Methanation of syngas from biomass gasification: Small-scale plant design in Aspen Plus

The objective of this study is to investigate the conversion of low-quality syngas derived from biomass gasification processes into a methane-rich gas stream. To achieve this, various plant designs are simulated and compared using the Aspen Plus software package. Additionally, this work examines reactor sizing and performance. The results demonstrate that a system comprising of four adiabatic fixed-bed reactors, inter-cooling, and efficient water removal achieves a favorable balance between performance and cost. Operating the system at a pressure of 5 bar is deemed adequate as it reduces the required catalyst mass and prevents solid carbon deposition. Notably, this configuration achieved good results, including a 99.4% CO conversion, 89.3% CO2 conversion, and 95.6% CH4 yield. The final methane molar content reached 26.4%, with a calorific value of 9.41 MJ/Nm3.