Chemical Processing in High-Pressure Aqueous Environments. 8. Improved Catalysts for Hydrothermal Gasification

Abstract

Improved catalyst formulations have been developed and tested for hydrothermal gasification of wet organics. A high-pressure (about 20 MPa) and high-temperature (about 350 °C) liquid water processing environment was used to treat organic chemical model compounds. The organic feedstocks were converted primarily to methane and carbon dioxide in the presence of a heterogeneous catalyst. Test results with different catalyst formulations showed that catalyst composition could be tailored for the hydrothermal environment to effectively process wet wastes and wastewater and to recover useful fuel gas.

Structural Evolution of Molybdenum Carbides in Hot Aqueous Environments and Impact on Low-Temperature Hydroprocessing of Acetic Acid

“…A commercial 5% Ru/C was also evaluated before and after a 48 h water aging for comparison purposes. Carbon supports are widely studied in the context of water-based catalytic processes due to their relative hydrothermal stability [28] and Ru is one of the best catalysts known for acetic acid hydrogenation [29,30] and low-temperature processing (stabilization) of bio-oil [6,9]. Some catalytically relevant properties of the 5% Ru/C reference catalyst are reported in Tables 1 and S2, and Figure S5.…”

“…However, the liquid products (so-called bio-oils) are not suitable for direct application as fuels in internal combustion engines due to their high content of oxygen (35)(36)(37)(38)(39)(40) wt.%, dry basis) and water (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) wt.%) [1]. For instance, various oxygenated hydrocarbon species present in raw bio-oils make these liquids unstable for long-term storage, corrosive, low in heating value, and poorly miscible with conventional hydrocarbon fuels.…”

SunCHem: an integrated process for the hydrothermal production of methane from microalgae and CO2 mitigation

“…Typical catalyst supports, e.g., silica and γ-alumina, cannot be used, as they will be severely degraded under the harsh conditions of the supercritical water. During the last 15 years, new catalyst formulations have been developed that use combinations of stable metals such as ruthenium (Ru), or nickel (Ni) bimetallics, and stable supports such as titania, zirconia, or carbon (Elliott et al 2006;Antal et al 2000;Waldner et al 2007;Peterson et al 2008;Vogel 2009). …”

Cogeneration of renewable energy from biomass (utilization of municipal solid waste as electricity production: gasification method)

“…The area of the working electrode was 25 cm 2 . Finally, the composite was heated at 573 K for 4 h to obtain the final form of the anode electrode [16]. Similarly, we have used magnesium oxide for cathode electrode.…”