Conversion of rice straw into 5-hydroxymethylfurfural: review and comparative process evaluation

Abstract

Biorefineries of agricultural waste have received a significant attention as a key concept to integrate waste biomass and production sectors towards a circular bioeconomy. The waste biorefinery product 5-hydroxymethylfurfural (5-HMF) is identified as a versatile platform chemical and an alternative to petroleum to produce fuels and chemicals. Currently, industrial production of 5-HMF depends on edible biomass, which is unsustainable at socioeconomic context. An agricultural waste like rice straw (RS) holds the key to viable mass production of 5-HMF. With the limitations for RS to 5-HMF direct conversion, this paper proposes a roadmap by detailing the existing RS to cellulose pretreatment methods, and cellulose to 5-HMF catalytic conversion processes for industrial-scale 5-HMF production. It was identified that energy-demanding pretreatment techniques and less feasible catalytic conversion processes are the most significant challenges that should be overcome prior to the practical implementation of industrial-scale 5-HMF production. Hence, insights into large-scale conversion are identified and systematically discussed to circumvent the challenges. In addition, a process evaluation method is introduced and applied to reveal the optimal process configuration for 5-HMF production.