Green Diesel Production Research Articles

Influence of Nickel Loading and the Synthesis Method on the Efficiency of Ni/TiO2 Catalysts for Renewable Diesel Production

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.

Nickel Supported on MIL-96(Al) as an Efficient Catalyst for Biodiesel and Green Diesel Production from Crude Palm Oil
 

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.

Mo promoted Ni-ZrO2 co-precipitated catalysts for green diesel production

The promoting action of Mo-species was studied for Ni-ZrO2 co-precipitated catalysts with high nickel loading used in the transformation of sunflower oil into green diesel. The catalysts were thoroughly characterized and evaluated using a high-pressure semi-batch reactor. The significant promoting action of molybdenum species was clearly demonstrated concerning the Ni-ZrO2 catalysts as Mo addition resulted in almost duplication of green diesel yield (from 35.2 to 68.4 %). This is manifested through the acceleration of the hydrodeoxygenation pathway of the reaction network. The increase of the activation temperature increases further the catalytic efficiency of the promoted catalysts resulting in 70.1 % green diesel yield. The promoting action of molybdenum was partly attributed to the increase of the specific surface area and the metallic nickel surface brought about by molybdenum but, principally, to a synergy between the oxygen vacancies developed on the very well dispersed Mo-species - and the nickel surface sites.

Transesterification and Hydrotreating Reactions of Rice Bran Oil for Bio-Hydrogenated Diesel Production

Two different methods of production of bio-hydrogenated diesel (BHD), simply called green diesel from rice bran oil (RBO), were performed. In the first route, a direct hydrotreating reaction of RBO to BHD catalysed by Pd/Al2O3 was performed in a high-pressure batch reactor. Operating conditions were investigated as follows: catalyst loading (0.5 to 1.5% wt.), temperature (325 to 400 °C), initial hydrogen (H2) pressure (40 to 60 bar) and reaction time (30 to 90 min). The optimal condition was obtained at 1% wt catalyst loading, 350 °C, 40 bar H2 pressure and 60 min. Yields of crude/refined biofuels and BHD achieved were approximately 98%, 81.71% and 73.71%, respectively. In another route, transesterification together with hydrotreating reactions of rice bran methyl ester (RBME) to BHD was performed using the optimal conditions obtained from the first route. The amount of 98% crude biofuel was obtained and was equivalent to production yields of refined biofuel (85.71%) and BHD (68.51%). Furthermore, physical and chemical properties of both RBO/RBME green diesel were also considered following ASTM standard methods. In summary, both catalytic reactions were achieved in the range of a low-speed industrial diesel and were further recommended for BHD or green diesel production from RBO.

Green Diesel Production via Deoxygenation Process: A Review

The environmental impact of traditional fuels and related greenhouse gas emissions (GHGE) has promoted policies driven towards renewable fuels. This review deals with green diesel, a biofuel obtained by catalytic deoxygenation of edible and non-edible biomasses. Green diesel, biodiesel, and petrodiesel are compared, with green diesel being the best option in terms of physical–chemical properties and reduction in GHGE. The deoxygenation process and the related types of catalysts, feedstocks, and operating conditions are presented. Reactor configurations are also discussed, summarizing the experimental studies. Several process simulations and environmental economic analyses—up to larger scales—are gathered from the literature that analyze the potential of green diesel as a substitute for petrodiesel. In addition, current industrial processes for green diesel production are introduced. Future research and development efforts should concern catalysts and the use of waste biomasses as feedstock, as well as the arrangement of national and international policies.

Selectivity of reaction pathways for green diesel production towards biojet fuel applications.

Green diesel is the second generation biofuel with the same structure as fossil fuels (alkanes), allowing this biofuel to provide excellent fuel properties over biodiesel such as higher energy content and lower hazardous gas emission. Generally, green diesel can be produced through the deoxygenation/hydrogenation of natural oil and/or its derivatives at 200-400 °C and 1-10 MPa over supported metal catalysts. This process comprises of three reaction pathways: hydrodeoxygenation, decarboxylation, and decarbonylation. The extent to which these three different pathways are involved is strongly influenced by the catalyst, pressure, and temperature. Subsequently, the determination of catalyst and reaction condition plays a significant role owing to the feasibility of the process and the economic point of view. This article emphasizes the reaction pathway of green diesel production as well as the parameters influencing the predominant reaction route.

Catalytic Deoxygenation of Oleic Acid Over CoMo/Zeolite Catalyst for Green Diesel Production

Due to the presence of certain oxygenated species, green diesel from deoxygenation (DO) technology was developed to replace traditional biodiesel. In this study CoMo-based catalyst was supported on zeolite for deoxygenation reactions. The catalyst was prepared by the wet impregnation method and then calcinated under a 20 mL min-1 N2 flow rate for 4 hours at a temperature of 550○C. The prepared catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Thermo-Gravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM) analysis. The effect of zeolite on the removal of the different oxygenated functional groups was investigated in the deoxygenation of oleic acid over supported CoMo catalysts at 350°C and atmospheric pressure. The deoxygenated liquid products were characterized by Fourier-transform infrared spectroscopy (FTIR), Gas Chromatography-Mass Spectrometry (GC-MS), and Higher heating value (HHV). Based on the study results, CoMo/Zeolite is give 90.86% hydrocarbon yield for 2 hrs. at 350°C and 300 rpm. Overall, The CoMo/Zeolite showed good catalytic performance due to its good physicochemical properties.

Development of nickel catalysts supported on silica for green diesel production

Two series of nickel catalysts supported on silica were prepared and evaluated for the selective deoxygenation of sunflower oil into green diesel, under conditions without solvent. The catalysts were characterized with various techniques (N2 physisorption, CO chemisorption, XRD, SEM-EDS, TEM, H2-TPR, NH3-TPD). The first series involves catalysts with Ni content ranging between 10 and 60 wt%, synthesized by successive dry impregnation. The green diesel in the liquid product seems to depend mainly on the active nickel surface and the moderate acidity, following a volcano trend which is maximized over the sample with 50 wt% Ni loading. The second series concerns catalysts with 50 wt% Ni, synthesized by the use of four different techniques: Successive Dry Impregnation (SDI), Wet Impregnation (WI), using Ni(en)3(ΝΟ3)2 (en: ethylene diamine) as the Ni precursor and Deposition – Precipitation at room temperature (DP-NH3), Deposition – Precipitation at high temperature (DP-Urea), using Ni(ΝΟ3)2 as the Ni precursor. SDI or WI results mainly to granular nickel supported nanoparticles, whereas DP-NH3 and mainly DP-Urea to the formation of filamentous structures of a nickel phyllosilicate phase. The performance of the catalysts towards the production of green diesel follows the order WI>SDI> DP-NH3 >DP-Urea. The catalyst synthesized by WI exhibits the higher active surface in combination with high population of sites of moderate acidity. The catalysts prepared by DP, although exhibiting a very high surface area and a very high nickel dispersion, did not appear more effective in the n-alkanes production, due to the formation of a very well dispersed nickel phyllosilicate phase, but not fully reducible even at very high temperatures and thus inactive in the selective deoxygenation of sunflower oil.

Ni-Fe-Al LDH derived Ni[sbnd]Fe nanosheet for green diesel production from lipid hydrotreatment

In order to deal with the deficiency of active sites in Ni catalyst, NiFe nanosheet (Ni-Fe/Al2O3-NS) catalyst was synthesized by using Ni-Fe-Al LDH as the precursor. The catalyst was further utilized in the lipid hydrotreatment for green diesel production. With a lamellar structure and large Ni loading (more than 60%), the Ni-Fe/Al2O3-NS catalyst possessed abundant Ni sties with high dispersion, large surface area, and strong acidity. Moreover, in Ni-Fe/Al2O3-NS the highly active Ni3Fe phase was formed, which promoted the decarbonylation route in hydrotreatment. The Ni-Fe/Al2O3-NS catalyst achieved 98.7% conversion with 98.1% alkane yield in oleic acid hydrotreatment under very mild conditions (220 °C, 2 MPa of hydrogen pressure, 3 h). The catalytic performance of Ni-Fe/Al2O3-NS was much higher than traditional Ni-Fe/Al2O3 and other catalysts reported in current related studies.

Heterogeneous Catalyst based on Nickel Modified into Indonesian Natural Zeolite in Green Diesel Production from Crude Palm Oil

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 <2 nm. The highest activity and selectivity on C

Sustainability assessment of a decentralized green diesel production in small‐scale biorefineries

AbstractIn this study, three scales of a biofuel‐driven biorefinery were evaluated in techno‐economic, environmental and geospatial terms for green diesel production from macauba oil. The results show that the relative capital expenditure on the small scale is four times higher than that on the large scale, being significantly affected by the hydrogen facilities. However, coproducts, tax deductions for family farming and carbon credits can sustain the small‐scale production of green diesel. The carbon footprint of the green diesel is lower than that of commercial biofuels. Finally, the geospatial analysis applied in Brazil reveals that macauba cultivation with low land‐use impact can be implemented near small‐scale biorefineries for local consumer markets. Therefore, the feasibility of the small scale depends on coproducts, public policies, decentralized hydrogen production and catalysts for low‐hydrogen demand routes. This biorefinery concept can decentralize the biofuel sector and make use of several types of biomasses besides macauba, generating socio‐economic and environmental gains. © 2022 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Production of green diesel via hydrogen-free and solventless deoxygenation reaction of waste cooking oil

This work was successfully produced green diesel from domestic waste cooking oil via hydrogen-free and solventless deoxygenation over nickel-cobalt/organosilane-SBA-15 catalyst. Highly effective mesostructured catalyst has been synthesized by functionalizing with selected loadings of 3-Mercaptopropyl (trimethoxysilane) (MPTMS) onto SBA-15 by co-condensation method, followed by nickel and cobalt impregnation to produce 5Ni5Co/SBA-15-SH 0.1, 5Ni5Co/SBA-15-SH 0.3 and 5Ni5Co/SBA-15-SH 0.5. The 5Ni5Co/SBA-15-SH 0.1 catalyst exhibits high surface area and pore size (509 m2/g, 4.6 nm), which proved that the addition of MPTMS had increased the surface area and pore size due to the interaction between MPTMS and TEOS. The acidity of the synthesized catalyst also remarkably increased after MPTMS functionalization, suggesting the presence of the sulfonic acid group derived from the oxidation of MPTMS has enhanced the acidity of the catalyst. The amount of nickel and cobalt successfully impregnated onto the catalysts also show increment (5%–9%) following the amount of MPTMS added, which attributed to a strong interaction between metal species and support surface result in a homogeneous distribution of nickel and cobalt as observed in HRTEM. The MPTMS functionalization has successfully enlarged the surface area and increased the catalyst's acidic properties, enhancing the catalyst's deoxygenation activity. The catalytic activity study via deoxygenation was performed in a solventless and hydrogen-free reaction system to produce green diesel (350 °C within 2 h using 5%wt. Catalyst loading). Based on GC-FID analysis, it was proven that 5Ni5Co/SBA-15-SH 0.1 exhibits high hydrocarbon yield (77%) and diesel selectivity (70%) with the reusable catalyst for 4 catalytic cycles by maintaining the catalyst's selectivity. Hence, this work can produce green diesel from low-cost waste cooking oil via the synthesized organosilane-functionalized catalyst.

Grey Wolf Optimizer for enhancing Nicotiana Tabacum L. oil methyl ester and prediction model for calorific values

Modelling and enhancing the production of green diesel in biodiesel industries have been hampered by the failure of the conventional approach to pursue space with continuous convergence velocity, being entombed in local minima, and maintaining unwavering resolutions. The study presented for the first time the optimization protocol for the development of biodiesel production from tobacco seed oil (TSO) on the batch reactor aided by the unique Grey Wolf Optimizer-Response Surface Methodology-Artificial Neural Network (GWO-RSM-ANN) techniques. Lower calorific value (LCV), higher calorific value (HCV), and specific heat capacity (Cp) correlations were postulated for tobacco seed oil methyl ester (TSOME/B100/TSOB) and diesel blends. RSM, ANN, and GWO approaches were used to model TSOME's main production yield. The ASTM test methods were used to examine the significant basic properties of the fuel categories, while the LCV and HCV were detected using standard procedures. Maximum TSOME yield (90.2%) was obtained at methanol/TSO molar ratio of 5.95, KOH content of 1.15 wt. %, and methylic duration of 77.6 min. The ANN model configuration (3-15-1) that was developed showed more adaptability and nonlinearity. The estimated coefficient of determination (R 2 ) of 0.9999, mean average error (MAE) of 0.00035, and RMSE of 0.00105 for the GWO model compared to those of R 2 of 0.9825, MAE of 1.3145, and RMSE of 1.7087 for RSM model; and R 2 of 0.9976, MAE of 0.2405, and RMSE of 0.6381 for ANN model vindicate the superiority of GWO model over the RSM and ANN models. The major fuel properties agreed with the ranges of the ASTMD6751 and EN 14214 specifications. The LCV, HCV, and Cp are also correlated with the TSOME fraction through the linear equations. There were excellent correlations between the analyzed and calculated values for the LCVs and HCVs. The maximum absolute error between the measured and estimated LCV and HCV are 0.108% for 20%TSOME (20% TSOME +80% diesel fuel), and 0.17% for pure diesel, respectively. The model and correlations can offer biodiesel and automobile industries with database information.

Hydrotreating and hydrodemetalation of raw jatropha oil using mesoporous Ni-Mo/γ-Al2O3 catalyst

During the hydroprocessing reactions, one of the major reason for the deactivation of the catalyst and pore blockage of the active sites of the catalyst is the metals present in feed. It is extremely important to remove the metals to improve catalyst aging, therefore a heterogeneous mesoporous Ni-Mo/γ-Al2O3 catalyst was used for hydrodemetalation (HDM) of untreated non-edible raw jatropha oil (RJO). The results show that the highest HDM of 83.4% was achieved at 250 °C temperature, 5 h−1 LHSV, and 666 (V/V) H2/feed ratio. The highest RJO conversion (97.2%) was obtained at 420 °C temperature with simultaneously 68.4% HDM. Lower temperature (250 °C) was more favourable for HDM due to minimum C–C cracking reactions than high temperature (420 °C), which favours more C–C/C-O bond cleavage. The catalyst shows prolonged activity up to 162 h, as compared to reported catalysts. TGA study of the spent catalyst indicates a 7.8 wt% coke deposition, complemented by TEM results. 13C solid-state NMR revealed saturated hydrocarbon-type compounds deposited over the catalyst supported by FTIR analysis. The physicochemical properties of bimetallic Ni-Mo catalyst show suitable surface area and pore diameter for the diffusion of triglycerides over the surface and pores of the catalyst. The catalyst showed the potential for HDM of RJO at a lower temperature of 250 °C and green diesel (C15-C18) production at a higher temperature of 420 °C.

Palm oil hydrodeoxygenation into green diesel over NiO/NbOPO4 catalyst: A novel approach of synthesizing NbOPO4 from NbCl5

Green diesel is an emerging alternative fuel that could be produced from a series of biomass conversion, of which is catalytic hydrodeoxygenation. Herein, we aimed to study the effect of pH and calcination temperature on the preparation of NiO/NbOPO4 catalyst for hydrodeoxygenation of palm oil into green diesel. The catalyst was prepared through a sol-gel method at pH 2, 4, 6, and 8, respectively. Subsequently, the calcination was carried out on the catalyst at a variation of temperature (600, 700, and 800 °C). The green diesel was produced using a hydrothermal autoclave reactor at 250 °C with a pressure of 3.5 MPa for 5 h. X-ray diffraction analysis confirmed the formation of NiO/NbOPO4, where the crystallinity index reached 77%. Morphological, elemental content, and functional group analyses, altogether revealed that the prepared catalyst had nano-size distribution along with various sets of Nb-P bonds. The hydrodeoxygenation using NiO/NbOPO4 catalyst, prepared at pH 8 and 800 °C calcination temperature, succesfully removed the oxygen content of saturated and unsaturated fatty acids from the palm oil with a yield as high as 85.747%. Gas chromatography-mass spectroscopy on the produced green diesel using NiO/NbOPO4 catalyst with 8% nickel loading showed the dominance of C12-C15 fraction (97.07%), which is mostly occupied by C15 (pentadecane) molecules (58.14%). Last but not least, we propose NiO/NbOPO4 as a very promising catalyst for industrial-scale green diesel production.

Renewable and Sustainable Green Diesel (D100) for Achieving Net Zero Emission in Indonesia Transportation Sector

Because of the significant demand for fuels in the transportation sector in Indonesia, as well as concerns about energy security and global warming, renewable, sustainable, and alternative energy sources such as biofuels are required to replace petroleum-based fuels. Promoting the production of green diesel from crude palm oil (CPO) using palm fatty acid distillate (PFAD) as its byproduct will make the overall process more efficient and environmentally friendly in Indonesia. As a result, CPO-based diesel production will be a green and high-value sector. By replacing fossil diesel with green diesel, a sustainable energy source can be assured without further depleting current fossil fuels, leading to cleaner and greener energy in the future and meeting the net-zero aim by 2060.

Simulation of the soybean oil hydrotreating process for green diesel production

Renewable diesel, or green diesel, is the biofuel with the fastest growing use in the world. Its use as a replacement for fossil diesel is important to reduce the impact of carbon emissions. Green diesel is formed by a mixture of hydrocarbons with a chemical composition similar to that of fossil fuel, making it a drop-in biofuel. Commercial processing employs hydrotreatment of vegetable oil, which, in addition to producing green diesel, can also be used to produce biofuel for aviation, bionaphtha and biopropane. The present paper proposes a model for the hydrotreatment of soybean oil for the production of green diesel. The process was simulated in Aspen Plus® v10; the decarboxylation, decarbonylation and hydrodeoxygenation reactions were carried out in a stoichiometric reactor in the presence of an NiMo/Al2O3 catalyst. In addition to the cracking reactions and fractionation, the fuels produced green diesel, aviation biofuel, and light gases. Brazilian soybean oil was used as the raw material to produce the green diesel. Sensitivity analyses were performed to adjust the best fractionation conditions, considering the composition of the product and the distillation column energy. The best results were chosen when the distillation column was configured with 22 stages, feed at stage 12 and reflux ratio equal to 0.8. The hydrogen/soybean oil ratio was 0.031. The energy used in the process was 1181 kW/h. More than 80% of the soybean oil was converted to renewable fuels, with approximately 65% to green diesel. In addition, a prediction of the simulated physical chemical properties was made and compared with the current Brazilian legislation for green diesel obtaining values within the established specifications. The ASTM D86 distillation curve was compared with simulated results from green diesel obtained from experimental data and fossil diesel. The experimental and simulated distillation curves agreed, showing only a small difference between curves up to 25% of recovered volume. This can be explained by the lighter components present in the experimental green diesel. The proposed simulation supported the potential of Brazilian soybean oil for the production of quality renewable fuels.

Enhancement of stability of Pd/AC deoxygenation catalyst for hydrothermal production of green diesel fuel from waste cooking oil

Nowadays, one of the most challenging problems in the production of green diesel fuel from fats sources is the deactivation of the deoxygenation catalyst after a certain period of time. The structure of the catalyst is damaged due to several problems and the performance is degrading over time. In this work, a high stability deoxygenation catalyst was prepared from agricultural waste and used for hydrothermal production of green diesel fuel from waste cooking oil. The support of the catalyst was prepared using apricot seeds. Palladium (Pd) was loaded by the incipient wetness impregnation method. The Pd/AC substrate was coated by a nanofilm aluminum protective layer using the sol–gel method to prevent rapid deactivation of the catalyst, prolong the catalyst lifetime and enhance the stability. The characterization tests showed good thermal stability, a uniform coating around the Pd/AC substrate, and a high surface area of 726.9 m2/g of the coated catalyst.Micropores increase the activity of oleic acid deoxygenation from attributed to improved acid site accessibility within the fluffy Pd/AC substrate. Kinetic experiments were carried out in a hydrothermal autoclave reactor under an inert atmosphere (N2) over the coated and the uncoated catalyst at a temperature range of 300–350 °C, pressure range 30–50 bar and residence time up to 3 h. The results showed that the catalytic deoxygenation of the oleic acid is a first-order reaction. The rate of deactivation of Pd/AC deoxygenation catalyst was determined at 350 °C and 50 bar in a hydrothermal autoclave reactor. The results showed that deactivation reaction of the Pd/AC catalysts followed first-order kinetics and occurred by the poisoning mechanism. The deactivation reaction was significantly altered due to coating of deoxygenation catalyst and elevating of the activation energy of the deactivation reaction.

Advances in catalytic decarboxylation of bioderived fatty acids to diesel-range alkanes

Biodiesel is an important alternative fuel as far as sustainability and environmental issues are concerned. The decarboxylation of bioderived fatty acids is receiving great attention for green diesel production, with resulting C1-shortened alkanes among the diesel-range alkanes typically existing in petroleum diesel. Alkane-containing green diesel possesses significant advantages including high caloric value, irreversibility of the production reaction and the existence in liquid form up to C17 alkanes. The decarboxylation approach has a significant potential in taking a central role in transformation of bioderived fatty acids into green diesel. In the present review, it aims at discussing the progress on both chemo- and bio-catalytic decarboxylation reactions and the pros and cons of their application for green fuel synthesis. Particularly, the mild biocatalytic decarboxylation reactions so far have not been included in reviews focusing on green diesel production.

Sustainable and carbon-neutral green diesel synthesis with thermochemical and electrochemical approach: Techno-economic and environmental assessments

In this work, techno-economic and environmental assessments were conducted for green diesel production. In particular, two green diesel production pathways through thermochemical and electrochemical processes, which have different syngas production methods, were covered to evaluate the sustainability in terms of economic and environmental perspectives. The process modeling was performed for three cases, classifying cases according to the component composition, and verified by comparing the physical properties of conventional diesel and green diesel produced from syngas. From process modeling results, case 2 has the most relevant properties of conventional diesel showing the potential for alternative diesel fuel. With the process modeling results, cost estimation was carried out to calculate the current unit diesel production costs for three scenarios (according to the renewable energy sources); 0.0507, 0.0647, and 0.0547 $ MJ−1 via the thermochemical process and 0.0477, 0.0606, and 0.0514 $ MJ−1 through the electrochemical process for hydropower, solar PV, and onshore wind, respectively, showing the infeasibility due to the lower conventional ones (0.0164–0.0276$ MJ−1). To make the green diesel production attractive, uncertainty analysis and projected cost analysis were conducted to obtain the possible cost ranges due to the cost fluctuations of key economic parameters and the estimated unit diesel production cost in 2030, with the projected levelized cost of electricity by 2030 and learning rates by cumulative production of H2 and CO demands. Moreover, environmental assessment should be performed to identify whether the green diesel production is more eco-friendly or not than conventional one, by considering direct emission and indirect one emitted from energy consumption. From environmental assessment results, lower CO2 emissions can be investigated according to the renewable energy sources for green diesel production and the electrochemical green diesel production with onshore wind has the lowest CO2 emission among all scenarios covered in this work.