Partial Oxycombustion and Amines-driven Waste-to-Methane for Improved Carbon Capture and Utilization (CCU)

Abstract

This study explores the design of new WtE plants for municipal solid waste management, emphasizing CO2 capture and conversion into CH4. Two scenarios are assessed: Waste-to-Gas and Partial OxyWaste-to-Gas, both employing standard 30 % MEA CO2 absorption technology. WtG integrates waste combustion with external hydrogen purchase for CO2 hydrogenation to methane. In contrast, Partial OxyWtG incorporates a PEM electrolyzer for oxygen production, enabling oxygen-enriched air for partial oxycombustion. This approach facilitates CO2 hydrogenation to methane alongside amine regeneration, thus mitigating the energy penalty typically linked with conventional amine processes. When considering realistic PPA prices and methane sale values, Partial OxyWtG emerges as potentially more cost-effective than current WtE plants without CO2 capture. The cost of methane produced is significantly lower in partial oxycombustion scenarios (201.64 €/MWh and 100–138 €/MWh), primarily due to reduced hydrogen costs, leveraging current PPA rates of 40 to 60 €/MWhe. Additionally, the cost of avoided carbon is computed at 58.72 and 61.88 €/ton CO2, respectively. Efficiency penalties decreased from 6.49 to 1.47 percentage points. A lifecycle analysis of the project underlines the significance of incorporating CO2 capture and utilization in WtE plant design, achieving optimal investment return within 9 years.