Supercritical water gasification: a patents review

Abstract

AbstractSupercritical water gasification (SCWG) is a very recent technology that allows conversion of organic wastewaters into a fuel gas with a high content of hydrogen and light hydrocarbons. SCWG involves the treatment of organic compounds at conditions higher than those that define the critical point of water (temperature of 374°C and pressure of 221 bar). This hydrothermal process, normally operated at temperatures from 400 to 650°C and pressures from 250 to 350 bar, produces a gas effluent with a high hydrogen content. SCWG is considered a promising technology for the efficient conversion of organic wastewaters, mainly wet biomass, into fuel gas. This technology has received extensive worldwide attention, and many research groups have studied the effect of operation conditions, reaction mechanisms, kinetics, etc. There are some recent reviews about the research works carried out in the last decades, but there is no information or analysis of almost 100 patents registered in relation with this new technology. A revision of the current status of SCWG patents and technologies has been completed based on the Espacenet patent database. The objective of this revision was to set down the new perspectives toward the improvement of this technology efficiency. Patents have been published with regard to process or device improvements as well as to the use of different catalysts. More than 71% of these patents were published since 2009, and a substantial climb in the number of patents on SCWG is expected in the coming years. One of the most important aspects where research is particularly interesting if the integration of renewable energy recovery systems with SCWG processes.