Laboratory exhaust air pollutants are many kinds of air pollutants, complex composition, emission with intermittent, the main air pollutants including organic gases and inorganic gases two categories. Organic gases include carbon tetrachloride, methane, ethyl ether, ethanethiol, benzene, aldehydes and so on. Inorganic gases include nitrous oxide, nitrogen dioxide, hydrogen halide, hydrogen sulfide, sulfur dioxide, and so on. These gases are emitted directly into the atmosphere, will exacerbate the formation of acid rain, constituting a serious social nuisance, if people inhale more will cause direct harm. Our current universities and schools laboratories are generally ventilated kitchen ducts directly outside the laboratory to form the protection of the laboratory experimenter, but the environment is adversely affected.
There is also a ventilated kitchen directly installed adsorption device, adsorption of harmful substances, but the filter must be replaced regularly (belonging to the dry processing).
Now popular wet, dry two categories of treatment:
1, wet treatment is installed outside the laboratory absorption tower spray, according to the type of waste gas reasonable choice of absorbent liquid, from the top of the absorption tower atomization spray, from the bottom of the absorption tower pressurized into the waste gas.
? 2, dry exhaust treatment refers to the gas mixture and porous solid contact, the use of solid surface exists in the unbalanced molecular gravitational force or chemical bonding force, the mixture of a component or some components adsorbed on the surface of the solid process. The solid with adsorption effect is called adsorbent, and the advantage of this method is simple equipment, convenient operation and easy to realize automatic control. But because of the different physical and chemical properties of the adsorbent, has a strong target, so the treatment of waste gas containing different harmful substances must be configured with different physical and chemical properties of the adsorbent, in order to play a good role in gas purification; if the waste gas through the adsorbent for a shorter period of time, the content of hazardous substances in the waste gas is too high, the effect of waste gas purification will not be ideal; in the waste gas through the adsorption medium, due to the air flow by the solid media blocking When the exhaust gas passes through the adsorption medium, because the airflow is blocked by the solid medium, it is necessary to increase the power of the fan in order to ensure the normal air speed of the ventilation system. The adsorbent needs to be replaced or regenerated periodically to ensure the normal operation of the absorption device. Therefore, this method in practical application needs to invest a certain amount of costs and manpower, this method is generally used for exhaust gas treatment of hazardous substances in the type of relatively stable and low content of exhaust gas, so as to facilitate the use of a targeted adsorbent. Dry exhaust treatment generally use organic gas activated carbon adsorption device, the principle is that the activated carbon has a lot of micropores and a large surface area, relying on molecular gravity and capillary effect, can make the solvent vapors and volatile substances adsorbed on the surface, but also according to the boiling point of different substances, the adsorption of the substance will be precipitated by steam. When using steam as a desorption medium, the precipitation of organic solvent vapor and water vapor together through the condenser condensation, into the separation of the barrel by the separation of the recovery of organic solvents.