Integration of Biomass Torrefaction and Gasification based on Biomass Classification: A Review

Abstract

Trace element migration and structure evolution are related to biomass gasification performance, which varies to a certain extent during torrefaction. This substantial summary of the integrated process based on biomass classification has practical significance for the consumption and commercialization of a bio‐refinery. Herein, biomass is divided into two categories and an understanding of the relevant variations is presented during the integrated two processes according to the classification. The effects of torrefaction on the organic (hemicellulose, cellulose, and lignin) and inorganic components (trace elements), and the physicochemical structural evolution (morphology, pore structure, functional groups) of biomass are reviewed. The differences (syngas generation and tar formation) between raw and torrefied biomass gasification are compared. Meanwhile, the effects of torrefaction on gasification performance and the possible gasification mechanisms are reviewed regarding pore structure, carbon structure, surface area, and alkali and alkaline earth metals (AAEMs). The gasification of the torrefied biomass materials on a pilot‐scale is outlined. Finally, future directions and technological challenges associated with the integrated technologies are proposed. More scaling‐up experiments should be conducted to investigate the mass and heat transfer in reactors during amplification and to improve the reactor's adaptability to biomass species in the contexts of economy and society.

Performance Evaluation of Torrefaction Coupled with a Chemical Looping Gasification Process under Autothermal Conditions: Flexible Syngas Production from Biomass

“…However, the high water content, low energy density, and high O/C ratio of biomass often make it impossible to use it in the CLG process directly . Torrefaction is an effective means to overcome the above problems. , Numerous studies have shown that biomass undergoes complex physical and chemical changes after torrefaction, complicating its impact on downstream processes . For example, some studies have shown that higher gasification efficiencies are obtained with torrefied biomasses because their properties are closer to those of coal. , In other studies, a decrease in CGE and reactivity has been observed .…”

“…26,73 Numerous studies have shown that biomass undergoes complex physical and chemical changes after torrefaction, complicating its impact on downstream processes. 74 For example, some studies have shown that higher gasification efficiencies are obtained with torrefied biomasses because their properties are closer to those of coal. 75,76 In other studies, a decrease in CGE and reactivity has been observed.…”

Study of Biomass Torrefaction Fundamentals and Properties

“…Gasification, a thermochemical process that exposes biomass to high temperatures and little oxygen, can be used to turn biomass into gaseous compoundsc [29][30][31] .…”

Oxidative torrefaction and torrefaction-based biorefining of biomass: a critical review

“…As a result, secondary and tertiary tar content is also expected to decrease. In addition, enhanced char reactivity due to increased alkali and alkaline earth metals, and a significant reduction in soot formation, are reported during torrefied biomass gasification (Lu et al, 2021). The gasification behaviour of torrefied biomass has been extensively studied in the literature.…”