Supercritical water gasification of biomass for H2 production: Process design

• Published in: Bioresource technology 2012-10, Vol.121, p.139-147
• Main Authors: Fiori, Luca, Valbusa, Michele, Castello, Daniele
• Format: Article
• Language: English
• Subjects: Biomass; biomass production; Biotechnology - methods; burning; Chromatography, Supercritical Fluid - methods; Combustion; Compressed; Energy analysis; energy balance; fuel cells; Gases - chemistry; Gasification; glycerol; Glycerols; grape pomace; Hydrogen - isolation & purification; Hydrothermal gasification; microalgae; phenol; Power plants; Pressure; Process design; Process modeling; sewage sludge; Simulation; Supercritical water gasification; Temperature; Turbines; Vitaceae; Water - chemistry
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2012.06.116

[Display omitted] ► A conceptual design for a SCWG plant for H2 production was developed. ► The process was simulated with five different (waste) biomass-water mixtures. ► SCWG reaction is self-sustainable at a 15–25% biomass concentration in the feed. ► The H2 production is maximal at a 15–25% biomass concentration in the feed. ► Utilizing PEMFC and turbines, a net power of ∼150kWe/(1000kgfeed/h) is obtained. The supercritical water gasification (SCWG) of biomass for H2 production is analyzed in terms of process development and energetic self-sustainability. The conceptual design of a plant is proposed and the SCWG process involving several substrates (glycerol, microalgae, sewage sludge, grape marc, phenol) is simulated by means of AspenPlus™. The influence of various parameters – biomass concentration and typology, reaction pressure and temperature – is analyzed. The process accounts for the possibility of exploiting the mechanical energy of compressed syngas (later burned to sustain the SCWG reaction) through expansion in turbines, while purified H2 is fed to fuel cells. Results show that the SCWG reaction can be energetically self-sustained if minimum feed biomass concentrations of 15–25% are adopted. Interestingly, the H2 yields are found to be maximal at similar feed concentrations. Finally, an energy balance is performed showing that the whole process could provide a net power of about 150kWe/(1000kgfeed/h).