Monte Carlo Simulation Of Natural Gas/Nitrogen Separation By Pressure Swing Adsorption

In this paper,we study the separation of nitrogen and methane in the natural gas that are collected from oil and gas field after the flooding of nitrogen gas.The high content of nitrogen will affect natural gas calorific,so the nitrogen removal is needed.While the nitrogen and methane are similar in physical and chemical properties and difficult to separate,so this paper researches the separation by pressure swing adsorption way,including the simulation of gas molecules adsorption on the adsorbent at the molecular level,the simulation of complete pressure swing adsorption separation process,and the optimization of the process parameters.From the simulation of CH₄ and N₂ molecular adsorption behavior in activated carbon at the molecular level,it analyzes the effects of adsorbent pore width and adsorption pressure on the adsorption capacity and separation factor of CH₄ and N₂molecules on activated carbon.For different proportions of methane and nitrogen,different adsorbent pore widths are recommended in combination with the saturated adsorption capacity and separation factor.It designs the process of natural gas pressure swing adsorption simulation on activated carbon and carbon molecular sieves.The operating parameters such as pressure,temperature,and adsorption time were analyzed,as well as the structural parameters like bed voidage,tower height and tower diameter.Based on the separation effect and the recovery rate of methane,it finds that the carbon molecular sieve is more suitable as adsorbents in this process,and defines the reasonable range values for each parameter.Considering the coupling effect of various factors,the combination of the different values of all influencing factors in the range of reasonable values is simulated and analyzed and determines the best plan in the pressure swing adsorption process.