How to measure the pressure at the bottom of the carbonization chamber

Measure the pressure at the bottom of the carbonization chamber: ① The pressure at the bottom of the carbonization chamber is measured once every six months (in summer and winter). Notify the coke pusher driver in advance to replace the furnace door directly below the air intake pipe with a furnace door equipped with pressure measurement holes. ②Before the middle stage of coking, seal the end of an iron pipe with a length of 1200 mm and a diameter of ½ inch tightly using asbestos rope, and place it obliquely inside the pressure measurement hole beneath the furnace door (300 mm above the bottom of the carbonization chamber). ③Measurements should be taken 30 minutes before coking begins. The rising tube cover must not be open during these measurements; the iron tube should be pierced until yellow smoke is visible. A rubber hose is used to connect the positive end of an inclined pressure gauge to the iron tube. The lower end of the other inclined pressure gauge is connected to the pressure measurement hole of the gas collection pipe. ④When the gas collection pipe pressure stabilizes within the specified range, contact the furnace operator; under their guidance, readings are taken simultaneously from both the top and bottom. Repeat this three times to calculate the average value, and then repeat the above process each time the collector pressure changes. ⑤The pressure of the change gas duct must be adjusted at least three times; one of these adjustments can result in a slightly negative pressure in the carbonization chamber, thereby facilitating detection, correction, and adjustment. When adjusting manually, the flap must not be closed tightly. Adjust the gas collection pipe pressure appropriately based on the measurement results to maintain a pressure at the bottom of the carbonization chamber of 0–5 Pa at the end stage of coking. ⑥Based on the information above, perform a final check before and after disconnecting the gas collection pipe from the furnace chamber, and pay close attention to the water level in order to determine the pressure of the gas collection pipe. ⑦After recording the pressure in the last gas collection pipe and the pressure at the bottom of the carbonization chamber, pull out the iron pipe and promptly seal the furnace door opening with a plug.

The \"Q&A on Coking Production\" mentions that iron pipes are inserted before coal loading, presumably for coke ovens that use top-loading of coal; this is absolutely not feasible in tamped coke ovens. Even in a top-loading coke oven, there’s no need to insert iron pipes before loading coal, right? What is mentioned on the 2nd floor is: measurements should be taken 30 minutes before coke discharge ； Some sources mention that measurements should start 2 hours before coke pushing, taken every half hour, with the final measurement taken 15 minutes before the coke is removed. In short, there are many opinions, and it’s unclear who is right and who is wrong.

Measuring the pressure at the bottom of the carbonization chamber is primarily aimed at adjusting the pressure in the gas collection ducts, ensuring that the carbonization chamber remains under positive pressure throughout the coking process. This prevents negative pressure from causing damage to the furnace and affecting the quality and yield of the coke and other products. The specific method of measurement depends on the inherent characteristics of the furnace, and one’s own set of procedures must be developed accordingly.

What is mentioned on the 4th floor is that measuring the pressure at the bottom of the carbonization chamber is primarily done to adjust the pressure in the gas collection ducts, ensuring that the carbonization chamber remains under positive pressure throughout the coking process. This prevents negative pressure from causing damage to the furnace and affecting the quality and yield of the coke and other products. ”This sentence is correct. However, during the initial stage of coal charging, a large amount of raw gas is produced and the pressure is high; by the end of coking, very little raw gas is generated and the pressure is low. Let me put it this way: as long as it is ensured that the pressure at the bottom of the carbonization chamber remains positive at the end of the coking process (that is, before coke pushing), then the entire coking process will also be under positive pressure. Some books also ask what the purpose is of measuring the pressure at the bottom of the carbonization chamber throughout the coking process

In a rammed coke oven, it is possible to open the pressure measurement holes and insert iron tubes right after coal loading is completed, which makes it easier to take measurements. Measurements can be taken 30 minutes before coke extraction; there is no need to wait two hours. After 30 minutes, measurements should be taken every 5 minutes until the pressure at the bottom reaches around 5 Pa. For measurements in the carbonization chamber, the lower end of the suction tube should be used, and the upper tube cover must be sealed tightly during measurement. These are the general requirements. When conducting measurements, we usually take readings for all five pressure points simultaneously

First of all, thanks for the kind advice about going upstairs. “Take measurements every 5 minutes after 30 minutes” – how many times in total should measurements be taken? Or when was the last measurement taken? “What does it mean by ‘until the pressure at the bottom is around 5 Pa’? Should we wait until it reaches around 5Pa on its own, or adjust the pressure of the gas collection pipe to bring it to around 5Pa?

What I said might be a bit incorrect; I’m sorry:P. The measurements should be taken 2 hours before coke pushing, with the last measurement taken 30 minutes before coke pushing. In total, about 4 measurements are needed. Since there’s no need to track the changes in bottom pressure, it’s sufficient to obtain just one value to determine which pressure level is suitable for the specified heating regime. Especially during the last measurement, the pressure in the collector duct can be adjusted accordingly (if the pressure cannot reach 5 Pa at the bottom). At the same time, the bottom pressure should also be monitored so that the pressure in the collector duct remains around 5 Pa. This value displayed as the pressure in the collector duct is the one that needs to be measured. It’s best to carry out these measurements during maintenance periods, to avoid any interference caused by coal loading operations. Additionally, pay attention to pressure fluctuations caused by changes in the direction of flow in the main pipes in the basement