Biofuels-based hybrid MCFC/gas turbine plant design and simulation for power and heat generation

Abstract

The present contribution reports on the theoretical design of an integrated process aiming at the generation of electric power from renewable sources. The core of the system is a 10 kilowatt-scale high-temperature Molten Carbonate Fuel Cell (MCFC) operating with direct internal steam reforming of biofuels. Nowadays, MCFCs are an attractive option to take advantage of streams with high content of carbon dioxide while producing electrical power. Quantification of the co-generation possibility is included as well. Biogas is considered as the main feedstock; however, different biogas/bioethanol cuts are analyzed as an alternative. The sensitivity analysis is extended to the influence of the cell temperature (550–650 °C), operating pressure (2–5 bar), steam-to-carbon ratio in feed (2.5–4.5) and current density (up to 180 mA/cm2). Simulations show that the proposed scheme arises as an efficient and interesting alternative aiming for off-grid power generation. Results are presented in terms of thermal efficiencies with and without cogeneration (up to 30 and 75%, respectively), electric potential, biogas flowrate requirements, and total power generation (up to 13 kW from which at least 75% is achieved from MCFC supply, completed by the net power production obtained by the turbine cogeneration).