Catalytic and homogeneous gasification of biomass model compounds in supercritical water

Biomass contains a large amount of chemical energy, and as a renewable resource, can serve as an energy source that is both sustainable and largely CO₂ neutral. A large percentage of the mass of harvested biomass is water. Removing this water prior to processing increases the energy requirements and cost needed to convert biomass to gas or liquid fuels. One general approach for converting wet biomass is to process the biomass in an aqueous phase. The specific implementation of this approach is supercritical water gasification (SCWG). SCWG involves the conversion of organic compounds to gaseous products (H₂, CO, CO₂, CH₄) via reactions in and with water at a temperature (374°C) and pressure (22.1 MPa) exceeding the thermodynamic critical point. The compounds were methanol, phenol, guaiacol, and glycine. Methanol was selected because it is among the simplest compounds that contain C, H, and O atoms, all of which are prevalent in biomass. The other compounds serve as models for the behavior of biomass in supercritical water-guaiacol and phenol as models for lignin, and glycine as a model for amino acids from proteins. The behavior of these compounds and their ability to produce gaseous fuels in SCW were studied. The catalyst used was nickel metal. This is an abstract of a paper presented at the AIChE Annual Meeting (San Francisco, CA 11/12-17/2006).