Principle
The NMP waste gas discharged from the coater reaches the filter box device through the exhaust pipe for purification and filtration, and then is sent to the waste heat recovery device and then to the condensing host device for cooling and condensation. Most of the NMP in the waste gas can be condensed out and enter the waste liquid system, and the concentration of NMP in the condensed waste gas is reduced to below 300ppm.
90~95% of the low-temperature waste gas after condensation is sent to the waste heat recovery device, where it exchanges heat with the high-temperature waste gas discharged by the coating machine, and then the low-temperature waste gas is heated to meet the return air requirement and sent back to the coating machine, thus fully realizing the heat energy recovery and saving the heating energy consumption required by the coating machine.
5~10% of the low-temperature waste gas after condensation is sent to the spray tower device. The spray tower uses the characteristics that NMP can be mutually soluble with water at any ratio and has high water solubility to circularly rinse and absorb the waste gas. After the NMP concentration in the liquid phase of the tower bottom reaches the set value, it enters the waste liquid system, and the gas-liquid separator is used at the top of the tower to separate and demist, so that the NMP in the waste gas is completely absorbed, and the concentration of the discharged tail gas meets the national environmental protection requirements.