Contents lists available at ScienceDirect Bioresource Technology Reports journal homepage: www.journals.elsevier.com/bioresource-technology-reports Production of green diesel from karanja oil (Pongamia pinnata) using mesoporous NiMo-alumina composite catalysts Sudhakara Reddy Yenumala 1 , Pankaj Kumar, Sunil K. Maity ⁎ , Debaprasad Shee Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502285, Telangana, India ARTICLE INFO Keywords: Green diesel Hydrodeoxygenation Karanja Oil NiMo-alumina Mesoporous catalysts ABSTRACT NiMo-alumina catalysts with a small quantity of Mo showed ordered mesoporous structure. For 4.3 mmol total metals content, mesoporous structure, however, became disorder for 1.7 mmol and higher Mo content. The C 18 alkane was the leading product among hydrocarbons (C 15 –C 22 ) formed during hydrodeoxygenation of karanja oil. The catalytically active NiMo complex and Mo oxide species with lower oxidation states were substantial in NiMo catalysts with the modest quantity of both Mo and Ni and relatively small for the other two extremes. The catalytic activity and selectivity to C 18 alkane were thus enhanced with the rise in Mo content up to 3.4 mmol. The catalytic activity was also improved with growing total metals content and temperature. The optimum catalyst (0.9 mmol Ni and 3.4 mmol Mo) showed the complete conversion of oxygenates with 13 wt% < C 18 , 75 wt% C 18 , and 12 wt% > C 18 alkanes at 340 °C and 4 h reaction. 1. Introduction Fossil fuels are the primary energy sources all over the world. The consumption of fossil fuels is increasing gradually to meet the energy demands of the growing population in the world. The gradual di- minution of fossil fuels, rise in crude oil price, and emission of green- house gases are the primary motivations for developing energy tech- nologies from sustainable resources. On the other hand, transportation fuels play an important role in today's society. The transportation fuels sector alone consumes about 28% of global energy. At present, trans- portation fuels are mainly produced from limited petroleum. The pro- duction of transportation fuels from the renewable sources of carbon such as biomass is thus indispensable to minimize the import of crude oil and hence improve the economics of the country (Maity, 2015). Biodiesel and bioethanol are accepted as the potential renewable transportation fuels. Biodiesel is currently manufactured from vege- table oils, microalgal oils, waste cooking oil, and animal fats by trans- esterification reaction with methanol. The transesterification reaction is generally carried out in the presence of an alkali catalyst under mild reaction temperature (around 50–80 °C). On the other hand, bioethanol is traditionally produced by yeast fermentation of biomass-derived su- gars. The sugars are generally obtained from either sugar or starchy biomass. Owing to the poor fuels properties, biodiesel and bioethanol are typically blended with diesel and petrol, respectively, to the extent of 15–20% for usage in unmodified combustion engines. The presence of oxygen in the structure of these biofuels also causes lower fuel mileage than petroleum-based liquid transportation fuels. The avail- ability of hydrocarbon biofuels from biomass is thus crucial to avoid the erection of capital-intensive new infrastructures. Triglycerides are composed of the long and linear hydrocarbon backbone with a lesser quantity of oxygen compared to sugar, starch, and cellulosic biomass. It is, therefore, considered as the attractive biomass for manufacturing hydrocarbon biofuels. Pyrolysis, catalytic cracking, and hydrodeoxygenation (HDO) are possible routes for manufacturing diesel-range hydrocarbons from triglycerides, com- monly known as green diesel. Among these processes, HDO is the widely accepted route owing to the high yield of green diesel. Ad- ditionally, this route is associated with minimal loss of fatty acid's carbons as volatile hydrocarbons. This route further offers the possi- bility of co-processing of triglycerides with crude oil fractions in the existing hydrotreatment unit. In general, HDO of triglyceride can be carried out through two distinct ways: (i) direct HDO, where green diesel is produced by HDO of neat triglycerides with propane as the co-product and (ii) two-step HDO, where mixed fatty acids are first produced by hydrolysis of ve- getable oils with glycerol as the co-product (Mailaram and Maity, 2019). The HDO of these mixed fatty acids is then carried out to pro- duce green diesel. Recently, Mailaram and Maity (2019) evaluated the https://doi.org/10.1016/j.biteb.2019.100288 Received 22 March 2019; Received in revised form 15 July 2019; Accepted 15 July 2019 ⁎ Corresponding author. E-mail address: sunil_maity@iith.ac.in (S.K. Maity). 1 Present address: Biomass Conversion Area (BCA), Materials Resource Efficiency Division (MRED), CSIR-Indian Institute of Petroleum (IIP), Dehradun 248005, India. Bioresource Technology Reports 7 (2019) 100288 Available online 17 July 2019 2589-014X/ © 2019 Elsevier Ltd. All rights reserved. T