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The Semi Coke Was Made Like This
- Oct 15, 2018 -

Many people will ask what is "semi coke", like coal? Let's introduce the production of LAN tan.

(1) coal washing system.

The raw coal is fed into the raw coal belt by the receiving coal hopper, and the raw coal belt carries the raw coal to the washing workshop and enters the jig separation. The separated clean coal products are dehydrated by a linear vibrating screen, and then enter the clean coal belt and feed into the coal preparation system in the next order. The filtered water enters the high-frequency screen for dehydration. After dehydration, the product is conveyed to the foamed coal site by the foamed coal conveyor belt. The high-frequency screen water is pumped into the high-efficiency deep cone thickener. The coal slurry discharged from the bottom of the deep cone thickener is pressed and dehydrated by a pressure filter. The overflow of the thickener and the filtrate of the filter press are mixed into the circulating cistern for recycling. Jigging gangue, after the dewatering and lifting of the bucket, goes to the gangue chute. After jigging, the coal is dehydrated and lifted to the coal chute and then enters the washing cycle again.


(2) coal preparation system.

The total water content (including internal and external water content) of the blended coal with 0-30mm raw material used for producing blue carbon is not more than 13%, and the pulverized coal whose particle size distribution is less than 6mm is less than 10%. The blended coal is conveyed to the coal storage bin by lifting belt.


(3) drying system.

The blended coal sent from the coal preparation process is conveyed to the top coal storage bin of the retorting furnace by the lifting belt conveyor, and a reciprocating moving bulk coal leveler is arranged in the coal storage bin, so that the blended coal conveyed from the belt conveyor to the coal storage bin can be evenly spread in the coal storage bin.


The mixed coal which is sent into the coal storage bin moves downward and parallel vertically. It first enters the drying section of the retorting furnace. In the drying section, the gas is used as fuel, and the high temperature flue gas produced by combustion in the burner is mixed with the circulating dust removal flue gas to 350 C as the drying heat source of the mixed coal. The flue gas produced in the drying process has a temperature of 120 C. Because of the entrainment of air flow, the flue gas contains less than 0.2 mm of coal dust. Then the dust-laden flue gas is sent to the bag filter. Some of the dust-laden flue gas is recycled after pressurization by the circulating flue gas fan. Some of the dust-laden flue gas is sent to the outside of the boundary for desulfurization treatment and is discharged at high altitude.


(4) dry distillation system.

The temperature of the blended coal from the drying section rises to 150 C, and the free water has been removed. The dehydrated blended coal moves down vertically and parallel into the retort section of the retort furnace. The upper part of the retorting section of the retorting furnace is equipped with a gas collector for recovering pyrolysis oil and gas, the middle part is equipped with a distributor for increasing the permeability of mixed coal, the lower part is equipped with 12 carbonization chambers, and a two-stage burner is installed in the carbonization chamber to heat the mixed coal through the carbonization chamber by lean oxygen combustion. The hot-carrier gas produced by lean oxygen combustion passes through the coal seam voids and carries on contact heat transfer to the blended coal which moves vertically downward. After heating, the blended coal undergoes thermal decomposition reaction. The pyrolysis oil-gas and the hot-carrier gas go up and enter the oil-gas cyclone dust collector through the gas collector. After dust removal, the pyrolysis oil-gas is sent to the oil-gas recovery unit.


The blended coal in the retort section of the retort furnace moves from top to bottom and contacts the high-temperature gas conversely from the combustion chamber. The blended coal is heated to 600 ~ 700 C in this section, and then carbonized into charcoal. The charcoal enters the cooling section from the carbonization chamber.


(5) cooling system.

The high-temperature blue carbon discharged from the carbonization chamber enters the waste heat recovery heat exchanger, and the water is vaporized into water vapor in the heat exchanger. Then the water vapor enters the vapor-liquid separator, and 0.7 MPa (G) saturated vapor is separated from the vapor-liquid separator. Except for partial preheating, the other parts are sent out of the device.


(6) coke quenching system.

After the heat recovery of the high temperature blue carbon and the waste heat recovery of the blue carbon, the temperature of the blue carbon will be about 200 degrees Celsius at 650 degrees Celsius. The water mist spray quenching device is installed at the bottom of the cooling section of the retort. When the spray water mist touches the hot blue carbon, the rapid expansion force when the water becomes steam makes the steam flow through the blue carbon layer. Steam is used to extinguish coke in the bin, reducing the contact time and water consumption between the water and the blue carbon. Finally, the coke was pushed back and forth by the coke pusher, dropped to the bottom of the coke scraper, scraped out from the bottom of the furnace by the coke scraper, weighed by the belt measurement and sent to the coke product warehouse by the belt conveyor.