Sorption enhanced gasification (SEG) of biomass for tailored syngas production with in-situ CO2 capture: Current status, process scale-up experiences and outlook

Sorption Enhanced Gasification (SEG) is being considered as a promising solid fuel conversion and carbon capture and sequestration technology since it can produce tailored syngas coupled with in-situ CO2 capture. Over the years, considerable research has been conducted with high grade biomass in laboratory and pilot scale facilities targeting technical and process scale-up viabilities of the SEG process. SEG has successfully been tested at semi industrial scale which demonstrates further scale-up potential (e.g. commercial demonstration plant) of this innovative technology. The results showed that the operation window of SEG laid at a gasification temperature ranging from 600 °C to 750 °C. By optimizing the process parameters, H2-rich syngas (>70 vol %db) and desired H2/CO ratios can be attained. Also, the total tar content of the optimized process is reported to be low compared to those obtained from classical fluidized bed gasification processes. So far, wood is mostly used as the feedstocks while tests with wastes including solid recovered fuels (SRFs) have also been conducted. Cheap and readily available natural sorbents (such as limestone) enable a satisfactory operation, however, issues associated with attrition and deactivation still need to be addressed. Accordingly, natural sorbents with improved properties, synthetic CaO-based sorbents as well as pre-treated natural sorbents are considered to overcome these limitations. This paper therefore discusses the current status of the SEG technology with an emphasis on its industrial applications for flexible syngas production with in-situ CO2 reduction. Moreover, challenges, process scale-up experiences and research gaps for the commercialization of this novel technology are identified in this review.