(91g) Technical and Economic Assessment of An Advanced Solid Oxide Fuel Cell-Based Power System

Technical and economic evaluation of an atmospheric-pressure solid oxide fuel cell capable of achieving strict carbon capture targets, while maintaining high system efficiency, is presented. In this design syngas is passed once-through the fuel cell stack; residual fuel in the anode gas is combusted using a slip stream of oxygen from the cryogenic air separation unit. The high quality heat from the combusted anode gas is combined with heat recovered from syngas cooling to feed a supercritical steam bottoming cycle. The fuel cell stack produces 80% of the power with the remainder coming from the steam cycle. Key fuel cell assumptions include: 0.7 volts, 500 mA/cm2 current density, and 85% fuel utilization in the fuel cell. The proposed system design has the following advantages (1) it achieves 46% coal conversion efficiency (HHV) without recycle or excessive heat recovery, (2) all the system components save the fuel cell stack are commercially available today, (3) it exhaust a compression-ready stream of 95% pure CO2, and (4) it allows capture and sequestration of nearly 100% of the carbon in the coal feedstock.