In the process of VOCs treatment by chemical combustion method, there are several potential safety hazards as follows: activated carbon fires in activated carbon adsorption desorption catalytic combustion method, explosion of catalytic oxidation furnace, and fire and explosion of the whole catalytic combustion treatment device.
1. Activated carbon fire phenomenon and preventive measures
In the process of VOCs enrichment in the early stage, because of the low ignition point of activated carbon and the high desorption temperature, when the adsorption saturated activated carbon is desorbed, the high temperature in the desorption chamber will cause the activated carbon to ignite.
There are two ways to solve this problem: one is to use activated carbon with high ignition point; the other is to strictly control the desorption temperature to make it far lower than the ignition point of activated carbon. Therefore, the following measures can be taken: strictly control the desorption temperature, select the desorption temperature sensor with good quality, install two temperature sensors in the appropriate position of the activated carbon adsorption box as far as possible, and install two temperature sensors in the PLC In the programming, add the desorption procedure when the desorption temperature is over temperature; at the same time, it is necessary to prevent the accident from happening. At the same time, add fire water pipe above the activated carbon adsorption box and connect the smoke alarm and automatic spray device to prevent accidental fire.
2. Explosion of catalytic oxidation furnace and preventive measures
在处理高浓度VOCs 时，由于炉内含有大量氧气，当废气浓度达到废气组份中大部分有机废气的爆炸极，就会有爆炸的危险。因此，要时刻监测炉内VOCs 浓度， 在进入催化氧化炉的废气管道上安装浓度稀释装置，将高浓度废气稀释到爆炸极限下。同时在催化氧化炉上增加压力排气阀，在压力过高时自动打开阀门进行减压排气，以防炉内温度压力过高引起爆炸（因废气在热氧化过程中迅速释放大量热能导致炉内热空气压力过大）。
When the concentration of VOCs reaches the explosion limit of most organic waste gas in waste gas components, there will be explosion risk due to the large amount of oxygen in the furnace. Therefore, it is necessary to monitor the concentration of VOCs in the furnace at all times, and install a concentration dilution device on the exhaust pipe entering the catalytic oxidation furnace to dilute the high concentration waste gas to the explosion limit. At the same time, a pressure exhaust valve is added on the catalytic oxidation furnace to automatically open the valve for decompression and exhaust when the pressure is too high, so as to prevent explosion caused by too high temperature and pressure in the furnace (due to the rapid release of a large amount of heat energy in the process of thermal oxidation of waste gas, resulting in excessive hot air pressure in the furnace).
3. Fire and explosion of the whole catalytic combustion treatment device and preventive measures
The fire and explosion of the whole catalytic combustion treatment device mostly occurred in the system with only one set of adsorption device. Due to the accumulation of a large number of high concentration organic waste gas particles in the pipe wall and equipment, the gap between the pipe air valves is too large, and the production is not stopped in the process of desorption catalytic combustion, The inlet valve of the workshop cannot be closed, and the whole pipeline is fully open. At this time, the desorption catalytic combustion is likely to cause fire and explosion of the whole system under the action of high temperature. In view of the above situation, the following measures should be taken: installation of high-quality air valve, frequent inspection of air leakage, shutdown treatment in the process of desorption catalytic combustion in a single adsorption unit system.