چكيده به لاتين
Gas separation processes have many industrial applications due to low-energy consumption and ease of operation in recent years. In the present work, investigation of a disc shape MFI membranes for H2/CO2 gas separation and a tubular SAPO-34 membrane for CH4/CO2 separation has been carried out and a model for describing binary mixture separation has been developed. The permeation of a gas through the zeolite membrane was considered as a couple of mechanisms, including viscous and Knudsen diffusion through support and defects and surface diffusion in zeolite crystals. One approache was used for modeling, including solving mass transfer equation in MATLAB. At first, single gas adsorption equilibrium and permeation data were used to find diffusivity of gas molecules in each zeolite. Order of magnitude of hydrogen, methane and carbon dioxide decreases respectively. Binary mixture separation modeling with these fitted parameters was performed. In this step, two following isotherms were used to describe binary adsorption equilibrium, multi component Langmuir model and ideal adsorption solution theory (IAST). Results showed that IAST has better predictions for both zeolites. For example, mean error of CO2 permeation using Langmuir was 51% and with IAST was 13.6% for MFI membrane. After modeling of SAPO-34 module with MATLAB software effect of change in feed flow rate and feed fraction were explored. Sensitivity analysis shows if feed flow rate decreases to one tenth of original value, then 94% CO2 permeate through membrane.
Keywords: Gas separation membrane, MFI, SAPO-34, modeling, computational Fluid Dynamics (CFD), surface diffusion.