HAPTER 4
DESCRIPTION OF PLANT
4.1
General Description of Process
4.1.1
Limestone Crushing & Transportation Limeston Limes tone e tak taken en from from qu quar arry ry is trans transpo porte rted d via du dump mp truck trucks s to concrete feeding hopper, and then transported to hammer crusher with with a rated rated capa capacit city y of 15 1500 00t/h t/h by varia variabl ble e spee speed d ap apro ron n feede feeder r (1600tph). (1600tph). The crushed limestone which is less than 70 mm (95%) is transported by long belt conveyors to pre-blending yard. A crane beam is equipped for crusher overhaul.
4.1.2
Limestone Preblending Limeston Limes tone e from from the crus crushin hing g de depar partme tment nt is trans transpor ported ted via be belt lt conveyor into plant site and is stored in a longitudinal preblending bed. The stacking capacity is 1500tph and reclaiming capacity is 900 tph. Longitudinal preblending bed reserves 2x35000t. Steel roof is constructed to against dust and rain.
4.1.3
Clay, Clay, Coal, Bauxite and Laterite Crushing and Transportation Clay, coal, bauxite and laterite taken from their quarries are fed into concr concrete ete fe feedi eding ng ho hoppe pperr resp respect ective ively ly by du dump mp truck trucks s an and d then then transported into their crusher for crushing. Clay crusher Capacity is 400tph 400t ph with variable variable spe speed ed apron apron fee feeders ders(40 (400tph 0tph). ). The crushed crushed materials, which are less than 80mm (90%), are transported by belt conveyors to the pre-blending yard.
4.1.4
Clay, Clay, Coal, Bauxite and Laterite Preblending and Storage Clay, coal, bauxite and laterite from the crushing departments are transported via belt conveyors into the plant site and stored in two longi longitu tudin dinal al prebl preblen endi ding ng be bed. d. Mat Materi eriel el rese reserve rve will will be de decid cided ed according to blend proportion. Steel roof is constructed to against dust and rain.
4.1.5
Raw Material Regulation and Transportation Four Four bins bins are are se sett in th the e raw raw ma mate terrials ials prop propor orti tion onin ing g stat statio ion n respectively respectively for limestone, limestone, clay, bauxite and laterite. Each material is discharged from bin via weighing feeder (Schenck China) according to certain proportion, and then fed into roller mill via belt conveyor (VVVF).
4.1.6
Raw Material Grinding & EGT A vertical roller mill from European European (Loesche, F.L. Smith, atox, Pfeiffer or plusius) is proposed to use for drying and grinding of raw materials. Under the condition that 1) feeding size ≤ 80 mm (95%), 2) feeding material moisture ≤ 6%, and 3) the residue of raw meal on 90μm< 90 μm< 12%; 12%; th the e out output put of the mill mill reach reaches es 43 430+3. 0+3.49 49%t/ %t/h. h. The
grinded material is collected by cyclones and sent to the raw meal silo via air slide and bucket elevator (Aumund). Part of exhaust gas out of the mill will be drafted back to mill for circulation, the rest will be dedusted by E.P. E.P. Part of the waste gas from the condition tower will be drafted to the mill for raw material drying, the rest will go into E.P. Raw Raw mill mill Fan and Raw mill EP fan (VVVF) (VVVF) will will be Ve Venti nti/So /Solyv lyvent ent Eruopean origin. 4.1.7
Raw Meal Silo & Kiln Feeding System A raw meal meal homogenizing homogenizing silo (IBAU type) of Ø22.5 Ø22.5 x62m (22000t) (22000t) is built for raw meal homogenizing. Raw meal extracted from the silo is transported to a standard bin which is equipped with flow control valves and motor controlled valve. Then the raw meal that is taken out of the bin through the valves and weighed by the impacting flow meter will be conveyed to the inlet duct of the first stage cyclones of the preheater via air slide and bucket elevator (Aumund).
4.1. 4.1.8 8
Clin Clinker ker Burni Burning ng Sy Syst stem em The clinker burning system is mainly composed of a low pressure drop drop 5-st 5-stag age e do doub uble le stri string ng susp suspen ensi sion on preh prehea eate terr an and d a TSD TSD precalciner, a tertiary air duct, a rotary kiln of Ø4.8 ×72m and a third generation grate cooler. At the outlet of the grate cooler, there is a hammer crusher. Its designed production capacity is 5700+6.14%t/d clinker. Heat consumption of the burning system is 700Kcal/kg.clinker(coal), 710Kcal/kg.clinker(Oil), 725Kcal/kg.clinker(Natural Gas) respectively. Refractory bricks for kiln burning zone will be Europe origin. Burners of kiln and precalciner will be European origin, Multiply burners (coal, gas and oil) will be used. The Raw meal is sent to the gas riser duct between the stage C1 and C2 by bucket elevator(Aumund) and air slide. TCDRI ’s preheater with its new generation of cyclones have a very high efficient heat exchange rate and low-pressure drop. The decarbonation degree of the raw meal at inlet of kiln is up to about 90%. The clinker from the rotary kiln is cooled by grate- cooler and crushed by the clinker crusher. The temperature of the clinker at outlet of the cooler is about 65°C plus ambient temperature. The cooled clinker is transported to the clinker shed by pan conveyor with weighing scale. A passenge passengerr lift will be be installed installed for going going up and and down the preheater preheater.. Cooler EP Fan (VVVF) and kiln ID Fan (VVVF) will be Venti/Solyvent Eruopean origin.
grinded material is collected by cyclones and sent to the raw meal silo via air slide and bucket elevator (Aumund). Part of exhaust gas out of the mill will be drafted back to mill for circulation, the rest will be dedusted by E.P. E.P. Part of the waste gas from the condition tower will be drafted to the mill for raw material drying, the rest will go into E.P. Raw Raw mill mill Fan and Raw mill EP fan (VVVF) (VVVF) will will be Ve Venti nti/So /Solyv lyvent ent Eruopean origin. 4.1.7
Raw Meal Silo & Kiln Feeding System A raw meal meal homogenizing homogenizing silo (IBAU type) of Ø22.5 Ø22.5 x62m (22000t) (22000t) is built for raw meal homogenizing. Raw meal extracted from the silo is transported to a standard bin which is equipped with flow control valves and motor controlled valve. Then the raw meal that is taken out of the bin through the valves and weighed by the impacting flow meter will be conveyed to the inlet duct of the first stage cyclones of the preheater via air slide and bucket elevator (Aumund).
4.1. 4.1.8 8
Clin Clinker ker Burni Burning ng Sy Syst stem em The clinker burning system is mainly composed of a low pressure drop drop 5-st 5-stag age e do doub uble le stri string ng susp suspen ensi sion on preh prehea eate terr an and d a TSD TSD precalciner, a tertiary air duct, a rotary kiln of Ø4.8 ×72m and a third generation grate cooler. At the outlet of the grate cooler, there is a hammer crusher. Its designed production capacity is 5700+6.14%t/d clinker. Heat consumption of the burning system is 700Kcal/kg.clinker(coal), 710Kcal/kg.clinker(Oil), 725Kcal/kg.clinker(Natural Gas) respectively. Refractory bricks for kiln burning zone will be Europe origin. Burners of kiln and precalciner will be European origin, Multiply burners (coal, gas and oil) will be used. The Raw meal is sent to the gas riser duct between the stage C1 and C2 by bucket elevator(Aumund) and air slide. TCDRI ’s preheater with its new generation of cyclones have a very high efficient heat exchange rate and low-pressure drop. The decarbonation degree of the raw meal at inlet of kiln is up to about 90%. The clinker from the rotary kiln is cooled by grate- cooler and crushed by the clinker crusher. The temperature of the clinker at outlet of the cooler is about 65°C plus ambient temperature. The cooled clinker is transported to the clinker shed by pan conveyor with weighing scale. A passenge passengerr lift will be be installed installed for going going up and and down the preheater preheater.. Cooler EP Fan (VVVF) and kiln ID Fan (VVVF) will be Venti/Solyvent Eruopean origin.
4.1.9
Clinker Storage and Transportation A circular shed (appox.Ø90m, (appox.Ø90m, 100000 100000t, t, 20days) 20days) is used for clinker storage. Clinker is discharged from the silo bottom by arc valves, and then transported to the dosing silo via belt conveyor. In keeping view of unburned clinker, an unburned clinker silo with capacity of 1000tons is considered.
4.1.10
Gypsum Crushing and Transportation Gypsum is transported to plant by trucks and stored in open yard, fed to the feeding hopper by wheel loader. A hammer crusher of 70t/h is used used for gypsu gypsum m crushi crushing, ng, an and d crush crushed ed ma mater teria iall will will be sent sent to cement proportioning bin.
4.1.11
Proportioning Station For Cement Grinding Three silos are set in the cement proportioning station respectively for clinker Additive and gypsum. Each material is discharged from silo via weighing feeder (Schenck China) according according to certain proportion, and then fed into cement mill via belt conveyor and bucket elevator.
4.1.12
Cement Grinding (2×150t/h, 3200cm 2 /g) Two sets of closed circuit tube mill (2-Ø4.2 ×13, 2x150t/h) with roller press will be used for cement grinding. Pres Presse sed d ma mate teri rial al to toge geth ther er with with blen blendi ding ng ma mate teri rial al is fed fed to Vseparat sep arator or.. Afte Afterr sep separat aration ion the coa coarse rse mat materia eriall goes to the roller roller press and the fine material goes to the cyclone separator then to the mill. Material after grinding Material grinding is introduc introduced ed to an O-SEPA O-SEPA sep separat arator or for classifying. The coarse material recycled into the mill for regrinding while the fine product is collected by bag filter and sent to cement silos by air slides and bucket elevators (Aumund). (Aumund) . Cement mill system Fan will be Venti/Solyvent Eruopean origin.
4.1.13
Cement Silo & Transportation Four circular circular silos silos (Ø18x44. (Ø18x44.5 5 m, 1170 1700tx4 0tx4)) are used for ceme cement nt storage.
4.1.14
Cement Packing & Dispatching Six sets of cement packer (8-spout rotary packer, 6x100t/h) will be fitted in the packing plant building.
4.1.15
Coal Grinding A vertical roller mill From European European (Loesche, F.L. Smith, atox,
Pfeiffer or plusius) is proposed for drying and grinding of coal. Under the condition that 1) feeding size <=50 mm (95%), 2) feeding material moisture <=10%, and 3) the residue of coal meal on 90μm < 10%; the output of mill reaches 40t/h. Grinded material is collected by bag filter and sent to coal silo. Pulverized coal are weighed by Pfister rotary feeders and transported to kiln and precalciner seperaterly. Part of the waste gas from the preheater will be drafted to the mill for coal drying (Moisture in fine coal <1%). 4.1.16
Compressed Air Station Two compressed air stations are installed, one is for materials and clinker burning system the other is for finished products system. Every station is equipped with three air compressors with capacity of 22m3/min. One compressor of them is for stand-by.
4.1.17
Fuel oil and Nature gas system The two furnace oil storing tanks will be utilized for the new production line. Furnace oil will be pumped to furnace oil heater after passing the fine filter, and heated to about 120 °C℃ and then sent to the burners of kiln and calciner respectively. A new thermal oil system will be installed for heating the furnace oil at the furnace heater and chaperonage heating of furnace oil transporting pipeline. Flow meters will be equipped to show the transient flow and cumulative flow. Fuel oil and gas supply system will be Pillard or Unitherm make.
4.2
Description of Electric and Instrument
4.2.1
Electricity
4.2.1.1 Voltage levels ¬1
Frequency
:
50 Hz
Ø2 Incoming Power
:
132 kV, 3 Phase, 3 Wires
Ø3 Medium Voltage (MV) Distribution
:
6.3 kV, 3 Phase, 3 Wires
Ø4 MV Motors
:
6.3kV, 3 Phase (P>=200kW)
Ø5 Low Voltage (LV) Distribution
415V, 3 Phase+PE
:
Ø6 LV Motors
400V, kW)
3
Phase+PE,(P<200
Ø7 VVVF Motors
6.3kV or 400V, 3 Phase+PE,
Ø8 Uninterrupted Power supply
:
230 VAC, 1 Phase+N+PE
Ø9 Lighting and Socket
:
400/230 VAC, 1 Phase+N+PE
Ø10
Maintenance Lighting Voltage
:
36/12 VAC
Ø11
Control Circuit for HV and MV Switchgear
Ø12
Control Circuit for LV Switchgear & MCC
:
220V, 1 Phase
Ø13
Instrumentation
:
220V, 1 Phase/24VDC
Ø14
Digital Inputs and Outputs
:
24 VDC
Ø15
Analog Inputs and Outputs
:
4-20 mA
4.2.1.2
:
110 VDC
Power supply It is assumed that 132kV incoming overhead line has transmitted to the main substation of the plant, which is excluded from the scope of the Contractor.
4.2.1.3
Main power station 132Kv/6.3kV indoor main power station will be setup for the 5000t/d production line. The capacity of the 132/6.3kV power transformer will be selected 2x20000KVA for ONAN with on-load changer automatic. The several 6.3kV switchgears will be located 6.3kV power distribution room of the main power station which will be feeding power to the local substation. SF6 Gas circuit breaker of 132kV will be adopted.
4.2.1.4
6.3kV Local Distribution Station According to the layout, there will be six 6.3kV local distribution stations respectively located at limestone crushing, raw material grinding, preheater, cooler, coal and cement grinding. 6.3kV power is led from the main substation. Each distribution station will supply power for MV equipment (MV motor, department distribution transformer etc.). The 6.3kV switchgear type will be Air Insulated Metal clad Switchgears.
4.2.1.5
Reactive Power Compensation
In order to reduce power transmission losses and to save capacity of transformers, cables, etc., the compensation equipment shall be designed to apply directly at the source. The capacitors are used to compensate for the reactive power of the main transformer. The large constant speed motors equal to or above 400kW shall be equipped with adequately sized individual capacitor banks connected to the motor feeder. The LV main distribution boards shall be equipped self-adjustable reactive power compensation. Corresponding capacitors banks shall be located in the separated cabinet. The improved power factor shall be over 0.95 4.2.1.6
Protection and Measurement The comprehensive protection devices have following functions: 1 6.3kV incoming line protection: three phase timing over current, over current trip, single-phase earthling. 2 Main transformer protection: differential protection, timing over current, over current trip, overload, gas and temperature protection, single-phase earthling. 3 6.3kV incoming line protection: three phase timing over current, over current trip, single-phase earthling. 4 6.3kV motor protection: inverse over current, over current trip, under voltage and single-phase earthling. 5 Capacitor compensator protection: three phase over current trip. 6 The protection system will be SIEMENS / ABB make. 7 Medium voltage protection will be preferably MRM make SEG Germany
4.2.1.7
Emergency Power 800kW/415VAC/50Hz emergency power supply shall be fed to cooler electrical room for safety of the equipment during a power failure.
4.2.1.8 LV distribution The low voltage power distribution shall comprise the following basic equipment: 8 9 10 11 12 13
Incoming circuit breaker with protective relaying Outgoing feeders for capacitor banks Outlets for auxiliary power distribution (i.e. lighting) Outgoing feeder to cranes Outgoing feeder to welding power switch Spare outlets for future use
The panels shall be of a strong steel construction, metal enclosed, free standing. The protection degree shall be IP40. 4.2.1.8.1 LV Distribution Electrical Room and Motor Control Centers (MCC) The electrical rooms are as follows: ℃
Limestone crushing electrical room Power supply scope: 14 Limestone crushing • Limestone storage & reclaiming
℃
Clay, Coal, Bauxite and Laterite Crushing Power supply scope: • • •
℃
Clay, Coal, Bauxite and Laterite Crushing Auxiliary material preblending Raw coal Preblending
Raw material proportioning Power supply scope: •
℃
Raw material proportioning hoppers
Raw material grinding electrical room Power supply scope: • • •
℃
Raw material grinding Exhaust gas treatment Top of raw meal silos
Pre-heater electrical room Power supply scope: • • • • • •
℃
Bottom of raw meal silos Raw meal feeding system Pre-heater Kiln Compressor air station Central control room (spare power supply)
Kiln cooler electrical room Power supply scope: • • •
℃
Cooler Central control room Top of clinker storage
Coal grinding electrical room
Power supply scope: • ℃
Coal grinding
Cement grinding electrical room Power supply scope: • • • •
℃
Cement grindings Bottom of clinker storage Top of Cement Silo Gypsum crushing
Packing plant • • •
Cement packing Bottom of cement silos Bulk cement loading for truck
4.2.1.8.2 MCC Control Signals 15 Protective motor interlocking is hard wired to the main contactor 16 All other interlocking are realized by means of the PLC 17 All signals are collected at the module 18 Basic Signals Circuit breaker status, voltage and overload control DI; ² ² Main contactor status DI; ² Start command DO; Local start command DI; ² Local stop command DI; ²
4.2.1.8.3
Local Control Switch Box All push/ pull buttons for process motors, valves, dampers, gates, solenoids etc. will be located near the field equipment for local control of equipment. Emergency stop will be arranged for MV motors. Push buttons for start/stop, position, etc., shall be clearly and permanently marked, equal in whole plant. The degree of protection for local control box is IP54.
4.2.1.9
Motor 1) Motor selection and starting Motors with a power capacity of equal and above 250 kW will adopt 6.3kV, below 250 kW will be 415V. According to start-up condition, the wound rotor winding motor and squirrel-cage motor should be adopted. MV motor will be ABB/SIEMENS make and comply with IEC standard. MV motors will be totally enclosed, dust proof, with forced
cooling and air to air-cooling type having Insulation class F & protection class IP 54. The accessories such as winding temperature monitoring , bearing temperature monitoring , anti-condensation heater are included for MV motors. Liquid Starter for the MV motors will be of European origin equipped with temperature limit observation devices, liquid level detector and automatic setting range limiting; the squirrel-cage motor less than 75kW will be directly started under rate-voltage; the LV motor equal and above 75kW shall be started by soft starter. 2) Speed regulation motor and its control Large drives will be MV frequency drives. All the variable drives will be Master Drives (Victor Control) Siemens Germany make. Motors for larger variable speed drives & kiln drive will be ABB / Siemens make. Input Reactor & Output Reactor for > 100 Kilowatt rating will be incorporated in the drive. Drive of Classifier will be equipped with Brake Resistors. For larger drives like Pre-heater ID Fan drive and Kiln DC drive etc. separate (isolate ) transformer will be used. 3) The basic technical specification · severe
duty, continuous maximum running duty of S1 in accordance with IEC 34 • motor insulation shall be “Class F”, with temperature rise limited to “Class B” (80 oC), in accordance with IEC 85 • The terminal box shall be IP54, equipped with feeder cable glands with grounding conductor. • For motors rated 500 kW and above: 6 x PT100. • Degree of Protection for MV motor is IP54 • Degree of Protection for LV motor is IP54 4.2.1.10
Cabling
4.2.1.10.1 Cable installation Cable installation is on cable trays. Power and signal cables on the cable trays will be separated. Cable tray constructions, supports etc., will be hot dip galvanized.
4.2.1.10.2 Cable types The main characteristics of the cable are indicated below: General data (MV cable) Type Multi-core screen Rated voltage 6kV Insulation XLPE Minimum section power circuits 50 mm 2 Conductor Copper General data (LV cable) Type 0,6/1 kV multicore Rated voltage 0,6/1 kV Insulation PVC Minimum section for power circuits 1,5 mm 2 Minimum section for auxiliary 1,5 mm2 circuits Minimum section for control circuits 1,0 mm 2 Conductor Copper The cable laying outdoors within the plant is done by cable tray. The laying of cable trays may go along the process pipeline or belt conveyor corridor to save investment. 4.2.1.11 Thunder Protection and Earthing The thunder and earthing protection of this project is done according to the regulations of the state thunder protection. All the earthing units for the whole plant shall be connected into an earthing network by copper flat strip or copper conductor. Double earthing of all the electrical equipment (transformers, panels, motors) will be done. 4.2.1.12
Lighting System Lighting intensity levels are indicated in the following table. The lighting intensity is measured in lx (Lux).
Area Plant Roads Open Yard, Conveyors, Platforms Remote controlled process areas Staircases, walkways Electrical Equipment Rooms Central control room Stores for various diverse goods Continuously occupied working places in process area
Lighting Intensity 20 lx 30 lx 50 lx 50 lx 150 Lux 300 lx 100 lx
High Pressure Sodium High Pressure Sodium High Pressure Sodium Mercury-vapor Lamp Fluorescent Fluorescent Mercury-vapor Lamp
100 lx
High Pressure Sodium
Method of Lighting
Some of lights will be with battery pack for emergency lighting in substations and electrical rooms. Lighting fixtures outdoor is IP65 4.2.1.13
Maintenance Power Supply Socket outlets will be provided at strategic locations throughout the plant and shall comprise: Three phase outlets for welding machine as well as for portable machines application, 3 pole + E, rated for 63 A Single phase outlets, 2 pole + E, each rated for 16A with residualcurrent circuit breakers.
4.2.2.1
Instrumentation
4.2.2.1
Instrument Requirements
• All
housings for instruments located outside of the electrical equipment
room shall be minimum IP65. • All
transmitters shall be of electronic design with electronic analog output,
similarly final control elements shall respond to electrical analog signals. • Analog
Electronic Signals: 4-20 mA DC
Electrical & Control part of the weighing system should be of Schenk make. Damper actuator for big fans should be from ABB/ Siemens and small fans from Youkogawa /Yamato Japan Infrared Pyrometer of reputed Western make shall be provided for the
monitoring of the following temperature. 19 Kiln – Burning Zone 20 Kiln Back End 21 Clinker cooler ( at inlet) 22 Clinker cooler ( at out let)
4.2.2.2
Field Instrument According to the requirements for process production it is necessary to have measuring units as for temperature, pressure, flow rate, level, speed and so on to detect and monitor the production situation of the process line and equipments.
4.2.2.3
Instrumentation Selection
• Speed • Limit
Monitor will be proximity switch, 2-wires.
Switch will be proximity switch with plastic enclosure and fast
connector, 2-wires. • Pressure
Transmitters will be diaphragm type, the accuracy of the
transmitter will be within 1 % of full scale with less than 0.1 % resolution. 2-wires. • Temperature ″
Thermocouples will be flanged with an adjustable setscrew and type K.
²
RTD ' s will be 3-wire type with 100 Ohm platinum PT.
²
Temperature transmitter will be linearizing programmable type. They will have a 0.2 % resolution and a repeatability of < 0.5 %.
Flow ²
Flow meters. The accuracy will be < 1 % of full range.
²
Electromagnetic type will be used for liquid; the accuracy will be ± 0.5%.
· Level
for continuous indication
″
Load cells
²
Radar measurement
²
Ultra sonic
· Level
switches
Capacitor type Field devices and instrumentation shall be of proven design. All the ″
instruments like Pressure Transducer, Diff. Pressure Transducer, Resistance Thermometer, Convertor,
Current
Speed
Transducer,
Sensors, V/I Power
Convertor,
Transducer,
Pull
R/I Cord
Switches, Drifft Switches & Thermocouple will be of Siemens, Fuji, Phoenix, Telemechanic or E&H make. Level measurement sensors and Transmitter will be of E&H make of western origin. 4.2.2.4
Gas Analyzers Gas analysis system will be of integrated design, purpose built for each specific application. Including Sample probes and interconnecting pipe work, fittings, gas processing equipment, etc.
Gas analyzers shall be provided as follows: Gas Analyzer Type Oxygen (O 2) Paramagnetic Carbon monoxide (CO) Non-dispersive infra-red absorption Nitric Non-dispersive ultra-violet The gas processing and analysis equipment will be housed in sheet steel cubicle enclosures for local mounting. Gas Analyzer System including Analyzer and sampling system will be from Fuji – Japan at following locations:i)
Kiln Inlet for measurement of CO, O2 & NoX components.
ii) Precalciner Outlet for measurement of CO, O 2 & NoX componenets iii) EP Inlet for measurement CO,CH 4 & O2. iv) Coal mill for measurement of CO & O 2.
4.2.2.4.1 Kiln inlet Gas Analyzer As per the specification mentioned in the annexure (electrical & I & C) 4.2.2.4.2 EP of kiln system, Coal Meal Bin Gas Analyzer As per the specification mentioned in the annexure (electrical & I & C) ‘4.2.2.5 Kiln Shell Temperature Measurement Kits (Kiln-shell Infrared Temperature Scanning) system analyze and process kiln shell temperature data, which collected by infrared temperature detector, indicate the distribution of surface temperature as well as more important information in form of image and data accurately, quickly and intuitively. Scanner should be of from reputed Western origin with KMS software. 4.2.2.5.1 Hardware Configuration ·
DELL GX260
• CPU℃Pentium
IV 2.4MHz and above.
• Memory ℃512MB • Hard
and above.
Disk℃40GB and above.
• 21”CRT • Display
Card ℃ AGP (can display 24bits real color).
• Network
Card℃Ethernet card with BNC connector.
• Operation
System ℃Windows NT Workstation.
4.2.2.5.2 Software Functions • Temperature • Two
Distribution Image
Dimension Image
• Three
Dimension Image
• The
Temperature Max, Min and Average Curve of Kiln Radial Line
• The
Temperature Curve of Kiln Radial and Axial Line
• Point • Kiln
Temperature
Shell Surface Temperature Zones Setting And Temperature Alarm
Limits Setting • Alarm • Kiln
Information Form
Radial and axial Direction Cutaway View
• History
Record Browse
• Temperature • Image
Print
• Password • Online
Setting
Help
• Assistant
4.2.2.6
Distribution Image Zoom View
Function
CCTV System It shall be with PC based digital processing system for monitoring of operation at following locations. The Camera should be with industrial housing. 07 No’s Colour Monitors 25” 01 No. multiplexing system. 02 Nos. Moving Camera’s at Raw meal Stacker / Reclaimer yard. 02 Nos. Moving Camera’s at Coal handling Stacker / Reclaimer yard. 01 No.
Fixed Camera at Raw meal weigh feeders.
01 No.
Moving Camera at Kiln exhaust.
02 Nos. High temp. Camera’s at Kiln outlet hood and Cooler 01 No.
Fixed Camera at Coal mill weigh feeder.
01 No.
Fixed Camera at Cement mill weigh feeder.
01 No.
Fixed Cameras at each loading bay at Packing plant.
4.2.3
Process Control System
4.2.3.1
Description of the Process Control System The DCS configuration will be designed and made with most famous brand products in the world, such as or SIEMENS-SIMATIC PCS7, or ABB-industry-IT etc.
4.2.3.2
Network Concept and Hardware Specification This DCS system is very distributed, and all computers and controllers are linked together via several kinds of communication network. The network of whole system consists of 3 communication layers. 23 The top layer is high speed Ethernet ring, It’s information
backbone, and it’s communication route way between PLCs & HMI. This architecture is an open system, could be easy connected to other system. 24 The middle layer is real time token network Field Bus (such as:
Modbus Plus, Devices Net or Profibus). It’s transfer commands, I/O states rapidly between controller and field I/O. 25 The bottom layer is Remote I/O bus. It’s a simple bus way to be
configing and extending with 10% spare capacity. 4.2.3.3
Specification of the Process Control System
4.2.3.3.1
Process Station The offered process station system for the entire plant is based on decentralized PLC system and distributed remote I/O modules for motor control, alarm handling and loop control. According to the production department arrangement in General layout, the system configuration as:
26 PLC1 - Limestone crushing
Comprising: 1- PLC- processor placed in limestone crushing electrical room. 1- Lot of control cabinets, incl. Internal wiring and power supply 1- Lot of I/O racks. 1- Set of digital input modules, 16 channels, 24 VDC 1- Set of digital output modules, 16 channels, 24 VDC (relay contract) 1- Set of analog input modules, 8 channels, 4-20mA 1- Set of analog output modules, 4 channels, 4-20mA 1- Set of remote I/O modules placed separately in Clay Crushing electrical room 1- PC Computer operator workstation Each PC is equipped with Pentium IV processor, 512 MB memory, 40GB hard disc capacity, CD-ROM drive, , 21 ″high resolution (1024 ×1280)
color monitor, keyboard, monitor, keyboard, mouse, Ethernet
controller, 1- Event/Alarm report printer 27 PLC2 - Raw meal grinding
Comprising: 1- PLC- processor placed in raw mill electrical room. 1- Lot of control cabinets, incl. Internal wiring and power supply 1- Lot of I/O racks. 1- Set of digital input modules, 16 channels, 24 VDC 1- Set of digital output modules, 16 channels, 24 VDC (relay contract)
1- Set of analog input modules, 8 channels, 4-20mA 1- Set of analog output modules, 4 channels, 4-20mA 1- Set of remote I/O modules placed separately in Raw material proportioning hoppers electrical room 28 PLC3 - Preheater and kiln system
Comprising:
1- PLC- processor placed in raw mill electrical room. 1- Lot of control cabinets, incl. Internal wiring and power supply 1- Lot of I/O racks. 1- Set of digital input modules, 16 channels, 24 VDC 1- Set of digital output modules, 16 channels, 24 VDC (relay contract) 1- Set of analog input modules, 8 channels, 4-20mA 1- Set of analog output modules, 4 channels, 4-20mA 29 PLC4 - Clinker cooler system
Comprising: 1- PLC- processor placed in raw mill electrical room. 1- Lot of control cabinets, incl. Internal wiring and power supply 1- Lot of I/O racks. 1- Set of digital input modules, 16 channels, 24 VDC 1- Set of digital output modules, 16 channels, 24 VDC (relay contract) 1- Set of analog input modules, 8 channels, 4-20mA Set of analog output modules, 4 channels, 4-20mA 30 PLC5 - Coal grinding Comprising: 1- PLC- processor placed in raw mill electrical room. 1- Lot of control cabinets, incl. Internal wiring and power supply 1- Lot of I/O racks. 1- Set of digital input modules, 16 channels, 24 VDC 1- Set of digital output modules, 16 channels, 24 VDC (relay contract) 1- Set of analog input modules, 8 channels, 4-20mA 1- Set of analog output modules, 4 channels, 4-20mA 31 PLC6 - Cement mill system Comprising: 1- PLC- processor placed in raw mill electrical room.
1- Lot of control cabinets, incl. Internal wiring and power supply 1- Lot of I/O racks. 1- Set of digital input modules, 16 channels, 24 VDC 1- Set of digital output modules, 16 channels, 24 VDC (relay contract) 1- Set of analog input modules, 8 channels, 4-20mA 1- Set of analog output modules, 4 channels, 4-20mA 32 PLC7 - Cement packing system Comprising: 1- PLC- processor placed in raw mill electrical room. 1- Lot of control cabinets, incl. Internal wiring and power supply 1- Lot of I/O racks. 1- Set of digital input modules, 16 channels, 24 VDC 1- Set of digital output modules, 16 channels, 24 VDC (relay contract) 1- Set of analog input modules, 8 channels, 4-20mA Set of analog output modules, 4 channels, 4-20mA 1- PC Computer operator workstation Each PC is equipped with Pentium IV processor, 512 MB memory, 40GB hard disc capacity, CD-ROM drive, , 21 ″high resolution (1024 ×1280) color monitor, keyboard, monitor, keyboard, mouse, Ethernet controller, 33 Event/Alarm report printer 4.2.3.3.2
Operator Station One operator computer hardware system, for operator humanmachine interface and for central control of main machineries/departments, located in the central control room, consisting of: 34 PC computer Server stations (redundant data servers). Each PC is equipped PIV/4G CPU,512M RAM,80G HARD DISK,48xcd,100M Ethernet Card, 8 GB tape backup unit , 21 ″high resolution (1024 ×1280) color monitor,32M DISPLAY ADATPTER, keyboard, mouse. 1set -Network equipment 4 - PC Computer operator workstations Each PC is equipped with Pentium IV processor, 256 MB memory, 40GB hard disc capacity, CD-ROM drive, , 21 ″high resolution (1024 ×1280) color monitor, keyboard, monitor, keyboard, mouse, Ethernet controller, 1- HP Laser 1300 1- Event/Alarm report printer 35 Hard copy HP 3820c
4.2.3.4
Functional Description The process control and automation system comprise of operator workstations for the man-machine interface and programmable logic controllers (PLC’s) for motor control and alarm handling, loop control and process value acquisition. Production management information system and kiln control system(KCS). A. Operator stations The basic functions are as follows: 36 Supervision 37 Control 38 Alarm-handling 39 Reporting
All these functions can be performed via any of the operator workstations. For each plant department, the following screens are defined: 40 Mimic displays: 41 42 43 44 45 46 47 Start-Up displays: 48 PID loop displays: 49 Alarm/event Surveys: 50 Trend curves: 51 Reports: 52 On-line creation and modification of screens, reports and trend curves groups.
B. Engineering workstation The basic engineering includes the choice and configuration of the hardware, its interconnection and start-up, the installation of the software modules, and the tests for correct operation. The application engineering includes programming of the software modules in accordance with the project requirements and with the available plant specifications, as well as all corresponding tests. For each department, it consists among others of: 53 Creation of system data base. 54 Creation of process displays. 55 Creation of start-up displays.
56 Dynamic animation of displays for start/stop sequences, PID loop, analog and digital values. 57 Configuration of alarms. 58 Configuration of trend curves. 59 Configuration of reports.
C. Process Station (PLC) The basic functions are as follows: 60 Motors & devices control (individual & group) 61 Process values acquisition 62 PID loops 63 Alarm handling 64 Communication with operator station 65 Communication with other PLC’s Note: The automation system will be as per specifications mentioned in the Annexure (electrical, I & C)
4.2.4
Quality Control System
4.2.4.1
General The automatic quality control system TRAWMIX consists of: 66 Automatic continuous sampling with manual transport system for raw meal. 67 Semi-automatic sample preparation in the laboratory with manual insertion into the X-ray analyzer. 68 Automatic analyzing of the samples in a multi-channel X-ray fluorescent quantometer 69 Automatic quality control of raw meal including calculation of raw materials and on/off-line setting of the weighing feeders of the raw material grinding plant.
The samples of raw meal and kiln feed shall be carried by manually to the sample preparation room. The supplied equipments and software shall have enough capacity with flexibility and easiness for the expansion of production line in future. 4.2.4.2
Automatic Sample Analyzing System The automatic sample analyzing system shall consist of:
4.2.4.2.1
Simultaneous X-Ray Analyser The X-ray analyzer shall be included X-ray florescent quantometer. The model of X-ray analyzer shall be Shimadzu XRF & XRD or PHILIPS twin type Cubix.
Description of PHILIPS twin type Cubix: 70 Cubix FAST XRD for cement
Complete ultra fast industrial XRD system consisting of console, fast sample loader, high precision sample spinner, Ni filter, to sets of PW 1812/35 press rings, programmable divergence slits, 0.04 rad soller slits, X’ celerator detector, X’ pert industry, profit software & X’pert high score software (with complete pakage). 71 Cubix-CEM XRF cement Package
Compact cubix 14 Channel x-ray spectrometer with sample surface up, equipped with fixed Channels for Na, Mg, Al, Si, S, K, Ca, Fe & Cl. The package includes detector gas system, SuperQ analytical software and internal cooling system (with complete pakage). Main components shall be including: Multichannel spectrometer unit X-ray tube X-ray generator Vacuum system X-ray tube cooling water system Pneumatic system 9 fixed measuring channels for elements Si, Al, Fe, Ca, Mg, K, Na, S, Cl 79 Pre-calibration standard reference sample for the 9 elements. 72 73 74 75 76 77 78
4.2.4.2.2
Laboratory Computer 1 - PC Computer is equipped with Pentium IV processor, 256 MB memory, 40GB hard disc capacity, CD-ROM drive, , 17 ″high resolution (1024 ×1280) color monitor, keyboard, monitor, keyboard, mouse. 80 Printer HP 1300
4.2.4.2.3
Software Package for Automatic Sample Analysing
″
² ²
Including: 81 Communication with X-ray florescent spectrometer for automatic adjusting, starting, supervision of analysis operation. 82 X-ray florescent spectrometer re-calibration, including graphical editing facilities, stability and calibration reports. 83 Analysis 9 specific elements for cement applications chosen from Si, Al, Fe, Ca, Mg, K, Na, S, Cl etc. following calculation facilities: linear or quadratic calibration equations. line overlap correction. drift compensation.
²
4.2.4.3
inter-element matrix corrections. Proportioning Control The proportioning controls will based be used automatic controlofofrawthe raw-mix chemical composition onfor periodical analysis mix samples compositions. Feeder set-points shall be calculated for on-line control to achieve optimization of the composition of the raw mix.
4.2.4.3.1
Function Function of the proportioning control system 84 Determining the quality of raw meal e by continuum accumulate of the batch quantity of raw materials 85 Product Statistic and administer 86 Recording the actual quantity of the feeder 87 Automatically calculate the ratio between feeders 88 Automatically receive analysis result from X-ray florescent spectrometer 89 The new feeder set-points shall be positioned automatically by the system or manually by the operator 90 real time PI control 91 batch quantity revising control
4.2.4.3.2
Specification 1 - PC Computer PC is equipped with Pentium IV processor, 256 MB memory, 40GB hard disc capacity, CD-ROM drive, , 21 ″high resolution (1024 ×1280) color monitor, keyboard, monitor, keyboard, mouse, Ethernet controller, 1- HP Laser 1300
4.2℃ 5
Intercommunication System 01 No. PABX200 digital lines telephone exchange (internal) with 15 external lines (Siemens make). Adequate public address system and paging system will be provided. One high power master set with 30 sets of hand walkie talkie for Intercommunication between the different plant sections
4.2.6
Analysis of Standard Samples 1Set of 60 standard samples for calibration of XRF & XRD will be prepared by BCL & analyzed by CBMC from any international Lab like FLS (Denmark).
4.2.7
PLC Software Back UP The password, Licence & back up of application software used for all PLC system and programmable remote PLC’s will be provided, for any rare case, if it can not be provided, then the back up programmed PLC will be provided as spare.
4.3 4.3.1
Introduction of Main Equipment Technical Description of Preheater and TSD Precalciner In the end of 1980s, TCDRI imported DD-furnace technique from KOBE Steel. After carefully study, absorbing latest big eddying flow and low pressure drop technique, TCDRI developed the new preheater and pre-calciner system and used them for 2000t/d ~ 10000t/d cement production line from then on. The cyclone of preheater developed by TCDRI has the characteristics of high efficiency and low pressure drop. The cyclone outlet diameter - effective diameter ratio is bigger than normal type, which insures lower outlet velocity thus reduce pressure drop under same cyclone-section velocity. There is a slope at the inlet of the cyclone which can reduce raw material pilling up, at the same time, this slope can guide the raw material to get a higher separating efficiency. The structure of the cyclone is simple which reduce failure possibility. The immersion tube is round style and is hanged up at the roof of cyclone. The immersion tube is composed by many pieces of heat-resistant steel plate or casting steel component. Flap valve is used for air-locking in the material chute of each stage cyclone. The shaft of the valve is supported with 2 SKF roller bearings at both sides, which make the flap swing flexibly. There is a cover on the casing of the valve behind the flap shaft, so that the flap with shaft can be drawn easily when removing the cover for maintenance. The furnace is the key part of the pre-calciner system. There are many processes such as fuel combustion, carbonate calcining, transporting of raw meal and air, etc. proceed in the furnace. For the low volatile ingredients coal fuel, we add a pre-combustion chamber before the pre-calciner to extend retention time of coal powder. The tertiary air drawn from the kiln hood has high oxygen content and high temperature. The temperature is above 900 ℃ at the inlet of the pre-combustion chamber. The tertiary air comes into pre-combustion chamber from tangential direction. The raw material from C4 cyclone is fed into the pre-combustion chamber from the roof of its tertiary air inlet, this position is far from the burner so that the coal powder can reach high firing temperature. The coal power, raw material and high temperature tertiary air are mixed sufficiently at the bottom of precombustion chamber before going into main pre-calciner. The retention time of the TSD Pre-calciner can reach about 6s. Raw meal shall be fed into C2-C1 gas duct and pass through C1, C2, C3, C4 and related connection gas ducts to be heated. The heated material is fed to TDF Calciner from C4 discharge outlet. Fuel is spouted to the firing zone of TDF calciner through two horizontal spray nozzles and the tertiary air from kiln hood also flows into this
zone through two symmetry inlets. Meanwhile, the high temperature waste gas from kiln end forms a boiling layer going through the beading between the calciner and the kiln inlet chamber to enter firing zone, which makes the fuel oil be gasified, calcined and quickly burnt in this zone and enter the main burning zone, where the heat is fast transfered to raw meal. After that, they enter the fully burning and calcining zone where the raw meal is calcined rapidly. Before the raw meal arrives at the inlet of C5 cyclone, the fuel oil/natural gas is completely burned out and the raw meal calcining rate reaches 90% or more. Inside the whole TSD calciner, fuel oil/natural gas, high temperature gas and raw meal are always doing the disorder movement through the ways spraying and striking from beginning to end that promotes the gas and the meal to be mixed better in order to improve heat sufficiently. At last, meal enters the kiln inlet chamber to be fed into the rotary kiln by going through the discharging device under C5 cyclone. During the process in pre-calciner, the raw meal moves from lower to upper, and they exchange heat sufficiently at the same time. In addition, a part of waste gas coming from the outlet of C1 cyclone is through the waste gas duct conveyed to the raw mill to be used as the heat source for drying raw material.
4.3.2
Technical description of TC Aeration Grate Cooler
4.3.2.1
Grate Plate The key technology of TC Aeration Beam Grate Cooler is TC Aerated Grate Plate (Patent License: ZL99205461.3) and TC High Resistance Grate Plate (Patent License: ZL99205460.5). The TC Aerated Grate Plate is used in the high temperature zone. This Grate plate is made of entire casting heat resistant steel to Resist Thermal Deformation. The Special Designed Air Stream Channel and Outlet of the Grate Plate get high outlet air velocity and high resistance. High outlet air velocity can separate the fine clinker up to the top of the clinker bed, extend the thermal exchange way and time, remove Red River. High grate plate resistance can buffer the resistance vary of the clinker bed which is caused by the thickness of clinker bed or clinker grain size. The air channel is labyrinth type which avoids leakage of clinker. TC High Resistance Grate Plate is used in the middle-high temperature zone. This grate plate is made of entire casting heat resistant steel to Resist Thermal Deformation too. The major pressure drop is distributed to high resistance grate plate to minimize the influence of the clinker uneven distribution. The air stream channel is labyrinth type too to reduce leakage of clinker. This grate plate uses chamber aerated which insure good cooling effect.
4.3.2.2
Grate The grate of TC Aeration Beam Grate Cooler is composed with TC Aerated Grate Plate and TC High Resistance Grate Plate. At the quench cooling zone and the thermal recovering zone, the TC Aeration Beam Device is adopted, among which the first 5 row are fixed aeration beam, after that there are 4 rows movable aeration beam and then is resistance grate. This arrangement can get high cooling efficiency and high thermal recovering efficiency and remove red river. We’d like to point out that the Fixed Aeration Beam Device used at the inlet of the cooler can decrease the failure rate dramatically. The service life of the TC Aeration Grate Plate and TC High Resistance Grate Plate is more than 2 years at normally operation. At the first chamber of the 2nd grate, there is also TC High Resistance Grate Plate and after which there is normal grate plate. The designed thickness of clinker bed is 600-700mm. Increasing the thickness of clinker bed can extend the thermal exchange time and increase the contact area between cooling air and clinker. So we can get a good cooling result and high secondary air temperature.
Normally the secondary air temperature can reach 1000-1050oC when the tertiary air is also drawn from the kiln hood. A thick clinker bed can also provide a cold clinker layer which can prevent the direct contact of hot clinker and grate plate thus protect the grate plate 4.3.2.3
Air Tight Device Good air tight device guarantees that the cooling air is used efficiently with a rational cooling air ratio. A movable air duct is adopted for the movable aeration beam and the sleeve sealing of this duct which has the characteristic of high reliability and maintenance convenience. A clinker hopper with electric air tight valve in the aeration chamber lays under grate to collect leaking clinker. In this hopper, the level of leaking clinker was detected by a detector and this detector can control the valve opening and closing intermittently to keep leaking clinker at a proper level to get a good air sealing effect.
4.3.2.4
Air Cannon Device To prevent the Snow Man, air cannons are installed on the front end wall above the fixed aeration grate. These cannons can be set to work in sequence.
4.3.2.5
Automatic Control for Grate Cooler Three-component control system is installed in TC Aeration Beam Grate Cooler. Automatic control can ensure effective, stable and safe operation of grate coolers. It is required that automatic control systems use corresponding variables of meter loop during process to implement control of related equipments. The content of the threecomponent control is as follows.
4.3.2.5.1
Control Loop for the Cooler Grate Drive It is necessary to keep stable clinker thickness on grate plate as designed thickness to achieve designed cooling efficiency and thermal recovery rate. Because material entering into grate cooler is waved, it is necessary to adjust travel velocity to get stable material thickness. That is, accelerate speed as the material get too thick or reduce speed as the material get too thin. The air pressure in the 2nd cooling air chamber of the first section is taken as monitoring and controlling conditions. The pressure shows the clinker bed resistance under a certain volume of air, high pressure means strong clinker bed resistance (clinker bed is thick or clinker is fine and dense); or vice versa. The reason why the second chamber of the first section is taken as monitoring basis is that the first compartment of this section is opposite to feed point, so it is not suitable to take first compartment as monitoring basis because of big disturbance of material bed and irregular wave of pressure. TC Aeration Beam Grate Cooler is equipped with DC motor or VFD motor which is used to control
driving speed of grate bed. Rectifying thickness of material bed can get the purpose of keeping certain resistance under a certain volume of air. 4.3.2.5.2
Control Loop for the Automatic Air Flow The cooling air flow that the grate cooler needs shall vary according to material amount and temperature. Under previous stated automatic control condition, the material bed resistance should be stable. To achieve this goal in complicated working condition, cooling air flow must be controlled automatically for cooling material, heat recovery and grate components protection.
4.3.2.5.3
Control for Excess Air (kiln hood draft control) During clinker cooling, cooling air becomes hot air, the hot air drawn from cooler by negative pressure at kiln hood will go into kiln as secondary air. The secondary air flow is influenced by negative pressure at kiln hood. Usually, the cooling air is more than required, so an exhaust fan is used to release surplus air. To ensure proper secondary air flow for kiln, negative pressure at kiln hood must be stable and the surplus air will be released base on required negative pressure value. The control method is as follows: The pressure in kiln hood is taken as monitoring condition. Holes connecting to pressure sensor are opened on hood for pressure measuring. The set range of negative pressure at kiln hood is –10~+2.5mm WG column. When kiln and grate cooler are in good operation condition, the negative pressure at kiln hood shown by controller is mini negative pressure near zero; this mini negative pressure can be taken as set value going into automatic control. The surplus air released by exhaust fan will be controlled by electrical damper. If the negative pressure at kiln head is more or less than the set value, the damper actuator will adjust open-limit base on control signal, thus keep the kiln running smoothly.
4.3.2.6
Hammer Crusher The hammer clinker crusher is set at the discharging end. Clinker of small particle size (<=25mm) is discharged on the clinker conveyor through gird bar. Blocks of clinker are fell into the crusher and thrown on the grate to be cooled and crushed until it meets the requirements. Impact plates are set at both sides and top of the crusher. The crusher driven by belt adopts AC motor whose installed power is 55kW, and the guarantee service life of the hammer is more than 10 months at normally operation.
4.3.3
Brief Introduction to Ø4.8x72m Rotary Kiln
Rotary kiln is one of the most important equipment in the cement process. The kiln with the capacity of 5700+6.14%t/d developed by TCDRI is designed on the basis of the situation and feed back of many kinds of rotary kilns in use, applying latest technology and manufacturing method. The rotary kiln is comprised of main kiln body and accessory equipments. The main kiln body includes kiln shell, three supporting devices, drive station and hydraulic thrust roller. The accessory equipment is consisting of kiln hood, air sealing device at kiln outlet and kiln inlet, main gear reducer oil line system and hydraulic oil feed station etc. Please refer to the following table for main technical specification. Technical Specification Diameter (m) Length (m) Capacity (t/d) Process Slope Number of Supporting Drive style
Total weight (t)
5700+6.14% pre-calcining 3.5% (sin) 3 single drive Main driving device (r/min) Auxiliary driving device (r/h) 831
4.8 72
0.396~3.96 11.45
The statements of the main parts of the rotary kiln are as the following: 1). Kiln shell The shell of kiln is rolled up with sheet of boiler steel No. 20g which has six mechanical characteristics and applies automatic welding while welding. Generally, the thickness of kiln shell is 28mm, and thickness at sinter zone is 50mm, the thickness under tyre is 75/80mm, the transition section between tyres is 42/55mm, therefore, the design of kiln shell is fairly reasonable, the rigid of cross section can be ensured and the bearing condition of supporting device can be improved as well. The heatproof and wear-resisting kiln nose retaining ring is respectively installed at the inlet and outlet of kiln shell. Of which, a divided sleeve space is consisted by kiln nose retaining ring and cold air sleeve. The cold air is sent into from the horn end of air sleeve and the non-work face of the kiln nose retaining ring is cooled so as to guarantee long term and safety operation of this part. There are three rectangular and solid tyres on the shell. The clearance between the tyre and the shell shim is determined on expand. When the kiln is normally operated, the tyres
can reduce the radial deflection of kiln body. In order to guarantee the reliable operation of the supporting device near the higher temperature kiln hood section, a special air-cooling device for shell is installed under the two tyres near kiln hood. 2). Supporting Device The kiln shell is supported by 3 supporting devices through the tyres and the correct Distribution of span between individual supporting points makes the design for supporting devices more reasonable. The sliding bearings are mounted in the supporting devices, which is lubricated by means of oil spoon. The cooling water device is installed inside the bearing and at the same time there is a temperature measuring instrument for every bearing. The working temperature of bearing bush can be checked in the central control room. A hydraulic trust roller is mounted at the supporting device near the kiln inlet to bear the downward force of the kiln and push the kiln to move upwards, therefore the kiln body can be forced move upwards in the required speed and slide downwards under controlling, so as to guarantee the average contacting of tyre and roller. 3). Driving Device Single driving is adopted, and the motor of driving device is a new type frequency conversion variable speed motor, and this motor’s start torque is 2.5 times to its rated torque, and the motor’s speed can vary from 100r/min to 1000r/min. The speed indicating generation is set at the rear of main motor to indicate the actual speed of kiln body. The reducer which matches with the main motor is a 3 stage hard tooth surface cyclindrlical gear reducer, which has a special concentration circular lubrication device with a heater for oil, so it can guarantee the oil line working properly in long term. The girth gear of kiln is fixed on shell by the tangential elastic plate. The girth gear and pinion is sealed by the gear case. The auxiliary drive connecting to the safety power supply and auxiliary drive power supply insures that the bearing operation of kiln can still executed when main power supply failed so as to prevent the shell from deformation and be convenient for inspection and maintenance. The elastic rubber coupling is used for the drive installation to increase the balance of drive. 4). Air Sealing Device at the Kiln’s Outlet and Inlet The cover and casing with labyrinth and spring shim air sealing is used for the kiln’s outlet, the cold air is sent into through the horn
