Thermodynamic improvement of solar driven gasification compared to conventional one

The driving of biomass gasification with the heat provided by medium temperature solar technology is thermodynamically studied to understand principally the theoretical potential of this integration in terms of cold gas efficiency and gas composition, without considering kinetic aspects and not breaking down in detail plant solutions and energy balances of plant components. In medium temperature solar driven gasification, solar heat is used to heat the gasification medium up to a temperature of 500 degrees C. The considered conventional gasification technologies are air gasification, air-steam gasification, allothermal steam gasification and supercritical water gasification. In air gasification the investigated independent variable is the equivalence ratio. In air-steam and allothermal steam gasification, the investigated independent variable is the steam/biomass ratio. In supercritical water gasification the investigated independent variable is the organic feed concentration. Gasification temperature was set at 800 degrees C for air-steam gasification and allothermal steam gasification; it was set at 600 degrees C for supercritical water gasification. The main dependent variable detected are dry gas yield, gas composition and heating value, char residue. The highest cold gas efficiency was calculated in the case of solar driven supercritical water gasification, it was 91%, when the organic feed concentration was 20 wt %.

Automated summary

The thermodynamic study of driving biomass gasification using medium temperature solar technology reveals the highest cold gas efficiency in solar driven supercritical water gasification, demonstrating its potential in this integration.