2500t/d new dry rotary kiln cement production line project

 

Main process flow and host configuration

 

1) Limestone crushing, conveying and storage. The limestone crushing is broken by an MB56/75 crusher (open-air layout). When the maximum size of the feed ore is ≤1500mm and the discharge size is ≤75mm, the crushing capacity of the crusher is 500-600t/h; the limestone of the crusher is sent by the belt conveyor to the Φ80m circular limestone pre-homogenization yard (reserve) Pre-homogenization and storage in 34100 t), stacker (stocking capacity: 800t/h) cantilever, loop continuous fabric, reclaimer (recovery capacity: 500t/h) bridge type, end material reclaiming, center unloading material. The homogenized limestone is sent to the raw material batching station by a belt conveyor.

 

2) Storage, crushing and transportation of auxiliary materials. The auxiliary raw sandstone and iron ore are transported into the factory by automobile and discharged to the open storage yard for storage. Among them, the sandstone open storage yard has a specification of 60 m×20 m and a reserve of 5100 t; the iron ore open storage yard is 32 m×20 m with a reserve of 2730 t. A PC1609 hammer crusher is used for sandstone and iron ore. When the feed size is ≤600mm and the discharge size is ≤25mm, the crushing capacity is 50~70t/h; the crushed sandstone and iron ore are sent to the belt conveyor. The raw material batching stations are stored in the respective ingredient stocks. The auxiliary raw material fly ash is transported into the factory by the bulk automobile, and is sent to the raw material batching station in the fly ash ingredient storage warehouse through the pipeline by the self-unloading system.

 

3) Raw material batching station. The raw material batching station is equipped with four batches of limestone, sandstone, iron ore and fly ash (all specifications are φ12 m×25m, reserves are 2200, 1600, 2200, 770t respectively), and the bottom of the library is equipped with weighing feeders. , various materials are given quantitatively according to the set ratio. The raw materials are fed into the vertical grinding system by a belt conveyor for grinding.

 

4) Raw material grinding and waste gas treatment. The raw material grinding adopts MLS3626 vertical grinding (open-air arrangement), and the drying heat source is the exhaust gas of the preheater. When the grinding mill material size is 90%≤75mm, the product fineness is 80μm square hole sieve sieve <12%, the raw material moisture is <8%, and the raw material moisture is <1%, the system production capacity is 185t/h ( After wear). After the raw material is separated by the fine powder separator, it is mixed with the dust collected by the humidification tower and the electric precipitator, and sent to the raw material homogenization storage tank for homogenization and storage through the chute and the bucket elevator; After being purified by an electric precipitator, it is discharged into the atmosphere.

 

5) Raw material homogenization pool and raw materials into the kiln. The qualified raw material for grinding and grinding is multi-pointed into the raw material homogenization tank of Φ18m × 50m CP type (effective reserves of 9000t) through the top material distributor, and then quantitatively discharged into the kiln system through the unloading device. The raw material into the kiln system has a load chamber, and the metering and flow control equipment is provided under the warehouse. The metered raw materials are fed into the kiln preheater system by bucket elevators and other equipment.

 

6) Clinker burning system and storage. The clinker burning system consists of a low pressure loss single series online five-stage preheater and a decomposition furnace (RF5/2500 type, the kiln decomposition rate is greater than 90%), Φ4.0×60m, LBT32216 new control rogue cooler Both are NCDRI technology. Among them: 1 After the kiln clinker is cooled by the grate cooler, it is sent to the 2-φ18×40m round bank (effective storage capacity 2-10000t) by the chain bucket conveyor and the disc conveyor, and the clinker is discharged. The device and the belt conveyor are sent to the cement clinker for transportation and the cement batching station; 2 the high temperature gas portion of the hot end of the cooler is introduced into the decomposition furnace as the combustion gas of the decomposition furnace through the tertiary air duct, and part of the hot gas at the middle temperature end is introduced into the coal mill as the raw coal for drying. The dry heat source; the exhaust gas discharged from the tail end is purified by the electric dust collector and discharged into the atmosphere through the chimney, and the dust concentration of the exhaust gas (under the standard condition) is less than 100 mg/m3.

 

7) Storage and transportation of raw coal, preparation and transportation of coal powder. The raw coal after the car transportation entered the factory was stored and pre-homogenized with a 21m×113m hanging garage (reserve 9300t). There are two original coal bunkers in the hanging garage. On the one hand, it is considered to shorten the walking distance of the crane. On the other hand, it is considered to match the two types of coal with different qualities. The bottom of the warehouse is equipped with a weighing feeder, which is conveyed by tape after being metered. The machine sends the coal to the coal mill for grinding. The pulverized coal is prepared by a MPF1713 roller-type coal mill, which is arranged in the open air. When the moisture content is ≤10%, the pulverized coal moisture is ≤1%; the original coal particle size is ≤50mm, and the pulverized coal fineness is 80μm. The system output is 20t/h. The pulverized coal powder enters the classifier for sorting with the airflow, and the finished pulverized coal is taken into the gas box by the air bag and collected by the dust collector. The screw conveyor is sent to two pulverized coal bins for storage. Into the atmosphere. A pulverized coal metering system is arranged at the bottom of the pulverized coal silo, and the pulverized coal is metered into the kiln head and the decomposition furnace for combustion.

 

8) Slag drying and conveying, gypsum crushing and conveying. The slag as a mixed material is transported into the open storage yard by the automobile, and the slag is sent to the bucket elevator by the forklift, and sent to the φ2.4×18.350m dryer for drying by the bucket elevator. Dry, its drying capacity ≥ 30t / h (material initial moisture 20%, final moisture 1.5%). Gypsum is transported into the factory by automobile, discharged to the open storage yard with reserves of 4000t, and then fed into the PFC-1609 counter hammer crusher by heavy plate feeder (when the feed size is ≤600mm, the output size is ≤25mm) The crushing is carried out within a capacity of 50 to 70 t/h, and the crushed gypsum is sent to a gypsum ingredient storage tank through a bucket elevator and a belt conveyor.

 

9) Cement grinding, conveying and storage. The cement batching station is equipped with four batches of clinker, gypsum, limestone and slag. The clinker bank is φ10 m×22m and the reserve is 2000t. The gypsum bank, slag pool and limestone are all φ8 m×22m, and the reserves are 800. 400 and 900t. Each of the library bases is provided with a weighing feeder, and various materials are quantitatively given according to the set ratio. The clinker batching library is also provided with clinker bulk facilities for clinker use. After the four materials are discharged in proportion by the feeding and metering equipment, they are sent by the belt conveyor to two sets of circulating cement grinding system consisting of Φ3.8×13m ball mill and high-efficiency classifier for grinding, when the cement specific surface area When the temperature is 3200～3400cm2/g, the production capacity of a single system is 75t/h; the material for grinding is sent to the high-efficiency classifier by the bucket elevator for sorting, the coarse powder is ground and the grinding is continued, and the cement finished product is from the gas box. After the pulse bag type dust collector is collected, it is stored in 8 φ15 m×34m cement storages (single storage capacity is 5300t) by air conveying chute and bucket elevator. The exhaust of the cement grinding system enters the high-efficiency air box pulse bag and is discharged into the atmosphere. After the unloading cement is discharged from the bottom discharge device, it is sent to the cement packaging workshop and the cement bulk storage bin by the belt conveyor, the bucket elevator and the air conveying chute. The cement packaging adopts two eight-nosed rotary packaging machines, each of which has a capacity of 90t/h, and the packaged bagged cement is sent to the 84m×30m bagged cement finished product warehouse for storage through the unloading bag conveying system ( The reserve is 6000t), and it can also be shipped directly. There are two cement car bulk facilities under the cement bulk bin for the bulk of the car.

 

Technical level and main technical features

 

(1) Creative general layout. The project occupies a steep hillside near the limestone mine and does not occupy farmland. In the overall planning, while meeting the smooth and reasonable process, the original fuel and cement products are combined into the factory, and the site topography is taken into account. And the surrounding transportation conditions, from the west to the east, the original fuel storage area, the main production line, the planned second-stage production line, and the factory front area are arranged in turn, each area is arranged in parallel, and the functional division is clear; and the high-differential section is used to set each area, and the visual effect is obtained. Beautiful and tidy. Another consideration is that the limestone mine is located on the west side of the site with higher elevation. According to this feature and combined with the process flow, the original fuel storage area is arranged in the higher part of the west, which not only reduces the amount of earthwork in the leveling of the site, but also shortens the belt conveyor distance and improves The land utilization rate has reduced the overall investment cost of the project. In addition, in order to avoid a flood gully in the central part of the plant, the clinker production line and the cement grinding system are arranged on both sides of the gully ditch in the overall plan, and the belt conveyor is used for material transportation, which not only satisfies the process flow but also makes reasonable use of it. The topography of the plant area avoids the impact of the gully flood on the entire production line.

 

(2) The selection of equipment fully reflects localization, advanced and reliable, energy saving and high efficiency. For example: 1 using a set of domestic vertical mill as the raw material grinding system, compared with the traditional ball mill system, it has the advantages of high grinding efficiency, strong drying ability, low power consumption, and low investment, among which only electricity consumption Compared with the ball mill system, it can save 4 to 6 kWh/t per unit of output, saving 4.76 million to 7.13 million kWh per year. 2 The vertical coal mill is used to replace the traditional air-jet ball mill, and the power consumption of the coal powder preparation system can be saved by about 30%. 3 The raw material homogenization library adopts a continuous homogenization library, and the unitized raw material homogenization power consumption is 0.3 kWh/t, which is 0.4 kWh/t less than the intermittent raw material mixing tank. 4 The firing kiln tail is a five-stage cyclone preheater system with an in-line type decomposing furnace. When the raw material enters the kiln temperature up to 900 °C, the decomposition rate of the kiln is over 90%, and the clinker firing heat energy is controlled. 3137kJ (750kCal) or less. 5 In addition to the new kiln head and kiln tail sealing device, a new high-efficiency three-channel coal injection tube burner is also adopted. By changing the ratio of internal and external wind speed and air volume, the flame shape and combustion intensity can be flexibly adjusted to suit the kiln work. In order to achieve the purpose of reducing coal consumption and increasing production. The clinker cooling adopts the control flow to drive the grate cooler, which has high heat recovery efficiency and energy saving. 6 Select high-efficiency dust collection equipment, etc., pay attention to environmental protection. The dust concentration of exhaust gas at each discharge point of the factory is lower than the national emission standard, which can save a lot of raw materials, fuel and electricity, and achieve energy saving and environmental pollution reduction. 7 Large fans and conveying equipment use low-cost equipment (such as air chute instead of screw conveyor), and the reserve factor does not exceed the specified range. In addition to raw materials into the preheater and pulverized coal transportation, all block and powder materials are mechanically transported to save energy.

 

The production practice proves that the new dry process line system technology adopted in this project is mature and reliable, the design is optimized, the debugging is smooth, and the layout of the general plan is reasonable and simple and beautiful. At present, the annual operating rate is over 90%, the average output has reached more than 2730t/d; the clinker heat consumption is <3136kJ; the outlet temperature of the preheater primary cylinder is <338°C; the resistance is 4590Pa; after testing, all discharge points are discharged. The dust concentration (under standard conditions) <70mg/m3, the benefits are obvious.