Parametric Study On Hydrogen Purification Performance Of Pressure Swing Adsorption

Hydrogen energy is an ideal green energy,and the development and utilization of it can effectively solve the energy problems.The separation and purification of hydrogen is very important for the widespread use of hydrogen,and the application of pressure swing adsorption?PSA?can effectively complete the separation and purification of hydrogen.For this purpose,this paper focuses on the simulation of PSA process of hydrogen purification,and some parametric studies have been done to study the effect of the performance.Firstly,based on the Langmuir adsorption isotherm equation,the adsorption process of single-component gas can be verified.And the extended Langmuir equation is used to describe the process of multicomponent gas adsorption equilibrium.Combined the extended Langmuir equation with the linear driving force equation,the ideal gas state equation and mass,energy and momentum conservation equation,a gas adsorption model with heat and mass transfer is built.Simulation has been done on Comsol using two-component gas?H2/CO2?in an activated carbon adsorption bed.The different component concentration and adsorption heat of CO₂are used to do some study on breakthrough curves and temperature profiles.Variable adsorption heat of CO₂ is used to improve the accuracy of the simulation in different pressure conditions.Secondly,Cu-BTC is being considered as a new adsorbent in the field of PSA.Models describing adsorption process and PSA cycles of two-component gas?H2/CO2?and three-component gas?H₂/CO₂/CH₄,H₂/CO/CO₂,H₂/CO₂/N₂?are built in a Cu-BTC adsorption bed.The model is implemented on Aspen Adsorption and validated by experiments on breakthrough curves,pressure and temperature profiles.On this basis,the effects of adsorption pressure and feed flow rate on adsorption process are studied by breakthrough curves,and the effects of adsorption pressure,adsorption time and feed flow rate on the performance of PSA cycles are also studied.Finally,some simulations are also done on the adsorption process and PSA cycles of five-component gas?H₂/CO₂/CO/CH₄/N₂?in activated carbon/zeolite beds.The breakthrough curves of five-component gas in the activated carbon adsorption bed are studied.Then zeolite layer is added to this adsorption bed and the difference of breakthrough curves are compared.Further simulation and validation of different PSA cycles for five-components gas in the layered beds are studied including single bed with four steps,double beds with steps six and four beds with eight steps.In the end,the influence of the high ratio of activated carbon and zeolite adsorbents on the performance of hydrogen purification is studied.In this thesis,based on the basic theory of adsorption and heat transfer,a model which can describe the adsorption,flow and heat transfer of gases is established to do simulations on adsorption process and PSA cycles,and parametric study on the performance of hydrogen purification is done,which has important significance and practical application value to the optimization design of the system.