CFD model for tubular SOFC fed directly by biomass

The increasing energy demand along with the growing attention on environmental issues require a change in the process of energy conversion, that can be accomplished through the exploitation of renewable sources and the development of new, sustainable and efficient technologies. Among renewable energy sources, biomass presents some positive characteristics: it is cheap, widely spread and can be exploited at any time. Moreover, if used at the same rate as it grows, biomass can be considered as not contributing to CO2 emission in the atmosphere. Thanks to the exploitation of the fuel cell technology, it is possible to convert the chemical energy contained in the fuel directly into electrical energy. Not all the fuel cells are able to work when fed with carbonaceous fuels, due to technological issues: solid oxide fuel cells (SOFC) appear to be the best choice, especially in the perspective of an integration between the two features. In the European context, the DB-SOFC project (Direct Biomass – Solid Oxide Fuel Cell) has been developed in order to exploit the biomass potential for the production of electricity. Integrated in this system, a in situ gasification process of biomass is foreseen to avoid the kinetic restrictions at the anode side, due to the limited contact between the electrolyte and anode electrode and the biomass solid particles. The aim of this thesis is to create a model for the tubular SOFC: for this purpose, the software COMSOL Multiphysics® 5.3 has been used. Firstly, the fuel cell operation when fed directly with syngas has been analysed and a comparison between different operating conditions (in terms of pressure and temperature) has been performed, to evaluate the behaviour of the device. After that, the further step has been the implementation of the gasification process and the coupling with the fuel cell, so to describe the complete system. The simulation of the polarization curves (i-V curves) in the different conditions will represent the goal of the study.