Since different components in VOCs have different saturated vapor pressure at different temperatures, temperature of system is gradually reduced by the refrigeration unit, so that vapor pressure of some hydrocarbon substances in the oil and gas reaches supersaturated state, supersaturated vapor is gradually condensed into liquid and collected, so as to recover oil and purify gas. With the multi-stage condensation technology, the system temperature can be reduced to -75 ℃ through three-stage condensation, which is usually used in the situation of high concentration of organic gas, and the recovery effect is intuitive and process is mature.
Binding force between components in VOCs gas and adsorption materials is different, so hydrocarbon components in VOCs can enter into pores of adsorbent and be adsorbed, and then hydrocarbon in oil and gas can be recovered by pressure swing desorption.
Low volatile or non-volatile liquid can be used as the absorbent, there are difference of solubility or chemical reaction characteristics of various components in the absorbent, so harmful components in waste gas can be absorbed by absorbent, so as to purify the waste gas.
Catalytic Oxidation Technology
By action of catalyst (Pt, Pd and other heavy metals), VOCs react with O2 at low temperature to produce CO2 and H2O.
Compared with common direct combustion method, advantages of this technology includes low ignition temperature, safe and reliable operation of equipment. For the treatment of VOCs with low concentration and need to meet the current national emission standards, catalytic oxidation technology is a suitable treatment technology