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.
VOCS zeolite molecular sieve runner is divided into adsorption treatment zone, cooling zone and desorption zone, and driven by motor, which makes the runner rotate slowly, continuously adsorb and regenerate, and recycle tail gas. 5~10% of the condensed waste gas is mixed with the high temperature air in the desorption zone and enters the surface cooling section of the runner, where it is cooled and condensed, and most NMP can be condensed out and enter the waste liquid system. Then it is sent to the adsorption treatment area, and the air that meets the standard after adsorption can be exhausted to the outside by a fan.
In addition, a small amount of qualified air is recycled for heat exchange in the cooling zone, so that the air is heated and the runner is cooled. The heated air is heated by a heating device (steam heating or electric heating or heat transfer oil heating), and then the NMP on the runner zeolite is desorbed in the desorption zone, and the high-temperature air containing NMP in the desorption zone is sent to the surface cooling section of the runner. The whole runner process makes full use of the recycling of heat energy and saves the heating energy consumption required by the coating machine.