Effect And Simulation Of Coupled Heat And Mass Transfer On Adsorption And Pressure Swing Adsorption

Presently, study on disposal and control of volatile organic compounds (VOCs) in environment protection area is a tropic subject. Adsorption is commonly used for purifying VOCs for its advantage of simple equipment, easy operation and low energy consumption. Pressure swing adsorption (PSA) is nearly 50 years for the development of gas purification, separation and purification of new technologies. Since 1960s, PSA technology had been applied in the recovery of light hydrocarbon from the organic exhaust. Adsorption process will produce adsorption heat and temperature and concentration of gas will have cross influence in this process,.In this paper, we studied the heat and mass transfer during adsorption and pressure swing adsorption process with acetone and toluene as adsorbate In accordance with the development of mathematical models of adsorption process, we selected the appropriate mass balance equations, energy balance equation, equation of adsorption equilibrium and mass transfer rate equation for these studies about the effect and simulation. In the equation considered the cross coupling effects of heat and mass transfer, established a mathematical model for both fixed-bed adsorption and pressure swing adsorption simulation. At the same time, we tested acetone and toluene in fixed-bed adsorption and pressure swing adsorption. Under the based of the experimental conditions, we simulated acetone and toluene bicomponent gas adsorption and pressure swing adsorption, used finite difference method, compiled FORTRAN program and chemical software Athena Visual Studio to solve the model. Compared the simulation with the experiment, model results were well consistent with the experimental results, and we proved that this model with a fixed-bed adsorption and pressure swing adsorption simulation is feasible.We simulated fixed-bed adsorption and pressure swing adsorption process with acetone, toluene bicomponent gas as adsorbate. Also we investigated the effect of axial thermal conductivity, inner heat transfer coefficient, outer heat transfer coefficient, axial diffusion coefficient, diffusion coefficient of adsorbed phase, Soret coefficient and Dufour coefficient on heat and mass transfer during fixed-bed adsorption and pressure swing adsorption process. The simulation results of fixed-bed adsorption and pressure swing adsorption process showed: heat transfer coefficient mainly affects heat transfer process, but doesn't affect mass transfer process. Mass transfer coefficient mainly affects mass transfer process, but doesn't affect mass transfer process, and mass transfer coefficients of each component only have influence on concentration of its own component. Dufour effect in both fixed-bed adsorption and pressure swing adsorption process can be ignored. In fixed-bed adsorption process, there can be found that Soret effect have influence on the concentration, while in pressure swing adsorption process, Soret effect can not be observed.