Thermodynamic analysis of syngas generation from biomass using chemical looping gasification method

•Mn2O3 was used as oxygen carrier in CLG to produce syngas from biomass.•Mechanism of CLG of biomass using Mn2O3 was introduced.•Thermodynamic analysis of syngas generation from biomass was performed.•The optimal thermodynamic conditions were determined.•The feasibility of using steam to modify the H2/CO in the syngas was investigated.

Chemical looping gasification (CLG) is a novel technology to convert carbon-containing feedstock into syngas. In the technology, lattice oxygen of oxygen carrier is used as oxygen source for char gasification, and then the reduced oxygen carrier is regenerated in air atmosphere. In this paper, the mechanism of CLG of biomass using Mn2O3 as oxygen carrier was discussed firstly and then thermodynamic analysis of syngas generation from biomass was performed by Gibbs free energy minimization method. Chemical equilibrium calculations were carried out to study the effects of Mn2O3/biomass, operation temperature, pressure, and steam/Mn2O3 on the gasification characteristics. The optimal thermodynamic conditions were determined to improve H2 and CO concentrations as high as possible. The optimal Mn2O3/corn cob is 0.18 to obtain the highest CO and H2 yields. The results suggest that the preferential conditions are achieved at 1000 °C and atmospheric pressure, under these conditions, the total dry concentration of CO and H2 is 98.8% in the syngas. Steam can be used in the CLG to modify the H2/CO in the syngas. The carbon conversion also increases under oxidizing atmosphere of steam.