Preparation Of Oil And Gas Separation Flat Membrane And Recovery Of VOCs Discharged By Oil Tanker

Many industrial processes handling organic solvents produce volatile organic compounds?VOCs?.These VOCs not only cause environmental pollution,but also cause economic losses.VOC removal and recovery has become a major problem to be addressed.Traditional VOCs removal and recovery techniques include carbon adsorption,condensation and adsorption,and none of them can meet every need.Membrane separation has become a good substitute or supplement technology for VOCs separation.In view of the technical difficulties in the preparation of gas separation membrane,the preparation of plasma polymerization gas separation composite plate membrane and its separation of volatile organic compounds from nitrogen were studied in this paper.Polyvinylidene fluoride flat film was prepared by phase transformation method,and a separation layerr having a thickness of less than 100 nmwas prepared on the substrate by plasma polymerization,thus forming a composite membrane.This study focused on the effects of plasma polymerization operating parameters and monomer species on the permeaselectivity of VOCs light hydrocarbon components and the recovery effect of VOCs heavy hydrocarbon components,and the surface morphology,cross section thickness and chemical composition of the membranes were measured.The results show that with the increase of polymerization time,the membrane thickness increases and the silicon content increases,which indicates that the deposition amount of sioxane increases,which leads to the decrease of permeance of VOCs light hydrocarbon components,the increase of separation ratio of nitrogen/VOCs light hydrocarbon components,and the increase of recovery rate of VOCs heavy hydrocarbon component,n-hexane.The plasma polymer films prepared by the three monomers follow this law.With the increase of polymerization power,the morphology and structure of the film surface change greatly.The permeance of VOCs light hydrocarbon component and the separation ratio of nitrogen/VOCs light hydrocarbon component fluctuate greatly,and the recovery rate of VOCs heavy hydrocarbon component,that is,n-hexane,fluctuates.The law of plasma polymerization film prepared by the three monomers is different.It is concluded that when the monomer is octamethylcyclotetrasioxane?OMCTS?,the permeaselectivity of VOCs light hydrocarbon is the best,the optimum permeance of n-butane is 1.02×10^-5mol/m²·s·pa,and the optimal nitrogen/n-butane separation ratio is3.36.When the polymeric monomer is hexamethylenetrisioxane?HMTrSO?,the recovery effect of n-hexane,the heavy hydrocarbon components of VOCs,is the best,and the optimum recovery rate of n-hexane is 67.4%.