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Production of green diesel alkanes (DA) from vegetable oils is highly efficient in reducing dependence on finite fossil fuels. Catalytic hydrodeoxygenation (HDO) of non-edible extracted Neem seed oil (NSO) in a batch reactor over Ni/nano zeolite catalyst was investigated. The main issues of the effective HDO in terms of high yield and selectivity towards long-chain alkanes in mild operating conditions have been addressed. It was revealed that in the HDO reaction of NSO over 30% Ni/nano zeolite, the highest DAs (C 10 –C 18) yields is 88.84% at 350 °C, process time of 4 h and hydrogen pressure of 8 bar. This performance can be attributed to the well-distributed Ni in the support surface as well as the acidity of the catalyst and proper textural properties. The results from current study demonstrated that the 30% Ni/nano zeolite catalyst is a potential HDO catalyst for the production of green diesel. In most experiments, the transformation of NSO into DAs was accomplished through decarboxylation (DCO 2) and decarbonylation (DCO) routes. However, the progress of the process to the obtained products from the HDO pathway was surprisingly increased at temperatures above 300 °C. • The production of biodiesel alkanes is considered through via catalytic HDO of NSO. • 30%Ni/nano zeolite catalyst is a potential HDO catalyst for the production of biodiesel. • NSO conversion into alkanes proceeds through decarboxylation and decarbonylation routes. • Highest biodiesel alkanes (C 10 –C 18) yields is 88.84% at 350 °C and H 2 pressure of 8 bar. • Ni/nano zeolite catalyst represents good activity and selectivity toward alkane's production. [ABSTRACT FROM AUTHOR]

A reduction in emissions in transportation is paramount to achieve full compliance with the European Union's 2050 targets. In this framework, a great boost to the carbon dioxide (CO2) emission of internal combustion engines fueled by petroleum-derived fuels can be obtained through the adoption of biomass-derived fuels that can be employed in conventional series production engine vehicles. This paper presents the results of an experimental activity on a two-cylinder turbocharged common rail diesel engine, whose main application is for urban mobility, fueled with renewable fuels: Neste MY Renewable Diesel and Eni HVOlution. Aimed at analyzing the potential employment of renewable fuels as drop-in alternative fuels, the engine performance and emissions were investigated under fixed settings of the injection parameters, in the complete range of the engine speed, at the full pedal position. The comparison with the data from tests in which the engine was fueled with fossil diesel highlighted minimal differences in the performance outcomes, while significant differences were observed in the emissions results. In more detail, there were reduced carbon monoxide (CO) emissions (HVO produced using Ecofining™ technology retained better behavior in relation to HVO produced using the NEXBTL™ technology), advantages in hydrocarbon (HC) and nitrogen oxide (NOx) emissions (HVO from NESTE Oil performed better than HVO from ENI), a decrease in the particle mass and number emissions (HVO from Ecofining™ technology was characterized by a lower particle number and court mean diameter in relation to HVO from the NEXBTL™ technology). The results highlight that an optimization of the engine settings based on the specific properties of each fuel could allow us to take full advantage of these fuels in reducing the environmental impact of cars. [ABSTRACT FROM AUTHOR]

Nickel-based catalysts promoted by Mo-oxo species have been proven to be quite promising for transformation of triglycerides into green diesel. The selection of the support for such catalysts is crucial. In the present study, pyrolyzed rice husk subjected to acid and/or alkaline post-treatment was studied as support for the aforementioned catalysts. Biochar produced by slow pyrolysis of raw material at 850 °C for 5 h under limited-oxygen conditions exhibited the most promising textural characteristics. These were substantially improved by alkaline post-treatment. Thus, the corresponding MoNi catalysts proved the most efficient for upgrading used cooking oil (UCO) to green diesel via a solvent-free hydrotreatment process, performed in a semi-batch reactor (at 310 °C, 40 bar, 100 mL/min H2, 100 mL UCO and 1 g of catalyst). The enhanced catalytic performance (complete conversion of UCO and 32 wt.% green diesel yield) of MoNi catalysts supported on biochar subjected at least to an alkaline post-treatment step has been attributed to their high SSA, suitable pore size distribution (enhanced mesoporosity), and acidity (enhanced population of acid sites with moderate strength), as well as to the high dispersion of the active phase. [ABSTRACT FROM AUTHOR]

Abstract In this study, the improvement of heat transfer was applied to eliminate hotspots of a highly exothermic reaction, Fischer–Tropsch synthesis (FTS), by means of two facile methods: (I) adding high thermal conductive materials media diluted in catalysts (SiC and Al chips), and (II) using structured reactors equipped with well-designed structured catalysts with advantages of heat dissipation/removal. The 20%Co/SiO2 catalyst powder prepared by simple impregnation was employed for constructing structured catalysts and granular packed bed catalysts. The structured catalyst was prepared by coating method of Co/SiO2 slurry on an aluminum spiral and plate substrate. The catalytic performance of as-prepared catalysts was then tested for FTS in a fixed-bed reactor at 210–230 °C, 20 bar. Both gaseous and liquid products were collected and analyzed. The heat transfer improvement of packed bed catalytic system and structured catalytic system were compared and discussed. As a result, the structured catalytic system with spiral structured catalyst can provide the best improvement of heat/mass transfer, resulting in enhanced diesel selectivity, though the oil production rate was unsatisfactory. Meanwhile, among the packed bed catalytic systems, SiC media possessed the best heat removal material, producing the highest oil yield. In addition, the fresh and spent catalysts were analyzed by several techniques including TEM, SEM, XRD, BET, ICP-OES, H2–TPR, and TGA to relate the physicochemical properties of the prepared catalysts and its FTS performance.

In this study, the improvement of heat transfer was applied to eliminate hotspots of a highly exothermic reaction, Fischer–Tropsch synthesis (FTS), by means of two facile methods: (I) adding high thermal conductive materials media diluted in catalysts (SiC and Al chips), and (II) using structured reactors equipped with well-designed structured catalysts with advantages of heat dissipation/removal. The 20%Co/SiO2 catalyst powder prepared by simple impregnation was employed for constructing structured catalysts and granular packed bed catalysts. The structured catalyst was prepared by coating method of Co/SiO2 slurry on an aluminum spiral and plate substrate. The catalytic performance of as-prepared catalysts was then tested for FTS in a fixed-bed reactor at 210–230 °C, 20 bar. Both gaseous and liquid products were collected and analyzed. The heat transfer improvement of packed bed catalytic system and structured catalytic system were compared and discussed. As a result, the structured catalytic system with spiral structured catalyst can provide the best improvement of heat/mass transfer, resulting in enhanced diesel selectivity, though the oil production rate was unsatisfactory. Meanwhile, among the packed bed catalytic systems, SiC media possessed the best heat removal material, producing the highest oil yield. In addition, the fresh and spent catalysts were analyzed by several techniques including TEM, SEM, XRD, BET, ICP-OES, H2–TPR, and TGA to relate the physicochemical properties of the prepared catalysts and its FTS performance. [ABSTRACT FROM AUTHOR]

The conversion of fatty acids into bio-hydrocarbons can be carried out through a deoxygenation (DO) reaction. Catalytic deoxygenation of fatty acids can occur through three reaction pathways: decarbonylation, decarboxylation, and hydrodeoxygenation. In this study, three kinds of silica were prepared: (i) silica obtained from the rice husk ash (RHA); (ii) synthetic mesoporous silica SBA-16; and (iii) commercial silica. All prepared silica was used as supported nickel (Ni) catalyst for bio-hydrocarbon production through DO reaction of oleic acid. The objective of this study was to investigate the effect of variations of silica on the reaction pathway and final products composition of DO reaction of oleic acid. The catalysts were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), surface area analysis, and NH3-temperature-programme desorption. Based on XRF and XRD analysis results, it can be concluded that nickel was successfully impregnated into all silica. All samples of catalysts were used in a reaction carried out at temperature of 285 °C under a pressure of 40 bar H2 for 2h. The results showed that all catalysts were able to convert oleic acid to bio-hydrocarbon with differences in products composition. The highest oleic acid conversion of 98.25% was achieved with Ni/RHA catalyst but the obtained liquid products was the lowest among other catalysts. It is found that this phenomenon was closely related to the acidity properties of the catalyst.

The role of mesoporous solid acid aluminosilicate in the oleic acid deoxygenation was elucidated using ZSM-5 and Al-MCM-41 impregnated with Ni. The mesoporous supports were synthesized using a similar initial Si/Al ratio but employing different templates to vary the mesopores. ZSM-5_T produced interparticle mesopores when using TPAOH (tetrapropylammonium hydroxide) as a template. Meanwhile, ZSM-5_S with a well-defined intraparticle mesoporous channel was formed using a silicalite template. Al-MCM-41 synthesized without a template produced one-dimensional highly ordered mesoporous channels. The arrangement of mesoporosity in aluminosilicate determined the mechanistic pathway of oleic acid conversion into hydrocarbon. Oleic acid underwent primary thermal cracking into carboxylic acid before progressing into the subsequent decarbonylation reaction. The diesel hydrocarbon yield was enhanced following the order of Al-MCM-41>ZSM-5_S>ZSM-5_T>blank reaction. Large intraparticle mesoporosity produced long-chain carboxylic acid from catalytic cracking of oleic acid, which was subsequently deoxygenated into long-chain hydrocarbons.

Hydrocarbons (fuel) derived from agricultural waste biomass are potential alternatives, and these hydrocarbons are within range of jet fuel and diesel. In the current research work, date seeds are considered a feedstock for bio-oil (composed of oxygenated hydrocarbons) and is subjected to hydro-deoxygenation to produce green jet fuel and diesel. Hydro-deoxygenation is exothermic reaction and involves cracking for which a novel heterogeneous catalyst is synthesised. The heterogeneous catalyst consists of an acidic nature precursor derived from waste glass (SiO2) and active metals (tungsten, nickel and palladium) to provide the acidic sites for better-desired product yield. The synthesised catalysts are characterised in detail by the following techniques X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDXS), Brunauer–Emmett–Teller (BET), Ammonia-Temperature programmed desorption (TPD) and X-ray Photoelectron Spectroscopy (XPS) and based on characterisation it is revealed that synthesised will be suitable for hydro-deoxygenation. The most appropriate combination of metal and precursor is Pd-SiO2. Product oil's optimised degree of deoxygenation (DOD) is found to be 93.7% with the following parameters: temperature 340 °C, time 4 h and 4 wt.% of Pd on SiO2. Further on, to prove the commercial viability of the catalyst, it was subjected to five consecutive experimental runs, and it was much active till 5th run if treated before each run. Thus, it can be concluded that bio-oil source is agricultural waste, and for catalyst precursor waste glass is considered; so by considering these factors, the product oil produced has components which lie within the range of jet fuel and diesel, which can be economical as well as eco-friendly source of fuel. [ABSTRACT FROM AUTHOR]

Liquid fuel production from biomass-derived molecules has received great attention due to the diminished fossil fuel reserves, growing energy demand, and the necessity of CO2 emission reduction. The deoxygenation of oils and fatty acids is a promising process to obtain "green" diesel. Herein, we report the results of the study of the deoxygenation of stearic acid to alkanes as a model reaction. Series of Ni-supported on schungite were obtained by precipitation in subcritical water (hydrothermal deposition) and for comparison via wetness impregnation followed, in both cases, by calcination at 500 °C and a reduction in H2 at 300 °C. The catalyst obtained via hydrothermal synthesis showed a three-fold higher specific surface area with a four-fold higher active phase dispersion compared to the catalysts synthesized via conventional impregnation. The catalysts were tested in stearic acid deoxygenation in supercritical n-hexane as the solvent. Under optimized process conditions (temperature of 280 °C, hydrogen partial pressure of 1.5 MPa, and 13.2 mol of stearic acid per mol of Ni), a close to 100% yield of C10–C18 alkanes, containing over 70 wt.% of targeted n-heptadecane, was obtained after 60 min of reaction. [ABSTRACT FROM AUTHOR]

To explore a green, cheap, and high-performance catalyst for lipid hydrotreatment into green diesel, the non-noble metal catalysts (Fe, Cu, Co, Ni, and Mo) with Al2O3 carrier were prepared. Their catalytic performance in oleic acid hydrotreatment was compared, and the metal loading was studied. The characterizations (XRD, N2 physical sorption, H2-TPR, and XPS) were utilized to elucidate the catalytic property. In oleic acid hydrotreatment, the catalytic activity of 5 monometallic catalysts was in the following order: Co > Mo > Ni > Fe > Cu, and the Co/Al2O3 catalyst achieved 94.4% conversion and 91.8% alkane yield. Among 6 Co loadings (5, 10, 15, 20, 25, and 30 wt%), 25 wt% was optimal because it reached the balance of the surface area and the number of Co active sites. Moreover, the lipid hydrotreatment over Co/Al2O3 catalyst occurred mainly via DCX/DCN route; meanwhile, the cracking reaction also happened. [ABSTRACT FROM AUTHOR]

Green diesel derived from sustainable biomass is an alternative and potential energy source to petroleum fossil fuel replacement in response to reducing carbon footprint and achieving a circular economy, which has sparked public interest and concern in advancing renewable energy development. Catalytic deoxygenation (CDO) is a promising method because it can process a wide variety of feedstocks and produce a diverse range of fuels. The CDO of soybean oil (SO) was executed using a modified low-cost dolomite catalyst denoted as NiO-CD catalyst and its performance has been compared with commercial zeolite heterogeneous-based catalysts such as ZSM-5, HY-zeolite and FCC. The NiO-CD catalyst exhibited exceptional deoxygenation ability, attaining an 88.6 % removal efficiency of oxygenated compounds, markedly surpassing all commercially available zeolite catalysts. The highest degree of CDO of SO via decarboxylation/decarbonylation (deCOx) reaction was achieved due to improvement in particle size, mesoporous structure and the presence of the synergistic effect of modified bi-functional acid-base properties of NiO-CaO/MgO catalyst. To investigate the effect of NiO-CD catalyst loading ranging from 1 to 7 wt%, a One Factor At a Time (OFAT) optimisation study was performed. The current study found that an optimised NiO-CD catalyst loading of 5 wt% yielded the highest green diesel (50.5 wt%) with an 88.63 % hydrocarbon composition. The influence of catalyst loading on deoxygenation activity is significant in green diesel production using NiO-CD catalyst.

Biodiesel has emerged as a possible replacement for fossil-based fuels, particularly in the transportation industry. Because of its high oxygen content, it has several limitations including high viscosity, pour point and cloud point. Converting biodiesel to hydrocarbons is one method of improving the poor flow properties. In this study, Reactive Force Field (ReaxFF) molecular dynamics was used to study the decarboxylation of methyl palmitate on α-NiMoO4, β-NiMoO4 and Ni3Mo catalysts. The results show that the reactions are faster in the presence of α-NiMoO4 and β-NiMoO4, and the number of stable products, carbon dioxide and ethene was higher than they were without the catalyst. With Ni3Mo catalyst, there is rapid initial formation of CO2 and C2H4 until a maximum is reached followed by a decrease in their quantity. The C2H4 was found to decompose to C2H2 and H2 while CO2 was reduced to CO. All reactions were found to follow first-order kinetics, from which the activation energies (Ea) were determined. The Ea drops from 36.89 kcal/mol for uncatalyzed reaction to 25.66, 19.34 and 11.69 kcal/mol for the α-NiMoO4, β-NiMoO4 and Ni3Mo catalysed reactions, respectively. The Ni3Mo catalysed system's Ea was also closest to the experimentally reported value of 10.11 kcal/mol [1]. [ABSTRACT FROM AUTHOR]

Petroleum fuel is the primary source of energy today. Its use often causes environmental problems, one of them SOx gas emissions. Palm fatty acid distillate (PFAD) is a by-product of crude palm oil refining and has great promise to be developed as a renewable energy source. This research investigates the effect of Ni/P catalyst ratios impregnated by activated natural zeolite as solid support to properties and performance of hydrodeoxygenation (HDO) of PFAD to green diesel. The HDO reaction was performed by varying Ni/P at a temperature of 350 °C for 2 h, and 40 bar H2 pressure. The highest conversion and selectivity of PFAD to green diesel are obtained at a ratio of NiP(2:1)/NZ0.5 catalyst.

JS.22 seed oil was transesterified into green diesel in an effort to create a nontoxic and environmentally friendly fuel. Mansonia altisima residual ash (MARA) was used to create an alkaline base catalyst, which was then evaluated using SEM, FTIR, BET, XRF, and qualitative analysis. Three factors (EtOH/OMR, reaction duration, catalyst quantity, and reaction temperature) were taken into account during process optimization utilizing the Stat Ease 360 optimizer.The catalyst reusability test was used to gage the strength of the utilized catalyst. The physical and chemical characteristics of oil made it suitable for transesterification. CaO-K2O-SiO2 is recognized as a catalyst composition by catalyst analysis. At the following conditions: reaction duration of 50 min, catalyst quantity of 2.0 (%wt), and E-OH/OMR of 4.0 (vol/vol), process optimization predicted a green diesel yield of 98.99% (vol/vol). Process optimization predicted a 98.99% (vol./vol.) green diesel yield under the following conditions: reaction time of 50 min; catalyst amount of 2.0 (%wt); and E-OH/OMR of 4.0 (vol./vol.). However, statistical analysis was validated, and the average means of 98.78% (vol./vol.) were obtained with p-values of 0.0001. The catalyst reusability test was suspended after the eighth cycle since the yield had significantly dropped.The green diesel qualities complied with the suggested green diesel standard.

This study investigated the hydrodeoxygenation of palm oil by different oxide nanocatalysts of transition metals α -Fe2O3, NiO, and NiFe2O4, which were synthesized by hot injection. All nanomaterials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and dynamic light dispersion. The catalytic evaluation was performed in a Parr-type reactor at 350°C, 3.5 MPa of H2 pressure, and 3 h of reaction. The liquid product obtained was analyzed by ultraviolet-visible light spectroscopy to identify the n-C16 generated during the reaction. The activity in the deoxygenation of fatty acids to produce n-C16 hydrocarbons has the following order: α-Fe2O3 < NiFe2O4 < NiO.

Green methanol, ethanol, and diesel-based hydrotreated vegetable oils are some of the renewable liquid fuels that show satisfactory performance in diesel engines. A notable advantage of these fuels is that they are renewable and do not require significant modifications in the existing engines for successful operation. Suitable fuel systems, especially their material compatibility, remain unresolved, and therefore, it is a weak link in their large-scale adaptation. Elastomer-based sealing O-rings lose their mechanical properties after a short exposure time to these fuels, adversely impacting their functionality. This research study evaluated the long-term material compatibility of different elastomer-based sealing materials by immersing the O-rings in these test fuels (hydrotreated vegetable oil, methanol, ethanol, and diesel) for different time intervals (i.e., up to 15 months). The material compatibility was assessed mainly by investigating these changes in various mechanical properties of these O-rings, namely tensile strength (ΔTs), elongation at break (ΔEb), Shore A hardness (ΔH), and mass (ΔM). The degradation of mechanical properties was studied and analyzed during the immersion interval from 0.9 to 15.2 months and compared with O-rings kept in a normal atmosphere. It was noted that individual fuels affect various mechanical properties significantly. In a short interval of 0.9 months (28 days), significant changes in the mechanical properties of the sealing O-rings were observed. [ABSTRACT FROM AUTHOR]

To produce green diesel from black soldier fly larvae (BSFL; Hermetia illucens), the maximization of lipids in production and hydrodeoxygenation (HDO) reactions was investigated. In this study, BSFL were fed 12 diets based on three different substrates (ground corn, food waste, and meat by-product). The proximate compositions of larvae were analyzed, and rearing time, production rate, and feeding mixture prices were also recorded. To maximize the lipid yield, the effects of growing temperature, drying method, and extraction temperature were investigated. The HDO reaction of BSFL oil with 1 wt % Pt/Al2O3 catalyst was carried out in a trickle bed reactor. The components of the lipids produced under optimal conditions and the components of lipids produced through the HDO reaction were compositionally analyzed. As a result of being fed ground corn, food waste, and meat by-products, it was confirmed that the diet with 30% ground corn and 70% meat by-product led to the highest lipid content in the BSFL. After considering the prices of the diets, we found that the most ideal feeding conditions that could be applied to actual insect farming were 70% food waste and 30% meat by-products. From the perspective of the rearing period, the most appropriate BSFL-rearing temperature was a medium temperature of 38 °C. After harvesting the BSFL, it was confirmed that the lipid yield improved when extracted at a temperature of 65–75 °C after drying using a microwave. The analysis results showed that the carbon distribution in hydrodeoxygenated BSFL oil offered an advantage when used as drop-in fuel, and this represents a promising future step for the HDO of BSFL lipids. [ABSTRACT FROM AUTHOR]

Natural zeolite (NZ) from desilication and activation was prepared to support the Ni catalyst. The catalyst was utilized for the hydrodeoxygenation (HDO) of the palm fatty acid distillate (PFAD) into green diesel. Desilication using sodium hydroxide (NaOH) solution increases the porosity, surface area, and acidity of the natural zeolite, thus increasing the catalytic activity. This study aims to determine the effect of the NaOH concentration utilized in the desilication process on the characteristics of support and catalytic activity of the Ni/NZ catalyst. Additionally, pure Ni and Ni/NZ without desilication were also investigated for comparison. NZ underwent desilication by varying the concentration of NaOH (0.5, 1, and 2 N). Desilicated zeolite was then activated using a 1 M ammonium acetate solution and impregnated with Ni metals. The desilication NZ increases the acidity and surface area at a low NaOH concentration, while the zeolite structure (clinoptilolite) is still intact. Therefore, the catalytic activity of the catalyst was also increased compared to Ni and Ni/NZ catalysts without desilication. Conversely, a higher concentration of NaOH decreases the Si/Al ratio, acidity, and surface area of support. As a result, the catalytic activity of the catalyst decreases, as evidenced by the reduced liquid product in the hydrodeoxygenation of PFAD. The Ni/NZ0.5 catalyst revealed optimal catalytic activity with a liquid fraction and green diesel selectivity of 83.64% and 92.74%, respectively.

In this study, a new class of heterogeneous catalyst in the form of metal-organic frameworks (MOFs), namely Material of Institute Lavoisier-96(Al), which is called MIL-96(Al), was employed for the production of biodiesel and green diesel. The synthesis of MIL-96(Al) was conducted via a hydrothermal method at 210 °C for 4 hours with dimethylformamide (DMF) as an assisting agent. The Ni was loaded into MIL-96(Al) via incipient wetness impregnation method with variations 3, 5, and 10 wt.% to form Ni/MIL-96(Al). Based on X-Ray diffraction (XRD) analysis, the obtained material has good crystallinity with characteristic peaks observed at 2? = 5.8°; 7.8°, and 9.1°. Fourier Transform Infrared (FTIR) analysis demonstrated an essential shift from 1715 cm-1 to 1666 cm-1, indicating the coordination of the carboxylate group with Al3+ metal ions. Moreover, MIL-96(Al) is stable up to 390 °C according to the thermogravimetric analysis (TGA). Based on structural and morphological analysis (using XRD, FTIR, and Scanning Electron Microscope (SEM)), the loading of Ni into MIL-96(Al) does not change the basic structure of MIL-96(Al). However, the pore diameter of MIL-96(Al) decreased from 5.7 nm to 1.4 nm after the Ni was embedded in the structure. The largest surface area was obtained from 10% Ni/MIL-96(Al) (up to 595.5 m2/g). The catalytic test exhibits that 3% Ni/MIL-96(Al) could attain an optimum yield of up to 85.24% of biodiesel, while in the case of hydrodeoxygenation (HDO) reaction, the optimum catalyst shown by 10% Ni/MIL-96(Al) with conversion and selectivity of C16 up to 90.70% and 55.22%, respectively.

The objective of this research was to prepare low-cost catalyst for green diesel conversion from vegetable oil. The catalyst of nickel-dispersed biochar (Ni/BC) was prepared by direct pyrolysis of nickel precursor with palm leaves waste under N2 stream at 500 °C. The obtained catalyst was examined by using x-ray diffraction, scanning electron microscope-energy dispersive x-ray, transmission electron microscopy, gas sorption analysis, FTIR and surface acidity examination. The catalytic activity testing was performed on rice bran oil hydrodeoxygenation at varied temperature and time of reaction. Based on analyses, the results showed the successful preparation of Ni/BC with the characteristic of single nickel nanoparticles decorated on surface. The increasing specific surface area of material was conclusively remarked the surface area enhancement by nickel dispersion along with the increased surface acidity, suggesting that the material can be applied for acid catalysis applications. The Ni/BC exhibited excellent catalytic conversion of rice bran oil with the high selectivity toward diesel fraction with 85.3% yield and 92.6% selectivity. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

There has been a considerable in converting palm oil to green diesel. Green diesel is a hydrocarbon compound similar to conventional diesel fuel's components. It is expected to substitute conventional diesel fuel in diesel vehicle engines. The process of producing diesel is also called the deoxygenation process. One of the deoxygenation processes is decarboxylation. The current study evaluates the performance of Ni-CaO/AC catalyst in the form of pellets by mixing a powder Ni-CaO/AC catalyst and phenolic resin. The aim of this study namely to evaluate the performance pellets of Ni-CaO/AC catalyst in the decarboxylation of palm oil under sub-critical water. This research includes catalyst activity carried out by decarboxylation in subcritical water with temperature variations: 300, 310, 320, and 330 °C using pellets of Ni-CaO/AC catalyst. The decarboxylation products obtained were analyzed with Gas Chromatography-Mass Spectroscopy (GC-MS). The results obtained in this study showed that the highest percentage composition and selectivity of green diesel were obtained at a temperature of 330 °C, with values of 18.08 and 22.07, respectively. These results suggest that higher temperature promotes the hydrogenationdecarboxylation reaction of palm oil. Pellets of Ni-CaO/AC catalyst can increase the selectivity of green diesel if the phenolic resin is replaced with a binder that can provide physical strength to the catalyst but does not damage the function and cover much of the active surface area of the catalyst. We can conclude that pellets of Ni-CaO/AC catalysts have the potential to do hydrothermal decarboxylation if the increased operating condition. [ABSTRACT FROM AUTHOR]

Triglycerides is a kind of natural oil widely existing in animals and plants, and it is also an ideal raw material for preparing biomass liquid fuel. Selectively hydrotreatment of unsaturated glyceride is an important strategy for the production of fuels and chemical feedstocks. In this work, catalytic hydrotreatment of triglycerides over Ni-based catalysts was investigated. Thus, an array of metal–organic frameworks derived Ni@C catalysts synthesized under different temperatures (350 °C, 400 °C, 450 °C) were prepared and applied for hydrotreatment of triglycerides. The highest conversion of triglycerides was 98.9% and the cracking rate could achieve 4.61% over the optimal Ni@C-BTC-400 catalyst in cyclohexane at 320 °C. The physicochemical characterizations were carried out by means of powder X-ray diffraction, scanning electronic microscopy, thermo gravimetric analyzer, N2 adsorption–desorption, and Raman. Based on the optimal reaction condition (320 °C, 3 h, 3.0 MPa H2), five typical vegetable oils and gutter oils were selected for the hydrotreatment study to investigate the adaptability of Ni@C-BTC-400 catalyst. The result indicated that Ni@C-BTC-400 catalyst performed good universality, and could transform oil raw materials with different fatty acid carbon chain structure to desired alkanes. Furthermore, the optimal Ni@C-BTC-400 catalyst could be carried out in next two consecutive recycling runs and could also be regenerated by H2 for the following experiments. [ABSTRACT FROM AUTHOR]

The efficiency of Ni/TiO2 catalysts for renewable diesel production was evaluated in the present study. Two series of catalysts were synthesized and characterized using various physicochemical techniques (N2 physisorption, XRD, SEM, XPS, H2-TPR, and NH3–TPD). In the first series of catalysts, successive dry impregnations (SDI) were used for depositing 10, 20, 30, 50, and 60 wt.% Ni. The yield towards renewable diesel is maximized over the catalyst with 50 wt.% Ni loading. Selecting this optimum loading, a second series of catalysts were synthesized via three additional preparation methods: wet impregnation (WI) and deposition–precipitation using either ammonia (DP-NH3) or urea (DP-Urea) as the precipitation agent. The catalysts' efficiency in the production of green diesel is influenced by the preparation method following the order: DP-Urea > DP-NH3 > WI ≈ SDI. The metallic surface area and the balanced acidity mainly determine the performance of the catalysts. [ABSTRACT FROM AUTHOR]

This study aims to utilize biochars derived from residual biomass as supports for Ni-based catalysts. For the preparation of the biochars, byproducts of agro-industrial activities were used, such as espresso coffee residue (C) and rice husks (R). Sufficient quantities of the respective biochars (BioC and BioR) were prepared via pyrolysis at 850 °C of the aforementioned materials under limited oxygen conditions. The biochars were further treated with hot water (WBioC, WBioR), H3PO4 or H2SO4 solution (BioC-P, BioC-S, BioR-P, BioR-S), and NaOH solution (BioC-A and BioR-A), and the obtained solids were characterized using various physicochemical techniques. The biochars produced were microporous with high surface areas (367–938 m2g−1). The most promising biochars were selected as supports for the preparation of nickel catalysts (10 wt.% Ni) with high Ni dispersion (mean crystal size: 8.2–9.8 nm) and suitable acidity. The catalysts were evaluated in a high-pressure semi-batch reactor for the transformation of waste cooking oil (WCO) into green diesel. The 10Ni_BioC-P catalyst exhibited the best performance, resulting in a complete conversion of the WCO but a low hydrocarbon yield (7.5%). Yield improvement was achieved by promoting this catalyst with molybdenum. The addition of Mo increased the hydrocarbon yield by almost three times (19.5%). [ABSTRACT FROM AUTHOR]

This review delves into the potential of renewable biomass for green diesel production. Deoxygenation technology offers a promising method for converting biomass-derived oxygenates oil into high-grade hydrocarbon factions. Hence, various deoxygenation pathways of biomass conversion under free‑hydrogen environment were explored. Additionally, the prospects of acid-base bifunctional catalysts to facilitate deoxygenation was discussed, highlighting the correlation between the physicochemical properties of the catalysts and catalytic activity. However, it should be noted that the acid-base characteristics of the catalysts contribute to the breaking of CO bonds of oxygenated oil via undesirable pathways, which contributed to unfavorable by-product and catalyst deactivation.

Green diesel is an alternative renewable and environmentally friendly fuel in the transportation sector. This study aimed to modify Indonesian natural zeolite (NZ) with nickel and apply it as a catalyst in green diesel production from crude palm oil (CPO). The materials were prepared with different Ni content of 3, 5, and 10 wt.% and characterized in detail using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Fourier Transform infra-red Spectroscopy (FTIR), and Surface Area Analyzer (SAA). Catalytic tests were performed in a batch reactor at a temperature of 375 °C and a pressure of 12 bar for 2 hours. Gas Chromatography-Mass Spectrometry (GC–MS) analysis was used to determine the liquid product. Based on XRD analysis, the crystallinity of materials tends to decrease after being modified with Ni. Concomitantly, the presence of Ni was indicated by new peaks with increasing intensity at 2? = 44°, 55°, and 76°. SEM analysis shows morphological changes in materials with decreasing particle sizes. The presence of Ni is also known by the presence of small spheres scattered in the material and black shades observed in TEM analysis. Based on IUPAC, the resulting isotherm graph is categorized as type I with type IV loop hysteresis and classified as micropore with an average pore size is

The selective deoxygenation of palm oil to produce green diesel has been investigated over Ni catalysts supported on ZrO 2 (Ni/Zr) and CeO 2 –ZrO 2 (Ni/CeZr) supports. The modification of the support with CeO 2 acted to improve the Ni dispersion and oxygen lability of the catalyst, while reducing the overall surface acidity. The Ni/CeZr catalyst exhibited higher triglyceride (TG) conversion and yield for the desirable C 15 –C 18 hydrocarbons, as well as improved stability compared to the unmodified Ni/Zr catalyst, with TG conversion and C 15 –C 18 yield remaining above 85% and 80% respectively during 20 h of continuous operation at 300 oC. The high C 17 yields also revealed the dominance of the deCO x (decarbonylation/decarboxylation) pathway. A fully comprehensive process simulation model has been developed to validate the experimental findings in this study, and a very good validation with the experimental data has been demonstrated. The model was then further utilised to investigate the effects of temperature, H 2 partial pressure, H 2 /oil feed ratio and LHSV. The model predicted that maximum triglyceride conversion was attainable at reaction conditions of 300 °C temperature, 30 bar H 2 partial pressure, H 2 /oil of 1000 cm3/cm3 feed ratio and 1.2 h−1 LHSV. [Display omitted] [ABSTRACT FROM AUTHOR]