A Review of Bio-Oil Upgrading by Catalytic Hydrodeoxygenation

Abstract

Fast pyrolysis is an attractive thermal conversion process to generate the alternative liquid fuel. However, the bio-oil obtained from biomass pyrolysis has polarity, instability and low energy density due to contained oxygenated compound. Hydrodeoxygenation (HDO) process is the most promising route for bio-oil upgrading through oxygen elimination. The products are suitable for co-feeding into the existing refineries. Metal catalyst and operating conditions play an important role in HDO efficiency. A summary of HDO process has been conducted with various metal catalysts, type of reactors, and reaction mechanisms. It also raises some challenges in improving catalyst efficiency, reducing hydrogen consumption, and effort to understand the HDO kinetics.

Advanced biofuels production by upgrading of pyrolysis bio‐oil

“…Bio‐oil HDO involves the processing of this liquid fraction under a hydrogen atmosphere and the presence of a catalyst, which allows the oxygen present in the bio‐oil to be removed in the form of water. This route has been extensively investigated in past years, so a great number of works have been reported using a variety of catalysts and operation conditions . Pyrolysis bio‐oil HDO has been tested using a broad range of pressures and temperatures, varying typically in the range of 50–150 bar and 200–350°C, respectively.…”

“…Regarding the catalysts employed for bio‐oil HDO, a great interest has been focused on using typical oil fractions hydrodesulfurization (HDS) catalysts, based on sulphided NiMo/Al 2 O 3 and NiCo/Al 2 O 3 , as this could allow bio‐oil coprocessing in refinery units . However, the oxygen content of bio‐oil is much higher than the sulphur present in petroleum fractions; hence, the catalytic behavior of those systems is far from being optimized for bio‐oil conversion.…”

“…Accordingly, many research works have been oriented in the past years to the development of specific catalysts for bio‐oil HDO reactions that may deal with the high concentration and diversity of oxygenated compounds present in bio‐oils . In this way, different types of catalytic systems have shown interesting results for bio‐oil HDO, such as noble metals (Ru, Pd, Pt, Rh and Re), base metals (Ni and Cu), and metal phosphides (Ni, Co, Fe and Mo).…”

The complete utilization of rice husk for production of synthesis gas

“…Biomass can be converted thermally, which leads to the production of liquids (bio-oil) and some gases and solids (char). [11][12][13][14][15][16] Bio-oil consists of different oxygenated compounds, such as acids, ketones, alcohols, phenols, and guaiacols, 17,18 which cannot be directly used as fuel or chemicals.…”

A review of thermochemical upgrading of pyrolysis bio‐oil: Techno‐economic analysis, life cycle assessment, and technology readiness

“…Prior literature has reviewed findings from biomass thermochemical conversion TEAs (Brown, 2015) and TEA together with LCA (Patel, Zhang, & Kumar, 2016). However, in recent years, much additional research has emerged specifically on the conversion and upgrading of bio-oils produced from fast pyrolysis of biomass (Bridgwater, 2012;de Miguel Mercader, 2010;Dutta et al, 2015;Elkasabi, Mullen, & Boateng, 2015;Fatih Demirbas, 2009;Fisk et al, 2009;Hangtao, Xiaoning, Qiang, & Changqing, 2014;Ko et al, 2012;Snowden-Swan & Male, 2012;Stefanidis, Kalogiannis, Iliopoulou, Lappas, & Pilavachi, 2011;Tran, Uemura, Chowdhury, & Ramli, 2014). Therefore, this review focuses on understanding the key benefits, differences, and trade-offs among select pyrolysis bio-oil upgrading methods under investigation at laboratory and pilot scales, whose potential for scale-up has been evaluated using LCA and TEA methods.…”