Comparative Analysis of Thermodynamic Performance of Two Cryogenic Systems for Biogas Upgrading Combined with Carbon Capture
Authors: Azeez SA, Garba U, Obalowu YA
Cryogenic systems have been recognized as a biogas upgrading technology that is more environmentally friendly and less energyintensive by capturing carbon dioxide in either liquid or solid form with negligible entrained methane concentration. Cryogenic distillation (D-SYS) and Liquefaction combined with desublimation (LD-SYS) are identified as cryogenic systems for accomplishing these functions. In this work, these alternatives of equal capacity were investigated and compared from a thermodynamic point of view, using standard measures: gas purity, removal efficiency, methane slip, energy consumption and exergy analysis. The simulation models of the two systems were performed using Aspen HYSYS 2006. The simulation results were in accordance with previous researches. It was shown that D-SYS displays better results in gas purity, methane loss, removal efficiency and energy consumption than LD-SYS; Moreover, the exergy efficiency of D-SYS and LD-SYS were found to be 95.59% and 92.80% respectively. It was also found that more that 80% of internal exergy loss occurs during cooling and refrigeration process. This work is useful for efficient thermodynamic design of cryogenic systems.
Affiliations: Department of Mechanical Engineering, Faculty of Engineering and Environmental Design, Usmanu Danfodiyo University Sokoto, Sokoto State, Nigeria
Keywords: Biogas Upgrading Technology, Carbon Capture, Cryogenic Distillation, Cryogenic Liquefaction, Exergy
Published date: 2019/06/30