Studies of CO2 gasification of the Miscanthus giganteus biomass over Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O promoter as catalysts

An assessment of the catalytic and non-catalytic gasification process of the Miscanthus giganteus (MG) biomass in an atmosphere of carbon dioxide was performed on the basis of thermogravimetric and thermovolumetric analyses. In the first step, the thermal behavior of biomass was determined by analyzing the mass loss during non-catalytic gasification with the use of TGA. The results of thermogravimetric analysis were used to assess the course of the biomass heating process in the atmosphere of CO2 and to distinguish the individual phases of this process. Then, the thermovolumetric measurements of MG gasification were taken with the use of Ni/Al2O3-SiO2 and Ni/Al2O3-SiO2 with K2O promoter as catalysts. The obtained results allowed determining the process rate as well as composition of the resulting gas and yields of main gaseous products (CH4, CO, H2). The use of Ni/Al2O3-SiO2 as catalyst resulted in the highest conversion rate of MG gasification into gaseous products with considerably increased contents of H2 and CO. The second analyzed catalyst—Ni/Al2O3-SiO2 with K2O promoter—did not catalyze the gasification process. However, the use of both tested catalysts had a positive effect on reducing the methane content in the resulting gas. One can also suppose that it promotes the decomposition of the tar formed in the process.