Integration of ASOFC with Gasification for Polygeneration

University essay from KTH/Kraft- och värmeteknologi


Solid Oxide fuel cells (SOFC), is one of the fuel cell types with a greater potential as a commercial electrical power generator. As a high temperature fuel cell type (600-1000ºC), presents one of the biggest opportunity to be integrated in a polygeneration system combining it with existing infrastructure to provide heat and power in a efficient way. Furthermore, unlike other types of fuel cells, SOFC can work using a wide variety of fuels, meaning that with some reformation; most of the commercially available fuels can be utilized, and even some relatively sustainable fuels that are not yet commercial, such as gasified biomass.

The main part of this thesis focuses on the design of two gasifier models, one for partial oxidation gasification and other for steam gasification, both models where verified using published experimental results and simulations. Afterwards the models were integrated to work with a SOFC system. Several key parameters where analyzed in other have a complete view of the behavior of the system. The system was studied by changing different parameters like fuel cell operating temperature, fuel cell operating pressure, fuel composition, and moisture content.

Finally another part of the thesis is to analyze two different systems, one integrating gasifier and SOFC, and other studying the integration of the gasifier system to a combine cycle system, SOFC-Micro Gas Turbine.

The study concludes, as expected, that there is an inverse correlation between the moisture level in the fuel and the efficiencies in all the systems. Also the model shows that increasing the cell operating temperature will reduce the number of cell needed in order to achieve the design power output.

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