1. Determination of equipment technology

The organic gas contained in the adsorption tank is removed, and the solvent is adsorbed by activated carbon, which has dual functions of adsorption and desorption. The specific process steps are as follows:

(1) The gas enters the exhaust gas purification tower at room temperature and then enters the activated carbon adsorption tank for adsorption.

(2) The entire adsorption process is almost carried out at normal pressure and temperature, and the adsorbent (activated carbon) in the adsorption tower is mainly used for adsorption and solvent recovery. Solvent recovery condensers, steam, cooling water, separators, etc. are the main equipment and auxiliary facilities for recovering solvents.

2. The working principle of activated carbon is divided into three parts: adsorption, desorption, and activated carbon drying treatment.

A、 Adsorption process:

After passing through the exhaust gas purification tower, the gas enters the activated carbon bed and is adsorbed by the activated carbon in the bed. The purified gas that meets the emission standards is discharged through a fan and then discharged outdoors.

B、 Detachment process:

The solvent adsorbed on activated carbon over a period of time (depending on the gas content and production time) should be desorbed using steam. The solvent adsorbed on activated carbon is then desorbed at high temperatures and condensed into a liquid through a condenser before entering the separator. The recovered solvent is separated from water in the separator.

C、 Activated carbon drying

The drying fan first blows ambient temperature air into the activated carbon filter, where some of the gas condenses into water droplets. Then, the air is heated by a heater, and the hot air circulates into the activated carbon filter, taking out the air containing moisture for condensation. This cycle continues.

(3) The flow velocity of gas entering activated carbon is less than 0.8 meters per second, which ensures the adsorption effect of activated carbon. The thickness of the activated carbon filling layer reaches 600mm, ensuring a 90% adsorption efficiency.

(4) Install a drying fan to dry the moist activated carbon after desorption is complete, in order to ensure the next round of adsorption of the activated carbon.

(5) During the drying of activated carbon, install one air heater to ensure the drying effect.

(6) The activated carbon adsorption tank is made of A3 steel plate. PTFE anti-corrosion is used at the connection points of the flange.

(7) The activated carbon used is Ningxia activated carbon with an iodine value of over 900.

3. Introduction to processing technology flow

This scheme adopts gas pretreatment, adsorption desorption and drying. At the same time as analyzing desorption, auxiliary facilities such as steam source, cooling circulating water, solvent recovery condenser, separator, etc. are equipped. The fan extracts air in negative pressure form. The entire system adopts PLC program control, human-machine interface, and achieves automation.