| Nowadays gasoline is easy to volatilize in the process of production,transportation and use,which will cause environmental pollution and endanger hunman health,as well as have negative influences to safety and fuel quality.Therefore,removal and recovery of gasoline vapor is of great significance,which can protect environment and also realize the effective utilization of resources.Adsorption is one of the most widely used methods in treating organic waste gas.Polymeric resins have gained much attention as adsorbent,attributed to high specific surface,stable physical and chemical properties and controllable pore structure.Lots of efforts have been made in gasoline recovery using polymeric resins.However,many researches focused on the single component in gasoline or simplied gasoline as single component,ignoring the competition of the complex gas composition in the adsorption process.In this paper,hypercrosslinked polymeric resin NDA-150 and macroporous resin NDA-1800 were selected as adsorbents;pentane,cyclohexane,and toluene,which were the representative components of gasoline,were selected as the adsorbates.The single,binary and ternary adsorption equilibria of pentane,cyclohexane and toluene onto resin NDA-150 and NDA-1800 were investigated and dynamic adsorption experiments of single,binary and trinary components were also researched.The main research contents and the results obtained are as follows:(1)The adsorption equilibria of pentane,cyclohexane and toluene vapor onto the NDA-150 and NDA-1800 were studied by the static adsorption method at 30?,40? and 50?.The results showed that the adsorption capacity on NDA-150 increase rapidly owing to the existence of micropore under lower concentration;while the adsorption capacity on NDA-1800 increase continuously under higher concentration.The D-A equation was the best one to fit the adsorption equilibria on NDA-150 with larger R2(>0.99),while the Freundlich model was the best one to fit the adsorption equilibria on NDA-1800 with larger R2(>0.92).The isosteric enthalpies of pentane,cyclohexane and toluene on NDA-150 is larger than these on NDA-1800,indicating that adsorption interaction of pentane,cyclohexane and toluene on NDA-150 is larger than that on NDA-1800.(2)The binary and ternary adsorption equilibria of pentane,cyclohexane,and toluene onto NDA-150 and NDA-1800 were studied by the static adsorption method at 30?,40? and 50?.The results showed that the binary and ternary adsorption capacities on NDA-150 was affected by the adsorption competition on micropore,and the adsorption capacity of pentane decreased obviously in binary and ternary mixtures compared to single component adsorption.The smaller the adsorption interaction of adsorbate on NDA-150 is,the more the decrease in adsorption capacity.On the other hand,the decrease of adsorption capacities of pentane,cyclohexane,and toluene on NDA-1800 was slight compared to single component adsorption.The ideal adsorbed solution theory(IAST)was used to predict binary and ternary adsorption equilibria of pentane,cyclohexane,and toluene onto the NDA-150 and NDA-1800.The predictedvalues were compared with experimental values.The IAST predicted the adsorption equilibria of toluene-cyclohexane in binary and trinary mixtures,with the mean relative deviation less than 20%.However,it couldn't accurately predict the the adsorption equilibria of pentane,with the mean relative deviation of pentane in trinary system more than 40%.(3)The binary dynamic adsorptions of pentane-cyclohexane,pentane-toluene,and toluene-cyclohexane vapor onto the adsorbents NDA-150 and NDA-1800 in the fixed bed were researched at 30?,40? and 50?.The results show that the adsorbate with weeker interaction on NDA-150 will be replaced by the stronger one,which will cause the higher outlet concentration of replaced adsorbate than the inlet concentration.The lower the temperature is,the the more significantly the phenomenon of replacement is.The lower the concentration of adsorbate with weeker interaction on resins is,the more significantly the phenomenon of replacement is.However,there was not obvious replacement for adsorption of binary mixtures on NDA-1800,indicating the coadsorption of binary components on NDA-1800.(4)The ternary dynamic adsorptions of pentane,cyclohexane,and toluene vapor onto the adsorbents NDA-150 and NDA-1800 were investigated in the fixed bed e at 30?,40? and 50?.The results show that pentane was first replaced and cyclohexane was second replaced for adsorption on NDA-150.The lower the temperature is,the higher hunchback-shaped peak is,indicating the more competition of the pentane,cyclohexane and toluene in micropore.However,the replacement of pentane and cyclohexane was not seen for the adsorption on NDA-1800,indicating that the coadsorption of ternary mixtures on NDA-1800. |
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