Sensitivity analysis of the H2S breakthrough curve in a column packed with type 13X zeolite: Parametric study of pressure swing adsorption process for CO2 separation and biomethane production

abstract

Biomethane is a renewable energy source obtained by purifying biogas, removing impurities such as H2S and CO2. The removal of H2S is essential due to its toxicity and corrosiveness, protecting equipment and improving process efficiency. Pressure Swing Adsorption (PSA) is used to separate CO2, which produces a methane-rich gas. This process is efficient, clean, and key to utilizing biogas as a substitute for natural gas. This study aims to perform a sensitivity analysis on the H2S removal stage using a packed column with 13X zeolite, and to conduct a parametric study of the PSA process to identify input variables that significantly affect CO2 adsorption and achieve high-purity biomethane (above 99%). Comparative results showed that a pressure of 10 bar at a temperature of 298 K achieved the lowest H2S removal (1100 ppm), in a period of 4000 s; however, the highest H2S removal was achieved at 2 bar and 440 K, reaching 1500 ppm removal in 900 s. In the case of CO2 retention, the input variables that have the least effect on biomethane purity and that present the least adsorption of CO2 were the feed pressure and purge pressure variables, achieving a biomethane purity between the ranges of 97.53 % and 98.86 % and adsorbing between 0.35 to 0.38 molar fraction using only 0.6 m of the total bed length. On the other hand, the input variables that achieved the highest adsorption capacity (0.5 molar fraction) were temperature and composition, achieving to use the longest length of the packed bed (0.8 m) and reaching a biomethane purity of 99.05%, which meets established international criteria to be used as biofuel. © 2025 The Authors.