INFLUENCE OF BIOMASS PRETREATMENT ON SUBSEQUENT PYROLYSIS AND HYDRODEOXYGENATION IN BIO-BASED TRANSPORT FUELS AND CHEMICALS PRODUCTION: A CRITICAL REVIEW

Abstract

The present article aims to review the influence of various biomass pretreatments on the production of bio-based transportation fuel and chemicals via pyrolysis and hydrodeoxygenation (HDO). The article includes the influence of different thermochemical pretreatments such as dry torrefaction (DT), wet torrefaction (WT), steam explosion treatment (SET), hot water extraction (HWE), acid treatment (ACT), and alkali treatment (AKT) on bio-oil yield and bio-oil properties. HDO primarily includes dehydration, hydrogenolysis, decarbonylation, and hydrogenation. HDO can be classified based on stages (single and two-stage HDO), reaction pressure (high and low), and hydrogen presence (ex situ and in situ). The recent developments, advantages, and drawbacks associated with different types of HDO processes have been included. The article includes recent studies on designing various catalysts based on HDO conversion of different bio-oil compositions or selective model compounds to targeted bio-based products. The various biomass pretreatments impact the concentration of certain families of organic compounds present in bio-oil. Hence, the present review article also includes recommendations of specific biomass pretreatments for various HDO catalysts designed for selective model compounds or different bio-oil compositions. Few praiseworthy techno-economic analysis (TEA) studies on the influence of different biomass pretreatments on the minimum selling price (MSP) of bio-based products obtained at various production stages have been discussed.