Experimental investigation on the simultaneous upgrading of biogas using iron sponge and zeolite 13x fixed bed columns

Abstract

Biogas technology is continuously being studied to enhance its quality and expand its power generation application. To increase its heating value and eliminate its corrosive effect on machine components, a biogas upgrading system was designed and developed. This study evaluates the developed upgrading system by its capability to increase the methane content through hydrogen sulfide and carbon dioxide reduction using the iron sponge and Zeolite 13x, respectively as adsorbent columns. The results show that by varying the volume flow rate of the biogas into the system could lengthen the contact time between the biogas and adsorbent and eventually increase the CH₄ content from the biogas. Furthermore, the highest methane content achieved at 63.1 % from a raw biogas concentration of 32% CH_4. Meanwhile, with the breakthrough adsorption capacity of zeolite 13x was 224 mg CO₂/g. This had reduced the CO₂ by 41.76% from its raw biogas composition. The maximum superior and inferior calorific values produced were 22.53 MJ/m³ and 20.29 MJ/m³ respectively. The simplified design of a simultaneous upgrading system intends to increase the methane content of the biogas and further extend its application as an alternative fuel for power generation applications.