Green Diesel Production Research Articles

A comprehensive experimental investigation of green diesel as a fuel for CI engines

ABSTRACTMany possibilities have been explored so far for replacing petro-diesel with biodiesel and hybrid fuel, but none of these bio-fuels could completely substitute the petro-diesel with or without modification in the CI engine. In this perspective, renewable diesel or green diesel has been gaining popularity due to its higher cetane index and calorific value than that of petro-diesel, biodiesel, and hybrid fuel. This study investigates the production of green diesel from waste cooking oil (WCO) by hydro-processing and TBP distillation. The fuel properties of the green diesel thus produced were estimated using ASTM/EN standards and thereafter green diesel (G100) and its blends (G10, G20, G30 & G50) were used as fuel in a CI engine to analyze the effect on engine combustion, performance and emission characteristics. The results obtained were compared with petro-diesel, optimized biodiesel blend B30 and hybrid fuel (HB-1) to explore its efficacy under same experimental test rig and operating conditions. Over the entire loading conditions, green diesel blends showed higher BTE with lower BSEC. The emissions of CO, UHC and smoke opacity reduced, but a slight increase in NOX level was observed. The shorter ignition delay and higher cetane index of green diesel generated peaks of CP, HRR and ROPR near TDC as compared to the other tested fuels.Abbreviations: G10: 10% Green diesel blended with 90% diesel; G20: 20% Green diesel blended with 90% diesel; G30: 30% Green diesel blended with 90% diesel; G50: 50% Green diesel blended with 90% diesel; G100: 100% Green diesel; B30: 30% biodiesel blended with 70% diesel; HB-1: Hybrid fuel-1; CP: Cylinder pressure; ROPR: Rate of pressure rise; HRR: Heat release rate; ID: Ignition Delay; CHR: Cumulative heat release; CD: Combustion duration; BTE: Brake thermal efficiency; BSEC: Brake specific energy consumption; EGT: Exhaust gas temperature; CO: Carbon monoxide; UHC: Unburnt hydrocarbon; NOX: Oxides of nitrogen

Nickel catalysts supported on palygorskite for transformation of waste cooking oils into green diesel

Nickel catalysts supported on palygorskite of varying Ni content were synthesized following the deposition–precipitation method. The catalysts were characterized using various techniques and evaluated in a semi-batch reactor for the transformation of waste cooking oils (WCO) into green diesel at 310 °C and hydrogen pressure 40 bar.The nickel nanoparticles supported on palygorskite were proved to be very active. The conversion of the WCO was about 100%. The green diesel content of the liquid product depends mainly on the nickel surface exposed per gram of catalyst, following a volcano like trend and maximized (81.9 wt %) over the sample with 30 wt % Ni. Taking into account the very high ratio of WCO volume to catalyst mass (100 mL/g) and that the evaluation of the catalysts was performed under solvent free conditions, these results demonstrate the successful use of mineral palygorskite for developing promising “natural catalysts” for green diesel production.

Production of green diesel from karanja oil (Pongamia pinnata) using mesoporous NiMo-alumina composite catalysts

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 C18 alkane was the leading product among hydrocarbons (C15–C22) 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 C18 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% < C18, 75 wt% C18, and 12 wt% > C18 alkanes at 340 °C and 4 h reaction.

Nickel catalyst with different supports for green diesel production

Green diesel or bio-hydrogenated diesel can be produced from vegetable oils and their derivatives via a catalytic reaction. This work carried out the synthesis and characterization of nickel catalysts for the production of n-alkane from palmitic acid. A nickel (Ni) metal catalyst was studied based on different properties of the supports which were zirconia (ZrO2), Zeolite Socony Mobil–5 (H-ZSM-5), and activated carbon (AC). All catalysts were prepared via the incipient wetness impregnation method. The reaction was carried out in semi-batch mode with the controlled hydrogen gas pressure as low as 10 bars. The results showed that Ni on ZrO2 provided the highest conversion (98.33%) and high n-pentadecane selectivity of around 76% due to the highest acidity of the ZrO2 surface. Methane gas was the main component in the gaseous products and due to the methanation reaction on CO, CO2 was produced. The successful synthesis of a Ni-catalyst for green diesel production (n-pentadecane) from palmitic acid at low pressure can be implemented via deoxygenation reaction to produce green diesel.

Green diesel production from upgrading of cashew nut shell liquid

In recent years, there has been a strong global interest in developing technologies for converting renewable and low-cost raw materials into green diesel and bio-jet fuel, which are made of hydrocarbons. In this work, cashew nut shell liquid (CNSL), which is an industrial waste, was used as a feedstock to produce green diesel. Different reaction conditions during the upgrading process (deoxygenation, hydrogenation and cracking) were evaluated using palladium over activated charcoal (Pd/C) as a catalyst. The catalyst was characterized by X-ray diffraction and specific surface area analysis. The influences of the reaction parameters, such as temperature (180, 250 and 300 °C), time (5 and 10 h) and pressure (10, 20, 30 and 40 bar), were investigated using 10% w/w Pd/C. The composition of the products was determined using gas chromatography coupled with mass spectrometry and infrared spectroscopy. Higher pressures and temperatures led to a higher degree of deoxygenation and hydrogenation. In contrast, lower pressures or temperatures resulted in higher degrees of cracking. From the optimization experiments, a 98% yield of hydrocarbons corresponding to the diesel range was obtained under a 40 bar H2 atmosphere at 300 °C, 10 h, and 500 rpm (in a batch reactor). Of these hydrocarbons, 89% were saturated alkanes, 3% were aromatic compounds and 6% were oxygenated compounds. This new and sustainable route is promising because it involves the conversion of a low-value residue into green diesel using mild experimental conditions. Biofuel production from CNSL allows the total valorization of the residues in the cashew-nut agroindustrial chain and has potential industrial applications in many countries.

Process simulation and techno-economic analysis of bio-jet fuel and green diesel production — Minimum selling prices

The simulation and techno-economic analysis for the production of bio-jet fuel and green diesel from hydrotreatment of vegetable oil is presented in this paper. Monte Carlo simulations are carried out to find the minimum selling price that allow the processes coping with uncertainty in capital investment, feedstock and product prices. The green diesel production involved hydrodeoxygenation (HDO) of vegetable oil, producing propane as a co-product. The bio-jet fuel process involved HDO and isomerisation/hydrocracking to yield bio-jet, green diesel, naphtha, and propane. Based on a proposed reaction scheme and model, the reaction conversions for the isomerisation/hydrocracking reactor are estimated considering constraints in observed bio-jet fuel composition and freezing point. The simulation and analyses were carried out in SuperPro Designer®, linked to Excel Visual Basic for Applications to perform Montecarlo simulations and obtain robust estimations of minimum selling price (MSP). The results showed that a 75 thousand barrels/y bio-jet fuel plant can be profitable, but a MSP of 1.35 US$/L is required to lower the risk of failure due to uncertainty. In the case of the green diesel, for a 63 thousand barrels/y production plant, the required MSP is 1 US$/L. Bio-jet fuel would need incentives or subsidies while the green diesel can be competitive with current fossil diesel prices. Therefore, under current price trends, green diesel production would be a more viable investment. However, bio-jet fuel production benefits from multi-fuel production and if large plant sizes and lower feedstock prices can be obtained, the risks can be mitigated.

Highly efficient Pt-MoOx/ZrO2 catalyst for green diesel production

Bimetallic Pt-MoOx supported on ZrO2 exhibits higher catalytic activity than known catalysts for converting fatty acids into green diesel at as low as 200 °C. A change in selectivity from decarboxylation/decarbonylation to hydrodeoxygenation and enhancement in the deoxygenation activity of Pt were observed when MoOx was also present in the catalyst composition. In X-ray photoelectron spectra, Pt 4f lines of 4Pt-8MoOx/ZrO2 occurred at lower binding energies than those for 4Pt/ZrO2. Part of Mo was reduced from +6 to +5 oxidation state in the presence of Pt. There seems to exist some electronic interaction between the support and metal, making 4Pt-8MoOx/ZrO2 a highly efficient and selective deoxygenation catalyst.

Transition Metal Phosphides for the Catalytic Hydrodeoxygenation of Waste Oils into Green Diesel

Recently, catalysts based on transition metal phosphides (TMPs) have attracted increasing interest for their use in hydrodeoxygenation (HDO) processes destined to synthesize biofuels (green or renewable diesel) from waste vegetable oils and fats (known as hydrotreated vegetable oils (HVO)), or from bio-oils. This fossil-free diesel product is produced completely from renewable raw materials with exceptional quality. These efficient HDO catalysts present electronic properties similar to noble metals, are cost-efficient, and are more stable and resistant to the presence of water than other classical catalytic formulations used for hydrotreatment reactions based on transition metal sulfides, but they do not require the continuous supply of a sulfide source. TMPs develop a bifunctional character (metallic and acidic) and present tunable catalytic properties related to the metal type, phosphorous-metal ratio, support nature, texture properties, and so on. Here, the recent progress in TMP-based catalysts for HDO of waste oils is reviewed. First, the use of TMPs in catalysis is addressed; then, the general aspects of green diesel (from bio-oils or from waste vegetable oils and fats) production by HDO of nonedible oil compounds are presented; and, finally, we attempt to describe the main advances in the development of catalysts based on TMPs for HDO, with an emphasis on the influence of the nature of active phases and effects of phosphorous, promoters, and preparation methods on reactivity.

Hydrogenation of Bio-Oil Model Compounds over Raney-Ni at Ambient Pressure

Lignocellulosic biofuels are the most promising sustainable fuels that can be added to the crude oil pool to refill the dwindling fossil resources. In this work, we tested a Raney-Ni catalyst for the hydrogenation of four bio-oil model compounds and their binary mixtures to assess their reactivity under mild conditions suitable for bio-oil stabilization preceding green diesel production from lignocellulosic biomass. The hydrogenation experiments were performed at ambient hydrogen pressure at temperatures in the range 30–70 °C. Raney-Ni was found to hydrogenate all investigated model compounds efficiently; both carbonyl groups and double bonds were saturated. In addition, it was also active in the demethoxylation of guaiacol. When studying the binary mixtures, furfuryl alcohol was found to significantly inhibit the hydrogenation of the other model compounds (guaiacol and methyl isobutyl ketone) due to their very strong adsorption.

The effect of metal loading over Ni/γ-Al2O3 and Mo/γ-Al2O3 catalysts on reaction routes of hydrodeoxygenation of rubber seed oil for green diesel production

Abstract Hydrodeoxygenation (HDO) of vegetable oil is one of the promising key processes designed for a possible convenient method for automotive clean fuel production. The HDO of rubber seed oil into diesel range hydrocarbon over non-sulphided monometallic (Ni/γ-Al2O3 and Mo/γ-Al2O3) catalysts were investigated. The catalysts were synthesized via conventional wet impregnation method using 3 wt.%, 12 wt.% and 15 wt.% Ni and Mo loading over γ-Al2O3 support, to examine the influence of metal loading on catalytic activity, coke deposition, and reaction routes. The synthesized catalysts were subjected to characterization techniques including XRD, FESEM coupled with EDX, BET, TEM, TGA, ICP-OES and H2TPR. All the catalysts were tested for HDO reaction at 623.15 K, 3.5 MPa, H2/oil of 1000 N (cm3/cm3) with WHSV = 1 h−1 in a continuous flow fixed bed tubular reactor. The hydrocarbon products were analyzed using gas chromatography, and intermediates were identified using GC–MS. The Ni supported catalysts showed comparatively higher surface area, small particle size, homogeneous dispersion of particles, higher crystallinity and lower reduction temperature, low coke deposition. Proposed reaction mechanism suggests the decarboxylation (DCO2) reaction occurred mainly over Ni supported catalysts. Whereas, higher Ni loading reduced the extent of decarboxylation (DCO2) reaction. Additionally, Mo supported catalysts allowed the deoxygenation reaction to occur and higher Mo loading enhanced the extent of hydrodeoxygenation (HDO). The triglycerides conversion for all the catalysts was 99.9%. The catalysts with higher metal loading showed overall higher catalytic activity for hydrodeoxygenation of RSO. 15 wt.% Ni loading produced higher hydrocarbon yield (55.1 wt.%) whereas, 15 wt.% Mo loading produced up to 61.7 wt.%. Mo comparatively produced high amount of C16 (15.7 wt.%), and C18 (30.7 wt.%) hydrocarbons. Whereas, Ni produced mainly C15 (20.9 wt.%) and C17 (20.3 wt.%) hydrocarbons. Significant findings were observed on hydrocarbon yield, intermediates, and amount of coke formation. Mo supported catalysts shows significant HDO activity with less concentration of oxygenated component in the mixture. Besides Mo supported catalysts exhibit the high amount of coke deposition compared to Ni supported catalysts.

Green diesel production over nickel-alumina nanostructured catalysts promoted by zinc

Abstract Following the one step co-precipitation technique we have synthesized a series of Ni-Zn catalysts supported on alumina. The series involves one non-promoted sample containing 60 wt % Ni and three zinc promoted samples containing 1, 2 and 5 wt % Zn and 59, 58 and 55 wt % Ni, respectively. The specimens were characterized using nitrogen sorption isotherms, H2-TPR, NH3-TPD, XRD, SEM-EDX, TEM and XPS. The catalytic performance of the samples prepared was evaluated in the selective deoxygenation of sunflower oil using a semi-batch reactor (310 °C, 40 bar of hydrogen, hydrogen flow rate equal to 100 mL/min and reactant to catalyst ratio equal to 100 mL/g). The control of the co-precipitation procedure and the direct reduction of dried precipitate resulted to mesoporous nano-structured catalysts with high surface area (247–290 m2 g−1). The non-promoted sample was mainly comprised from NiAl2O4 particles and the promoted ones from Ni-Zn alloys and intermetallic oxo-phases (IMPs) supported on largely amorphous Al2O3 nano-grains. Zinc increased the total yield of alkanes in the diesel range (n-15, n-16, n-17, n-18) though it does not affect the mechanistic scheme of the selective deoxygenation of sunflower oil which is largely realized via decarbonylation/decarboxylation. The promoting action of zinc was attributed to the favoring of the Ni-Zn alloys and IMPs formation. It is more pronounced in the sample with the medium zinc content (58 wt % Ni, 2 wt % Zn, 40 wt % Al2O3) in which an increase of 18% in the total yield of hydrocarbons has been obtained. The maximization of the zinc promoting action in this sample reflects the good compromise between the extent of alloying and surface acidity.

Techno-economic evaluation of two alternative processes for production of green diesel from karanja oil: A pinch analysis approach

Hydrodeoxygenation (HDO) of vegetable oil is a potential technology for the production of green diesel for direct application in unmodified combustion engines. This study provides the conceptual process design for HDO of karanja oils by two different routes: (i) direct HDO of vegetable oils (direct HDO) and (ii) HDO of fatty acids derived from hydrolysis of vegetable oils (two-step HDO). Pinch analysis was carried out to obtain energy targets and the maximum level of heat recovery and to design the heat exchange network. An economic analysis was then performed using USD 0.5 per kg as the retail price of karanja oil. The production costs of green diesel were estimated as USD 0.84 per kg and USD 0.798 per kg for direct and two-step HDO, respectively, for an optimum plant capacity of 0.12 × 106 metric ton per annum of karanja oil. The analysis was further extended to understand various cost-contributing factors and the effect of feedstock and the price of co-products on the manufacturing costs of green diesel. A discounted cash flow analysis was carried out to determine the minimum selling price of green diesel.

Green Diesel: Biomass Feedstocks, Production Technologies, Catalytic Research, Fuel Properties and Performance in Compression Ignition Internal Combustion Engines

The present investigation provides an overview of the current technology related to the green diesel, from the classification and chemistry of the available biomass feedstocks to the possible production technologies and up to the final fuel properties and their effect in modern compression ignition internal combustion engines. Various biomass feedstocks are reviewed paying attention to their specific impact on the production of green diesel. Then, the most prominent production technologies are presented such as the hydro-processing of triglycerides, the upgrading of sugars and starches into C15–C18 saturated hydrocarbons, the upgrading of bio-oil derived by the pyrolysis of lignocellulosic materials and the “Biomass-to-Liquid” (BTL) technology which combines the production of syngas (H2 and CO) from the gasification of biomass with the production of synthetic green diesel through the Fischer-Tropsch process. For each of these technologies the involved chemistry is discussed and the necessary operation conditions for the maximum production yield and the best possible fuel properties are reviewed. Also, the relevant research for appropriate catalysts and catalyst supports is briefly presented. The fuel properties of green diesel are then discussed in comparison to the European and US Standards, to petroleum diesel and Fatty Acid Methyl Esters (FAME) and, finally their effect on the compression ignition engines are analyzed. The analysis concludes that green diesel is an excellent fuel for combustion engines with remarkable properties and significantly lower emissions.

Developing Nickel–Zirconia Co-Precipitated Catalysts for Production of Green Diesel

The transformation of sunflower oil (SO) and waste cooking oil (WCO) into green diesel over co-precipitated nickel–zirconia catalysts was studied. Two series of catalysts were prepared. The first series included catalysts with various Ni loadings prepared using zirconium oxy-chloride, whereas the second series included catalysts with 60–80 wt % Ni loading prepared using zirconium oxy-nitrate as zirconium source. The catalysts were characterized and evaluated in the transformation of SO into green diesel. The best catalysts were also evaluated for green diesel production using waste cooking oil. The catalysts performance for green diesel production is mainly governed by the Ni surface exposed, their acidity, and the reducibility of the ZrO2. These characteristics depend on the preparation method and the Zr salt used. The presence of chlorine in the catalysts drawn from the zirconium oxy-chloride results to catalysts with relatively low Ni surface, high acidity and hardly reduced ZrO2 phase. These characteristics lead to relatively low activity for green diesel production, whereas they favor high yields of wax esters. Ni-ZrO2 catalysts with Ni loading in the range 60–80 wt %, prepared by urea hydrothermal co-precipitation method using zirconium oxy-nitrate as ZrO2 precursor salt exhibited higher Ni surface, moderate acidity, and higher reducibility of ZrO2 phase. The latter catalysts were proved to be very promising for green diesel production.

Evaluation of processing route alternatives for accessing the integration of algae-based biorefinery with palm oil mill

Algae biomass has gained attention as a potential feedstock for renewable energy production in a biorefinery due to its capability to assist on carbon sequestration and wastewater remediation. Since algae can be grown using CO2 and wastewater, the integration the algae-based biorefinery with other industry that produced CO2 and discharge water as wastes may improve the economic and environmental aspects of the biorefinery. In this study, the economic potentials of five processing route alternatives for algae processing (1000 t/y of dry algae feed basis) in an integrated algae-based biorefinery with palm oil mill were assessed. The alternatives evaluated were: (A1) Combustion of residual algae, (A2) Production of biogas from the Palm Oil Mill Effluents (POME), (A3) Production of biochar and bio-oil, (A4) Production of biogas and bio-oil, (A5) Production of green diesel. The economic assessments of the processing route alternatives were compared with the baseline scenario, which was the processing of algae into biodiesel and glycerol without the palm oil mill integration. Depending on the alternatives, the algae could be processed to produce up to 20.6 GWh/y of electricity, 100 t/y of biodiesel, 139 t/y of bio-oil, and 13.9 t/y of green diesel. The capital costs (CAPEX), operating costs (OPEX), revenue (REV), and energy demand (ED) for the baseline scenario and alternatives were calculated. The CAPEX for the baseline scenario and all of the integrated biorefinery alternatives evaluated varied between 9.239 × 105 USD/y to 9.526 × 105 USD/y while the OPEX varies between 7.765 × 106 USD/y to 8.474 × 106 USD/y. Based on the specific case study, all alternatives were not economically feasible since evaluation on all alternatives resulted in loss. Palm oil mill integrated algae-based biorefinery for biogas production was the alternative with least loss of −6.240 × 106 USD/y.

Simulation of Hydrotreating of Vegetable Oil in a Slurry Bubble Column Reactor for Green Diesel Production

Simulation of Hydrotreating of Vegetable Oil in a Slurry Bubble Column Reactor for Green Diesel Production

Sulphated Zr–Al2O3 catalysts through jatropha oil to green-diesel production

Composite materials of zirconia–alumina (Zr–Al2O3) with Al/Zr 10 ratio was successfully synthesized by sol–gel method and followed by different sulfiding methods. The synthesized catalysts were characterized by various techniques such as X-ray powder diffraction (XRD), N2-sorption, NH3-Temperature Programmed Desorption (NH3-TPD), Diffuse Reflectance UV–Vis Spectrophotometers (DR UV–Vis), Scanning Electron Microscopy (SEM), and the biodiesel was analyzed by Gel permeation chromatography (GPC) and Gas chromatography–mass spectrometry (GC–MS). The jatropha oil conversion of above 96% was obtained at optimized conditions of 110 °C, 1:20 jatropha oil to methanol ratio, 1.5 g of catalysts and 3 h reaction time. The catalysts reusability study was performed for 6th cycles using sulphated Zr–Al2O3 under hydrothermal (H) method, denoted as SO42−/Zr–Al2O3 (10)–H and the activity is correlated with physico-chemical properties.

Pyro-lytic de-oxygenation of waste cooking oil for green diesel production over Ag2O3-La2O3/AC nano-catalyst

Green diesel derived from deoxygenation technology has been developed to replace instability of fatty acid alkyl ester (biodiesel) due to the presence oxygenated species. Herein, the green diesel was synthesized via catalytic deoxygenation (DO) of waste cooking oil (WCO) over synthesized Ag2O3–La2O3/ACnano catalyst under hydrogen-free environment. Based on the study, the effect of silver (Ag) species (10–30 wt%) towards DO reactivity and product distribution was investigated. It was revealed that the Ag2O3(10%)–La2O3(20%)/ACnano formulation resulted in a higher yield (∼89%) of liquid hydrocarbons with majority of diesel fractions selectivity (n–(C15+C17) at ∼93%. In addition, decarboxylation and decarbonylation reaction processes of the WCO to DO was promoted by the presence of acid and basic active sites on Ag2O3(10%)–La2O3(20%)/ACnano catalyst. The high stability of the Ag2O3(10%)–La2O3(20%)/ACnano catalyst was proven by maintenance of six continuous runs with constant yield (>80%) of hydrocarbons and (>93%) selectivity of n–(C15+C17) under mild reaction conditions.

Catalytic hydrodeoxygenation of rubber seed oil over sonochemically synthesized Ni-Mo/γ-Al2O3 catalyst for green diesel production

Hydrodeoxygenation is one of the promising technologies for the transformation of triglycerides into long-chain hydrocarbon fuel commonly known as green diesel. The hydrodeoxygenation (HDO) of rubber seed oil into diesel range (C15–C18) hydrocarbon over non-sulphided bimetallic (Ni-Mo/γ-Al2O3 solid catalysts were studied. The catalysts were synthesized via wet impregnation method as well as sonochemical method. The synthesized catalysts were subjected to characterization methods including FESEM coupled with EDX, XRD, BET, TEM, XPS, NH3-TPD, CO-chemisorption and H2-TPR in order to investigate the effects of ultrasound irradiations on physicochemical properties of the catalyst. All the catalysts were tested for HDO reaction at 350 °C, 35 bar, H2/oil 1000 N (cm3/cm3) and WHSV = 1 h−1 in fixed bed tubular reactor. The catalyst prepared via sonochemical method showed comparatively higher specific surface area, particles in nano-size and uniform distribution of particle on the external surface of the support, higher crystallinity and lower reduction temperature as well as higher concentration of Mo4+ deoxygenating metal species. These physicochemical properties improved the catalytic activity compared to conventionally synthesized catalyst for HDO of rubber seed oil. The catalytic performance of sonochemically synthesized Ni-Mo/γ-Al2O3 catalyst (80.87%) was higher than the catalyst prepared via wet impregnation method (63.3%). The sonochemically synthesized Ni-Mo/γ-Al2O3 catalyst is found to be active, produces 80.87 wt% of diesel range hydrocarbons, and it gives high selectivity for Pentadecane (18.7 wt%), Hexadecane (16.65 wt%), Heptadecane (24.45 wt%) and Octadecane (21.0 wt%). The product distribution revealed that the deoxygenation reaction pathway was preferred. Higher conversion and higher HDO yield in this study are associated mainly with the change in concentration ratio between oxidation states of molybdenum (Mo4+, Mo5+, and Mo6+) on the external surface of the catalyst due to ultrasound irradiation during the synthesis process. Consequently, the application of sonochemically synthesized non-sulphided catalysts favored mainly hydrodeoxygenation of diesel range hydrocarbon.

Fe/Indonesian Natural Zeolite as Hydrodeoxygenation Catalyst in Green Diesel Production from Palm Oil

The Petroleum diesel-based fossil fuel remains the primary source of energy consumption in Indonesia. The utilization of this unrenewable fuel depletes fossil fuels; thus, an alternative, renewable fuel, such as one based on biohydrocarbon from biomass-green diesel-could be an option. In this work, green diesel was produced through the hydrodeoxygenation from palm oil and processed in a batch-stirred autoclave reactor over natural zeolite (NZ) and NZ modified with 3 wt.% Fe metal (Fe/NZ) as heterogeneous catalyst. NZ showed high crystallinity and suitability to the simulated pattern of the mordenite and clinoptilolite phases according to X-ray diffraction (XRD) analysis. The presence of Fe metal was further confirmed by XRD, with an additional small diffraction peak of Fe0 that appeared at 2θ = 44-45°. Meanwhile, NZ and Fe/NZ were also characterized by Scanning electron microscopy (SEM) with Energy Dispersive X-ray (EDX), X-ray Fluorescence (XRF), and Surface Area Analyzer (SAA). The obtained materials were tested for the conversion of palm oil into diesel-range hydrocarbons (C15-C18) under conditions of 375 °C and 12 bar H2 for 2 h. NZ and Fe/NZ produced a liquid hydrocarbon with straight-chain (C15-C18) alkanes as the most abundant products. Based on Gas Chromatography-Mass Spectrometry (GC-MS) measurement, a higher conversion of palm oil into diesel-like hydrocarbons reached more than 58% and 89%, when NZ and Fe modified NZ (Fe/NZ), respectively were used as catalysts.