Main process flow:
1. Limestone crushing: limestone from auto-dumper will enter into hopper, then it will be conveyed to limestone pre-homogenization yard by belt conveyor after crushing by hammer crusher. Then cantilever stacker will be used to stack & reclaim in layer. Stacked limestone will be transported to raw material proportioning station & limestone proportioning bin by belt conveyor. Set electromagnetic iron separator on inlet belt conveyor of bin to remove all possible iron parts in limestone. Set metal detector on head of belt conveyor to check whether there are iron parts in raw material to avoid damage to raw material roller press.
Raw material proportioning station configures limestone, silica, iron ore gauge and wet fly ash proportioning bin. At the bottom of each proportioning bin sets apron feeder and constant feeder, four raw materials will be discharged according to the requirements of proportioning by its constant feeder, mixed material will be fed into small bin of raw material roller press via belt conveyor.
2. Raw material grinding utilizes roller press together with Ф4.6m×（10+3.5）m middle-discharge mill system, meanwhile high temperature waste gas exhausted from kiln tail will be used as hot source for drying. Material will be dried and classified by V type separator after extruded by roller press, while part of fine powder will be sent into raw meal homogenization silo via air side and bucket elevator after separating by high efficient separator. The other part of rough powder and wet fly ash will enter into raw mill for grinding. Material will be grinded and dried in raw mill, outlet raw mill will enter into separator via elevator, meanwhile rough powder will return back to mill and fine power will enter into raw meal homogenization silo via air slide and bucket elevator after separating. Outlet waste gas of mill via separator will be exhausted into the air after treated by EP filter of waste gas treating workshop.
3. Coal mill sets in kiln tail, part of waste gas of kiln tail will be used as hot source for drying raw coal after treated by cyclone. Waste gas of kiln tail will enter into EP filter at kiln tail directly after treated by air conditioning tower. The sprayed water volume of air conditioning tower can be auto-controlled according to the temperature of outlet waste gas, it makes the temperature of waste gas be in the allowable range of EP filter of kiln tail and the waste gas treated by dust collector will be exhausted into air by blower. The kiln ash collected by air conditioning tower will be sent into kiln feeding system or raw meal homogenization silo via conveying equipment. Configures one Ф18m continuous raw meal homogenization silo, raw meal inside of silo will be discharged into mixing room from surrounding circle zone after being inflated in alternate partitions and the raw meal will be mixed evenly by inflated air. The inflated air at the bottom of silo will be supplied by relevant Roots blower. Homogenized raw meal will pass through air slide and bucket elevator after being measured and they will be fed to two inlets of double series pre-heater via distributor and air lock valve.
4. Burning workshop is composed of five-stage double series suspension pre-heater, calciner, rotary kiln, grate cooler and relevant dust collecting system with the capacity of 3000t clinker per day. Raw meal fed into pre-heater will be preheated by pre-heater and de-composed by calciner, and then it will be fed into kiln for sintering. Outlet clinker with high temperature will be cooled by grate cooler. Large block clinker will be crushed by crusher, and it will be sent into clinker silo via clinker chain type bucket elevator together with small clinker under air room. Part of the hot air from clinker bed will be used as 2nd air and 3rd air of kiln and calciner, the rest of waste gas will be exhausted into air after treated by EP filter. Clinker will sent to bulk car loading station via belt conveyor after being discharged via discharging device at bottom of silo and bulk clinker will be directly loaded into car by dustless bulk loader at the bottom of silo.
5. Coal powder manufacturing utilizes vertical grinding system and the high temperature waste gas exhausted from kiln tail will be used as hot source for drying. Raw coal will be fed into coal mill for drying and grinding via raw coal constant feeder, outlet coal powder will enter into bag type dust collector comply with air flow, qualified coal powder will be collected and sent into coal powder silo with load sensor via screw conveyor. Measured coal powder will be sent to kiln head burner and kiln tail calciner for sintering. Dust gas will be exhausted into air after being treated by static-free EP filer. Coal powder bin and bag type dust collector sets CO detector and explosion-proof valve.
The whole plant sets one central laboratory which will check all raw fuel, half-finished product and finished product; and one air compressor station which supply compressed air to the whole plant for production.
Energy-saving technical characteristics
The limestone crushing system, raw material grinding system, burning system, coal powder manufacturing system of this project utilizes one series self-developed, advanced, high efficient and energy saving system, technology and equipment.
1. Limestone crushing utilizes single-stage hammer crusher with imported technology, its process and process is very simple and the power consumption of unit product is low.
2. Raw material grinding utilizes roller press together with Æ4.6m×（10+3.5）m middle-discharge closed-circle mill system which can save about 5kW×h/t per unit raw meal compared with traditional middle discharge mill system and wind swept coal mill. It saves construction investment and reduces the power consumption of product.
3. Coal powder manufacturing utilizes energy-saving and high efficient vertical roller mill system which could save about 11.0kW×h/t power consumption of unit coal powder compared with traditional wind swept ball mill, dynamic rough powder separator and high concentration plenum pulse bag type dust collector system.
4. Clinker burning system utilizes NC type double series low pressure loss five –stage cyclone pre-heater and calciner system, NC high efficient rotary kiln, NC high efficient coal powder burner, control-flow type new technology cooler, etc. equipment with high performance which effectively reduces the heat consumption and power consumption of clinker burning. The heat consumption of clinker burning is less than 750×4.182kJ/kg.Cl and comprehensive clinker power consumption is less than 58kWh/t.Cl.
5. Material conveying utilizes high efficient, energy-saving process equipment with low consumption, so that the power consumption could be reduced to the maximum. Concerning bucket elevator will be used to convey raw meal into silo and pre-heater, it could save 2.5~3kW×h/t conveying power consumption of unit raw meal.
6. Utilizes DCS computer control system to monitor and control the whole production line which implements stable control, optimizing operation, energy-saving and consumption reduction and improve the labor capacity.
Comprehensive & effective utilization of heat energy, adequately utilizes the waste gas exhausted from kiln tail pre-heater as hot source for drying of raw grinding and raw coal drying of raw coal manufacturing system. Utilizes new technology cooler whose heat recovery could reach over 75%, it can not only recovers the heat energy of kiln clinker, but also improves the temperature of 2nd air and 3rd air and reduces the clinker burning heat consumption.
8. Kiln burning device utilizes multi-pipes coal burner which could reduce the 1st air rate of kiln to about 10%, improve high temperature 2nd air volume, improve the burning condition inside of kiln and raise the burning efficiency.
During the engineering design, we try our best to implement better process flow, avoid round-trip transportation of material and save material conveying power consumption. Strengthen measuring, improve efficiency, reduce raw material consumption and product loss, sets various measuring equipment and instruments with high quality and high accuracy in every important point and sets various dust collecting equipment with stable operation and high efficiency in every dust-raising point which makes the bug dust exhaustion meet the standard, this could prevent circle environment and reduce pollution.