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Second‐generation biofuel (e.g., ethanol, renewable diesel) can be made from crop residues. However, the availability of residues for biofuel production is uncertain, because farmers have the option to grow different crops and use the residues for alternative purposes, such as livestock bedding and feed, or leave them in the field to improve soil quality. Taking Canadian wheat straw supply as an example, we develop a dynamic programming model to investigate a farmer's wheat straw supply decision in response to different wheat straw and grain prices. Our model considers crop choices between wheat and canola in the context of disease risk, the trade‐off between the immediate payoffs a farmer may receive from bailing and selling wheat straw, and the long‐term adverse effects that removing wheat straw from the soil surface may have on wheat and canola yields. The results from this study provide insights into how farm‐level supply decisions, in response to wheat straw price changes, affect soil quality dynamics and scale up to regional wheat straw supply for biofuel production. This information also has implications for land use change and the sustainability of feedstock supply for biofuels. [ABSTRACT FROM AUTHOR]

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]

To compare the different effects of petroleum hydrocarbons on intertidal Ulva macroalgae, three dominant Ulva species (U. prolifera, U. linza, and U. lactuca) were exposed to two water-accommodated fractions (WAFs) of 0# diesel oil and crude oil at three concentration levels. The results indicated that two WAFs had significant concentration effects on the physiological characteristics of Ulva, the toxicity of 0# diesel oil was greater than crude oil, and crude oil had hormesis effect. Exposure of high WAFs concentrations, the growth, pigment, carbohydrate, and protein contents of Ulva were inhibited, while the antioxidant system was activated. In addition, the integrated biomarker response (IBR) indicated that U. prolifera had higher resistance to WAFs than U. linza and U. lactuca. Considering that U. prolifera is the main species of green tide in the Yellow Sea (YS) of China, the comparative effects of WAFs on different development stages of U. prolifera were also explored. The results showed that spore was the most sensitive to WAFs, while adult thalli was the most tolerant. The increased resistance of U. prolifera thalli and the hormesis effect triggered by crude oil may influence the outbreak scale of green tides. This study provides a new perspective for understanding the formation of green tides in the YS. [ABSTRACT FROM AUTHOR]

This paper provides a power-sharing strategy designed for an islanded grid that becomes isolated from the main grid due to faults or natural disasters. The proposed topology is introduced for post-disaster scenarios where the restoration process may be time-consuming (from a few hours to a few months). This system is equipped with a step-by-step power-sharing strategy based on priority, inputs from photovoltaic sources, and a diesel generator to enhance reliability. The DC–AC inverter control and AC–DC–AC control for the diesel generator are presented, which provide flexible real and reactive control. The system is divided into three priority load areas, and power sharing is conducted based on these priorities. The distinctive feature of the proposed strategy lies in its ability to manage power-sharing under different power generation conditions, prioritizing critical loads. The proposed method is implemented using the MATLAB Simulink environment. Simulation studies are performed under different solar irradiances and variations in the diesel generator's output to validate the performance of the proposed method. The results demonstrate the practicality of the proposed algorithm in harnessing renewable resources and diesel generators and dynamically managing the energy consumption in loads. [ABSTRACT FROM AUTHOR]

This study examines FischerTropsch Diesel as a source of decarbonisation by use of lignocellulosic residues (wheat, barley, and maize) contributing to the European maritime sector. A techno-economic methodology from the literature and well-to-tank analyses were used to calculate the production, cost, and carbon emissions of the fuel. By exploiting an area of 23.27 million hectares, nine countries could potentially produce 4.9 million tonnes of renewable diesel annually, to be distributed to their respective ports. That amount could eliminate 8.4% of the current CO2 emissions of the sector in Europe, at a cost ranging from 51.20 to 68.69 €/GJ. The study includes a sensitivity analysis of biomass, electricity, interest rate, and sub-product cost variables, as well as blend variation (1–100%) with the current marine fossil fuel used, with a cost of CO2 saved varying between 678.46–1,457.86 €/tCO2. [ABSTRACT FROM AUTHOR]

As byproducts generated by commercial and domestic food-related processes, FOGs (fats, oils, and grease) are the leading cause of sewer pipe blockages in the US and around the world. Grease trap waste (GTW) is a subcategory of FOG currently disposed of as waste, resulting in an economic burden for GTW generators and handlers. This presents a global need for both resource conservation and carbon footprint reduction, particularly through increased waste upcycling. Therefore, it is critical to better understand current GTW handling practices in the context of the urban food–energy–water cycle. This can be accomplished with firsthand data collection, such as onsite visits, phone discussions, and targeted questionnaires. GTW disposal methods were found to be regional and correspond to key geographical locations, with landfill operations mostly practiced in the Midwest regions, incineration mainly in the Northeast and Mid-Atlantic regions, and digestion mainly in the West of the US. Select GTW samples were analyzed to evaluate their potential reuse as low-cost feedstocks for biodiesel or renewable diesel, which are alternatives to petroleum diesel fuels. Various GTW lipid extraction technologies have been reviewed, and more studies were found on converting GTW into biodiesel rather than renewable diesel. The challenges for these two pathways are the high sulfur content in biodiesel and the metal contents in renewable diesel, respectively. GTW lipid extraction technologies should overcome these issues while producing minimum-viable products with higher market values. [ABSTRACT FROM AUTHOR]

As the world aims to address the UN Sustainable Development Goals (SDGs), it is becoming more urgent for heavy transportation sectors, such as shipping and aviation, to decarbonise in an economically feasible way. This review paper investigates the potential fuels of the future and their capability to mitigate the carbon footprint when other technologies fail to do so. This review looks at the technologies available today, including, primarily, transesterification, hydrocracking, and selective deoxygenation. It also investigates the potential of fish waste from the salmon industry as a fuel blend stock. From this, various kinetic models are investigated to find a suitable base for simulating the production and economics of biodiesel (i.e., fatty acid alkyl esters) and renewable diesel production from fish waste. Whilst most waste-oil-derived biofuels are traditionally produced using transesterification, hydrotreating looks to be a promising method to produce drop-in biofuels, which can be blended with conventional petroleum fuels without any volume percentage limitation. Using hydrotreatment, it is possible to produce renewable diesel in a few steps, and the final liquid product mixture includes paraffins, i.e., linear, branched, and cyclo-alkanes, with fuel properties in compliance with international fuel standards. There is a wide range of theoretical models based on the hydrodeoxygenation of fatty acids as well as a clear economic analysis that a model could be based on. [ABSTRACT FROM AUTHOR]

Renewable diesel as a potential sustainable energy source in future requires catalysts to convert the feedstocks into end products. Among various type of catalysts, bimetallic catalysts are widely applied in the renewable diesel production due to their unique catalytic properties and enhanced catalytic activities, which differ from their parent monometallic catalysts. This mini review comprised of the brief introduction on technologies in producing renewable diesel and aims to discuss the underneath knowledge of synergistic interactions in bimetallic catalysts that synthesized through various techniques. The novelty of this review reveals the recent development of renewable diesel production, highlighting the mechanisms of bimetallic catalysts in the enhancement of the catalytic activity, and exploring their possibilities as practical solution in industrial production. [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]

This study investigates the co‐combustion of palm oil biodiesel fuel, as a renewable alternative for diesel fuel, inside natural gas flame to enhance the flame thermal specifications and NOx reduction. A power natural gas burner with a maximum heat capacity of 418,400 kJ/h was installed at the inlet of a laboratory furnace and biodiesel fuel was injected inside natural gas burner with a 100 μm in diameter solid cone nozzle. Flame temperature, thermal radiation, Infrared radiation, and CO, CO2 and NOx emission were measured. The results revealed that biodiesel injection increases the flame size and turns the non‐luminous blue flame into yellow‐colored flame. Furthermore, higher flash point and Sauter Mean Diameter of biodiesel promote the thermal decomposition of fuel droplets and increase the concentrations of Intermediate Soot Particles in the flame which in turn increases the flame emissivity coefficient and consequently flame thermal radiation. Also, the oxygen content of biodiesel fuel has an important role in the complete combustion of Intermediate Soot Particles to CO2 which increases the heat release of biodiesel combustion and raises the flame temperature. The average enhancement in thermal radiation and flame temperature were 5.6% and 43.38%, respectively. Finally, although biodiesel injection increases the flame temperature, it also increases the flame surface reaction and eliminates the hot spot region in the flame. Therefore, the rate of heat generation per unit volume of flame decreases and this decreases the rate of NOx emission as much as 10.84%. [ABSTRACT FROM AUTHOR]

The selectivity limitation has long posed a significant challenge in the conversion of CO or CO 2 into liquid hydrocarbon-based sustainable fuels via Fischer–Tropsch synthesis (FTS) and other related processing pathways due to the Anderson–Schulz–Flory (ASF) distribution. The unique pore structure, thermal stability, and acidic sites of ZSM-5 have enabled its widespread applications in various catalytic processes of value-added chemicals and sustainable fuels. In the reaction pathways from CO / CO 2 to liquid HCs of interest, incorporating ZSM-5 into metal catalysts provides new opportunities to enhance product selectivity and catalytic activity, and even lower the reaction energetics. This review highlights recent advancements over the past five years in the structural design of ZSM-5-based catalysts aimed at improving the conversion selectivity of advanced liquid biofuels such as renewable diesel and sustainable aviation fuel. It explores innovative strategies for optimizing catalyst composition, the acidity, mesoporosity, and structures of ZSM-5 to design more efficient, selective, and robust catalysts. Additionally, the review addresses the direct hydrogenation of CO and CO 2 into C5+ liquid hydrocarbons, focusing on catalyst selection, acidic site optimization, and the structural configuration of ZSM-5. The mechanisms involved in these processes are also surveyed. [ABSTRACT FROM AUTHOR]

The use of renewable fuels for internal combustion engines marks a significant stride towards sustainability in transportation and power generation. Ensuring the compatibility of these fuels with existing diesel engines and infrastructure is paramount for a smooth transition. Diesel engines capable of harnessing the advantages of alternative fuels without extensive modifications offer a pragmatic approach to sustainable power for vehicles and industries. This article investigates the impact of carbon-neutral renewable fuel types (hydrogenated vegetable oils, or HVOs, and biodiesel) on the operation of a high-pressure injection pump, focusing on rotational speed and delivery pressure as key parameters. Our investigation, based on pump operating cycle analysis and volumetric efficiency measurements, aimed to investigate to what extent shaft speed and fuel type influence pump performance. Hydrogenated carbon-neutral fluids (HVOs) demonstrate adequate hydraulic capabilities compared to conventional fossil fuels. The findings underscore that while the fluids under consideration vary in viscosity and compressibility modulus, it is the compressibility modulus that predominantly affects the pump's operation cycle. Diesel (fossil) fluid exhibits intermediate characteristics compared to hydrogenated fossil diesel fluids and biodiesel. The differences in terms of volumetric efficiency are finally reported, showing that hydrogenated carbon-neutral fluids do not significantly hinder the pump's flow rate transfer capability. [ABSTRACT FROM AUTHOR]

This paper explores green hydrogen-based carbon dioxide (CO 2) hydrogenation for the production of oxygenates, presenting it as a pivotal strategy for mitigating carbon emissions and advancing sustainable energy solutions. The conversion of CO 2 into oxygenates through hydrogenation emerges as a promising avenue, particularly in the context of transportation applications where the storage of hydrogen poses challenges. The substitution of fossil diesel and gasoline fuels with green hydrogen-derived dimethyl ether, or methanol/ethanol, is advantageous from a life cycle analysis (LCA) CO 2 emission perspective even without the capture of the CO 2. However, the greatest sustainability appeal is contingent on the crucial aspect of capturing CO 2 when utilizing these fuels, which is an aspect currently absent in the literature. This narrative review comprehensively explores catalytic processes, mechanisms, sustainability perspectives, and the current state of research in this evolving area. It encompasses both the production of oxygenates through CO 2 hydrogenation and the subsequent utilization of these oxygenates in fuel cells or combustion systems, emphasizing the integration of CO 2 capture technologies. The paper contributes to the discourse surrounding the environmental and technological dimensions of energy storage ecosystems, providing a holistic view of their potential to foster sustainable energy solutions. [ABSTRACT FROM AUTHOR]

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]

This document is a summary of a special issue of the journal "Nanomaterials" titled "Nanocatalysis for Environmental Protection, Energy, and Green Chemistry." The issue features 11 high-quality contributions covering recent research progress in the field of nanocatalysis. The topics include the synthesis and performance of perovskite catalysts, photocatalytic CO2 reduction, electrochemical promotion of catalysis, catalytic production of H2 from formic acid, synthesis gas production through co-electrolysis, transformation of sunflower oil into green diesel, upgrading biodiesel to renewable diesel, selective hydrogenation of crotonaldehyde, photocatalytic and adsorptive remediation of dyes, green production of bio-Graphene, and enhancing photogenerated charge separation for solar-hydrogen conversion. The authors of the summary express their gratitude to the authors and editors involved in the special issue. [Extracted from the article]

The excessive utilization of fossil fuels has worsened global warming and exacerbated the levels of air pollution in the environment, forcing us to consider alternative fuels for compression ignition engines. The current research aims to explore the possibilities of renewable fuels outperforming diesel fuel in terms of combustion, performance, and emission characteristics. Biodiesel is an environmentally friendly and renewable alternative fuel. The major drawback of biodiesel is the significant rise in nitrogen oxide (NOx) emissions. The main novelty and objective of this research is to investigate the performance and emission characteristics of variable compression ratio diesel engine using DPA antioxidant additive. For this investigation, diesel, Jatropha biodiesel (B30) and 100 ppm of phenolic antioxidant diphenylamine (DPA) blended with B30 have been used as fuel named B30+DPA100. From experimental outcomes, the inclusion of diphenylamine to B30 blend resulted in brake-specific fuel consumption (BSFC) and exhaust gas temperature (EGT) being reduced by 8.86% and 4.12%, respectively, compared to B30. Simultaneously, there was a 1.11% increase in brake thermal efficiency (BTHE). The B30+DPA100 fuel blend demonstrates effective control over NOx and other emissions. The emissions of NOx, carbon monoxide (CO), hydrocarbon (HC), and smoke from the B30+DPA100 blend have shown a reduction of 6.8%, 5.34%, 7.86%, and 15.67%, respectively, when compared to diesel. However, there has been an increase in carbon dioxide (CO2) by 7.8%. One notable advantage of the B30+DPA100 blend is the significant decrease in NOx emissions. Additionally, the cylinder pressure for B30+DPA100 has been lowered by 4.93% compared to B30. On the other hand, the net heat release rate (NHR) has experienced a 1.72% increase. The particle size of different elements present in the crankcase oil has been calculated by Zetasizer Nano. The analysis revealed varying particle sizes for different elements in the crankcase oil: aluminum (2.724 μm), chromium (2.78 μm), iron (2.423 μm), and lead (2.587 μm). [ABSTRACT FROM AUTHOR]

This work systematically investigated the influence of catalyst reuse and reaction time on the yield and quality of organic liquid products (OLP) obtained in a cracking pilot plant at 450 °C and 1.0 atm. The distillation of OLP produced 04 (four) distilled fractions (gasoline, kerosene, and green diesel). The biofuels-like fractions are liquid mixtures with high content of hydrocarbons (alkanes, alkenes, and aromatics) with potential application as substitutes for fossil fuels in internal combustion motors. The quality of the biofuels was certified by physical-chemical analysis and FT-IR and GC-MS analysis. The experimental results showed the feasibility of applying the spent sodium carbonate twice in the catalytic cracking of vegetable oils. The physical-chemical properties (density, viscosity, acid value, saponification value, and flash point) of OLP decrease as the reaction time increases. The distillation of OLP yields 62.35% (wt.), producing green-like gasoline, kerosene, and diesel fractions rich in hydrocarbons. Therefore, biofuel-like fractions produced by distillation of OLP have a great potential for replacing partially petroleum-derived fuels. [ABSTRACT FROM AUTHOR]

This paper presents a framework for the electrification of an isolated rural residential area through a decentralized hybrid renewable plus diesel energy system. Solar/wind/diesel power units have been combined to supply continuous electrical power to a small isolated rural community in the Kurdistan Region of Iraq. The selection of the unit rates for an optimum cost -effective solution is evaluated. The framework activities include wind/solar speed/Radiation data collection via monitoring instruments on the test location and a time-based load forecasting calculation method. Based on the available data for the wind/solar attributes a control system is designed to manage the hourly synchronization of the three units. The system is tested by the MATLAB simulator with satisfactory results. [ABSTRACT FROM AUTHOR]

Alternative fuels especially those produced in a green way are essential for meeting supplying the world's growing energy needs. Biodiesel is becoming more prominent to meet international maritime organization regulations, minimize reliance on fossil fuels, and lessen the rising harmful emissions in the maritime sector. Four different generations have been investigated in the production stage in which a wide range of fuel types have existed including biodiesel, bioethanol, and renewable diesel. To investigate all facets of biodiesel usage as a marine fuel, the SWOT-AHP method is utilized in this paper in which 16 maritime experts with an average of 10.5 years of experience participated. SWOT factors and sub-factors have been developed in light of the literature review focused on biomass and alternative fuels. The AHP method is utilized for data acquisition from specified factors and sub-factors according to their superiority to each other. The analysis demonstrates the main factors 'PW and sub-factors' IPW values, and CR values to calculate the local and global rank of factors. Results highlighted that "Opportunity" has the highest prominence among the main factors; however, "Threats" remain at the lowest level. Moreover, "Tax privilege on green and alternative fuels supported by the authorities" (O4) is the one with the highest weight compared to the other sub-factors. Noteworthy energy consumption will be fulfilled in the maritime industry in addition to the development of new-generation biodiesel and other alternative fuels. This paper will be a quite valuable resource for experts, academics, and industry stakeholders to lessen the ambiguity around biodiesel. [ABSTRACT FROM AUTHOR]

Reclaimed municipal wastewater is a crucial component in biofuel production, especially in regions experiencing increasing freshwater scarcity. However, accurately estimating the potential for fuel production is challenging because of the uneven distribution of biofuel feedstock regions and wastewater treatment plants (WWTPs). This study assesses the viability of using reclaimed municipal water for algal biomass production in pond systems co-located with WWTPs under scenarios driven by biomass production and based on water transport logistics. We performed state- and county-level analysis of reclaimed water resources throughout the United States based on WWTP facility data. We overlaid these data onto estimated algae facility sites and examined the temporal resource availability to address seasonal variations in cultivation demand. Our findings reveal that 2694 billion liters per year of reclaimed water could potentially be used to produce 42.2 million metric tons (ash-free dry weight) of algal biomass, equivalent to 29.2 billion liters of renewable diesel equivalent (RDe). The use of reclaimed water would double current national water reuse and expand such reuse significantly in 455 counties across the United States. However, when we limit the construction of algae facilities to counties that can fully meet their water demand in order to minimize water transport burdens, the available supply decreases by 80%, to 512 billion liters, resulting in annual production of 12.2 billion liters of RDe, which still doubles current biodiesel production. Our analysis highlights the degree to which the location and flow of WWTPs and water transport affect the deployment of algae biofuel facilities and tradeoffs. These findings underscore the importance of improving the current WWTP infrastructure for reclaimed water reuse, especially in southern states. [ABSTRACT FROM AUTHOR]

This study examines the economic viability of an emerging technology for potential upscaling and commercialization in a specific location: the village of New Stuyahok, Alaska. The proposed technology is hydrothermal liquefaction, which utilizes kelp macroalgae and fishing waste as feedstock. These materials were chosen due to their easy availability in the village and their alignment with the local economy. The economic evaluation is based on the net present value (NPV) and sensitivity models. Different feedstock ratios (on a dry basis), such as 100:0, 50:50, and 30:70 of kelp and fishing waste, respectively, were evaluated to determine the optimal combination. The results indicated that the process is economically viable only when a high proportion of fishing waste is used. This can be ascribed to the constrained output yield of the kelp biomass and the relatively negligible influence exerted by alginate production on the NPV. However, the ratio 50:50 appears to be economically promising if the costs can be reduced by at least 13.5% or the benefits can be increased by 12.1%. Nevertheless, government support could play a crucial role in expediting the implementation of this technology once it becomes market-ready. This means being practical, scalable, and economically viable, enabling reduced investments or increased benefits that signify its readiness. Utilizing such a tool offers valuable insights into the framework of the proposed technology and the use of local natural resources. [ABSTRACT FROM AUTHOR]

Highly mesoporous Ba(HPW12O40) heterogeneous acid catalysts were successfully synthesized by the two-step impregnation method and characterized for their catalytic activities, the trans-esterification reaction of Karanja oil was evaluated. The various amounts of catalyst were loaded in the acidic medium and then Barium salt of tungstophosphoric acid. The acid catalyst was characterized using a techniques like FT-IR, XRD, BET, TGA, SEM and EDX. The results indicate that Ba2+ was incorporated into the HPW12O40 framework via isomorphous substitution between Ba2+ ions. During the tests, it was observed that Ba (HPW12O40), for transerterification of pongamia oil (89%) at optimized reaction conditions of 120 °C, 16:1 methanol to reactant molar ratio, 0.75 wt% catalyst loading, and 3 hrs reaction time. The results show that all of the solids have catalytic activity in the cracking reaction, which lowers the ultimate acidity of the products. The solids also have catalytic activity in the transesterification of triglycerides, resulting in high ester yields of 95% from Pongamia oil. The biodiesel production from pongamia oils was characterized by FTIR analysis and ¹H- NMR spectroscopy. With significant activity and stability, the used catalysts could be recycled up to three times. [ABSTRACT FROM AUTHOR]

Bio-diesel or green-diesel consists of a long chain mixture of FAMEs (fatty acid methyl esters). It can be produced when a major component of triglycerides and free fatty acids (FFAs) reacts with methanol and using a catalyst. The catalyst increased the reaction rate to produce green diesel. This study aims to compare the performance of SiO2/CaO superbase and sulfated-TiO2/ZnO superacid nanocomposite catalysts for single-step synthesis of green diesel in esterification-transesterification reactions. The SiO2/CaO superbase was prepared by mixing SiO2 and CaO using solgel methods and the sulfated-TiO2/ZnO superacid by impregnation of sulfuric acid on TiO2 powder and ZnO powder, then mixed by physical mixing-calcination methods. Synthesis of green diesel was carried out by converting used cooking palm oil (UCPO) in the single-step process. Results have shown that the performance of the SiO2/CaO catalyst was relatively higher than the sulfated-TiO2/ZnO catalyst, with a conversion efficiency of green diesel of 86.14% and 83.65%, respectively. However, the performance of the sulfated-TiO2/ZnO catalyst in reducing FFAs was relatively higher than SiO2/CaO catalyst. The catalyst's characteristics, namely surface area, basicity-acidity, and active sites exposed on the surface were determinants of the conversion efficiency of green diesel. Mean crystallite size distribution and surface morphology correlated with surface area and performance of the catalysts. The main conclusion is that the superbase and the superacid solid catalysts can be considered for their activity to convert UCPO into green diesel in a single-step process. [ABSTRACT FROM AUTHOR]

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]

One of the key pathways that can contribute to net‐zero goals is to enhance the use of renewable and sustainable biofuels. However, uncertainties remain owing to critical challenges to selecting the right sustainable biofuels technology most suitable for the longer term. These uncertainties can be partly addressed using a multidisciplinary perspective for scenarios and multicriteria decision‐making analysis. Multicriteria decision support tools (DSTs) are a powerful means to conduct the comparison of technology pathways at different technology readiness levels (TRLs). For this case study, a multidimensional DST was used to compare two technology pathways: (1) gasification combined with Fischer–Tropsch; and (2) hydrothermal liquefaction (HTL) to produce biofuels. The metrics available in the DST were examined, and five metrics related to evaluating profitability, robustness and capital efficiency as well as socio‐economic performance were selected. HTL was found to have a higher yield for renewable gasoline and diesel, largely due to higher economic performance and reduced environmental footprint as compared with the integrated gasification Fischer–Tropsch process. However, the TRL of 8–9 of biomass gasification was higher than that of HTL, which was still at 5–6, reflecting that the gasification process is essentially proven at a pre‐commercial scale. Based on sensitivity and scenario analyses, the importance of government support for capital cost and of biofuel price production incentives was identified as critical. From this comparison, HTL emerges as an attractive process for the future because of its outperformance from technical and environmental perspectives, but further demonstration efforts are still needed at the commercial scale. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Diesel engines are highly efficient but rely on diminishing fossil fuels. To address this, researchers partially replaced diesel with mahua biodiesel and added di-ethyl ether (DEE) to improve the combustion rate. B20, a blend with 20% biodiesel, showed higher brake thermal efficiency (BTE). Combining B20 and DEE as AD-20 increased BTE and reduced fuel consumption by 11.8% compared to diesel. AD-20 also significantly lowered tailpipe emissions, offering a cleaner and greener solution for diesel engines. [ABSTRACT FROM AUTHOR]

Biodiesel has gained wide acceptance as an alternative to petroleum-derived fuel due to its environmentally friendly characteristics such as low aromatic and sulfur content, biodegradability and low exhaust gas emission. Although many types of feedstock could be used to produce biodiesel, waste cooking or frying oil (WCO) is a promising multiple-advantage solution. However, the use of WCO biodiesel has some drawbacks: the high viscosity and the low volatility create difficulties in atomization and in fuel–air mixing. Experiments were performed to investigate the potential employment of aviation fuels in blends with biodiesel obtained from WCO, renewable diesel and petrol diesel. The objective of the research was to evaluate Jet A's potential to improve the blend properties, thus helping to overcome the difficulties in biodiesel usage, enabling the percentage of renewable fuel in the blend to be increased and therefore allowing a reduction in the engine's environmental impact. The experimental activity was carried out on a small-displacement, common rail diesel engine; during the tests, the engine control unit settings were unchanged, with the aim of reproducing the engine behavior when it operated with different fuels. [ABSTRACT FROM AUTHOR]

The use of hydrogen in internal combustion engines is pointed out as an alternative to reduce greenhouse gas emissions. In applications that require high levels of torque and low engine speeds, compression ignition (CI) engines are more appropriate. However, because of the high auto-ignition temperature of hydrogen, its use in these engine types is more suitable when the dual-fuel concept is applied. This study comprehensively investigates, through experimental techniques, the use of hydrogen port-injection in a four-stroke single-cylinder CI engine operating with the renewable diesel-like fuels hydrotreated vegetable oil (HVO) and farnesane, in comparison to fossil diesel dual-fuel operation. In this sense, the present work aims to fill a gap in the literature by performing a novel analysis of dual-fuel operation with hydrogen, considering different substitution fractions, and using groundbreaking biofuels, such as HVO and farnesane. The results showed that in-cylinder pressure and temperature were increased with H 2 enrichment for every pilot fuel, but green diesel fuels presented lower values than those for diesel operation. Furthermore, hydrogen port injection slightly delayed the start of combustion and increased the ignition delay, but a reduction in both premixed and diffusion combustion duration was observed. Reductions in PM, CO, and CO 2 emissions were reported during H 2 addition for every pilot fuel, while increased NO x was observed. Despite this increase, both HVO and farnesane decreased the emissions of this pollutant in single and dual-fuel operations, compared with fossil diesel. In addition, both renewable diesel fuels presented higher BTE than diesel for every studied H 2 mass flow. • Neat diesel, HVO, and farnesane were enriched by hydrogen in a dual-fuel CI engine. • Port-injection of H 2 increased peaks of AHRR, in-cylinder pressure, and temperature. • Dual-fuel mode increased NO x , but decreased PM, CO, and CO 2 for all pilot fuels. • HVO and farnesane decreased some drawbacks observed in diesel-H 2 dual-fuel. • HVO/farnesane enrichment with H 2 may improve performance and decrease emissions. [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]

In the present work, natural mordenite originated from volcanic soils in Greek islands, activated using HCl solution and HCl solution followed by NaOH solution, was used as support for preparing two metallic nickel catalysts (30 wt.% Ni). The catalysts were thoroughly characterized (XRF, N2 adsorption–desorption, SEM, XRD, TEM, H2-TPR, NH3-TPD) and evaluated for biodiesel upgrading to green (renewable) diesel. Double activation of natural mordenite optimized its supporting characteristics, finally resulting in a supported nickel catalyst with (i) enhanced specific surface area (124 m2 g−1) and enhanced mean pore diameter (14 nm) facilitating mass transfer; (ii) easier nickel phase reduction; (iii) enhanced Ni0 dispersion and thus high active surface; (iv) balanced population of moderate and strong acid sites; (v) resistance to sintering; and (vi) low coke formation. Over the corresponding catalyst, the production of a liquid consisting of 94 wt.% renewable diesel was achieved, after 9 h of reaction at 350 °C and 40 bar H2 pressure, in a semi-batch reactor under solvent-free conditions. [ABSTRACT FROM AUTHOR]