Stack anode exhaust stream

The thermal management subsystem of a SOFC system consists of (i) those components downstream of the stack whose primary functions are to react any remaining combustibles in the anode exhaust and to preheat the various streams that eventually find their way to tlie stack inlets [8, 40-42] and (ii) insulation. The primary components of this subsystem may include, but are not limited to. 

Back diffusion of water depends on water concentration on both sides of the membrane, water diffusivity through the membrane, and membrane thickness. Because water concentration is not uniform, it is not easy to explicitly calculate back diffusion for the entire cell or a stack of cells. For the sake of mass balance, back diffusion may be expressed as a fraction, p, of electroosmotic drag. When P = 1, back diffusion is equal to electroosmotic drag, that is, there is no net water transport across the membrane. The coefficient p may be determined experimentally by carefully condensing and measuring water content in both anode and cathode exhaust streams. 

Combined Brayton-Rankine Cycle The combined Brayton-Rankine cycle. Figure 9-14, again shows the gas turbine compressor for the air flow to the cell. This flow passes through a heat exchanger in direct contact with the cell it removes the heat produced in cell operation and maintains cell operation at constant temperature. The air and fuel streams then pass into the cathode and anode compartments of the fuel cell. The separate streams leaving the cell enter the combustor and then the gas turbine. The turbine exhaust flows to the heat recovery steam generator and then to the stack. The steam produced drives the steam turbine. It is then condensed and pumped back to the steam generator. 

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