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DOE OSTI · 1819882

An Integrated High Pressure SOFC and Premixed Compression Ignition (PCI) Engine System

Kokjohn, Sage
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Abstract

Components for a transformative, high pressure, intermediate temperature solid oxide fuel cell (SOFC) and premixed compression ignition (PCI) engine system were developed. The resulting system is a 1 MWe natural gas fueled hybrid SOFC and reciprocating internal combustion engine system capable of achieving over 70% electrical efficiency at a cost of $0.87/W. To achieve 70% electric efficiency, the SOFC system operates at 80% fuel utilization; however, when operating at this high level of fuel utilization, fuel to the engine (anode tailgas) is extremely dilute. Accordingly, a substantial portion of the effort focused on development and assessment of the combustion strategy capable of consuming this dilute fuel mixture. The engine testing effort showed that pre-chamber assisted compression ignition provides the best combination of controllability, efficiency and emissions. The engine experiments showed that high efficiency combustion can be achieved with near zero criteria pollutants. It is likely that the engine system could operate with minimal aftertreatment requirements, reducing complexity, cost, and precious metal usage. System level modeling was used to assess the overall efficiency, determine cost and efficiency tradeoffs, and demonstrate the potential to perform load following with the hybrid system. Finally, advanced manufacturing was used to demonstrate the potential to fabricate heat exchangers needed for the hybrid system from low chromium materials, which addresses the issue of chromium poisoning of the SOFC stack material.

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03 NATURAL GAS30 DIRECT ENERGY CONVERSION32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATIONdistributed generationefficiencyengineLTCPCIprinted heat exchangerSOFC

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Kokjohn, Sage. 2021-09-14. An Integrated High Pressure SOFC and Premixed Compression Ignition (PCI) Engine System. https://doi.org/10.2172/1819882

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