Biomass gasification in an industrial-scale entrained flow gasifier and effects of various parameters on gasification performance: An approach based on numerical models

Although coal entrained flow gasification is a dominant (>70 %) technology, it is understudied for biomass. Hence, a CFD-based entrained flow gasification model is built and validated against lab-scale experiments using Beechwood powder. The study numerically analyses the validity of TGA-derived kinetic data and char gasification models for biomass gasification for entrained flow reactor. Unlike coal-specific gasification models, a biomass-specific multi-pore model is deployed. The model is next scaled up to industrial-level (605 tonnes/day handling capacity), addressing the performance prediction of biomass gasification at large scales. The effects of the equivalence ratio (ER), particle size, inlet pressure and gasifying agent are studied to provide an insight into product formation. Air gasification at ER 0.2 results in an optimum syngas yield with a lower heating value (LHV) of 4.5 MJ/kg, Cold gas efficiency (CGE) of 90 % and carbon conversion efficiency (CCE) of 90 %. Although the smaller particle sizes improve the gasification performance, a 200 to 300-µm particle size is recommended to save milling energy. A higher inlet pressure favours improved gasification performance. Using oxy-steam as a gasifying agent does not significantly enhance hydrogen yield compared to air gasification. In addition, the LHV (almost 1 MJ/kg reduction) and the CGE (20 % reduction) are reduced compared to air gasification, while the carbon conversion remains almost unchanged at 89 to 90 %. The results of this study are expected to make a pioneering contribution to the industrial-scale biomass gasifier design and selection of suitable operating parameters.