The tar box is used to store the condensed tar in the raw gas,making it easy to concentrate.If tar boxes andπtubes are not installed,tar can easily accumulate in the pipeline.

The tar box is used for gas-liquid separation and impurities and coal sludge in tar.Theπshaped tube is also set for gas-liquid separation.Due to the need to adjust the pressure,in order to prevent viscous substances such as tar from sticking to the regulating flap,gas-liquid separation is set up,and ammonia spray is set on theπshaped tube.The tar on the flap is flexible in operation.

Nowadays,there are also designs that do not include a flip plate and tar box structure.Instead,the flip plate is designed to the outer tube of the cold drum,where gas-liquid separation is designed.

The tar box has the following functions

1.Isolate the direction of gas and tar ammonia water,and then collect them in the suction pipe section(mainly the shelf inside the tar box)

2.Depositing large tar residue to prevent clogging of the suction pipe caused by sedimentation in the suction pipe section,and having a cleaning port for easy cleaning of debris

3.The liquid level in the Balanced set is used to determine whether the suction pipe section is blocked for liquid drainage,because the liquid level rises back,causing tar and ammonia water to emit from the cleaning hole of the tar box

After the ends of the tar box and suction pipe are blocked,a large amount of reflux ammonia water overflows from the tar box,and the ammonia water in the gas collection pipe has exceeded half of the pipe.The raw gas will burst open the cover of the rising pipe due to the inability to be introduced into the gas collection pipe.To this end,we have taken the following measures.

(1)Immediately stop the fan,stop coal loading,and close the circulating ammonia water valve.Open the vent pipe and all rising pipe covers(except for the rising pipes in the carbonization chamber at the end of coking to prevent ignition of gas)to vent the gas and prevent damage to the gas collection pipe,bridge pipe,and valve body due to severe temperature rise.

(2)Melt the tar blockage by passing steam through the ammonia spray pipe at the top of the tar box and the U-shaped tube.But the steam pressure is low,and the tar box cannot be blown through.Later,a temporary opening was made at the end of the tar box and the suction pipe connecting the tar box,and a high-pressure ammonia water nozzle was installed to wash away the accumulated tar blockage with high-pressure ammonia water.The tar box and suction pipe were quickly cleared,and normal production was resumed.

When starting a new coke oven,in order to avoid the occurrence of the above accidents,the following points should be done well.

(1)The crushing fineness of coal loaded into the furnace should be strictly controlled.

(2)The temperature of circulating ammonia water should be controlled between 75-80℃,and the tar and ammonia water have good fluidity in the raw gas pipeline.

(3)When starting the fan,it is advisable to avoid prolonged negative pressure in the gas collection pipe to prevent excessive coal powder from being sucked into the raw gas export system and increasing the viscosity of the tar.

(4)A high-pressure ammonia water blowing device should be installed on the raw gas pipeline in front of the gas-liquid separator.

(5)Regularly use high-pressure ammonia water to purge the gas collection pipe,suction pipe,and tar box to prevent the accumulation and blockage of tar residue.

(6)When the tar box is severely blocked,a large flow of high-