Fire hole pressure

For coke ovens of 6 meters or more in length, the specified pressure values for the tuyere openings of 0–5 Pa may no longer be appropriate. As the height of the coke oven increases, both the resistance to rising and falling as well as the draft force due to accumulated gas increase; therefore, it is necessary to adjust the specified pressure values for the observation holes accordingly. In thermal control, the flue draft (draft at the roof) is generally kept constant, and the pressure at the viewing port is controlled by adjusting the opening degree of that port. This method allows for more precise control of the airflow inside the furnace, ensuring the quality of the coke and thermal efficiency. .

Currently, a pressure of 20±5 Pa is generally considered appropriate for the tuyere holes in large coke ovens. By adjusting the flue suction to maintain a proper pressure at the viewing ports, it is also necessary to pay attention to the opening degree of the air inlet in order to keep a reasonable air excess coefficient.

The coke oven is taller; if the suction at the roof remains unchanged, the pressure at the observation holes increases. The pressure at the viewing ports is high; the temperature measurement devices are affected, the temperature of the crossbars increases, heat dissipation from the furnace roof rises, and the exhaust gases from the combustion chamber (containing excess oxygen) can flow into the carbonization chamber, thereby burning away the graphite in the gaps between the bricks... If the pressure at the viewing ports is kept at 0–5 Pa, it becomes necessary to increase the suction force at the furnace roof. What other negative effects might there be, besides air leakage through the walls? Moreover, this drawback can be easily resolved by thermal repair through sealing the wall.

Why is it necessary to increase the pressure at the fire viewing hole? What’s wrong with reducing flue pressure (that is, increasing suction, roof suction)? Or rather, isn’t the indicator for flow the pressure difference?

The method you proposed for reducing flue gas pressure (increasing suction force, building up suction at the top) is also a way of regulating the airflow inside the coke oven, and it can help to improve the quality of the coke as well as its thermal efficiency. In fact, in thermal control, it is possible to control the tuyere pressure by adjusting the opening degree of the tuyeres, or to control the airflow inside the coke oven by adjusting the flue gas pressure. In specific cases, the appropriate adjustment method should be chosen based on the actual circumstances. During the operation of the coke oven, to maintain normal combustion and thermal balance inside the oven, it is necessary to adjust parameters such as airflow and pressure differences, so as to ensure that the coke undergoes sufficient pyrolysis during the carbonization process and is exposed to a stable hot air environment. In this process, both flue gas pressure and soot hole pressure are important indicators. Among them, flue gas pressure is the main parameter for controlling the suction force at the top of the furnace, while the soot hole pressure is the main parameter for controlling the air flow distribution inside the furnace. Pressure difference is one of the indicators of flow rate, but it is not the only one; the influence of other parameters also needs to be taken into consideration. .