Novel techniques of pretreatments and post-treatments for bio-oil upgrading: A comprehensive review
Behnam Rezvani
Abstract
The increasing demand for sustainable energy sources has driven important advancements in the field of bio-oil production and upgrading. This article explores recent literature on bio-oil upgrading, focusing on both pretreatment and post-treatment methods addressing the challenges of raw bio-oil, such as high oxygen content, acidity, and instability. The study contains a useful review of bio-oil upgrading pretreatments, such as torrefaction, steam explosion, ammonia fiber expansion, and hydrothermal, biological, acid, and alkali pretreatments. Additionally, it delves into post-treatment methods including hydrotreatment, supercritical fluid extraction, membrane separation, vacuum and molecular distillation, catalytic cracking, emulsification, electrochemical hydrogenation, ultrasound-assisted extraction, esterification, and plasma processing. This comprehensive review aims to show their advantages and disadvantages and novel ways to guide future research and development efforts in the quest for efficient and effective bio-oil production and upgrading.