Contents lists available at ScienceDirect Journal of Analytical and Applied Pyrolysis journal homepage: www.elsevier.com/locate/jaap Integrated catalytic hydrodeoxygenation of Napier grass pyrolysis vapor using a Ni 2 P/C catalyst Le Kim Hoang Pham a , Sang Dinh Ngo a , Thi Tuong Vi Tran a , Suwadee Kongparakul a , Prasert Reubroycharoen b , Chaiyan Chaiya c , Dai-Viet N. Vo d , Guoqing Guan e , Chanatip Samart a, ⁎ a Department of Chemistry, Faculty of Science and Technology, Thammasat University, Pathumthani 12120, Thailand b Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand c Department of Chemical Engineering, Rajamangala University of Technology Thanyaburi, Pathumtani 12110 Thailand d Faculty of Chemical and Natural Resources Engineering, Universiti Malaysia Pahang, Lebuhraya Tun Razak, Gambang, 26300 Pahang, Malaysia e Institute of Regional Innovation, Hirosaki University, Aomori 030-0813, Japan ARTICLEINFO Keywords: Ni 2 P/C Hydrodeoxygenation Napier grass Bio-oil Pyrolysis ABSTRACT A series of nickel phosphide/activated carbon (Ni 2 P/C)catalystswithvaryingnickelloadinglevelsandnickel-to- phosphorous molar ratios (Ni:P) were synthesized by wet co-impregnation and treated by temperature pro- gramed reduction. The Ni 2 P phase was clearly present in the Ni 2 P/C catalyst with a Ni:P ratio of 1.5 and a 5.37mmolNiloadinglevel.Thecatalystswerethenevaluatedforthehydrodeoxygenationofthepyrolysisvapor derived from the integrated pyrolysis and upgrading of Napier grass, with two fxed bed reactors in series, at diferent upgrading temperatures and space velocities. The reaction could be carried out at atmospheric pres- sure. The maximum bio-oil yield was obtained at an upgrading temperature of 340 °C, while the major com- ponents of the bio-oil were phenolic compounds (> 50%). An upgrading temperature of 360 °C did not only present dehydration but aromatization was also predominant. Moreover, the phenolic compounds decreased with increasing space velocity. The oxygen content in the pyrolysis vapor was catalytically removed via the dehydration pathway, which signifcantly decreased the oxygen/carbon ratio from 0.24 to 0.17. Due to ad- vantages spanning from highly efcient deoxygenation activity to the requirement of mild conditions, the Ni 2 P/ C catalyst shows great potential as a catalyst for bio-oil upgrading. 1. Introduction With the depleting level of non-renewable fossil fuels and increasing global warming through an unbalanced carbon cycle, renewable fuel resources are becoming a major energy source. Biomass, which is pro- duced from both plants and animals, is one such important energy re- source. Biomass energy from fuels such as biodiesel and bioethanol was initially developed from food stocks as 1 st generation biofuels. Subsequently, 2 nd generation biofuels were developed to produce bio- mass energy from a variety of (waste) non-food feedstocks, including lignocellulose and non-edible and waste oils [1]. These 2 nd generation biofuels have since become important energy sources due to their wide availability, environment-friendliness, and role in energy recovery and balancingthecarboncycle[2]. Lignocellulosic biomasses, such as forest residues, agro-wastes, energy grasses, and algae, are interesting re- sources of non-food 2 nd generation biofuels due to their large sustain- ably renewable availability. One highly potential lignocellulosic biomass is Napier grass or elephant grass (Pennisetum purpureum). This isduetoitsfastgrowth,whichallowsuptofourcultivationsayear;low water and nutrient requirements, allowing it to be grown on non-arable land; and high energy output-to-energy input ratio [3]. The conversion process for the production of 2 nd generation biofuels usually involves one of two diferent approaches: thermochemical conversion and bio- logical conversion. Thermochemical conversion is generally used to produce liquid fuel from biomass, especially from waste cooking oils and cellulosic materials [4,5]. It has several advantages over biological conversion, including fexibility of feedstock, fast reaction rate, and ease of control [6]. However, due to the presence of oxygenated com- pounds, the obtained bio-oil displays poor fuel properties, including a poor calorifc value, low stability, corrosiveness, and high viscosity. The pyrolysis oil from Napier grass contains high levels of oxygenated compounds, such as acetic acid, phenol, and ketones [7], which com- prise ≤40% of the compounds in the organic phase [3]. Therefore, the obtained oil needs to be upgraded to remove the oxygen atoms through https://doi.org/10.1016/j.jaap.2019.03.012 Received 26 December 2018; Received in revised form 28 February 2019; Accepted 18 March 2019 ⁎ Corresponding author. E-mail addresses: chanatip@tu.ac.th, s_chanatip@hotmail.com (C. Samart). Journal of Analytical and Applied Pyrolysis xxx (xxxx) xxx–xxx 0165-2370/ © 2019 Elsevier B.V. All rights reserved. Please cite this article as: Le Kim Hoang Pham, et al., Journal of Analytical and Applied Pyrolysis, https://doi.org/10.1016/j.jaap.2019.03.012