Engineering aspects of hydrothermal pretreatment: From batch to continuous operation, scale-up and pilot reactor under biorefinery concept

Abstract

Different pretreatments strategies have been developed over the years mainly to enhance enzymatic cellulose degradation. In the new biorefinery era, a more holistic view on pretreatment is required to secure optimal use of the whole biomass. Hydrothermal pretreatment technology is regarded as very promising for lignocellulose biomass fractionation biorefinery and to be implemented at the industrial scale for biorefineries of second generation and circular bioeconomy, since it does not require no chemical inputs other than liquid water or steam and heat. This review focuses on the fundamentals of hydrothermal pretreatment, structure changes of biomass during this pretreatment, multiproduct strategies in terms of biorefinery, reactor technology and

Co-production of biofuels and value-added compounds from industrial Eucalyptus globulus bark residues using hydrothermal treatment

“…2A), hence their glucose potential, the differences on glucose production in this case were most likely due to different recalcitrance levels of the pretreated solids. Indeed, the application of higher temperatures during hydrothermal pretreatments is generally more effective in disrupting lignocellulosic structures [4], leading to increased Fig. 3.…”

“…Lignocellulosic materials are the only renewable raw material in sufficient amount to partially replace fossil sources, which are cheaper and usually do not compete with food crops [3]. However, and because they present a very recalcitrant structure for most of the cases, their conversion also involves more complex operations, such as the application of an initial pretreatment [4]. Lignocellulosic pretreatments aim to disrupt the lignocellulosic structure, generally associated with the presence of lignin and to the crystallinity of cellulose, thus improving enzymes accessibility to cellulose [5].…”

“…Aiming the application of environmentally-friendly processes, higher attention has been given to the utilization of hydrothermal pretreatments, namely autohydrolysis (or liquid hot water) and steam-explosion, as they do not require the utilization of harmful chemicals [8] or expensive anticorrosion materials [9]; water acts here as a sole external catalyst through its ionization products (H 3 O + and OH − ), being complemented with acetic acid originated from acetyl groups from the raw-material. In a biorefinery scheme, the hydrothermal treatment represents one of the best options for the initial biomass processing, as it allows selective solubilization of hemicelluloses, originating a final solid mostly composed by cellulose and lignin [4,10].…”

Green and Sustainable Valorization of Bioactive Phenolic Compounds from Pinus By-Products

“…Ethanol is a well-known biofuel product of the second generation biorefinery. Second generation or lignocellulosic biorefinery usually begins with the pretreatment of the biomass in order to increase the digestibility of cellulose, to solubilize the hemicellulose, and to relocate the lignin [12]. Pretreatments can be mechanical, chemical, physicochemical, or biological [13].…”

Two‐Step Autohydrolysis Pretreatment: Towards High Selective Full Fractionation of Wheat Straw

“…The carbohydrate biopolymers in lignocellulosic biomass can be hydrolyzed and dissolved in water. The degradation of the dissolved hemicellulosederived pentoses to furfural is a significant challenge for the technological advancement of lignocellulose biorefineries [4][5][6].…”