Design of a combined heat, hydrogen, and power plant from university campus waste streams

This paper presents analysis of a combined heat, hydrogen, and power (CHHP) plant for waste-to-energy conversion in response to the 2012 Hydrogen Student Design Contest. Our team designed the CHHP plant centered on a molten carbonate fuel cell (Fuel Cell Energy DFC-1500) fueled by syngas derived primarily from an oxygen-fed municipal waste gasifier. Catalytic methanation and supplemental utility natural gas increase the fuel methane content to meet the DFC-1500 fueling requirements for maintaining stack thermal energy balance. Internal reforming converts excess fuel from the fuel cell to an H2-rich stream, which is purified downstream in a pressure-swing adsorption system. The separated H2 (1000 kg per day) is compressed for storage to provide fuel for a campus fleet of PEM fuel cell buses. The system provides more than 1.1 MWe for the campus grid with approximately 20% of the fuel cell power used for H2 compression and running the plant. Heat recovery steam generators provide steam for the methanation reactor and 0.4 MW of thermal energy for district heating or steam turbine-driven chillers. Cost analysis indicates that the system requires incentives for economic viability with current estimated operating costs, but advances to reduce capital expenses of comparable urban waste-driven CHHP systems can make them attractive for future implementation.