What is the best scenario to utilize landfill gas? Quantitative and qualitative approaches for technical, economic, and environmental feasibility

Abstract

To overcome the globally increasing trend in the generation of landfill gas (LFG), an environmentally harmful waste, which is derived from the huge amount of municipal solid waste, various investigations into the utilization of LFG have been actively conducted. In this study, an extensive investigation of the technical, economic, and environmental aspects for several scenarios of LFG utilization, in which LFG streams with different levels of CO₂ capture (HG, MG, and LG) are utilized in the production of H₂ (HG-H₂, MG-H₂, and LG-H₂), electricity (HG-E, MG-E, and LG-E), and the valuable materials methanol (MeOH) (HG-MeOH and MG-MeOH), dimethyl ether (DME) (HG-DME and MG-DME), and formic acid (FA) (HG-FA and MG-FA), is presented. All the investigated scenarios are simulated using Aspen Plus^®, and the derived results are used in an itemized cost estimation to evaluate the process cost of each scenario. Profitability analysis reveals net present values of 24.9 and 18.4 M$ for HG-H₂ and HG-FA, and the subsequent scenario analysis indicates the significant effect of H₂ and product selling prices on economic feasibility. In addition, significant annualized CO₂ emissions of 21 589 tonCO₂ years⁻¹ are obtained for MG-MeOH using integrative carbon footprint analysis, whereas LG-E exhibits the lowest emissions of 2610 tonCO₂ per years. Based on quantitative and qualitative analysis of the comprehensive feasibility of each scenario, the great potential of MG-FA to be a versatile utilization route and the environmental benefits of the LG-based utilization scenario are presented.