Integrated drying and gasification of wet microalgae biomass to produce H₂ rich syngas – A thermodynamic approach by considering in-situ energy supply

A novel integrated drying and gasification of microalgae wet biomass process, involving a chemical-looping combustion (CLC) option to supply energy, is developed using Aspen Plus. The integrated gasification system consists of four primary units, including (i) a wet biomass drying unit, (ii) the gasification system, (iii) the CLC section, and (iv) the gas purification process. The model shows a good accuracy (relative error < 10%) in predicting the product compositions as compared to the experimental results under consistent operating conditions. The performance of the integrated gasification system is evaluated using Spirulina microalgae at various moisture contents (0–45 wt%). The effect of gasifying agents O₂/steam and the fraction of the produced char used in the CLC section on the gasification performance is also evaluated. The tar is successfully reformed into syngas in the pyrolysis stage by adjusting the O₂ flow rate. The C (char) to CLC provides to a positive effect on the syngas composition, particularly for gasification of wet biomass, but brings an adverse impact on the yield of the syngas product. The integration of the CLC process and CO₂ absorber in the gasification system provides high-quality syngas by removing CO₂. The separated pure CO₂ can be used as a feedstock for other chemical industries.