Production process of 5000tpd clinker cement


  Production Process

1. Limestone  Mine

  Limestone crushing adopts single-stage crushing. The limestone is poured  into the receiving hopper by the belt, and fed into a heavy-duty double-rotor  single-stage hammer crusher through a heavy-duty plate feeder of EBP2200-10.  When the feeding particle size is ≤1000mm, When the discharge particle size is  less than or equal to 25mm, the crushing capacity is 1200t/h. Since the raw mill  system is planned to use the vertical mill production process, the incoming  grinding particle size is required to be ≤80mm (≤85%), the crusher requires that  the discharge particle size can be relaxed to ≤75mm, and the crushing capacity  can be increased to 1500t/h. Heavy-duty plate feeder Feeding capacity≥1600t/h.  The crushed limestone is sent to the limestone pre-homogenization yard by the  belt conveyor.

  2.   Limestone pre-homogenization yard

  In order to homogenize and store limestone, a limestone pre-homogenization  yard with a diameter of 90m is set up. The total storage yard is 52,000t, the  effective storage is 47,000t, and the validity period is 7.4 days. One  cantilever stacker is used for stacking, and the stacking capacity is normal. It  is 600t/h, and the maximum can reach 800t/h. A bridge scraper reclaimer is  selected for sampling. The reclaiming capacity is normally 450t/h, and the  maximum can reach 550t/h. The homogenized limestone is sent to the conveyor belt  conveyor. In the limestone warehouse of the raw material batching station.

  3.  Sandstone crushing and conveying

  The forklift shovels the sandstone in the sandstone yard into the hopper in  front of the crusher. After the sandstone is screened, the small pieces are  directly sent to the auxiliary raw material pre-homogenization yard by the belt  conveyor, and the large pieces are crushed by the impact type hard material  crusher. Afterwards, it is sent to the auxiliary raw material pre-homogenization  yard by the belt conveyor for storage. When the incoming particle size is less  than or equal to 600mm and the discharge particle size is less than or equal to  25mm, the crusher capacity is 90t/h.

  4.  Auxiliary raw material pre-homogenization yard  and transportation

  The yard is a 30×180m long pre-homogenization yard. Clay, sandstone and  sulfuric acid slag are stacked by cantilever stacker in layers, and reclaimed by  side reclaimer. The extracted clay, sandstone and sulfuric acid slag are  respectively sent to the raw material mixing station by the belt conveyor. The  stacking capacity of the stacker is 250t/h, and the reclaiming capacity of the  reclaimer is 150t/h.

  5.  Raw material batching station

  The raw material distribution station is equipped with 4 round warehouses,  1 φ10×24m warehouse to store limestone, and 3 φ8×20m warehouses to store clay,  sandstone and sulfuric acid slag respectively. Each material is unloaded from  each warehouse in proportion by the quantitative feeder, and sent to the raw  material grinding mill by the belt conveyor. There is an electromagnetic iron  remover on the grinding belt conveyor to remove possible iron parts in the raw  materials. There is a metal detector at the head of the belt conveyor to detect  whether there are iron parts left in the raw material to ensure that the  vertical mill is not damaged.

  6.   Raw material grinding and waste gas treatment

  The raw material grinding adopts a vertical mill system, the production  capacity of this system is 400t/h, the fineness of the raw material is 80um  sieve residue <12%, the comprehensive moisture content of the grinding  material is <8%, and the comprehensive moisture content of the grinding  material < 0.5%.

  The raw materials from the batching station are sent to the vertical mill  for drying and grinding through the belt conveyor and the inlet lock air valve.  The coarse powder is returned to the mill for grinding again. The fine powder is  sent to the raw meal homogenization silo together with the kiln dust collected  from the electrostatic precipitator and the humidification tower through the  elevator and the air conveying chute as the finished product. When the raw  material mill stops grinding, the kiln dust can be transported to the raw  material feeding kiln system.

  The waste gas discharged from the preheater at the kiln end is sent to the  raw material mill as a drying heat source by a high temperature fan, and the  other part of the waste gas is sent to the humidification tower for cooling and  tempering, and then enters the electrostatic precipitator together with the raw  material mill waste gas for purification and then discharged into  atmosphere.

  The drying medium uses the exhaust gas discharged from the preheater. Part  of the exhaust gas from the mill is circulated into the mill after the powder  separator and cyclone separator, and the remaining part is sent to the waste gas  treatment electric precipitator. The normal emission concentration of the flue  gas treated by the electrostatic precipitator is less than or equal to 50mg/m3  (standard) When the moisture content of the dust collected by the humidification  tower is too large, the screw conveyor under the humidification tower is  reversed, and the moisture collected by the humidification tower is reversed.  The material is discharged from the other end.

  The raw material grinding system is equipped with an automatic continuous  sampling device. The sample is detected by X-fluorescence analyzer and the  mixing ratio of various raw materials is automatically controlled and adjusted  by the computer, so as to adjust the raw material ratio and ensure the qualified  chemical composition of the milled raw material. with stability. The raw  material grinding system is equipped with an auxiliary hot blast stove as a  backup heat source. When the raw material mill is not running, the exhaust gas  from the kiln tail is cooled and tempered by the humidification tower, and then  directly enters the electrostatic precipitator for purification. The normal  emission concentration of the flue gas treated by the electrostatic precipitator  is ≤50mg/m3 (standard).

  7.  Raw  meal homogenization and kiln feeding system

  A raw meal homogenization warehouse with a diameter of 22.5×52m is set up,  and the effective storage of the warehouse is 17000t. The silo is a central  cone-type multi-flow continuous homogenization silo, which makes the incoming  raw materials arranged in layers. There is an inflatable chute at the bottom of  the silo, which is supplied by a Roots blower. The annular space around the  conical shape of the bottom of the silo is divided into six large discharge  areas and 12 inflatable areas. Roots blowers take turns to inflate each area.  The material in the upper part of the inflatable area falls to form a funnel  shape, and at the same time, multiple layers of raw materials and raw materials  are cut. Multiple streams of material are formed at the discharge port, and the  material is discharged simultaneously through the two top discharge ports in the  center of the warehouse in turn. The raw meal out of the warehouse is sent to  the raw meal feeding and measuring bin through the flow control valve. The lower  part of the bin is equipped with a load cell and an inflatable device inside,  which integrates the functions of mixing, weighing and feeding. The raw meal out  of the mixing bin is measured by a solid flow meter and sent to the kiln tail  bucket elevator by an air conveying chute.

  8.   Clinker calcination system

  The clinker firing system is composed of rotary kiln, dual series 5-stage  low pressure loss cyclone preheater and NDF decomposition furnace. The daily  output of clinker is 4500 tons, and the heat consumption of clinker is  3178kJ/kg. clinker.

  The sintering process is briefly described as follows: the raw material  from the raw material homogenization warehouse is lifted by the bucket and sent  to the connecting air duct of the C1 and C2 cyclone cylinders, and is brought  into the C1 cylinder by hot air, and the material enters C1, C2, and C3  sequentially from top to bottom. , C4, decomposition furnace, C5 cyclone into  the kiln. The hot air flows from bottom to top and finally enters the high  temperature fan through the C1 tube.

  Part of the hot air from the high-temperature fan enters the humidification  tower, the other part is used as the drying heat source for the raw meal mill,  and finally enters the kiln tail electric precipitator and is discharged into  the atmosphere through the chimney. Clinker calcination adopts a φ4.8×72m rotary  kiln with three-speed support, the slope is 3.5%, and the rotation speed is  0.35~3.5r/min. The kiln head and precalciner are equipped with multi-channel  pulverized coal burners.

  In the 5-stage cyclone preheater, except for the C1 tube, the rest are all  low-pressure loss cyclone tubes. Under the condition of keeping the separation  efficiency unchanged, the resistance of the cyclone tube itself can be reduced  by 40%. The resistance of the entire pre-decomposition system including the  precalciner is controlled below 4800Pa. The ratio of coal used in the kiln and  the calciner is 40%:60%, and the temperature of the exhaust gas from the  preheater is 320-350℃.

  The easy-to-block parts of the preheater are provided with shovel cleaning  holes and air cannons, and the cone parts of the cyclones at all levels are  equipped with a double-ring compressed air purging system. Through the control  program, it can realize timing automatic purging, according to the blockage  signal, it can blow and clear the blockage by itself. When the blowing is  invalid, it will automatically alarm.

  9.   Clinker cooling

  Clinker cooling adopts a controllable airflow grate cooler, and the  temperature of the clinker out of the cooler is ambient temperature +65℃. In  order to crush large pieces of clinker, a hammer crusher is installed at the  outlet of the cooler to ensure that the particle size of the clinker out of the  cooler is less than or equal to 25mm. The cooled clinker is sent to the clinker  storage warehouse by the chain bucket conveyor.

  Part of the gas discharged from the cooler enters the kiln as the secondary  air at the kiln head, and part is sent to the kiln tail calciner through the  tertiary air duct. The heat source is dried, and the rest are discharged into  the atmosphere after being purified by the electrostatic precipitator. The  normal emission concentration of exhaust gas is ≤50mg/m3 (standard).

  10.  Clinker storage and transportation, clinker bulk

  Set up a φ45m clinker tent warehouse, the storage capacity is 52500t, the  effective storage capacity of the warehouse is 45000t, and the effective storage  period is 10 days. The characteristics of the library are low investment and  good heat dissipation effect, which is conducive to the improvement of clinker  strength.

  The cooled clinker is sent to the top of the clinker tent warehouse by the  chain bucket conveyor, and falls into the center cylinder of the warehouse.  There are 13 unloading points at the bottom of the silo, which are unloaded into  3 heat-resistant belt conveyors through the unloading equipment, and then merged  into the same belt conveyor to be sent to the cement batching station.

  The bulk clinker is loaded directly by the loader.

  11.   Coal pre-homogenization yard and pulverized coal preparation

  The raw coal is transported into the factory by car or train, stored in the  open coal yard, unloaded into the pit by the loader, sent to the raw coal  pre-homogenization yard by the plate feeder and belt conveyor, piled into two  piles, and picked up by the bucket wheel. The feeder is sent to the belt  conveyor into the coal mill grinding head bin.

  The coal mill adopts a vertical mill system. When the moisture of the raw  coal is ≤8%, the moisture of the pulverized coal is ≤1%, the particle size of  the raw coal is ≤70mm, and the fineness of the pulverized coal is 80µm and the  remaining 10% is screened, the system output is 38t/h.

  The coal mill is set at the kiln head, and the waste gas of the grate  cooler is used as the drying heat source. The raw coal is metered by the  quantitative feeder under the raw coal bunker and fed into the mill, and the  dried and pulverized coal enters the bag filter together with the waste gas. ,  the collected pulverized coal is sent to the pulverized coal bins of the kiln  and the decomposition furnace respectively through the screw conveyor. The  exhaust gas purified by the bag filter is discharged into the atmosphere, and  the normal emission concentration of the flue gas is ≤30mg/Nm3.

  There is a pulverized coal metering and conveying device under the  pulverized coal silo, and the pulverized coal can be accurately sent to the kiln  head and the decomposition furnace through this device.

  The pulverized coal preparation system is equipped with strict safety  measures, such as explosion-proof valve, CO detector device, CO2 automatic fire  extinguishing system, fire water system, etc.

  12.   Gypsum crushing and conveying

  The gypsum is transported into the factory by truck, stored in the open  yard, and then fed into the unloading pit by the loader, and fed into a heavy  hammer crusher by the medium plate feeder. The crushed gypsum is sent to the  cement batching station by belt conveyor and elevator.

  13.  Slag drying and conveying

  It is planned to use a Φ3.6×32m dryer for drying. When the initial moisture  is 12% and the final moisture is <1.5%, the capacity of the dryer is 100t/h,  and a set of GXDF type boiling hot blast stove is also equipped. The dried slag  is sent to the cement batching station by belt conveyor and elevator.

  14. Cement  batching station

  There are 4 batching warehouses of φ8×20m in the cement batching station,  of which 2 store clinker with a reserve of 1300×2=2600t and a storage period of  12.5h; 1 store slag with a reserve of 1000t and a storage period of 1.5 days; 1  One store of gypsum has a reserve of 1260t and a storage period of 3.2 days; two  φ12×22m fly ash warehouses have a reserve of 2×1800t and a storage period of  1.8d. Each material is unloaded from the bottom of the silo by the  speed-adjusting quantitative feeder produced by the imported technology  according to a certain proportion, and the matched material is sent to the  cement mill through the belt conveyor and the air-locking air valve.

  15. Cement  grinding

  The cement grinding adopts 2 sets of φ2000×1500mm roller press + 2 sets of  φ4.2×11m ball mill system, equipped with 2 sets of V-type powder separator and 2  sets of improved powder separator. When the particle size of the grinding  material is less than or equal to 25mm, and the specific surface area of the  cement is 320-350m2/kg (for grinding P.042.5 ordinary Portland cement), the  production capacity of the system is 340t/h.

  The mixed materials in the cement batching station are sent to the V-type  powder separator through the bucket elevator of the belt conveyor, and the  selected coarse powder is fed to the roller press. After crushing, the bucket  elevator is sent to the V-type powder separator; The dust-laden gas from the  type powder separator is processed by the cyclone dust collector, and then the  coarse powder is fed to the ball mill, and the waste gas enters the improved  type powder separator. The pulverized materials are sent to the improved powder  separator through the mill tail bucket elevator. The coarse powder selected by  the powder separator is sent back to the grinding head of the ball mill through  the air conveying chute, and the fine powder enters the air box with the air  flow from the powder separator. Pulse bag dust collector, the collected cement  products are sent to the cement storage system through the air conveying chute.  The purified gas of the air box pulse bag dust collector is discharged into the  atmosphere through the exhaust fan.

  16. Compressed  air station
There is a compressed air station, a total of 5 sets  of 40m3/min screw air compressors and refrigerated air drying devices, which can  provide compressed air with a pressure of 0.8MPa, one of which is a 40m3/min air  compressor for backup. The compressed air station provides air source for pulse  bag dust collectors, various pneumatic devices and air cannons.

  1.1.19 Low temperature waste heat power generation system

  The exhaust gas (about 350°C) exiting the first-stage cylinder at the kiln  end is reduced to about 230°C after heat exchange by the SP furnace. The waste  gas from the grate cooler at the kiln head (about 350°C) is settled in the  settling chamber (pre-dust collector) and then enters the AQC furnace. After  heat exchange, it enters the dust collector to purify and meets the standard,  and then joins with the waste gas at the tail of the clinker cooler. into the  atmosphere through the chimney.

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