Thermodynamic equilibrium modeling of biomass gasification: Effects of operating conditions on gasifier performance

Abstract

Biomass has remarkable potential to reduce harmful emissions and ensure stable and sustainable energy production. In this paper, various parameters such as operating temperature, type of gasifying agent, air–fuel ratio and steam-fuel ratio are investigated on the qualitative characteristics of the syngas obtained from biomass gasification. The qualitative indicators considered were the percentage of combustible components under the energy aspect and the percentage of undesirable components under the environmental aspect. The composition of the syngas was determined for a temperature range of 500–1000 °C as an equilibrium composition using the Gibbs free energy minimisation method. The results showed that increasing the gasification temperature above 900 °C had a positive effect on the energy and environmental properties of the syngas. Air and water vapour were selected as possible gasifying agents. The results showed that water vapour was significantly more favourable than air as a gasifying agent in terms of syngas quality. In the best case, the H2 yield for gasification with air is 35 %vol, while this value reaches 65 %vol for gasification with steam. In addition to the type, the ratio of the gasifying agent to the amount of fuel was also analysed. The analysis showed that it was more favourable to carry out the gasification process at lower air-to-fuel and steam-to-fuel ratios, which is consistent with the work of other authors.