Energetic analysis of gasification of biomass by partial oxidation in supercritical water

Partial oxidation gasification in supercritical water could produce fuel gases (such as H2, CO and CH4) and significantly reduce the energy consumption. In this work, an energetic model was developed to analyze the partial oxidative gasification of biomass (glucose and lignin) in supercritical water and the related key factors on which gasification under autothermal condition depended upon. The results indicated that the oxidant equivalent ratio (ER) should be over 0.3 as the concern about energy balance but less than 0.6 as the concern about fuel gas production. Feedstocks such as glucose and lignin also had different energy recovery efficiency. For materials which can be efficiently gasified, the partial oxidation might be a way for energy based on the combustion of fuel gases. Aromatic materials such as lignin and coal are more potential since partial oxidation could produce similar amount of fuel gases as direct gasification and offer additional energy. Energy recovered pays a key role to achieve an autothermal process. Keeping heat exchanger efficiency above 80% and heat transfer coefficient below 15 kJ·s− 1 is necessary to maintain the autothermal status. The results also indicated that the biomass loading should be above 15% but under 20% for an autothermal gasification, since the increase of biomass loading could improve the energy supplied but decrease the efficiency of gasification and gaseous yields. In general, some specific conditions exist among different materials.

The conventional SCWG requires a significant amount of energy to pre-heat and maintain a desired high temperature for the reactions, to reduce the energy-cost is the key issue for its industrialized application. In this work, energetic model was developed to analyze partial oxidative gasification of biomass (glucose and lignin) in supercritical water, which tries to provide detailed information to optimize the process under autothermal status.Figure optionsDownload as PowerPoint slide