title: Use of wastewater treatment plant biogas for the operation of Solid Oxide Fuel Cells (SOFCs).
abstract: Solid Oxide Fuel Cells (SOFCs) perform well on light hydrocarbon fuels, and the use of biogas derived from the anaerobic digestion (AD) of municipal wastewater sludges could provide an opportunity for the CH4produced to be used as a renewable fuel. Greenhouse gas (GHG), NOx, SOx, and hydrocarbon pollutant emissions would also be reduced. In this study, SOFCs were operated on AD derived biogas. Initially, different H2dilutions were tested (N2, Ar, CO2) to examine the performance of tubular SOFCs. With inert gases as diluents, a decrease in cell performance was observed, however, the use of CO2led to a higher decrease in performance as it promoted the reverse water-gas shift (WGS) reaction, reducing the H2partial pressure in the gas mixture. A model was developed to predict system efficiency and GHG emissions. A higher electrical system efficiency was noted for a steam:carbon ratio of 2 compared to 1 due to the increased H2partial pressure in the reformate resulting from higher H2O concentration. Reductions in GHG emissions were estimated at 2400 tonnes CO2, 60 kg CH4and 18 kg N2O. SOFCs were also tested using a simulated biogas reformate mixture (66.7% H2, 16.1% CO, 16.5% CO2, 0.7% N2, humidified to 2.3 or 20 mol% H2O). Higher humidification yielded better performance as the WGS reaction produced more H2with additional H2O. It was concluded that AD-derived biogas, when cleaned to remove H2S, Si compounds, halides and other contaminants, could be reformed to provide a clean, renewable fuel for SOFCs.
authors.affiliation: Department of Civil Engineering, Queen's University, Ellis Hall, 58 University Ave., Kingston, ON, K7L 3N6, Canada; Queen's - RMC Fuel Cell Research Centre, Queen's Innovation Park, 945 Princess Street, Second Floor, Kingston, ON, K7L 3N6, Canada.
authors.forename: Jillian
authors.initials: J
authors.lastname: Lackey
authors.affiliation: Department of Civil Engineering, Queen's University, Ellis Hall, 58 University Ave., Kingston, ON, K7L 3N6, Canada; Queen's - RMC Fuel Cell Research Centre, Queen's Innovation Park, 945 Princess Street, Second Floor, Kingston, ON, K7L 3N6, Canada; Department of Chemical Engineering, Queen's University, 19 Division St., Kingston, ON, K7L 3N6, Canada. Electronic address: pascale.champagne@queensu.ca.
authors.forename: Pascale
authors.initials: P
authors.lastname: Champagne
authors.affiliation: Queen's - RMC Fuel Cell Research Centre, Queen's Innovation Park, 945 Princess Street, Second Floor, Kingston, ON, K7L 3N6, Canada; Department of Chemical Engineering, Queen's University, 19 Division St., Kingston, ON, K7L 3N6, Canada.
authors.forename: Brant
authors.initials: B
authors.lastname: Peppley
mesh_terms: D056804:Biofuels; D017752:Greenhouse Effect; D010087:Oxides; D012722:Sewage; D062065:Wastewater
chemical_list: D056804:Biofuels; D010087:Oxides; D012722:Sewage; D062065:Wastewater
keywords: Anaerobic digestion; Biogas; Renewable; Solid oxide fuel cell; Wastewater treatment