required.
Insulation. Phenolic resins are used to bond glass and rock wool fibers for thermal and acoustic insulation.
Plywood. Phenol formaldehyde resins for plywood glues are alkaline – catalyzed liquid one step resins.
Foundry use. Phenolic resins are employed in several metal casting applications.
Coatings. Phenolic resins are used in coatings both as the sole film former and to fortify drying oils. Resins used as the sole reactive ingredient are alkaline catalyzed one step phenol formaldehyde resin.
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4. LITERATURE SURVEY
Phenol-formaldehyde (PF)
Overview Phenol-formaldehyde (PF) resin was the first wholly synthetic polymer to be commercialized (1). It has become one of the most widely utilized synthetic polymers since Baekeland developed a commercial manufacturing process in 1907. Phenol-formaldehyde resin can be tailored to different properties suitable for various applications such as molding compounds, paper impregnates, adhesives, coatings, etc. By varying the catalyst type and the formaldehyde (F) and phenol (P) molar ratio, two classes of PF resin can be synthesized: resoles (resols) and novolaks (novolacs). Resoles are synthesized under basic conditions with excess formaldehyde (i.e. F/P>1); novolaks are synthesized under acidic conditions with excess phenol (i.e. F/P<1). Resoles and novolaks are inherently different: resoles are heat curable
while
novolaks
require
addition
of
a
cross
linking
agent
such
as
hexamethylenetetramine (HMTA) to cure. For most novolaks, this additional step results in slower cure rates and lower cross linking than resoles . PF resins were first introduced as binders for particleboard and plywood in the mid 1930’s; they have since become one of the most important thermosetting adhesives in the wood composites industry, especially for exterior applications. In 1998, PF resins comprised approximately 32 percent of the total 1.78 million metric tons of resin solids consumed in the North American wood products industry. Almost all PF resins currently used in wood bonding applications are resoles. PF resoles are desirable for exterior applications due to their rigidity, weather resistance, chemical resistance and dimensional stability. PF resoles, in either a liquid or a spray-dried form, are currently used as binders for the manufacture of an important structural wood panel, oriented strand board (OSB). Compared to polymeric diphenylmethane diisocyanate (PMDI), the only other binder currently used in OSB manufacturing in North America, PF resoles have the advantage of low cost, good thermal stability and reasonably fast cure. xii
PF Resole Synthesis PF Resoles are polycondensation products of phenol (P) and formaldehyde (F) in an alkaline aqueous medium with excess formaldehyde. Formaldehyde is often used in the form of an aqueous solution during commercial production of PF resoles. The polymeric form of formaldehyde, Para formaldehyde, is rarely used in industrial processes due to its high cost. PF resoles used as wood binders are typically synthesized under 100oC with a formaldehyde/phenol (F/P) ratio of 2 to 1 . The most commonly used catalyst in commercial resole preparation is sodium hydroxide (NaOH). Besides its catalytic effect, sodium hydroxide also improves the solubility of PF resoles in aqueous solution, which allows resoles to be synthesized with a high degree of advancement for fast curing, while maintaining good process ability.
4.1PROCESS SELECTION Process selection is an important criteria for any manufacturing unit. This selection gives direction to obtain the required product with high efficiency , quality and within the cost to be produced. The applications of the product defines the condition and changes required for manufacturing. Importance of process selection has been the key tool for many of the manufacturing units. Phenol formaldehyde resin is been manufactured , mainly by two process. Depending on the application of resin the required process can be chosen. The two process are explained in brief below, Manufacture of phenol formaldehyde resin using alkaline catalyst. PF resins are manufactured in batch process. Phenol and formaldehyde are charged into the kettle in specified quantaties. The kettle is kept under continuous agitation. An alkaline catalyst is added to initiate the reaction. Exotherms are controlled and cooking temperature is maintained by circulating cooling water and by cooling oil within the pipe and the outer jacket respectively. After 2 hours of reaction continuous distillation takes place for 6 hours . The whole manufacturing process takes place under vaccum. Once the
xiii
distillation starts heating oil is circulated in place of cooling oil. After achieving the viscosity/water tolerance , vaccum distillation is stopped and the reactor is cooled to below 40ºC. then the contents are discharged into specific containers. The product is kept in a cold room at below 10ºC till the time of dis patch. Manufacture of phenol formaldehyde resin using acid catalyst Novolak resins are ordinarily manufactured by batch process in a jacketed acid resistant stainless steel kettles equipped with shell and tube vapour condensers and heavy duty achor or turbine blade agitator. In a typical reaction reaction cycle molten phenol at 60-65ºC and warm 37-40% formaldehyde are charged to the kettle from weigh tanks. Agitation is started and is continuous throughout the cycle.the acid catalyst is then added and the batch is tested for pH.steam heat is applied to raise the temperature .this heating is necessary for 3-6 hours.at the end of reflux period the condensate is re routed to a reciever and the water is distilled from the kettle.vaccum is applied when temperature reaches to 120-150ºC.melting point or solution viscosity is used to test the sample for checking its completion. When the resin is completed , it is discharged .
5. PROCESS DESCRIPTION This is a batch process, which takes place for about eight hours . Phenol and formaldehyde are taken from the raw material storage room. Vacuum is first created in the reactor kettle, and then charging of phenol is done. Before adding phenol, vacuum pressure is created and cooling water supply is started. After charging phenol, formaldehyde is charged into the kettle. The molar ratio of phenol to formaldehyde is of 1:1.5. Now, sodium hydroxide, which is the catalyst, is added. It is mixed with necessary amou nt of water. Charging of raw materials in the reactor kettle takes place at 30°C. Reactor consists of an outer jacket and a coil around its circumference. The outer jacket carries the cooling oil for the first two hours of the reaction and the cooling water is circulated in the coil within the reactor for the same time. Now, after the entire charging section is complete, condenser valve is opened. As the stirring continuously takes place, the reaction temperature increases to about 102º C, the reaction
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being an exothermic one. The cooling oil and cooling water helps to control the reaction temperature at about 60-70ºC. Now, the reaction continues for about 2 hours at the same temperature. The extent of the reaction or amount reacted is tested by WATER TOLERANCE TEST also known as GEL TIME TEST. The water tolerance reduces from infinity to 600, as the reaction continues.
STEP: 1
C6H5OH + 2CH2O → C8H10 O3
STEP: 2
2n C8 H10O3 → [C8H8O2 ] n + n H2O
OVERALL REACTION
2n C6H5OH + 4nCH2O → n C8H7O2Na + n H2O {naoh}
Now, after two hours of reaction, the reactor behaves as a distillation column and continuous condensation takes place. Cooling is cut off and hot water and oil is circulated through the coils and outer jacket respectively. Distillation continues for about 6 hours at about 60 - 70 °C. The distilled water is collected in the receiver. Condensation takes place in the condenser; thereby changing the phase of vapour to liquid and directing it towards the distillation receiver. As the condensation takes place, the resin is checked for its viscosity periodically. The viscosity check is done in FORKED VISCOMETER. This is
xv
one of the widely used viscometer known for its accuracy and efficiency. The following table shows the values of the viscosity test. TABLE NO 5.1
TIME 15 SEC
SAMPLE
25SEC
SECOND SAMPLE THIRD SAMPLE
37 SEC 54 SEC
FIRST SAMPLE
FOURTH SAMPLE
Finally, the viscosity of resin is measured as 3000 cpi from BROOKFIELD
VISCOMETER, the distillation is stopped and the discharging is done at about 40-55°C. The discharged phenol formaldehyde resole contains about 20% water. This is taken and stored in the PVC containers and is stored in cool room at temperatures below 15 °C. Thus semi solid resin, which may be dissolved in organic solvents such as alcohols and used as varnish or coating or it, may be applied to sheets for subsequent lamination. The water from the distillation receiver tank, which contains some amount of phenol goes to the EFFLUENT TREATMENT PLANT.
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RAW
RAW
MATERIAL
MATERIAL
1
BALANCE
A R G E I T W A A I T C T H T O O R R
2
C O N D E N S E R
D R S I E T C I E L I V A E T I R O N
V T A A C N U K U M
ETP
RESIN RECEIVER
FIGURE 5.1
15
5.1 xvii
5.1PROCESS DESCRIPTION OF EFFLUENT TREATMENT SCREENING AND EQUALISATON The effluent is screened in the bar screen and taken to the equalisation tan k where the flow and parameters are equalised. Oil is separated by belt oil and skimmer mechanism . the equalisation tank is designed to hold 24 hours retention of effluent.
CHEMICAL TREATMENT Then the equalised and neuralised effluent is pumped to the reaction cum settling tank where alum,lime and polyelectrolyte solutions are added. The reacted effluent is allowed settled and the clear effluent is taken on furthur treatment to bio filter and where as a setteled sludge is applied on the sludge drying beds for disposal.
BIO FILTER A population of micro-organism attached to the filter media degrades the organic matters in the waste water. Organic matter from liquid is adsorbed on to the biological film or, shine longer. In the outer positions of the biological slime layer , the organic matter is degraded by aerobic micro organisms. As the micro- organisms grow , the thickness of the slime layer increases and the diffused oxygen is consumed before it can penetrate the full depth of the biological slime layer. Thus anaerobic environment is established at the surface of the media, as the slime layer increases in thickness the adsorbed organic matter is metabolised before it can reach the microorganisms near the media surface. As a result of having no external organic source available for cell carbon , the microorganisms near the media surface enter into an endogenous phase of growth and loose their ability to cling to the media surface.The liquid then washes the slime of media and the new slime layer is called SLOUGHING and is primarly a function of organic and hydraulic loading on the filter.The hydraulic loading accounts for the sheer velocities and the organic loading accounts for the rate of metabolism in the shine layer.
PROCESS MICROBIOLOGY AND ANALYSIS The biological community in the filter consists primarly of protests including aerobic , anaerobic and facultative bacteria ,fungi,algae and protozoa. Higher animals such as norms insects, larve and snails are also present .
xviii
Facultative bacteria are the predominating microorganisms in the bio filter. Fungi present are also responsible for the waste stabilization but their contribution is usually important only under low pH Conditions or, with certain induatrial wastes . the protozoan are predominating of ciliate group and their function is to control the bacteria population. In predicting the performance of bio filter the organic and hydraulic loading and the degree of purification required are the most important factors to be considered. Due to the unstable characteristics of the biological slime layer and the unpredictable hydraulic characteristics , a generalised kinetic model of the bio filter is very difficult to develop. The main problem encountered is the design of bio filter is the d termination of macimum organic material that can be applied to the filter before oxygen becomes a limiting variable. Two stage bio filter is the envisaged for the treatment process.
AEROBIC PROCESS The clear overflow of grvitates to the aeration tank for biological degradaiton. A single stage extended aeration activated sludge system has been adopted for treatment of organics. The process of ACTIVATED SLUDGE PROCESS is to remove organics that ecape from the primary treatment. “ ACTIVATED SLUDGE “ describes a continous flow , biological treatment system characterized by a suspension of aerobic microorganisms maintained in a realtively homogenious by mixing and turbulence induced in conjuction of aeration process. Waste water is received in aeration tank where aerobic microorganism is maintained in suspension. Suface aerators are provided to supply oxygen to the microorganisms , to completely mixed conditions. The aerobic micoorganisms degrade the solube and suspended organics in the effluent. The mixed liquor flows from the aeration tank to settling tank where the activated sludge is settled. A portion of the settled sludge is returned to aeration tank to maintain proper microorganisms (MLSS) concentration in aeration tank to permit rapid bio – degradation of organic matter . the excess sludge is wasted. Basically the Activated Sludge Process uses aerobic mocrorganisms in suspension to oxidise soluble and colloidal organics in the presence of molecular oxygen. During the oxidation process , a portion of the organic material is synthesised into new cells. A part of the synthesised cells then undergo auto oxidation ( self oxidation or endogenous respiration) in the Aeration Tank, Oxygen is required to support the synthesis and endogenous respiration reactions.
xix
Sufficient numbers of aerators shall be installed in the aeration tank to transfer , required oxygen necessary to sustain the activity of the microrganisms. In addition to the oxygen requirements the aerobic microbes require macro nutrients, nitrogen and phosphorus to sustain the microbial activity. Nitrogen being avaliable in the form of Ammonia would be readily utilised by the microbes. The aerobic microbes are capable of utilising about 65-70% of the nitrogen in the feed. Phosphorus on the other has to be supplemented with phosphorus salts. The overflow ffrom the aeration tank will contain a high concentration of solids. A secondary clarifier helps in separating the microbes from the liquid stream to produce a high quality effluent . the secondary clarifier also aids in maintaining a thick undeflow sludge concentrtion , crucial to the effective operation of the activated sludge process. The aeration tanks would be equiped with diffused aeration system to transfer oxygen to sustain the activity of microbes. The overflow from the aeration tank shall be settled in in secondary settling tank. A portion of the settled sludge shall be recycled to maintain the desired mixed liquor suspended solids in the aeration tank. The overflow from the secondary settling tanks shall be collected in a treated effulent sump to be taken up for furthur treatment and disposal.
SLUDGE TREATMENT AND DISPOSAL The sludge from the waste activated sludge from the extended aeration activated sludge plands shall be drained to sludge drying beds to dewater the sludge. The sludge drained to the sludge drying beds shall be allowed to dry for a period of about 7 days. The dried sludge would be scrapped from the sludge drying beds and used as manure, since this sludge, which only comprises of biological solids is rich in nitrogen and phosphorus. The filtrate from the sludge drying beds shall be taken up for furthur treatment and disposal. The solids settled in the primary settling tanks following neutral isation treatment shall be dried to the sludge drying beds and stored for safe land fillings.
TERITARY TREATMENT PLANT After secondary clarifiaction the efluent is subject to filtration followed by activated carbon filtration. Pressure land filter comprises of a mild steel pressure vessel containing the media, provided externally with valves and piping to direct and control flow of water during
xx
treatment and for cleaning. The media is supported by layers of crushed gravel and graded pebbles of specific sizes. And inlet distributor in the form of inverted bell-mouth funnel directs the inflow of raw water upwards towards thew top dished ends to ensure even distributon across the surface area of filter beds. Filtered water leaves the filter uniformly by means of a bottom collecting system which also serves to distribute evenly the flow of water used to xlean the filter. The bottom collecting system is either a false bottom type or either a header with perforated laterals depending on the type of filter and diameters. The internal syrface of sand media filter is painted with anti corrsosive bituminous paint. After filtration the water is passed throught activated carbon filter for odour removal also excess chlorine removal. Activated carbon filter comprises of a mild steel pressure vessel containing the media, provided externally with valves and piping direct and control flow of water during treatment for cleaning. The media is supported by layers of crushed gravel and graded pebbles of specific sizes.
xxi
FLOW SHEET Raw Effluent
Bar Screen FeSO4,Lime R aw effluent collection tank
Batch settler flash mixer sludge Rec cle tank Bio Filter - 1 Bio Filter - 2 Aeration tank
Settlin Tank Collection Tank Dual Media Filter
Fig 5.2 flow sheet
xxii
Sludge Filtrate to recycle tank
6. MATERIAL BALANCE STEP: 1
C6H5OH + 2CH2O → C8H10 O3
STEP: 2
2n C8 H10O3 → [C8H8O2 ] n + n H2O
OVERALL REACTION
2n C6H5OH + 4nCH2O → n C8H7O2Na + n H2O {naoh}
Material balance for the reactor Basis: 1000 kg of phenol input. Molecular weight of resin: 295 Molar ratio of phenol to formaldehyde = 1:2 FIG 6.1 REACTOR BALANCE Phenol = 1000kg CH2O solution = 1704 CH2O = 37% H2O = 63%
Reactor
NaOH solution = 132kg NaOH = 31.8% H2O = 68.2%
Reactant side :
xxiii
Resin = 1413kg Unreacted phenol = 94kg Unreacted CH2O= 60kg Unreacted water= 1164 kg
Total amount of phenol added = 1000kg Mole basis = 1000/94 = 10.5 kmoles Total amount of formalin solution added in mole basis = 21kmoles Total amount of formalin solution added by weight = 21*30 = 630 kg. formalin solution contains 37% of formaldehyde amount of formalin solution
= 630 kg = 630 /.37 = 1704kg
amount of water in formalin solution
= 1704-630 =
NaOH catalyst solution : 10% of phenol in kmoles NaOH =42kg Water content in NaOH =90kg Total amount of reactant water = 1074+90 = 1164 kg total weight of reactant
= 2836 kg
Product ( 90% conversion) Total resin = 295*.45*10.5 = 1413 kg total reaction water = .45*18*10.5 = 86.17 kg water from NaOH = 1.05 kmoles = 1.05*18 = 18.9 kg total unreacted water
= 1164 kg
total unreacted formaldehyde =30*2 = 60 kg total unreacted phenol
= 94 kg
total weight of the product
= 2836 kg
reactor outlet: unreacted phenol: 1kmole = 94 kg
xxiv
1074kg
unreacted formaldehyde: 2 kmoles = 60kg total unreacted water : 1269kg total resin produced : 1413kg
Material balance for condenser
Resin+ water = 2836 kg
CONDENSER
Resin = 1667kg FIG 6.2 CONDENSER BALANCE Total feed entering the condenser = 2836 kg Total amount of water in the mixture=1269kg 20% of water remains in the resin product=1269*0.2=254kg therefore, total liquid resin
=254+1413 =1667kg
total amount of vapour coming out =(1269*0.8)+94+60 =1169kg condenser balance is given as: feed = vapour + liquid 2836 = 1667 + 1169 =2836kg.
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Total distillate = 1169kg
7. ENERGY BALANCE Energy balance for the reactor
Phenol = 1000kg CH2O solution = 1704 NaOH solution = 132kg
(30ºC)
Resin = 1413kg Unreacted phenol = 94kg (60ºC)
ISOTHERMAL REACTOR
Unreacted CH2O= 60kg Unreacted water= 1164 kg (60ºC)
FIG 7.1
Amount of water circulated in the reactor =200 kg DATA TABLE 7.1: Compound
Mass ,kg
Specific heat capacity, Cp
MCp∆ T
Phenol
1000
2.34
11700
Formaldehyde
1704
0.5
4262.5
Resin
2836
1.18
117126.8
Water at 55 C
200
4.175
-
Standard heat of reaction:
xxvi
∆H
(reactants)=( mCp∆ T)phenol+ (mCp∆ T)formaldehyde =(1000*2.34*5)+(1705*0.5*5) =11700+4262.5 =15962.5
∆H
(products)=( mCp∆ T)products = ((60-25)*1.18*2836) = 117126.8
∆H
=∆H°+ ( ∑∆H) products - ( ∑∆H) reactants = 163.05+117126.8-15962.5 = 101327.35
Mass of oil to be circulated: ∆H
=( ∑∆H) oil+( ∑∆H) water
101325.35 = (m*1.70*(70-20))+(200*4.175*(60-25)) m
= 848
Mass of oil circulated in the reactor is: 848 kg CONDENSER:
H2O (20ºC)
Vapour (60ºC)
H2O (60ºC)
H2O(60ºC)
Fig 7.2
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Enthalpy balance: mλ
= mCp∆ T
Mass of vapour =1169 kg λ
at 60ºC = 2358.4 kj/kg
Cp of water = 4.182 kj/kgºC ∆ T=
mλ
35º C = mCp∆ T
1169*2858.4 = m*4.182 m
= 18835.6 kg
Therefore, mass of cooling water in the condenser = 18,835.6 kg
8. DESIGN OF EQUIPMENTS REACTOR Data required for design of reactor: Density of formaldehyde Density of phenol
815.3Kg/m3
:
1056.93kg/m3
:
Density of water
1000 kg/m3
:
Mass flow rate of the reactants :
2836 kg/batch
Hours of operation
:
H/D ratio Average density :
8 hours :
:
1.5 957.41 kg/m3
To find the volume of the vessel : Volume to be handled = m/ρ = 2836*8/957.41 =23.69 m 3/batch
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To find the volume of reaction vessel: Assuming 10% excess volume Volume = (23.69*(10/100))+23.69 = 26.059 m 3/batch total volume = volume of the cylindrical portion V = ( πD2 H)/ 4 26.059
=
π D2 (1.5D)/4
=
π D3 *1.5/4
= {(26.059*4)/ π *1.5}1/3
D
= 2.8 m H = 1.5D = 1.5*2.8 = 4.2 m The diameter of the vessel is 2.8m . Height of the reactor is 4.2m.
AGITATOR Type : turbine type Turbine diameter,Da :30-50% Dt Diameter of the tank,Dt: 2.8m Peripheral speed : 200-250 m/min Viscosity of resin: 3010-3 kg/ms Specific gravity of resin:1.6 Density of water: 1000kg/m3 Density of resin : 1.6*1000 = 1600 kg/m3 tube turbine diameter = 0.4(Dt) = 0.4*2.8 =1.12m tube peripheral speed = 225 m/min therefore,
πDaN=225 xxix
225/( π*1.12)=N N=64 rpm Consider the ratio of the reduction gear available 1/5,1/10,1/15……. Take 1/15 as the ratio of the reduction gear. Therefore speed of the motor = 64/(1/15) = 960 rpm Power consumption: = DV ρ/µ
Reynolds number, Nre V
= N*D = (64/60)*1.12 = 1.2 m/s
now, Nre
= (1.12*1.194*160)/30*10-3 = 71,321.6
From Np vs Nre graph, Np
= 6
Np
= ρg c / ρN 3 Da5
P Power consumption
(6*1600*1.063*1.125 )/9.8
= =
2053.988
=
2053.988/75
=
27.38 HP
Now take transmission and other losses as 20%. Then actual power requirement is, = 27.38*1.2 = 32.856 HP Power at the start, P max
= P*1.5 = 32.856*1.5 = 49.284 HP
To calculate diameter of shaft: P= 2 π NT/75 . . . . . . . . . . . . . . .(1) Torque T is given by, T = π*Dsh3 Fsh/16
xxx
Dsh - diameter of the shaft Fsh
- shear stress of the shaft.
N
- motor speed N = 960/60 = 16 rps
from (1) T = P*75/ (2* π*N) = (49.284*75)/(2* π*16) = 36.78 T = π* Dsh3 *Fsh/16 Dsh3 = 36.78*16/ π*9800000 Dsh = 0.0267m Shape factors: S1 = 0.33 S2 = 0.33 S3 =0.25 S4=0.2 S5=0.1 S6=1.0 S3=L/Da=0.25 L =0.25*1.12 = 0.28m S4 = W/Da =0.2 W = .2*1.12 =.224m W=0.224m S5 = J/Dt = 0.1 J = 0.1*2.8 = 0.28m Agitator dimensions Diameter of the turbine: 1.12m Length of the blade : 0.28m Thickness of the blade : 0.28m Width of the blade : 0.224m
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Diameter of the shaft: 0.026m
HEAT EXCHANGER 1,1 SHELL AND TUBE HEAT EXCHANGER Tube side - cooling water Shell side - vapour Water inlet temperature = 30ºC Water outlet temperature = 55ºC Vapour inlet temperature = 60ºC Vapour outlet temperature = 60ºC Mass of the steam entering = 1169 kg Inside diameter ,Di
=0.0225 m
Out side diameter,Do
=0.025m
Length of the condenser = 4m DATA TABLE 8.1 HEAT TRANSFER PROPERTIES Sl no.
PROPERTY
WATER at 42.5ºC
VAPOUR at 60ºC
1.
Specific heat capacity ,Cp
4.179 kj/kg k
1.920 kj/kg k
2.
Viscosity, µ
631*10-6 kg/m sec
1.49*10-6 kg/m sec
3.
Thermal conductivity ,K
634*10-3 w/m k
22.0*10-3 w/m k
4.
Prandtl number, Pr
4.16
0.916
5.
Latent heat of vaporization,
-
2354 kj/kg
λs LMTD = ∆ T1-∆ T2/ ln( ∆ T1/ ∆ T2) =(5-30)/ln(5/30) =13.95 Mass of cooling water =18835kg Per hour operation
=18835/6
Mass flow rate
= 3139.6kg/hr
Volumetric flow rate = mass flow rate/density of water =3139.6/1000 xxxii
=3.1396 m 3/ hr velocity
= volumetric flow rate/ area =3.139*4/ ( π*0.02252 *3600 ) = 2.19 m/sec
Reynolds number, Nre
= DV ρ/µ = 0.0225*.19*1000/(631*10 -6 ) =79,675.11
Prandtl number, Pr
= 4.16
Nusselt number , Nu
= 0.023*(Nre)0.8 (Pr)0.4 =0.023*(79,675.11) 0.8 (4.16)0.4 =339.175
Nu Hi
= Hi D/K =9557.186 kj /hr m2 ºC
Shell side steam coefficient, Ho= 8518.35 w/ m2 ºC Heat lost by steam = heat gained by cooling water Q= m Cp ∆ T =1169*4.179*30 =146557.53 U = 1/{ (1/Hi)*(Do/Di) + ln(Ro/Ri)*(Ro/k) + 1/Ho} = 3847.72 Q = UA ∆ T A = 146557.53/(3847.72*5) = 7.617 m2 A = πDoLN N = 24 TUBES. Number of tubes = 24
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SKIRT SUPPORT To know the weight of the reactor: W v = 240C v Dm(H v + 0.8Dm )t Assume thicknes of vessel to be 3mm. C v = 1.08 Dm = 2.8m H v = 4.2m W v = 240*1.08*2.8(4.2+0.8*2.8)*3*10-3 = 14.02 KN Approximate weight =п * 2.8 2*4.2*1000*9.81 = 253.7*10 3 KN total weight = 14.02+253.7*103 = 253.71*10 3 KN (a) stress due to dead weight f dw = Є W/ п Dsk Tsk = 28.48*10 3 / Tsk Assume height of the skirt = 1m Msb = 2/3 * Є W*Ht*0.08 = 2/3*253.7*10 3*5.2*0.08 = 70.35*10 3 Nm Stress due to seismic load f sb = 4*Msb*1000/п*Ds*Tsk = 4*70.35*10 3*1000/п*2.82*Tsk = 11.42*10 6/Tsk Maximum tensile stress in the skirt support f t = f sb- f dw = 11.42*106/Tsk - 28.48*10 3 / Tsk Permissible tensile stress of the material = 61.3 * 106 N/m2 f t = 11.39*106 / tsk
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tsk = 185mm Maximum compressive stress in the skirt f c = f sb + f dw = 11.42*106/Tsk +28.48*103 / tsk Permissible compressive stress of the material
= 82.2 N/mm2
Therefore, tsk = 138.27 mm Design of the skirt bearing plate Approximate bolt circle diameter = 2.2m No of bolts = 2200 п/600 = 11.5 no of bolts = 12 take bolt design stress = 125 N/mm2 Ms = 3919 KNm take W = operating value = 14.06 KN f b
= maximum allowable bolt stress
Area of cross section Ab = 1/Nb*f b ( 4*Ms/Db – W) = (1/125*10 6*12)(4*3919/(2.2) – 14.02*10 3 ) = 4740.9 mm 2 total compressive load on the base ring is given by f b = 4*Ms/п Ds2 + W/ п Ds = 4*3919000/ п 2.8*2.8 + 1402000/ п*2.8 = 638.95 KN/nm taking the bearing pressure as 5 n/mm2 Lb = f b/f c = 638.05/5 = 127.61mm actual width = Lb + tsk + 50 = 127.61+138.27+50 = 315.88 mm Lb = f b/f c’
xxxv
f c’ = 638.05/127.61 = 5 N/mm2 Tb = LbҐ(3*f c’/f b ) Tb
= 19.56 mm
bolt circle diameter = 2.2m bearing thickness
= 19.56 mm
bearing length
= 127.61 mm
Area of cross section = 4740.9 mm2 Skirt thickness
= 185 mm
9. PROCESS CONTROL Temperaturecontrol - The capability of the cooling system to remove the heat generated by the reaction is critical to the safe operation of an exothermic process. Facilities should evaluate capacity of cooling system with respect to controlling unexpected exotherms. Condensation cooling of reflux is commonly used to cool exothermic reactions that generate vapor as a byproduct, but has several limitations to Control unexpected exotherms. Reflux cooling is limited until the reaction mass reaches the boiling point of the liquid and cannot control exotherms that begin while the reaction temperature is below the liquid’s boiling point. As a runaway reaction proceeds, the increased generation rate of vapor increases the vapor velocity, the mass flow rate, and the inlet temperature in th e overhead condenser. The increased heat load on the condenser results in only partial condensation and reflux of water.
Addition of rawmaterials - Frequently, the reaction rate is controlled by the addition rate of one reactant or the catalyst and should be determined based on chemistry studies.
xxxvi
Facilities must pay attention to the order of ingredients, the addition rates, under- or overcharging, and loss of agitation.
Administrativecontrols- If administrative controls, such as training and standard operating procedures, are used as a safeguard against process deviation and accidental release, consideration must be given to human factors to ensure reliability, especially if an administrative control is the Sole layer of protection. Humans make mistakes; the consequences of a human error should not lead to a catastrophic release. Processes, equipment and procedures must be designed with potential for human error in mind. For manual operations, preventive measures should be considered to minimize the likelihood of human error, for example, interlocks. SOP’s must be understandable, periodically reviewed, and kept up-to-date. Employees must be trained on the SOP’s and mechanisms set up to ensure that SOP’s are followed at all times. The consequences of deviation from SOP’s must be well understood by all employees.
QUALITY CONTROL Quality control of phenolic resins begins with control of the raw materials. Phenol is generally USP grade. Specifications for phenol include f p , 40.9º C min ; bp, 181.8ºC min ; and sp gravity , 1.0563 (45/20ºC) . Formaldehyde, also USP grade, is monitored for assay by the hydroxylamine hydrochloric test, nominal 37% grade should contain 36.8% - 37.2% CH2O and 1% methanol wax.
xxxvii
10. PLANT LAYOUT INTRODUCTION The economic construction and efficient operation of a process unit will depend u pon how well the plant and equipment specified on the process flow sheet is laid out and on the profitability of the project with it scope for future expansion. Plant location and site selection should be made before the plant layout.
Plant location and siteselection: The location of the plant has a crucial effect on the profitability of the project. The important factors that are to be considered while selecting a site are: 1. Location, with respect to market area 2. Raw material supply 3. Transport facilities 4. Availability of labour 5. Availability of utilities 6. Availability of suitable land 7. Environmental impact and effluent disposal 8. Local community considerations 8. Climate 9.Political and strategic considerations 1. Marketing area
xxxviii
For materials that are produced in bulk quantities, such as cement, mineral acids, and fertilizers where the cost of product per tone is relatively low and the cost of transport a significant fraction of the sales price, the plant should be located close to the primary product. This consideration will be less important for low volume production, high priced products, such as pharmaceutical.
2. Rawmaterials The availability and price of suitable raw materials will often determine the site location. Plants producing bulk chemicals are best located close to the source of major raw material, where this is also close to the marketing area. For the production of formaldehyde the site should be preferably near a methanol plant.
3. Transport Transport of raw materials and products is an important factor to be Considered. Transport of products can be in any of the four modes of Transport.
4. Availability of labour Labour will be needed for construction of the plant and its operation. Skilled construction workers will usually be brought in from outside the site area, but there should be an adequate pool of unskilled labours available locally; and labour suitable for training to operate the plant. Skilled tradesman will be needed for plant maintenance. Local trade union customs and restrictive practices will have to be considered when assessing the availability and suitability of the local labour for recruitment and training.
5. Environmental impact and effluent disposal All industrial processes produce waste products, and full consideration must be given to the difficulties and cost of their disposal. . The disposal of toxic and harmful effluents will be
xxxix
covered by the local regulations and the appropriate authorities must be consulted during the initial survey to determine the standards that must be met.
6. Local community consideration The proposed plant must fit n with and be acceptable to the local community. Full consideration must be given to the safe location of the plant so that it does not impose a significant additional risk to the community on a new site, the local community must be able to provide adequate facilities for the plant personnel.
7. Land Sufficient suitable land must be available for the proposed plant and for future expansion. The land should ideally be flat, well drained and have suitable l oad-bearing characteristics full site evaluation should be made to determine the need for piling or other special foundations.
8. Climate Adverse climatic conditions, at a site will increase costs. Abnormally low temperatu res will require the provision of additional insulation and special heating for equipment and pipe runs.
9. Political and strategic considerations Capital grants , tax concessions and other inducements are often given by governments to direct new investment to preferred locations such as areas of high unemployment. The availability of such grants can be overriding consideration in the site selection. After considering the location of the site the plant layout, is completed. It involves placing of equipment so that the following are minimized: The various units that should be laid out include: 1. Main processing unit xl
2. Storage for raw materials and products 3. Maintenance workshops 4. Laboratories for process control. 5. Fire stations and other emergency services 6. Utilities: steam, boilers, compressed air, power, generation, and refrigeration. 7. Effluent disposal plant 8. Offices for general administration 9. Canteens and other amenity buildings, such as medical centers 10.Car parks
1. Processing area Processing area also known as plant area is the main part of the plant where the actual production takes place. There are two ways of laying out the processing area 1.) Grouped layout 2.) Flow line layout
Grouped layout Grouped layout places all similar pieces of equipment adjacent. This provides for ease of operation and switching from one unit to another. This is suitable for all plants.
Flow linelayout
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Flow line layout uses the line system, which locates all the equipment in the order in which it occurs on the flow sheet. This minimizes the length of transfer lines and therefore reduces the energy needed to transport materials. This is used mainly for- small volume products.
2. Storage house The main stage areas should be placed between the loading and unloading facilities and the process they serve. The amount of space required for storage is determined from how much is to be stored in what containers. In raw material storage, liquids are stored in small containers or in a pile on the ground. Automatic storage and retrieving equipment can be substantially cut down storage.
3. Laboratories Quality control laboratories are a necessary part of any plant and must be included in all cost estimates. Adequate space must be provided in them for performing all tests, and for clearing and storing laboratory sampling and testing containers.
4. Transport The transport of materials and products to and from the plant wil l be an overriding consideration in site selection. If practicable, a site should be selected that is close to at least two major forms of transport: road, rail, waterway or a seaport. Rail transport will be cheaper for long distance transport of bulk chemicals. Road transport is being increasingly used and is suitable for local distribution. Road area also used for fire fighting equipment and other emergency vehicles and for maintenance equipment. This means that there should be a road around the perimeter of the site. No roads should be a dead end. All major traffic should be kept away from the processing areas. It is wise to locate all loading and unloading facilities as well as, plant offices, personnel facilities near the main road to minimize traffic congestion within the plant and to reduce danger. xlii
5. Utilities The word "Utilities" is now generally used for ancillary ser vices needed in the operation of any production process. These services will normally be supplied from a central site facility and will include: Electricity, Steam for process heating, Cooling water, Water for general use, Inert gas supplies.
Electricity: Electrical power will be needed at all the sites. Electrochemical processes that require large quantities of power need to be located close to a cheap source of power. Transformers will be used to step down the supply voltage to the voltages used on the purpose.
Steam for process heating: The steam for process heating is usually generated in water tube boil ers using the most economical fuel available. The process temperature can be obtained with low-pressure steam. A competitively priced fuel must be available on site for steam generation.
Cooling water: Chemical processes invariably require large quantities of water for cooling. The cooling water required can be taken from a river or lake or from the sea.
Water for general use: Water is needed in large quantities for general purpose and the pl ant must be located near the sources of water of suitable quality, process water may be drawn from river from wells or purchased from a local authority.
Offices: The location of this building should be arranged so as to min imize the time spent by personnel in traveling between buildings. Administration offices in which a relatively large number of people working should be located well from potentially hazardous process.
xliii
Canteen: Canteen should be spacious and large enough for the workers with good and hygienic food.
Fire station: Fire station should be located adjacent to the plant area, so that in case of fire or emergency, the service can be put into action.
Medical facilities: Medical facilities should be provided with at least basic facilities giving first aid to the injured workers. Provision must be made for the environmentally acceptable disposal of effluent. The layout of the plant can be made effective by: 1) Adopting the shortest run of connecting pipe between equipments and the least amount of structural steel work and thereby reducing the cost. 2. Equipment that need frequent operator attention should be located convenient to control rooms. 3. Locating the vessels that require frequent replacement of packing or catalyst outside the building 4. Providing at least two escape routes for operators from each level in process buildings. 5. Convenient location of the equipment so that it can be tied with any future expansion of the process.
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FINISHED PRODUCT COLD STORAGE
EXTENSION
SCRAP
AREA
YARD
PROCESSING
ETP
AREA C A N SAFETY &
T
HEALTH
E
CARE
FIRE STATION
E
DEPARTMEN
N
T
W O R K S H O P
ADMINISTRATIVE OFFICE
PARKING AREA
SECURITY OFFICE
ENTRY
FIGURE 10.1 51
11. COST ESTIMATION xlv
EXIT
ESTIMATION OF THE TOTAL CAPITAL INVESTMENT The total capital investment“I” involves thefollowing: A. The fixed capital investment in the process area, IF. B. The capital investment in the auxiliary services, IA.
C. The capital investment as working capital, IW. i.e.,
I = IF + IA + IW
A. FIXED CAPITAL INVESTMENT IN THE PROCESS AREA, IF. This is the investment in all processing equipment within the processing area. Fixed capital investment in the process area, IF = Direct plant cost +Indirect plant cost. The approximate delivered cost of major equipments used in the proposed manufacturing plant are furnished below: DATA TABLE 11.1 S.No. 1 2 3 4 5 6 7 8 9 10 11 12
Equipment Reactor Condenser Distillate collection tank Storage tank-phenol Storage tankformaldehyde Storage tank-resin Bio filters Storage tanks- ETP Flash mixer Vacuum tank Cooling tower Miscellaneous TOTAL
Units 1 1 1 1 1
Cost in lakhs/unit 30 20 10 10 10
1 3 5 1 1
10 15 10 10 10
10 45 50 10 10
1
20
20 125 350
CALCULATION OF FIXED CAPITAL INVESTMENT
1) Direct cost factor: DATA TANLE 11.2 DIRECT COST FACTOR S.No 1 2 3
Items Delivered cost of major equipments Equipment installation Insulation
Cost (in lakhs Rs) 30 20 10 10 10
Direct cost factor 50 15 15
xlvi
4 5 6 7 8 9
Instrumentation Piping Land & building Foundation Electrical Clean up Total direct cost factor
15 25 30 10 15 5 180
Direct plant cost = (Delivered cost of major equipments)(Total direct cost factor) / 100 Direct plant cost = (350 * 180) / 100 = 630 lakhs
2) Indirect costfactor: DATA TABLE 11.3 INDIRECT COST FACTOR S.No. Item 1 Overhead contractor etc. 2 Engineering fee 3 Contingency Total indirect cost factor
Indirect cost factor 30 13 13 56
Indirect plant cost = (Direct plant cost)(Total indirect cost factor) / 100 = (630 * 56) / 100 = 352.8 lakhs Fixed capital investment in the process area, IF = Direct + Indirect plant cost = 630 + 352.8 = 982.8 lakhs
B. THE CAPITAL INVESTMENT IN THE AUXILLARY SERVICES, IA. Such items as steam generators, fuel stations and fire protection facilities are commonly stationed outside the process area and serve the system under consideration. DATA TABLE 11.4 AUXILLARY COST FACTOR
xlvii
S.No. 1 2 3 4 5 6 7 8 9 10
Items Auxiliary buildings Water supply Electric Main Sub station Process waste system Raw material storage Fire protection system Roads Sanitary and waste disposal Communication Yard and fence lighting Total
Auxiliary services cost factor 5 2 1.5 1 1 0.7 0.5 0.2 0.2 0.2 12.3
Capital investment in the auxiliary services = (Fixed capital investment in process area)*( Auxillary services cost factor) / 100 = (982.8* 12.3) / 100 = 120.8 lakhs Installed cost
= Fixed capital investment in the process area + Capital Investment in the auxiliary services = 982.8 + 120.8 = 1103.6 lakhs
C. THE CAPITAL INVESTMENT AS WORKING CAPITAL, IW. This is the capital invested in the form of cash to meet day-to-day operational expenses, inventories of raw materials and products. The working capital may be assumed as 15% of the total capital investment made in the plant ( I ). Capital investment as working capital, IW = ((982.8+120.8)* 15)/85 = (1103.6* 15) / 85 = 194.75lakhs Total capital investment
I = IF+ IA+IW = 982.8 + 194.75+ 120.8 = 1298.35lakhs
xlviii
ESTIMATION OF MANUFACTURING COST The manufacturing cost may be divided into three items, as follows: A. Cost Proportional to total investment B. Cost proportional to production rate C. Cost proportional to labour requirement
A. COST PROPORTIONAL TO TOTAL INVESTMENT This includes the factors, which are independent of production r ate and proportional to the fixed investment such as -
Maintenance-labour and material
-
Property taxes
-
Insurance
-
Safety expenses
-
Protection, security and first aid
-
General services, laboratory, roads, etc.
- Administrative services
For this purpose we shall charge 15% of the installed cost of the plant = (Installed cost * 15) / 100 = (1103.6* 15) / 100 = 165.54 lakhs
B. COST PROPORTIONAL TO PRODUCTION RATE The factors proportional to production rate are -
Raw material costs
-
Utilities cost – power, fuel, water. Steam, etc.
-
Maintenance cost
-
Chemical, warehouse, shipping expenses
xlix
Assuming that the cost proportional to production rate is nearly 60% of total capital investment, Cost proportional to production rate = (Total capital investment * 60) / 100 = (1298.35 * .6) = 779.01 lakhs
C. COST PROPORTIONAL TO LABOUR REQUIREMENT The cost proportional to labour requirement might amount to 10% of total manufacturing cost. Cost proportional to labour requirement = (165.54 + 779.01)*(0.1) / (0.9) = 104.95 lakhs Therefore, manufacturing cost
= (165.54 +779.01+ 104.95) = 1049.5 lakhs
SALES PRICE OF PRODUCT
Market price of
= Rs. 100/kg
Production rate
=1460000 Kg PA
Total sales income
=1460000*100 = 1460 lakhs
PROFITABILITY ANALYSIS
A. DEPRECIATION According to sinking fund method: R = (V-VS) I / (1+ I)n
l
R = Uniform annual payments made at the end of each year V = Installed cost of the plant VS = Salvage value of the plant after n years N = life period (assumed to be 15 years) I
= Annual interest rate (taken as 15%)
R
= (1103.6 * .15) / (1+0.15)15-1 = 23.19 lakhs
B. GROSS PROFIT Gross profit = Total sales income - manufacturing cost = 1460 - 1049.5 =410.5 lakhs
C. NET PROFIT It is defined as the annual return on the investment made after deducting depreciation and taxes. Tax rate is assumed to be 40%. Net profit = Gross profit-Depreciation-(Gross profit*Tax rate) = 410.5-23.19-(410.5*0.4) = 223.11 lakhs
D. ANNUAL RATE OF RETURN Rate of return = (100*Net profit/Installed cost) = (100*223.11) /1103.6) = 20.2%
E. PAYOUT PERIOD Payout period = Depreciable fixed investment/((profit)+(depreciation)) = 1103.6 / (223.11 + 23.19) = 4.48 years
li
12. SAFETY INTRODUCTION In recent years there has been an increased emphasis on process safety as a result of number of serious accidents. This is due in part to the worldwide attention to issues in the chemical industry brought on by several dramatic accidents involving gas releases, major explosions and several environmental accidents. Public awareness of these and other accidents has provided a driving force for industry to improve its safety record. Local and national governments are taking a hard look at safety in the industry as a whole and the chemical industry in particular. There has been an increasing amount of government regulations.
For many reasons, the public often associates chemical industry with environmental and safety problems. It is vital for the future of the chemical industry that process safety has a higher priority in the design and operation of chemical process facilities. INDUSTRIAL ACCIDENTS
An accident hasbeen defined as an unplanned or unexpected event, which causes or is likely tocause an injury. An accident occurs as a result of unsafe actions or exposure to an unsafe environment. Unsafe actions or unsafe mechanical or physical conditions exist only because of faults of a particular person. Faults of persons are inherited from the environment and reasons for the faults are: i.
Improper attitude
ii.
Lack of knowledge or skill
iii.
Physical unsuitability
iv.
Improper mechanical or physical environment
lii
ACCIDENT PREVENTION From the foregoing, it will be seen that the occurrence of an injury is the culmination of a series of events or circumstances that invariably occur in a fused and logical order. Knowledge of the factors in the accident sequence guides and assists in selecting the point of attack in prevention work. It permits simplification without sacrifice of effectiveness. The most important point is that unsafe conditions or actions are the immediate cause of accidents. The supervision and management can control the actions of employed persons and so prevent unsafe acts and also guard or remove unsafe conditions, even though previous events or circumstances in the sequence are unfavorable. The four factors that converge to cause accidents are: i.
Personal factor
ii.
Hazard factor
iii.
Unsafe factor
iv.
Proximate casual factor
The solution under the four factors would also lead to two steps. These are planning and organizing to: i.
Prevent unsafe mechanical or physical conditions
ii.
Prevent unsafe action being committed.
HANDLING GUIDELINES
1) Always handle with rubber gloves. 2) Avoid direct skin contact. 3) Wear EYE GOGGLES while handling product. 4) Use a breathing mask while in close proximity to product
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5) Wear an apron while handling product. DO NOT allow product to come in direct contact with clothes 6) Avoid any direct contact with skin. 7) All employees working inside factory should wear safety shoes. 8) Every employee inside the factory should wear safety helmet to avoid head injuries. 9) Company should have well equipped medical center. FIRST AID MEASURES 1) GENERAL INFORMATION: Instantly remove any clothing soiled by the product. 2) After inhalation supply fresh air, consult doctor in case of symptoms. 3) After skin contact instantly wash with water and soap and rinse thoroughly 4) After eye contact rinse opened eye for several minutes under running water. 5) After swallowing rinse mouth and drink plenty of water.
FIRE FIGHTING MEASURES 1) Carbon dioxide, extinguishing powder or water jet is normally used in fires. 2) For large fires water jet or alcohol-resistant foam is used. 3) Collect contaminated fire fighting water separately,it must not enter drains. SPILLAGE 1) Spray material with water to prevent air pollution through dispersion of particulate matter. 2) Collect the spilled material using a scrapper. 3) Avoid exposure of spilled material to a direct flame or heat source.
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13. STORAGE AND TRANSPORTATION Phenol formaldehyde resin in usually stored in cold storage at about 15 degree Celsius.
Storageguidelines 1) The product must be stored in cold storage room. 2) The storage area must be free from moisture. 3) The storage area must be well insulated from any heat source (direct flame). 4) The shelf life for the product which is stored in cold storage room is only 6 months. 5) Advisable to use the product immediately or before 6 months 6) The storage facility must have good ventilation. 7) Clean water must be available in plenty in the vicinity in the event of emergency. 8) The storage area must be designed to avoid direct exposure of the product to the atmosphere. 9) The containers used for storage should be well sealed containers.
TRANSPORTATION: Phenol formaldehyde resin is stored in air tight containers and is transported from one place to other by: lorries, trucks, ships.
DISPOSAL: After the shelf life period of Phenol formaldehyde resin must be disposed as solid waste disposal techniques outlined by the pollution control board of the local government.
14. CONCLUSION
The phenol formaldehyde is the largest used resin in the world. Today it is used in all common places like wood working industry, abrasives, molding and insulation compounds. The market demand for this resin is always high. The economic importance of phenolic
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