CFD model for tubular SOFC cell fed directly by biomass – complete integrated system

"CFD model for tubular SOFC cell fed directly by biomass – complete integrated system" The DB-SOFC project, in which this thesis is involved, is based on an innovative solution to produce electrical power gasifing, inside the stack, the residual biomass derived from the pruning of the grapevines and olive trees and the production waste of the olive oil that has been properly pre-treated; in particular in this thesis it has been analyzed the last type of biomass for which has been made some studies by University of Western Macedonia (UoWM) in collaboration with Technical University of Crete (TUC). The project derives from the necessity to cover the increasing need of electrical power avoiding the usage of non-renewable sources and to make it with unused, or badly used, sources that are present in the Mediterranean area. For this purpose, in the thesis has been conducted many simulation on the tubular cells of 2 configuration of stack to evaluate if the power that could be extracted from them is higher than the prefixed goal of the project of 200 W. In this work, the fuel that powers the cells has supposed to be only syngas, derived by 2 different pre-treated biomass (OK500 and OK800) studied by UoWM and TUC, without solid charcoal in contact with the lower part of the cell (the real configuration should be this), supposing three different linear temperature distribution of it between the inlet of biomass and the outlet of syngas. Also 2 cooling systems has been analyzed to select the best solution to extract more power: the fluid selected for the analysis are liquid water in pressure and air. From the simulations has emerged that the cooling system that permits to avoid high reduction of temperature near the contact zone between the cell and the cooling system is the one with air. Instead, comparing the two types of biomass, simulated with air as cooling fluid, results that the best performance is obtained with the squared stack with biomass OK500 because it provides 6 W more than the correspective system powered by syngas derived by the gasification of biomass OK800: all the two results are obtained with a linear temperature distribution between 800 °C and 750°C. The other two types of distributions don’t permit to satisfy the target of 200 W in every configuration. Moreover, it results the circular stacks are always worse than the squared stacks due to the managing of the current collection.