Steam Hydrogasification Process
Authors:Sean Franco, Kyle Hunter
Mentor:Chan Seung Park, Associate Research Engineer, University of California, Riverside
Renewable Natural Gas (RNG) has been identified by the California Energy Commission (CEC) as an alternative fuel that can contribute to achieving a number of goals related to conventional fuel replacement. RNG is often produced from waste matter through anaerobic digestion and feedstock decomposition. These methods are often inefficient and result in lower gas quality then fossil source fuels. Gasification offers high conversion efficiencies while generating higher quality gas. Conventional process based RNG projects often lack economic viability due to the high costs. The Steam Hydrogasification Reaction (SHR), which has been developed at the University of California, Riverside (UCR), can produce energy products from carbonaceous resources in a cost effective and efficient manner. The objectives of this project is to demonstrate the technology using co-mingled bio-solids and biomass as the feedstock in a bench scale Process Demonstration Unit (PDU) and to provide a preliminary modeling evaluation and design for a 5 tons/day pilot scale facility. The PDU was designed, fabricated and operated in the gasification laboratory at UCR. A Water Gas Shift (WGS) reactor was integrated to the PDU. This reactor filters out the carbon monoxide from the gas mixture produced by the SHG Reactor through a chemical reaction. It also returns hydrogen back into the SHG Reactor so it can be reused. The PDU was tested by pumping bio-solid slurry at a variety of conditions. The conditions that were adjusted from test to test include slurry, hydrogen, and steam feed rates. The highest carbon conversion of 36% was achieved by pumping slurry at 48g/min, a hydrogen flow rate of 16.5 L/min, and a steam feed rate of 18.75 mL/min. These results demonstrate the viability of SHG and support the need to upscale into a pilot scale facility.