Advances in process design, techno-economic assessment and environmental aspects for hydrothermal pretreatment in the fractionation of biomass under biorefinery concept

The development and sustainability of second-generation biorefineries are essential for the production of high added value compounds and biofuels and their application at the industrial level. Pretreatment is one of the most critical stages in biomass processing. In this specific case, hydrothermal pretreatments (liquid hot water [LHW] and steam explosion [SE]) are considered the most promising process for the fractionation, hydrolysis and structural modifications of biomass. This review focuses on architecture of the plant cell wall and composition, fundamentals of hydrothermal pretreatment, process design integration, the techno-economic parameters of the solubilization of lignocellulosic biomass (LCB) focused on the operational costs for large-scale process imple-mentation and the global manufacturing cost. In addition, profitability indicators are evaluated between the value-added products generated during hydrothermal pretreatment, advocating a biorefinery implementation in a circular economy framework. In addition, this review includes an analysis of environmental aspects of sus-tainability involved in hydrothermal pretreatments.

Automated summary

The development and sustainability of second-generation biorefineries are crucial for producing high-value compounds and biofuels at an industrial scale. Hydrothermal pretreatment, specifically liquid hot water (LHW) and steam explosion (SE), is considered the most promising process for biomass fractionation, hydrolysis, and structural modifications. This review focuses on the plant cell wall architecture, hydrothermal pretreatment fundamentals, process design integration, techno-economic parameters, and profitability indicators, highlighting the implementation of biorefineries in a circular economy framework. The review also analyzes the environmental sustainability aspects of hydrothermal pretreatments.