Biodiesel Research Articles

Enhancing diesel engine efficiency and emission performance through oxygenated and non-oxygenated additives: A comparative study of alcohol and cycloalkane impacts on diesel-biodiesel blends

This study evaluates the impact of renewable fuel additives on diesel engine performance, combustion, and emissions. Safflower seed oil was converted into biodiesel (BD) through transesterification, achieving a 94.12 % conversion yield, verified by spectroscopic analysis. Test fuels were prepared by adding 5 %, 15 %, and 25 % n-pentanol (PE, oxygenated) and cyclohexane (CHx, non-oxygenated) to diesel fuel (DF) and BD. These blends were tested in a single-cylinder diesel engine under varying loads. At maximum load, BSFC values were 0.251 for DF, 0.333 for 25 % PE, and 0.269 kg/kWh for 25 % CHx. BTE values were 32.184 % for DF, 27.028 % for 25 % PE, and 31.147 % for 25 % CHx. The peak in-cylinder pressure and net heat release for the 25 % PE blend, which were the highest among the test fuels, were 58.148 bar and 37.010 J/°CA, respectively. Average NOx emissions were 171 for DF, 135.75 for 25 % PE, and 170.50 ppm for 25 % CHx. CO emissions were 171 for DF, 149.25 for 25 % PE, and 170.25 ppm for 25 % CHx. Smoke opacity values were 0.75 for DF, 0.308 for 25 % PE, and 0.675 m-1 for 25 % CHx. Despite higher costs, CHx offers reduced environmental impact without significantly compromising engine performance.

Green diesel synthesis from palm fatty acid distillate using a nickel phosphide catalyst: Optimization by box behnken design

The persistent global energy crisis is propelling significant innovations, including the use of palm fatty acid distillate (PFAD) as a renewable resource for producing green diesel (GD). Therefore, this study aimed to intensify GD synthesis from PFAD by optimizing the process using a Response Surface Methodology-Box Behnken Design (RSM-BBD). Optimization was achieved with a nickel phosphide catalyst supported by natural zeolite through hydrodeoxygenation method. RSM-BBD was used to design the process, considering time (1−3 h), temperature (300–350 °C), catalyst concentration (5–15 %), and pressure (20–60 bar). The results showed that the optimum conditions consisted of 11 % catalyst concentration, 3 h of reaction time, 342 °C temperature, and 29 bar pressure, leading to a 96.35 % GD yield. All conversion parameters, except pressure, significantly influenced GD yield. The quality of the synthesized GD showed high quality and compliance with Indonesian as well as European diesel fuel standards.

Use of biochar as a catalyst for biodiesel production

The economic viability of biodiesel (BD) production is highly dependent on conversion techniques using inexpensive oil feedstocks. In this study, BD was synthesised by the thermally induced (non-catalytic) transesterification of oil extracted from camellia seed (42.23 wt% lipid content). The BD yield from the non-catalytic transesterification of camellia oil was higher than that from the alkali-catalysed process. The BD yield from the alkali-catalysed transesterification of camellia oil for 60 min was 84.1 wt%, whereas that from the non-catalytic process for ≤ 1 min at 360 ˚C was 93.5 wt%. To realise a virtuous circle in the production of BD, this study sought a strategic way to valorise oil-extracted biomass waste (lignocellulose-based). Specifically, this study sought a method for valorising biochar as an effective catalyst, hypothesizing that earth alkaline metals finely dispersed within the porous structure of biochar would effectively enhance catalytic capability. The BD yield in the presence of camellia biochar was 92.4 wt% (saturated at ≥ 240 ˚C). Thus, the reaction kinetics for the transesterification of camellia oil over camellia biochar was catalytically accelerated. Such efforts provide opportunities to enhance economic viability and realise the concept of a sustainable cycle in BD production.

Advancements in biofuel research: Understanding the physical and chemical characteristics of green diesel

Green diesel is a potential biofuel that offers certain advantages over traditional fossil diesel, such as low environmental pollution and no sulfur. However, there is little information available regarding the density and viscosity of green diesel, which is crucial for the quality control of biofuels and their performance in engines. In this study, the properties of green diesel produced from palm and soybean oils hydrotreatment were investigated, and models were developed to predict the physical properties of green diesel and n-alkanes. The experimental measurements had uncertainties of 1×10-4 g/cm3 and 1×10-2 mPa s in density and viscosity, respectively. The models were found to be in good agreement with the experimental values. The study highlights the importance of density and viscosity for quality control and engine performance of biofuels. The developed models for predicting the physical properties of green diesel and n-alkanes can be useful for quality control and optimization of biofuel production processes. The findings can be useful for researchers, engineers, and policymakers working in the field of biofuels and renewable energy. Further research is needed to explore the applicability of the developed models to other types of biofuels and to investigate the environmental and economic sustainability of green diesel production.

Production of green diesel from waste cooking oil via catalytic deoxygenation reaction using metal doped eggshell catalyst

Abstract Green diesel production via catalytic deoxygenation of waste cooking oil (WCO) over metal doped eggshell catalyst was investigated in this work. The catalyst was prepared through liquid-liquid precipitation of 5 transition metal solutions and ground eggshell (ES) as the catalyst support. The prepared catalyst, Fe-ES, Cu-ES, Co-ES, Zn-ES, and Ni-ES were characterized using BET surface area and Scanning Electron Microscopy (SEM) analysis. BET surface area data and SEM images of the catalyst shows a promising catalyst physical properties that tailor to the deoxygenation reaction. Gas Chromatography Mass Spectrometry (GCMS) was used to determine the hydrocarbon composition of the oil yield product from the reaction. The reaction also produces gas, soap and liquid acid phase while the remaining unreacted WCO becomes coke. The percentage of all products and coke were calculated using mass balance. Deoxygenation of WCO with Ni-ES catalyst produced highest oil yield at 61.6% with the hydrocarbon content of 56.11%. Ni-ES also produced 22.9% coke; the least percentage compared to other catalyst. The findings proved that Ni-ES catalyst exhibited the highest conversion of WCO into gas and liquid product with a greater yield of oil and minimal coke formation. These findings demonstrate the feasibility and practicality of using eggshell catalysts as substitutes for commercial catalysts in green diesel production.

Hydrogen Use in a Dual-Fuel Compression Ignition Engine with Alternative Biofuels

Recent progress has been made towards decarbonisation of transport, which accounts for one quarter of global carbon dioxide emissions. For the short to medium term, new European Union (EU) and national energy and climate plans agree on a strategy based on the combination of increasing shares of electric vehicles with the promotion of sustainable fuels, especially if produced from residual feedstock and routes with low or zero net carbon emission. Hydrogen stands out among these fuels for its unique properties. This work analyses the potential of using hydrogen in a dual-fuel, compression ignition (CI) engine running with three diesel-like fuels (conventional fossil diesel, advanced biodiesel (BD) and hydrotreated vegetable oil (HVO)) and different hydrogen energy substitution ratios. The results were confronted with conventional diesel operation, revealing that dual-fuel combustion with hydrogen demands higher exhaust gas recirculation (EGR) rates and more advance combustion, leading to a remarked reduction of NOx emission at the expense of a penalty in energy consumption due mainly to unburnt hydrogen and wall heat losses. Unreacted hydrogen was ameliorated at high load. At low load, the use of BD dual combustion permitted higher hydrogen substitution ratios and higher efficiencies than diesel and HVO.

Effect of ZnO nanoparticle on combustion and emission characteristics of a diesel engine powered by lemongrass biodiesel: an experimental approach

Biodiesel (BD) is one of the efficient alternative fuels for diesel engines (DE) which can be employed sans any modifications. The present study is focused on the extraction of BD from a lemongrass plant and analyzing combustion, efficiency, and emission characteristics of the DE by adding NPs at different concentrations to reduce both hydrocarbon, carbon monoxide, and NOx emissions simultaneously from the DE. The fuel samples were prepared by adding different dosages of zinc oxide nanoparticles (ZnO NPs) with neat lemongrass biodiesel (LGB) such as 50 ppm, 100 ppm, 150 ppm, 200 ppm, and 250 ppm per liter. From the results, it is found that the properties of BD were improved by the addition of ZnO NPs and it increased oxygen concentration in the sample resulting in better combustion and lower exhaust pollutants. The DE tested with the LGB + 150 ppm sample has registered maximum brake thermal efficiency (BTE) and lower specific fuel combustion (SFC) for all loading conditions compared to other samples. The value of heat release rate (HRR) and in-cylinder pressure are higher for LGB + 150 ppm due to its specific properties compared to other LGB blends. The presence of ZnO NPs in LGB has reduced harmful emissions from the DE such as carbon monoxide (CO), hydrocarbon (HC), oxides of nitrogen (NOx), and smoke by 4.01%, 5.56%, and 19.01%, when compared to neat LGB.

Assessment of greenness of catalytic deoxygenation of crop oil for green diesel production

Green fuels and chemicals significantly contribute to the Sustainable Development Goals (SDGs). However, their green nature remains questionable in the absence of proper justification of greenness. There is a need for detailed assessment of greenness of claimed processes, fuels, or chemicals. The qualitative method discussed in this study establishes the greenness of a cleaner process of catalytic deoxygenation of waste cooking oil (WCO), leading to the production of green fuels and chemicals. All principles of green chemistry are considered for the assessment. The qualitative analysis of findings shows that 9 out of the 12 principles of green chemistry are fulfilled while the rest of the principles are not applicable for this process. Such discussion could be included in future studies to avoid any uncertainty about their claims of greenness of products or processes. If largely commercialized, catalytic deoxygenation of WCO could be a substantial benefit to the circular bioeconomy of the world.

Surface functionalization of SBA-15 with organosilane for the preparation of bimetallic Ni-Co/SBA-15 catalyst: An innovative approach to convert waste cooking oil into advanced biofuel energy

This research investigates the utilization of bimetallic nickel-cobalt supported SBA-15-silane catalysts for the production of green diesel from waste cooking oil (WCO), aiming at sustainable energy solutions. The catalysts underwent surface-functionalization with three distinct silane types: mercaptosilane (-SH), aminosilane (-NH2), and phenylsilane (-Ph). Notably, the incorporation of -NH2 silane in the fabrication of bimetallic NiCo/SBA-15-NH2 catalyst led to significant improvements in catalyst properties. Specifically, enhancements were observed in pore characteristics, with a surface area of 424 m2/g and a pore size of 4.8 nm, along with an increase in acidity to 5038.91 μmol/g. This rise in acidity is attributed to the presence of amino groups (-NH2), which foster stronger electrostatic interactions between the support and nickel-cobalt particles, subsequently affecting the particle size of Ni-Co (as confirmed by HRTEM analysis). Parametric studies unveiled the superior performance of the NiCo/SBA-15-NH2 catalyst, demonstrating a notable hydrocarbon yield of 80 % and diesel selectivity of 90 % at a reaction temperature of 300 °C, with sustained optimal performance for up to 6 h of reaction time. Furthermore, the blended green diesel (G2.5 & G5) derived from this process exhibited favorable fuel properties including lower kinematic viscosity, higher cetane number, and lower pour point in comparison to commercial petrol-diesel. These findings underscore the significant potential of silane in catalyst preparation for the conversion of WCO into biofuel energy, thereby highlighting a promising avenue for sustainable energy production and waste management.

Predictive modeling of engine performance and emissions for castor oil ethyl ester biodiesel blends: A Gaussian process regression approach

Replacing fossil fuels with cleaner alternatives is essential. This study examines a biodiesel-diesel blend containing 8 % castor oil ethyl ester (COEE8) and its impact on engine performance, combustion characteristics, and exhaust emissions. A single-cylinder diesel engine was tested under consistent conditions: an engine speed of 1500 rpm, varying engine loads (25 %, 50 %, and 75 % of maximum torque), and compression ratios (16, 17, and 18). Engine-out emissions were measured with Testo flue gas analyzers. The results showed that COEE8 combustion significantly decreased HC, CO, and smoke emissions compared to diesel fuel but increased NOx emissions. Additionally, COEE8 exhibited comparable brake-specific fuel consumption (BSFC) and brake thermal efficiency (BTE) to diesel fuel. The optimal engine operating parameters were determined using the Non-dominated Sorting Genetic Algorithm-II (NSGA-II), a multi-objective optimization technique. Due to limited data availability, Gaussian Process Regression (GPR), a machine learning algorithm for small datasets, modeled the multi-objective functions with compression ratio and engine load as input variables. The GPR model demonstrated high prediction performance across all output parameters (BSFC, BTE, HC, smoke, NOx, and CO) for both diesel and COEE8 fuels, with average coefficients of determination (R2) of 0.9896 and 0.9953, respectively, indicating a strong correlation between predicted and actual values. The mean absolute percentage error (MAPE) was also low, averaging 3.11 % and 2.26 %, respectively, demonstrating the model's accuracy. Using the GPR model, the NSGA-II identified the optimal trade-off between NOx and smoke index for both diesel and COEE8 fuels. The optimal compression ratio was 16 for both fuels, while the optimal engine load varied, ranging from 20 % to 30 % for COEE8 and around 30 % (almost 40 %) for diesel fuel.

Heterogeneous alkaline catalyst synthesized from local bovine bone wastes for transesterification of palm oil into biodiesel

Abstract Local bovine bone wastes, which are abundant in Aceh Province, have been successfully used as biomineral sources to produce heterogeneous catalysts that result in alkaline oxide. This study aimed to produce alkaline oxides by employing a high heat breakdown approach on local bovine bone particles at atmospheric pressure. The physicochemical analysis of the obtained inorganic particles revealed that the predominant component of those obtained inorganic oxide particles was calcium oxides (CaO). Furthermore, the produced alkaline oxide was employed as an alkali oxide catalyst for the transesterification of palm oil (RPDPO) with methanol, yielding methyl ester compounds, which are well recognized as a sustainable and green diesel energy source.

The criteria for qualifying fuels as a replacement fuels for internal combustion engines

The article presents the classification of motor fuels into conventional and unconventional. The concept of replacement fuels is formalized as fuels that can replace conventional petroleum fuels for spark ignition and self-ignition engines without any structural or regulatory changes. The criteria for qualification unconventional fuels as replacement fuels are presented. This article also introduces the results of empirical research conducted on a single-cylinder research engine powered by diesel fuel and rapeseed methyl esters (RME) in summer version and winter version. The engine was tested and the combustion phenomenon in the cylinder was analyzed. Very similar engine properties were observed for diesel fuel and rapeseed methyl esters (RME) in the summer version, while greater differences were found for rapeseed methyl esters (RME) with winter additives. In light of the empirical research and the physicochemical properties of the fuels, it is concluded that RME warrants consideration as replacement fuel for engines with self-ignition, especially in the case of biofuel in the summer version.

Tuning of the acid sites in the zeolite-alumina composite Ni catalysts and their impact on the palm oil hydrodeoxygenation reaction

The hydrodeoxygenation (HDO) of bio-oil is one of the potential approaches to produce green diesel. However, HDO catalyst requires the development of bifunctionality which translates to the simultaneous presence of acidic and metal sites for desired catalytic activity and selectivity. Zeolites and their composites are attractive candidates for the conversion of biomass to fuels. In the present work, a series of Ni-incorporated Al2O3-zeolite beta bifunctional composite catalysts with distinct Al2O3 (25–75 wt%) and Ni contents (5–15 wt%) were synthesized via a facile one-pot method directly from nickel acetate, nano-boehmite (γ-AlO(OH)) and the NH4+ form of beta zeolite (NH4+-BZ). The nano-boehmite particles, due to the positive charges on their surface, electrostatically attract negatively charged beta zeolite crystals, which leads to the assembly of a hierarchical pore structure upon calcination. Interestingly, the composite catalysts synthesized were quite homogeneous with uniform dispersion of Ni particles. All composite catalysts were thoroughly characterized using XRD, SEM-EDX, SEM-mapping, HR-TEM, H2-TPR, H2-TPD, NH3-TPD, XPS, 31P MAS NMR, 27Al MAS NMR and N2 sorption analysis. The synthesized composite catalysts with distinct Al2O3 contents showed diverse textural properties, distinct nature of acid sites and improved performance in hydrodeoxygenation of palm oil. Particularly, the Ni/BZ-Al50 (with BZ:Al2O3 = 50:50) composite catalyst significantly enhanced the conversion of palm oil (up to 90%) and yield of n-C15-C18 hydrocarbons (up to 69%) at moderate temperature of 375 °C as compared to 10Ni/BZ catalyst (Conv. = 75%, yield of n-C15-C18 = 52%). The higher catalytic performance realized with composite catalysts can be ascribed to its hierarchical pore structure, moderate acidity (chemisorption studies), tuned acid sites nature (solid state NMR) and homogeneous distribution of active Ni sites (H2 chemisorption) which helps to improve product selectivity by minimizing side reactions. The time-on-stream (TOS) experiments were carried out up to 20 h which clearly showed that composite catalysts are more stable suggesting the lower amount of coke deposition (TPO studies) and suppression of metal sintering.

Effect of neem oil biodiesel on the surface and structural integrity of carbon steel alloy: Chromatographic, spectroscopic, and morphological investigations

This study explores the impacts of neem oil biodiesel (BD), which was produced and characterized using GC–MS, FTIR, and UV–Vis spectroscopic techniques to elucidate pure and corrosion-product neem oil BD at room temperature (25 °C) and different immersion durations of 0, 28, 42, and 56 days. The OM and SEM were also employed to study the surface, structural integrity, and interphase interaction between the BD and the carbon steel (C1020) before and after immersion for different durations. The dominant fatty acid (FA) group in both pure and corrosion-product neem oil BD was C18, with a total composition of 72.3 %, hence determining the nature of the BD interaction with the carbon steel. The study revealed that carbon steel (C1020) was susceptible to attacks by neem oil BD, and the duration of immersion had substantial influence on the surface morphology and structural integrity of the steel. It is therefore anticipated that this study will significantly advance the field of alternative fuel research.

Efficient hydrodeoxygenation of methyl palmitate over NiMo/ZrO2 catalyst with electron transfer between Ni and Mo

The hydrodeoxygenation of biomass into high quality fuels is one of the effective technologies to produce green diesel and solve the environmental pollution of fossil fuels at source. In this work, the catalytic performances of NixMoy/ZrO2 catalysts for methyl palmitate hydrodeoxygenation were evaluated, and the characterization results were combined to understand their role of physicochemical and structural properties in modulating the specific selectivity of alkanes. Under mild reaction condition (270 °C, 3 MPa), the Ni1Mo1/ZrO2 catalyst showed the best hydrodeoxygenation reactivity (conversion: 99.4%) and alkane selectivity (95.0%, hexadecane: 73.6%) of methyl palmitate. It was found that the electron transfer from Mo to Ni in Ni1Mo1/ZrO2 catalyst promoted the active site Ni anchoring and H2 molecules activation, which were associated with the better hydrodeoxygenation activity. In addition, the highest oxygen vacancies and Mo5+ content in Ni1Mo1/ZrO2 catalyst benefited the adsorption and breaking capacity of CO/C-O bonds and hexadecane yield. The Ni1Mo1/ZrO2 catalyst maintained excellent catalytic performance and structural stability after a long-term test of 60 h, which could be efficiently applied for hydrodeoxygenation of methyl palmitate.

The mechanism of oleic acid deoxygenation to green diesel hydrocarbon using porous aluminosilicate catalysts

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.

Optimization of Engines performance and emission for Biodiesel blended with Nanoparticle using regression analysis approach

Conventional Fuels used in IC engines such ad diesel, petrol etc. are on the verge of extent. Bio-diesel acts an alternative to conventional fuels as it is renewable, bio degradable, nontoxic, less polluting in nature. Present study investigate the effect of various blend of biodiesel & nanoparticle on the performance of engine and emission level. During the study, it is observed that the important parameter that affects the performance concentration of Bio Diesel & nanoparticle in diesel and Engine load are independent parameter. Effect of emission output parameter such as NOX, CO2, CO, HC, are measured. Performance of engine such as brake power and SFC are also measured. Mathematical relation was established among mentioned independent and dependent variables. The ANOVA method is establish relation between these parameters. Experiments were carried out for the nanoparticles (GO) concentration of 10ppm, 20 ppm and 30ppm, biodiesel blend of 20% and 40% at different varying engine load of 25%, 50%, 75% and 100%. Equations are formulated to establish relation between the independent and dependent parameters. The accuracy was calculated in terms of root mean square and to be 0.9094, 0.96, 0.98, 0.96, and 0.949 for NOx, CO, HC, and CO2 and Brake power. From the regression study, optimum BP, NOx, CO, HC, CO2 were found to be 3.49KW, 137.77ppm, 0.7262%, 122.66 ppm, and 3.22%.

Frustrated Lewis pair catalyst realizes efficient green diesel production

Hydrotreating renewable oils over sulfided metal catalysts is commercially applied to produce green diesel, but it requires a continuous sulfur replenishment to maintain catalyst activity, which inevitably results in sulfur contamination and increases production costs. We report a robust P-doped NiAl-oxide catalyst with frustrated Lewis pairs (i.e., P atom bonded with the O atom acts as an electron donor, while the spatially separated Ni atom acts as an electron acceptor) that allows efficient green diesel production without sulfur replenishment. The catalyst runs more than 500 h at a weight hourly space velocity (WHSV) of 28.3 h−1 without deactivation (methyl laurate as a model compound), and is able to completely convert a real feedstock of soybean oil to diesel-range hydrocarbons with selectivity >90% during 500 h of operation. This work is expected to open up a new avenue for designing non-sulfur catalysts that can make the green diesel production greener.

Application of simultaneous rapeseed oil extraction and interesterification with methyl formate using enzymatic catalyst

A novel method of interesterification of rapeseed oil utilising methyl fomate and an enzymatic catalyst to produce biodiesel without the need for glycerol separation was researched. Using the enzyme preparation Lipozyme TL IM as a catalyst, the simultaneous processes of oil extraction from rapeseed and interesterification in-situ were investigated. Three independent variables were assessed for their interaction and impact on the yield of rapeseed methyl esters: the mass ratio of methyl formate to rapeseed, the time, and the amount of catalyst. Utilising surface response methodology, process optimisation was performed, and a model explaining the impact of independent variables on the yield of rapeseed methyl esters was developed. Lab testing has verified that the optimal process parameters have been identified, resulting in a 94.24 % rapeseed methyl ester yield. Using a 48:1 mass ratio of methyl formate to rapeseed and 23.33 % of the enzymatic catalyst in 64.5 h produced the highest yield. The reaction product contained conventional biodiesel (rapeseed methyl esters) along with mono-, di-, and triformyl glycerides. The interesterification product's physical and chemical characteristics were identified, and the resulting quality indicators were compared with the specifications of standards for biodiesel and mineral diesel fuel.

Measuring risk of renewable diesel production processes using a multi-criteria decision strategy

This study proposes measuring the risk of five alternative renewable diesel production technologies using a multi-criteria decision matrix strategy. Evaluated criteria include environmental, economic, technological, social, and process safety risks. The subjective Analytical Hierarchy Process (AHP) with stakeholder input provides criteria and sub-criteria weightings and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) ranks alternatives. Alternative renewable diesel options are Green Diesel from first, second, and third-generation feedstocks, Fischer-Tropsch Diesel from second-generation biomass, and the transesterification of vegetable oils (VO) to make biodiesel. This study is a response to an earlier work measuring the sustainability of the same renewable technologies. While the previous work indicated Fischer-Tropsch Diesel as the most sustainable, this current work indicated the process as the “most risky,” suggesting that risk is a significant driver of decision making over sustainability, and newly developed decision tools should address both perspectives.