Measurement of various pressures in coke ovens

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I. Measurement of the pressure at the bottom of the carbonization chamber. The pressure at the bottom of the carbonization chamber serves as a basis for determining the pressure in the gas collection duct; under any operating conditions, this pressure should be higher than atmospheric pressure at the end of the coking process. The measurement of the pressure at the bottom of the carbonization chamber is taken through a pressure sensing hole on the furnace door of the carbonization chamber, directly below the air intake pipe on the machine-side coke side. The pressure gauge tube is usually a stainless steel tube that is 1 meter long and about 10 mm in diameter; the end of the tube that is inserted is positioned about 20 mm away from the surface of the furnace door lining bricks. To prevent the steel pipe from being blocked by coke, the inserted end of the pipe is plugged with aluminum silicate fiber rope, while the exposed end is connected to the pressure measurement device; it is necessary to ensure a tight seal at the junction between the steel pipe and the furnace door. The measurement is taken 30 minutes before coke pushing. During measurement, the steam in the rising tube or the high-pressure ammonia water system is shut off, and the cover of the rising tube is tightly closed ； When the gas collection pipes are managed in segments, the closed bridge pipe flaps should be opened. Before measurement, pierce the pressure tube with a metal probe. When the measured value is less than (or greater than) 5 Pa, the pressure in the gas collection pipe should be increased (or decreased) to keep the pressure at the bottom of the carbonization chamber within 5 Pa; the pressure in the gas collection pipe at this point is the pressure that should be maintained during that coking time. II. Measurement of the pressure at the sight hole: The pressure in the combustion system is primarily determined by the pressure at the sight hole. The fire hole pressure was measured in the upward airflow temperature-measuring flue 5 minutes after the exchange. The measurement point is located 150–200 mm below the fire viewing port cover. Connect one end of the measuring hose to the positive terminal of the inclined micromanometer, and the other end to the metal tube inserted into the vertical flue. Be careful during measurement to prevent the coal loading hole cover and the viewing hole cover from damaging the rubber hoses. III. Measurement of the suction at the top of the regenerator The suction at the top of the regenerator is one of the important tasks that must be carried out during burner adjustment. Since the pressure in the combustion system changes during the switching interval, the suction at the top of each regenerator remains roughly constant as the coking time progresses. For ease of comparison, when measuring the suction at the top of the regenerator of the entire furnace, the suction of the standard regenerator is measured first, and then the relative suction difference between each other regenerator and the standard regenerator is determined. For standard regenerative chambers, two adjacent ones are selected on each side of the machine and furnace; it is required that the temperature of the corresponding combustion chambers be normal, the resistance in the combustion system be normal, and there should be no abnormal phenomena such as flame leakage or backflow. For the convenience of measurement, the standard regenerator is generally located in the middle of a coke oven bank, but it is best to avoid being directly below the air intake pipe. Before measurement, check whether the heating regime is normal, and adjust the damper opening and the elevation of the exhaust weight to be consistent. Place the inclined micromanometer near the standard heat storage chamber and adjust the zero point; check whether the pressure measuring tube is leaking or unobstructed. First, adjust the suction at the top of the standard regenerator to meet the requirements, so that the suction of the rising and falling air currents in the standard regenerator is the same during the two exchange intervals. The time after the suction torque of the standard regenerator is exchanged should be the same each time; generally, measurements begin 3 minutes after the exchange. Connect the negative terminal of the inclined micromanometer to the pressure measurement port of the standard regenerator, and the positive terminal to the pressure measurement port of the regenerator to be measured. The reading of the inclined micromanometer represents the difference in suction at the tops of each regenerator compared to that of the standard regenerator; from this value, the suction at the top of each regenerator can be calculated. After measurement, record the heating regime at that time, the suction at the top of the standard regenerator, and the suction difference between each regenerator and the standard regenerator. During the measurement process, the heating regime of the coke oven must be stable, and the carbonization chambers associated with the standard regenerator should not be in the stage of coke pushing or initial coal charging. Measurements of the suction at the top of the regenerator are generally not carried out during strong winds or heavy rain. IV. Measurement of the regenerator resistance: The resistance of the regenerator is measured in order to check for blockages in the grid bricks. A diagonal micropressure gauge is used to directly measure the pressure difference between the small flue of each regenerator and the top of the regenerator for ascending or descending air currents. Measurements start one by one from the furnace side 3 minutes after the exchange. During measurement, the positive end of the inclined micromanometer is connected to the top of the heat storage chamber, while the negative end is connected to the pressure measurement hole in the small flue, and the pressure difference is read. To obtain comparable data, for each measurement, the suction at the top of the regenerator under the two airflow conditions is set to be the same as that in the previous measurement, or the measured results are converted without changing the suction at the top of the regenerator before comparison. The heating regime at that time must be recorded after each measurement. The measurement results are used to calculate the average pressure difference between the rising and falling air streams in each regenerator side (separately for the air regenerator and the gas regenerator). The difference in pressure between the upper and lower parts of the counterflow regenerator equals the sum of the resistances within the regenerator. V. Measurement of the five-point pressures: The measurement of the five-point pressures in the combustion system is carried out to determine the actual pressure distribution within the coke oven combustion system as well as the resistance levels in various sections. Therefore, such measurements should be conducted in a combustion system where the temperature of the combustion chamber is normal, the adjacent carbonization chambers are in the middle stage of coking, the control devices in all parts of the combustion system are functional, and the furnace structure is airtight. During measurement, two inclined micromanometers were used in the regenerator corridor to measure the pressures at the top of the regenerator for the upward and downward air flows, respectively; while one inclined micromanometer was used on the furnace roof to measure the pressure at the viewing hole of the temperature-measuring flue connected to the regenerator being measured. 5 minutes after the exchange, the readings of the 3 gauges were taken simultaneously. Subsequently, the pressure difference between the gas regenerator and the air regenerator was measured, as well as the pressure differences at the temperature measurement points on the top of the regenerators and in the small flue ducts. Additionally, the pressure difference at the observation ports for detecting counterflow was measured; these readings were taken again after every 1 minute, for a total of 3 measurements. After reversing, perform the measurement using the same method. After the measurement, the pressure at each point is calculated, and a pressure curve for the five points is drawn. And record the heating regime at that time. VI. Measurement of the pressure in the horizontal pipe: When the pressure in the horizontal pipe changes significantly, it indicates that there is a change in the amount of heating gas supplied; therefore, measuring this pressure can serve as a reference for adjusting the temperature. Measurement is carried out directly at the pressure measurement points on the cross tubes using a U-tube manometer. When measuring the pressure of all the cross tubes, taking into account the errors caused by the gas pressure, a cross tube with a relatively normal furnace temperature can be selected in the middle as a standard, and the pressure difference between this \"standard cross tube\" and the other cross tubes is measured. Then it is converted into the pressure of each row of horizontal tubes.