Study On The Removal Of Benzene From Waste Gas Using Membrane-based Gas Absorption And Decompression Membrane Distillation Combined Process

In this paper, using C6H6/N2gas mixture as the research system, with a hydrophilic organic solvent N-formylmorpholine (NFM) aqueous solution as the absorbent, porous hydrophobic polypropylene hollow fiber membrane reactor, and process experiment device, developed membrane gas absorption-vacuum membrane distillation combined process for purification of waste gas containing benzene research. The research contents include membrane gas absorption-vacuum membrane distillation, membrane process properties research for membrane wetting mass transfer performance and the effect of the combined process of industrialization promotion research.Membrane gas absorption process in self-made experimental device, with NFM solution as the absorbent, polypropylene hollow fiber membrane assembly for gas, liquid membrane contactor, launched a membrane gas absorption purification of waste gas containing benzene performance research, analysis of gas, liquid, gas flow, liquid inlet concentration, initial temperature of absorption liquid, absorption liquid the concentration of NFM, operation mode and membrane module structure of operation parameters such as benzene removal efficiency and total mass transfer coefficient effect.The results showed that:in the absorbent NFM40%volume fraction, gas phase flow in50～300mL·min-1, liquid phase flow under the condition of15～75mL·min-1, dealing with the concentration of1.7～10.1mg·L-1C6H6/N2mixed gas, benzene removal rates for44.1%～99.3%, total volumetric mass transfer coefficient of0.007～0.074s-1.In addition, the continuous operation of experiment, membrane gas absorption process has high stability and maneuverability.In a self-made vacuum membrane distillation process experiments, carried out membrane gas absorption experiment NFM absorbent regeneration experiment, analysis of operation time, the flow rate of the feed, the feed temperature, degree of vacuum of the cold side and membrane module structure of operation parameters such as the regeneration efficiency and membrane flux.In the NFM volume fraction of40%, absorbent flow in10～90mL·min-1, benzene concentration is0.25～1.Og·L-1, an initial temperature of25～37℃, cold vacuum degree0.3-0.9MPa condition, the absorbent regeneration efficiency of8.1%～99.3%, membrane flux is0.2～8.1×10-3mg·cm-2·min-1.The experimental results show that:the vacuum membrane distillation for benzene in aqueous solution of NFM with higher regeneration efficiency and mass transfer flux. Membrane gas absorption technology in treatment of waste gas containing benzene, launched the film wetting on membrane mass transfer performance of.Comparison of membrane hole filling and full inflation under the two conditions of the membrane’s mass, and the analysis of the two sides of the membrane, solution gas pressure load and temperature on membrane effect of Kong Runshi.The experimental results show that:film hole filling when the total volumetric mass transfer coefficient was only fully inflated by about50%, two sides of the membrane and gas pressure on membrane Kong Runshi effects were larger, an increasing load and absorbent temperature increased, will lead to more easily wetting film hole.Taking experiment data as the basis, the design and manufacture of small membrane gas absorption membrane distillation combined process pilot plant, and the effects of operation conditions.The experimental results show that:the flow of absorbent for300mL·min-1, benzene exhaust flow1000mL·min-1, benzene removal rate can reach95%.