A review on the upgradation techniques of pyrolysis oil

• Published in: Renewable & sustainable energy reviews Vol. 58; pp. 1543 - 1568
• Main Authors: Gollakota, Anjani R.K., Reddy, Madhurima, Subramanyam, Malladi D., Kishore, Nanda
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-05-2016
• Subjects: Bio-oil; Catalytic cracking; Esterification; Hydrodeoxygenation; Steam reforming; Supercritical extraction; Upgrading; Hydrodeoxygenation; Upgrading; Bio-oil; Supercritical extraction; Steam reforming; Esterification; Catalytic cracking
• ISSN: 1364-0321; 1879-0690
• DOI: 10.1016/j.rser.2015.12.180

This paper provides insights on the properties of bio-oil obtained from various feedstock and several available mechanisms for bio-oil upgrading. A comprehensive detail on the catalytic cracking, hydrodeoxygenation, esterification, supercritical extraction and steam reforming processes are reviewed. Each upgrading technique has both advantages and disadvantages. The hydrodeoxygenation which has the major breakthrough in the bio-oil upgrading, even though there is no specific inference on the process chemistry in addition to various unfavorable conditions, this process holds good in reducing the oxygen contents of raw bio-oil. Various types of catalysts, their limitations along with the advantages, the use of novel catalysts and catalyst deactivation due to char formation at specified conditions among different upgrading techniques are presented. From this review, it was found that there is no specific catalyst for the specific compound upgrading. There is no specific reaction pathways defined for the processing of bio-oil. All the reviews and researches so far are constrained to the individual compounds of bio oil rather than as a whole. Some key points which are to be addressed for established process of bio-oil upgrading may include finding multifunctional catalysts which can improve the bio-oil properties suitable to blend with existing transportation fossil fuels or to directly use as transportation fuels, studies at pilot plant level, establishment of design concepts as in existing petroleum refineries, and numerical approaches to find various possible reaction pathways leading to upgraded bio-oil.
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