| With the acceleration of industrialization and economic growth in our country,the annual emission of Volatile organic waste gas,VOCs has increased rapidly in recent years and has become an important source of pollution endangering people’s health and environmental quality in our country.Zeolite runner adsorption is one of the hot technologies for the treatment of VOCs waste gas with low concentration and high air volume in petrochemical,printing and coating industries.In this paper,the process of zeolite runner adsorption of ethyl acetate,a typical component of VOCs waste gas,was taken as the research object.The experimental platform of zeolite adsorption process based on electrical impedance tomography(EIT)method and the numerical simulation model of flow-adsorption process based on coupled adsorption kinetic model were established.The influence of runner speed,exhaust flow rate and other factors on the adsorption process of ethyl acetate by zeolite runner was analyzed.The main work and research results of this paper are as follows:1.The fixed bed adsorption experiment platform of zeolite was used to test the performance parameters of zeolite adsorption of ethyl acetate under different working conditions,and the Lagergren model,McKay model and Boyd model were used to fit the adsorption test results.The results showed that the first-order reaction kinetic model had the highest correlation.The adsorption property and adsorption process of zeolite for ethyl acetate can be better characterized.Therefore,the governing equation of zeolite adsorption based on Lagergren first-order kinetic model is established.2.The coupled adsorption governing equation,porous media model and Euler Euler multiphase flow simulation model of flow-adsorption process were established,and the process of zeolite adsorption of ethyl acetate waste gas under different working conditions was numerically simulated,the concentration and pressure distribution of ethyl acetate in the adsorption process were analyzed,and by comparing with the adsorption test results,The effectiveness of the simulation model is preliminarily verified.3.The experimental platform of zeolite adsorption process was built based on electrical impedance tomography(EIT)method,and the distribution images of ethyl acetate adsorption saturation at different sections of zeolite adsorption bed at different adsorption times were obtained,and compared with the cloud map of ethyl acetate concentration distribution obtained by numerical simulation method.The results show that the adsorption of ethyl acetate waste gas by zeolite adsorption bed is gradually diffused from the boundary to the center.The concentration fraction of ethyl acetate in the simulation results and the average resistivity of EIT imaging results show the same trend over time,which further verifies the correctness of the simulation model of zeolite flow-adsorption process.4.Combined with the actual size of adsorption equipment and adsorption conditions of zeolite runner,a numerical simulation model for the flow-adsorption process of zeolite runner for the adsorption of ethyl acetate waste gas was established,and the influence of different runner speed and exhaust gas flow conditions on the adsorption process was analyzed.As the rotational speed increased,the gas flow rate at both ends of the zeolite runner increased,the pressure of ethyl acetate on both sides and the concentration of ethyl acetate increased,showing a concave distribution of high on both sides and low in the middle.The ethyl acetate on both sides could not be completely adsorbed,and the adsorption rate of the runner on ethyl acetate decreased.With the increase of inlet flow rate,more saturated zeolite was absorbed at the front end,and the adsorption zone shifted to the right with the increase of flow rate.With the increase of pressure in the same area and the increase of ethyl acetate concentration,ethyl acetate could not be completely adsorbed,and the adsorption rate of zeolite runner to ethyl acetate decreased. |
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