The performance of pressure swing adsorption (PSA), membrane separation, and gas absorption systems for H2 recovery from refinery off-gas stream was studied by simulation-based data. The PSA process was simulated using adsorbents of silica gel and activated carbon for removing heavy and light hydrocarbons. The mole fraction profiles of all components and the relationship between hydrogen purity and recovery as a function of feed pressure were examined. The solution-diffusion model was applied for modeling and simulation of a one-stage membrane process. The gas absorption process with a tower tray was simulated at sub-zero temperature and the correlation between hydrogen purity and recovery as a function of tower pressure and temperature was evaluated at different solvent flow rates.