Energy conversion and utilization in supercritical water oxidation systems: A review

Supercritical Direct-Methane-to-Methanol Coupled with Gas-to-Wire for Low-Emission Offshore Processing of CO2-Rich Natural Gas: Techno-Economic and Thermodynamic Analyses

“…In supercritical DMTM, the properties of the reaction medium (supercritical solvent properties) can be adjusted by manipulating the pressure and temperature [24]. Supercritical water (SCW) (P > 22.12 MPa, T > 374.3 • C) is an effective supercritical DMTM solvent since it readily dissolves the formed methanol, stabilizing it and preventing further oxidation perpetrated by the gaseous air, i.e., creating a special reaction medium [25]. Savage et al [24] investigated DMTM-SCW's feasibility (T = −481 • C) and obtained methane conversion of up to 6%, oxygen conversion of up to 100% and methanol selectivity ranging from 4 to 75%.…”

“…The authors showed that methane was oxidized mainly to CO, CO 2 and methanol, wherein the highest methanol selectivity reached ≈35% for 1-3% methane conversion at 400-410 • C. The authors also detected the small formation of hydrogen and attributed it to the water-gas shift reaction. Regarding the operational difficulties brought by supercritical DMTM, they are obviously the high pressure and temperature [25], but these conditions would be also encountered in the case of methanol production through the conventional NG reforming and synthesis gas conversion route [25], which, in fact, is a much more complex and expensive process. Moreover, NG production and NG processing on oil-and-gas offshore rigs are essentially characterized by high pressure (e.g., membrane skids operating at 70 bar or higher, gas lift injection lines at pressures around 200 bar or higher, CO 2 injection lines at 400 bar or higher, water injection lines above 200 bar, etc.).…”

Kinetics study of total organic carbon destruction during supercritical water gasification of glucose

“…Among hydrothermal processes, supercritical water gasification (SCWG) is an economically viable and ecologically safe destruction technology for treating wet biomass waste from agricultural or industrial residues into combustible gases without requiring a feedstock drying procedure. 2,3 The physical properties of supercritical water (SCW) differ significantly from those of liquid water. Its dielectric constant and number of hydrogen bonds are substantially lower and its strength is considerably weaker compared to liquid water.…”

“…Hydrothermal processes have shown great potential and effectiveness in the treatment of industrial wastewater with high organic concentrations, such as sewage sludge, agricultural waste, and food processing waste. Among hydrothermal processes, supercritical water gasification (SCWG) is an economically viable and ecologically safe destruction technology for treating wet biomass waste from agricultural or industrial residues into combustible gases without requiring a feedstock drying procedure 2,3 …”