【Q&A on the Production Operations of Haichuan Coke Ovens】8. Under what circumstances is the heating of the coke oven stopped? What are the procedures for stopping and resuming heating?

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In 2026, during the 25th National “Safety Production Month”, everyone should prioritize safety and be capable of responding to emergencies; risks and hidden dangers must be identified and rectified. -------------------------------------------------- 8. Under what circumstances should a coke oven cease heating? What are the procedures for stopping and resuming heating? Answer: The heating of a coke oven should be stopped immediately in any of the following situations. (1) When the pressure of the main gas pipeline is below 500 Pa. (2) When the gas pipeline is damaged or explodes, affecting normal heating. (3) When a malfunction occurs in the flue system, making it impossible to maintain the required suction. (4) When switching equipment (such as switches and switch chains, etc.) malfunctions and cannot be repaired in a short period of time, thereby affecting normal switching. (5) Temporary power outage. Steps to stop heating: (1) Immediately activate the switch to move the switching cock to the fully closed position, and cut off the power supply for automatic switching. If there is a power outage, cut off the power first, engage the upper clutch, and use the manual operation device to move it to the fully closed position. (2) Close the machine and the flue flap on the coke side to reduce the suction force to 120–140 Pa, then set it in a fixed position. (3) Close the heating gas on/off valve. (4) Stop the coke pushing operation. (5) Cover the exhaust air inlet with asbestos board, leaving a 5 mm gap. (6) Replace the exhaust thallium and air cover as usual every 30 minutes, but reversing to the intermediate position is prohibited. When an automatic reversing device is installed, the control selector lever must be placed in the stop position; it is strictly forbidden to open the replacement valve or lift the gas thallium when the regulating valves are not closed. (7) After stopping heating for more than 2 hours, the pressure in the gas collection pipe should remain 20~30 Pa higher than normal. (8) When stopping heating for an extended period, the valve on the heating gas pipe should be closed; when mixed gas is being used, the valve for the mixed gas must be tightly closed. (9) When using coke oven gas for heating, the gas valves leading to various locations should be closed, and the heating steam should be shut off tightly. (10) Turn off the switches on each instrument (except for the main pressure pipe). (11) Assign a dedicated person to check whether the handling in various areas meets the requirements. Procedure for resuming heating: Heating can be resumed only after the faults affecting the heating of the coke oven have been resolved, the pressure in the main gas pipeline has risen above 4000 Pa, and permission has been granted by the energy management center. (1) The gas supply operation is under the unified command of the production supervisor, who assigns operators to various positions and clarifies their responsibilities. (2) It is prohibited to supply gas to two coke ovens simultaneously. (3) During the entire gas supply period, pushing coke is prohibited, and welding or open-flame operations are not allowed within 40 meters of the furnace unit. (4) After purging the gas pipeline with steam or nitrogen, open the main gas pipeline valve, introduce steam or nitrogen, and after allowing 10 minutes for venting, take samples for a gas explosion test. Once two consecutive tests are successful, close the vent pipe valve. (5) Drain the water accumulated in the coal gas pipeline, open the valve connected to the water seal tank; the water seal tank should remain filled with water, and the valves and flap switches of all instrument pipelines should be in the correct position. (6) Restore the inlet opening degree and the flue suction exhaust flap to normal conditions. (7) Assign a dedicated person to monitor the gas pressure; during the gas supply process, pay attention to the pressure in the main gas pipeline – supply should be stopped if it falls below 1000~1500 Pa. (8) Check whether the switch is in normal operation: first restore the suction pressure to a level 20–30 Pa higher than normal, then start opening the upward (or downward) air flow control valves one by one from the end of the pipeline, completing this process within two switches. To prevent insufficient gas pressure, open the valves to 1/2 position first; once all the gas has been delivered, open them fully if the pressure is sufficient. (9) When the temperature in the combustion chamber is below the ignition point (down to below 800°C), matchsticks or other ignition materials must first be inserted into the combustion chamber, followed by the introduction of gas. The flame combustion should then be checked and adjusted to normal levels. (10) Once the gas supply is normal for combustion, production is resumed, and the heating regime is adjusted according to the temperature conditions.