Effect of CO2 addition on lignite gasification in a CFB reactor: A pilot-scale study

The addition of carbon dioxide to the gasification media during lignite gasification is introduced. The paper presents thermodynamic grounds of CO2 enhanced gasification using a simplified equilibrium model. Experimental tests conducted using a pilot-scale circulating fluidized bed gasifier are discussed. Detailed analysis of the CO2/C ratio on process conditions, namely on the process gas composition, lower heating value and H2/CO ratio, is provided. Process gas composition implies that the gas is suitable for heat and power generation. Alternatively, CO2 enhanced gasification could be considered as a carbon capture and utilization technology when external, renewable heat supply to the process is used. The results thus obtained are the initial step toward development of the CO2 enhanced gasification process.