Common Problems of Coke Ovens and Technical Measures (2)

1.Why must the α value be controlled at about 1.2 when using coke oven gas for heating?

The α value is about 1.2, which can make the gas burn completely and prevent high temperature accidents. If the value of α is too small, the amount of air will be insufficient, resulting in incomplete combustion. If the α value is too large, excessive air will cause the furnace temperature to rise rapidly, causing high temperature accidents and damaging the furnace body. Therefore, it is generally better to control the value of α between 1.2 and 1.25.

2.Why can't the temperature of the small flue be lower than 250℃?

Because the height of the chimney is constant and the temperature of the outside atmosphere does not change, the higher the temperature of the exhaust gas, the greater the buoyancy. In order to ensure the buoyancy of the flue, the temperature of the small flue is specified to be no less than 250°C.

3.The principles of the pressure system?

The gas pressure in the coking chamber should be greater than the pressure in the adjacent combustion chamber and higher than the outside atmospheric pressure; the gas pressure in the coking chamber should maintain a positive pressure during the entire coking period, under any circumstances; during the same coking time, along the height of the heating system The pressure distribution should be uniform and stable.

4.Factors that affect the straight travel temperature

It is related to coal charging system, coke discharge operation, furnace body maintenance, heating gas composition and nature, turnaround time, raw gas leakage, etc. 

5.What must be paid attention to when exchanging hot gas, air and exhaust gas?

The gas must be turned off during the exchange to prevent residual gas in the heating system to avoid an explosion accident; after the gas is turned off, a short interval should be passed before the exchange of air and waste gas, so that the residual gas can be completely burned out. After the air and exhaust gas have been exchanged, the gas should be turned on after a short period of time, so that there is enough air in the combustion chamber, and the gas can burn immediately after it enters.

6.Under what circumstances should the drop in cooling temperature be measured?

When the reversing interval changes, the coking time changes more than 1h, the heating system has a major change, under normal circumstances, it is corrected once every six months, and the heating gas is used for more than one month.

7.Some common temperature regulations.

The temperature at any point of all fire channels shall not exceed 1450°C and not lower than 1100°C after 20s of exchange. The temperature of the small flue should not exceed 450°C and should not be lower than 250°C; the sub-flue should not exceed 350°C. The temperature at the top of the regenerator shall not exceed 1320°C and shall not be lower than 900°C. The center temperature of the coke cake is 1000±50℃, and the temperature difference between the upper and lower points of the blast furnace gas heating shall not exceed 100℃, and the temperature of the coke oven gas shall not exceed 120℃. The temperature of the furnace top space should not exceed 850°C. The temperature of the gas collecting pipe is 80~100℃, and the pressure is 100~140Pa. Heating coke oven gas temperature is 40~45℃, blast furnace gas is not higher than 35℃.

8.What are the reasons for the difficulty in pushing focus?

(1) The cohesiveness of the coal charged in the furnace is not good, and it cannot be coked in the carbonization chamber; (2) The coke cake is poorly heated, and there is overgrowth or overfire; (3) The furnace wall or the furnace bottom bricks are deformed; (4) The coal in the carbonization chamber is incorrectly loaded, the flat coal is not good, and the coal charging hole is blocked; (5) The coking time is too long, causing the coke cake to overfire; (6) The coking time is too short and the furnace temperature is too high, causing a large amount of graphite to be produced on the furnace wall ; (7) The coke oven machinery itself fails.

9.What are the hazards of negative pressure generated in the carbonization chamber?

(1) Affect the recovery of coal gas and chemical products; (2) Affect the output and quality of coke; (3) Damage the coke oven body and affect the life of the furnace body; (4) Cause local high temperature; (5) Burn the furnace wall bricks Cracked graphite, causing cross leakage.

10.What are the advantages and disadvantages of a single gas collector?

Advantages: less steel consumption, less investment; better ventilation on the stove top. Disadvantages: When coal is loaded, the airflow resistance in the carbonization chamber is large, and the crude gas discharge is relatively slow, which is easy to cause smoke and fire, which is unfavorable to the mechanization of the furnace top coal loading operation.

Post time: Jan-05-2022