Thermodynamic analyses of synthetic natural gas production via municipal solid waste gasification, high-temperature water electrolysis and methanationThermodynamic analyses of synthetic natural gas production via municipal solid waste gasification, high-temperature water electrolysis and methanation Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2020-04-012019enThe production of synthetic natural gas (SNG) from syngas derived through waste gasification is an attractive option for converting waste into useful fuel. However, the carbon conversion ratio of traditional SNG production is usually below 50% due to the limited amount of H2, while the excess CO2 needs to be removed. To realize a higher utilization of carbon, a novel SNG production system combining a municipal solid waste (MSW) gasifier, a solid oxide electrolyzer cell (SOEC) and a methanation unit is proposed and analyzed by thermodynamic modeling using ASPEN Plus®. Comparison is made with a similar system without the SOEC unit. The SOEC unit is used to electrolyze water into H2 required for higher CH4 production, thus eliminating the need of CO2 removal. Theoretical calculations show that the integration between SOEC with the gasifier produces H2-rich (greater than18 vol% H2) SNG without CO or CO2, allowing direct use of existing town-gas pipelines for easy transportation. With an equivalence air ratio of 0.3 for the gasification process, the carbon conversion ratio can achieve 98% with an efficiency of 67% when the ratio of H2O supplied to the SOEC unit to the carbon in the MSW reaches 2.75. In comparison, the system without SOEC unit can only achieve a carbon conversion ratio of 44% with an efficiency of 78%. Parameter selection of the proposed system in practical implementation is discussed considering the trade-off between the carbon conversion ratio and the efficiency. At the end, preliminary economic analysis also shows that the proposed system is financially attractive.http://creativecommons.org/licenses/by/4.0/Energy Conversion and Management202December 2019 Pan Zehua Chan Weiping Veksha Andrei Giannis Apostolos Γιαννης Αποστολος Dou Xiaomin Wang Haiming Lisak Grzegorz Lim Teikthye Elsevier ASPEN Plus® Municipal solid waste (MSW) gasification Solid oxide electrolyzer cells (SOECs) Synthetic natural gas (SNG) Thermodynamic modeling