Questions about the treatment of organic waste gases from crude benzene?
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At the beginning of 2021, the crude benzene processing unit of our plant’s coke oven gas facility put into operation a process involving activated carbon adsorption, nitrogen desorption, and condensation in order to treat the organic waste gases emitted from various vents in that unit. With four activated carbon tanks used for adsorption and one for desorption, after each desorption cycle, the levels of benzene and total non-methane hydrocarbons detected by the organic waste gas monitors at the chimney exceeded the allowable limits by a large margin. I would like to ask the experts here – why is that?
This excess may be temporary, as activated carbon is a porous material; even with desorption processes in place, the organic substances that were originally adsorbed on the medium come off during desorption, and they are not removed promptly and completely by the desorption process. When it is put into use next time, the situation mentioned by the poster might occur. It is recommended to extend the desorption time appropriately and blow with hot nitrogen for a while before completion, which may reduce the occurrence of this phenomenon.
Hello, 1st floor: Considering that the previous desorption process may have resulted in levels exceeding the limits due to its short duration, this time the desorption process lasted 14 hours, which is far longer than the designed 8 hours. Additionally, the levels exceeded the limits almost immediately after operation, then decreased gradually; after 2 days, the benzene level dropped from 103 to 15. Please give more guidance: handshake
It can enter the gas negative-pressure system; however, this adsorption process cannot achieve complete absorption. Once under negative pressure, there is no chimney to handle the subsequent treatment of environmental pollutants and wastewater
The organic waste gas enters the negative-pressure pipeline before the primary cooler; our company has been using it for half a year, and it is operating well.
Activated carbon adsorption is suitable for situations where the concentration of organic waste gases is low. If the concentration of such gases is high, the ability to remove 30% of them through adsorption drops significantly. If you have a large volume of waste gases with high concentrations, it is recommended to use incineration as a treatment method