Recent Insights into Lignocellulosic Biomass Pyrolysis: A Critical Review on Pretreatment, Characterization, and Products Upgrading

Abstract

<jats:p>Pyrolysis process has been considered to be an efficient approach for valorization of lignocellulosic biomass into bio-oil and value-added chemicals. Bio-oil refers to biomass pyrolysis liquid, which contains alkanes, aromatic compounds, phenol derivatives, and small amounts of ketone, ester, ether, amine, and alcohol. Lignocellulosic biomass is a renewable and sustainable energy resource for carbon that is readily available in the environment. This review article provides an outline of the pyrolysis process including pretreatment of biomass, pyrolysis mechanism, and process products upgrading. The pretreatment processes for biomass are reviewed including physical and chemical processes. In addition, the gaps in research and recommendations for improving the pretreatment processes are highlighted. Furthermore, the effect of feedstock characterization, operating parameters, and types of biomass on the performance of the pyrolysis process are explained. Recent progress in the identification of the mechanism of the pyrolysis process is addressed with some recommendations for future work. In addition, the article critically provides insight into process upgrading via several approaches specifically using catalytic upgrading. In spite of the current catalytic achievements of catalytic pyrolysis for providing high-quality bio-oil, the production yield has simultaneously dropped. This article explains the current drawbacks of catalytic approaches while suggesting alternative methodologies that could possibly improve the deoxygenation of bio-oil while maintaining high production yield.</jats:p>

Improving the Conversion of Biomass in Catalytic Pyrolysis via Intensification of Biomass—Catalyst Contact by Co-Pressing

“…Biomass is described by high moisture content, low calorific value, large volume and low bulk density which poses difficulties in it is collection, processing, transportation and storage, as well as low conversion efficiency to hydrocarbon fuels [15]. The low bulk density associated with lignocellulosic biomass has been a consistent factor that negatively influences the pyrolysis product yields and compositions [16]. To address these issues different biomass pre-treatment techniques have been developed, which include the widely reported torrefaction and pelletization [15].…”

“…To address these issues different biomass pre-treatment techniques have been developed, which include the widely reported torrefaction and pelletization [15]. These technologies can convert biomass into densified products for pyrolysis process [16]. The densified products produced using these technologies have improved bulk density, handling efficiency and compositional quality, as well as conformance to specifications for conversion technologies [2].…”

Advanced process integration for supercritical production of biodiesel: Residual waste heat recovery via organic Rankine cycle (ORC)

“…Further, biofuels are superior to fossil fuels as being renewable, non-toxic, biodegradable and producing less greenhouse gases (GHG) emissions. Finally, biomass valorisation into biofuels is projected to play a key role in circular bioeconomy via thermo/biochemical conversion technologies [ [9] , [10] , [11] , [12] ].…”

Glycerol Assisted Pretreatment of Lignocellulose Wheat Straw Materials as a Promising Approach for Fabrication of Sustainable Fibrous Filler for Biocomposites

“…Physical methods refer to techniques that do not use chemicals or enzymes during pretreatment processes such as comminution, extrusion and steam explosion. In hydrothermal methods, fiber is cooked in liquid water at elevated temperatures under high pressure [ 9 , 10 ].…”