Process flow diagram：

Product principle：

Return air type water spray adsorption NMP recovery unit

Water as the absorbent medium in?NMP recovery process, which?contains two-stage absorption process, as follows：

The hot exhaust air?with high concentration of NMP from the coater is recovered by the air-to-air heat exchanger, and then sent to the NMP comprehensive absorption tower?by process fan. The absorption tower is composed of the lower and upper two-stage absorption towers, which are at towers on the bottom?and top. The NMP-containing air?is sent to the bottom of the lower absorption tower through, and the absorption liquid (80-85% NMP aqueous solution) is sprayed on the top of the lower tower.?

when the absorption liquid is lowered to the tower bottom, it will be sent to the ?top of the tower for circulating absorption through the circulation pumps.

When the liquid level exceeds 40% (the setting value can be adjusted) and the concentration of the circulating liquid reaches 80~85% (the setting value can be adjusted), the system will automatically send the solution containing about 80~85% of NMP (can be adjusted according to demand) to the NMP collection tank.

The air?absorbed by the lower tower enters the upper absorption tower, and the upper tower will use a solution containing about 10% of NMP for circulating absorption, then the absorption liquid will be lifted to the top of the tower by a circulating pump for circulating absorption, and the top of the upper tower will spray a small amount of process water.

After absorption treatment, the NMP content of the air?has dropped below 35mg/m3. Most of the exhaust gas is heated up by the air-to-air heat exchanger, then sent back to coater, a small part of air will be vented to adjust the negative pressure of the oven.

Non-return air type water spray adsorption NMP recovery unit

Water as the absorbent medium in?NMP recovery process, which?contains two-stage absorption process, as follows：

The hot exhaust air?with high concentration of NMP from the coater is recovered by the air-to-air heat exchanger, and then sent to the NMP comprehensive absorption tower?by process fan. The absorption tower is composed of the lower and upper two-stage absorption towers, which are at towers on the bottom?and top. The NMP-containing air?is sent to the bottom of the lower absorption tower through, and the absorption liquid (80-85% NMP aqueous solution) is sprayed on the top of the lower tower.?

when the absorption liquid is lowered to the tower bottom, it will be sent to the ?top of the tower for circulating absorption through the circulation pumps.

When the liquid level exceeds 40% (the setting value can be adjusted) and the concentration of the circulating liquid reaches 80~85% (the setting value can be adjusted), the system will automatically send the solution containing about 80~85% of NMP (can be adjusted according to demand) to the NMP collection tank.

The air absorbed by the lower tower enters the upper absorption tower, and the upper tower will use a solution containing about 10% of NMP for circulating absorption, then the absorption liquid will be lifted to the top of the tower by a circulating pump for circulating absorption, and the top of the upper tower will spray a small amount of process water.