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TECHNOLOGY
Technology of Blue Carbon Production in SJ Low Temperature Dry Distillation Furnace
Brief introduction
SJ low temperature distillation furnace was designed and completed by China Coal Chemical Research Institute on basis of reheating vertical furnace in 1996. At present, more than 500 SJ low-temperature distillation furnaces have been designed and constructed in Yulin area of northern Shaanxi Province and Dongsheng area of Inner Mongolia. SJ-Yao low-temperature dry distillation furnaces are excellent ones for production of blue carbon at present. They have low investment, large output and good operation.
Blue carbon has high fixed carbon, high specific resistance and high chemical activity. It has low ash content, low aluminum, low sulfur and low phosphorus. It can replace metallurgical coke, anthracite and charcoal.
It is widely used in the production of calcium carbide, metal silicon, ferroalloy, ferrosilicon, ferrochrome, silicomanganese, silicon carbide, and fertilizer products, and has better effects than metallurgical coke.
1. Auxiliary coal box; 2. Gas collecting umbrella; 3. Climbing ladder; 4. Flower wall; 5. Furnace body; 6. Small arch wall; 7. Coke discharging box; 8. Furnace bottom platform; 9. Pushing coke disc; 10. Scraper; 11. Water sealing box
Production of blue carbon coal quality requirements:
Table 1
Note: Coking coal cannot be used, and the characteristics of cinder cannot be >4. The smaller the better.
The coal quality of Shaanxi Shenmu blue coal production is as follows:
Coal Mine Coal Quality Inspection Report Table 2
3. Process flow
The production of blue coal is mainly carried out in the form of square shaft furnace. Its process includes:
A. Coal Washing Section - Raw Material Warehouse - Coking Shaft Furnace - Water Washing Tower - Electric Tar Catching - Gas Fan - Gas Storage Tank
B. Coking Shaft Furnace-Coke Quenching Box-Coke Pusher-Scraper-Dryer-Blue Carbon Product Warehouse
C. Washing Tower and Electric Tar Catching - Residue Pool - Oil Pool - Ammonia Pool - Pump House - Coke Quenching Box and Washing Tower Cycle
After secondary crushing of raw coal, the lump size is 20-80 mm, which is fed into the coal storage bin above the retort furnace through the coal conveyor belt. The coal miner adds the lump according to the treatment capacity of the dry distillation furnace, and the amount added is based on the principle of no loss of material on the top of the furnace. Raw coal gradually decreases in the dry distillation furnace, then passes through the drying section, the dry distillate section and the cooling section. Finally, it is pushed down to the quenching pool by a pusher. The blue carbon is sent to the dryer by a scraper machine for drying. After drying, the transdermal belt conveyor is sent to the screening machine to screen the finished products of the blue carbon.
Coke oven gas enters the gas collecting tank from the riser and bridge pipe at the top of the dry distillation furnace. There is a sprinkler in the bridge pipe. The gas is first cooled by the circulating water of the hot ring pool. After the initial cooling, the gas enters the Venturi Tower from the top of the tower, and the hot circulating water sprays down from the top of the tower. The gas and the descending hot circulating water come into full contact in the Venturi pipe, about 80. % tar is brought to the bottom of the tower by cooling water, and the gas which cools and removes most of the tar is exported from the bottom of Venturi tower and enters the swirl plate tower. In the swirl plate column, the cold circulating water from the cold water circulating system countercurrent with the gas, and the gas is cooled continuously and the tar contained therein is removed.
After two-stage cooling and De-Tar treatment, the gas continues to descend, enters the electric tar trap to further remove the tar in the gas, and then enters the gas fan. Through the gas blower, part of the gas is sent to the dry distillation furnace, part to the blue carbon dryer, and the rest to the accident torch emptying, power generation or other purposes.
The tar removed from each part of the process is statically stratified in each circulating pool and then pumped into the tar tank through the tar pump.
4. Brief introduction of each section:
4.1. Coal preparation section
Main facilities and equipment of preparation coal and soil section: equipment coal yard, loader, coal pit, conveyor belt, coal screen building, dust removal equipment, coal bunker, belt weighing, hopper, reversible belt, loadometer.
4.2. Carbonization section:
The main facilities and equipment in the carbonization section include SJ-low temperature dry distillation square furnace, gas collecting umbrella, steel structure furnace top cover, auxiliary coal box, riser, bridge pipe, gas water seal box, coke discharging box, coke pusher, scraper, water seal tank, return furnace heating facilities, coke quenching water tank and water pump.
Each single furnace is continuous production. The raw coal gradually decreases in the dry distillation furnace, and then passes through the drying section, the dry distillate section and the cooling section. After being cooled by a water-cooled jacket coke discharging box at the bottom of the furnace, the blue carbon formed by pyrolysis falls into the coke quenching pool through a coke pusher through the coke guide nozzle. The coke is quenched with clean water,
The coke-drawing disc and scraper immersed in the water seal are under the action of the transmission,the blue carbon is sent to the gas dryer for drying until the moisture content is 15-20%. The blue carbon is sent to the sieving machine by belt conveyor for sieving. The products of different grades are obtained and classified in the coke yard.
The generated coke oven gas passes through the gas gathering umbrella to the top riser of the dry distillation furnace, is initially cooled and separated by the bridge pipe, enters the gas collecting pipe, and is sent to the Venturi Tower. The gas flow power comes from the suction of the gas fan set in the process.
The dry distillate furnace adopts internal heating type, and the temperature in the dry distillate furnace is controlled by adjusting the ratio of heating gas to air. Gas and air branches are equipped with flowmeters, pressure gauges and control valves. The air blower adopts two standby one work schemes, and the air volume of each furnace is regulated separately. The gas system is equipped with pressure, temperature and flow measurement and control instruments to monitor the gas system.
4.3. Purification Section
The main facilities and equipment of the purification section include: Venturi Tower, Swirl Plate Tower, Electric Tar Collector, Gas Fan, Air Fan, Circulating Water Pump, Tar Pump, Clear Water Circulating Pool, Hot Circulating Water Tower, Cold Circulating Pool, Heat Exchanger, Glass Fiber Reinforced Plastic Cooling Tower, Tar Aggregation Pool, Distribution Control Cabinet, Instrument Cabinet, Test Pressure, Temperature flow meter, circulating water pump room, tar pump room, distribution instrument room.
4.4. Screening Coke Section
Main Facilities and Equipment of Coke Screening Section
Belt conveyor, buffer bin, screen coke building, vibrating screen, dust collector, unloading belt, focal field, load meter, loader.
Procedures and characteristics of coke screening section:
The blue carbon dried by the dryer is conveyed to the buffer bin by the coke belt conveyor. The output of blue carbon can be stored for 3 hours in the buffer warehouse. B800 belt is installed under the buffer warehouse to convey the blue carbon to the sieve coke building. Vibrating screen is installed in the sieve coke building. The blue carbon sieve is divided into four particle sizes and stored in four warehouses at the bottom of the sieve coke building. B800 coke belt is installed at the bottom of the warehouse, and the materials of four coke warehouses are sent to the unloading belt machine respectively. The coke unloading belt conveyor is set in the coke field with a height of 13 meters. The different specifications of blue carbon are stacked separately and sold out by loaders. All belt conveyors are equipped with belt corridors for closed operation. A dust collector is installed in the closed operation of the sieve coke building.
4.5. Sewage Treatment Section
The main facilities and equipment of sewage treatment section include: sedimentation deoiling tank, air floatation deoiling tank, regulating tank, anaerobic tank, aerobic tank, mixed adsorption tank, final sedimentation tank, sewage pump, heating and water supply facilities, distribution equipment.
4.6. Procedures and Characteristics of Sewage Treatment Section
Ammonia water from the cold ring tank enters the precipitation tank. After stratification, heavy oil is recovered to the tar tank. Ammonia water enters the floatation deoiling tank. After separation of light oil, ammonia water enters the regulating tank to supplement domestic sewage and clean water.
4.7. Thermal circulating water system
The thermal circulating water system mainly provides the ammonia water circulation of Venturita. The main processes include: the circulating ammonia water from the thermal circulating pool enters the top of the Venturi tower as cooling water, exchanges heat with gas in the tower, the cooling water with tar flows out from the bottom of the tower, enters the thermal circulating pool, separates oil from water in the thermal circulating pool, and the tar is regularly pumped into the tar storage tank, and the circulating water is pumped into the Venturi tower for circulation. When the hot ring pool water is insufficient, the circulating water in the cold ring pool is pumped in to supplement.
4.8. Cold circulating water system
The circulating water cooled by clean water in the heat exchanger enters the swirl plate tower from the top of the tower for secondary cooling of gas. After exchanging heat, the circulating water temperature of the outlet tower is about 45-55c. It discharges from the bottom of the tower and enters the cold circulating pool for oil-water separation. Tar is sent to the tar storage tank. The circulating water is cooled by heat exchanger and the remaining circulating water is one part. It is supplemented to the thermal cycle pool,other part of which enters the sewage treatment system for reasonable treatment, and the standard water is supplemented to the coke swallowing and extinguishing pool. Fresh water should be replenished regularly in the cold circulation pool.
4.9. Clean Water Circulation System of Heat Exchanger
In the clear water circulation system of heat exchanger, the heat exchanger adopts tubular heat exchanger. Its main function is to cool the circulating water in the cold ring pool with clean water. The cold circulating water runs through the tube and clean water runs through the shell. The circulating water emits heat in the process of heat exchange. When the temperature drops to 45-50 C, it enters the swirl plate tower for secondary cooling of gas, and the temperature of clean water rises from 30 ^ 40 C to 35 ^ 45 C, which is sent to the cooling tower for cooling and then circulates to the circulating pool of clean water.
5. Requirements of raw materials for producing blue carbon in SJ low-temperature retort furnace:
Coal indicators:
SJ low-temperature dry distillate furnace parameters for production of blue carbon products:
Product Inspection: Table 1-3
