Biodiesel (methyl esters) has been produced using numerous catalysts to enhance its quality and related productivity. Generally, the raw materials for biodiesel production and its catalysts ...significantly impact the produced biodiesel's quality. In addition, the heterogeneous catalysts are promising as catalysts in the transesterification for biodiesel production and can be used continuously during this production. In particular, these catalysts are essential for green biodiesel production because of their high activity, thermal stability, and reusability. Hence, several homogeneous and heterogeneous (acidic and alkaline) catalysts for biodiesel production, particularly the naturally derived heterogeneous catalysts, are reviewed in this article. Further, the different heterogeneous catalysts for biodiesel production have been studied extensively as replacements for the respective homogeneous catalyst. Specifically, this replacement is aimed at the simultaneous esterification and transesterification of the nonedible and low-cost biomasses under moderate conditions producing biodiesel. Moreover, this study analyzes biodiesel's impact and long-term performance in various applications. Finally, it also reports the advancements in biodiesel production in terms of the catalysts used in it and its processes to aid further developments in biodiesel production.
•A comprehensive review of hydrogen production techniques.•Performance and emissions parameters are discussed for SI and CI engines.•A review on fuel injection techniques.•Technical challenges for ...hydrogen-fueled engines.
The development of new energy sources to change or lessen the use of conventional nonrenewable energy is also driven by the growing concern over pollution from internal combustion engines. In this situation, it is discovered that using hydrogen in internal combustion engines offer a possible solution to these problems. The unique physical and chemical characteristics of hydrogen for internal combustion engines (ICEs) are called out. There are several hydrogen production techniques are discussed as water electrolysis (solar & wind energy), gasification of biomass, coal gasification, methanol and ammonia decomposition, steam reforming process and photochemical splitting of water. The majority of research found that hydrogen enrichment fuels significantly improved engine performance in terms of thermal efficiency, energy consumption, and fuel consumption. Furthermore, given suitable operating circumstances, both spark-ignition (SI) and compression-ignition (CI) engines can achieve declines in exhaust pollutants such as HC, CO, CO2, NOx, smoke, and soot, and also summarize the utilization of hydrogen in the SI and CI engines aided improvements in engine performance and exhaust emissions under appropriate operating conditions. An assessment of various fuel induction techniques (fuel carburation, port fuel injection and direct injection) and the paybacks of using the synergies of particular solutions is offered, as well as an overview of the use of hydrogen as an internal combustion fuel, covering operations in both SI and CI engines. The objective of this study is to deliver a comprehensive review related to the hydrogen production techniques, the effect on performance and emissions of hydrogen addition as a fuel and injection techniques in a spark ignition and compression ignition engine, and future challenges have been discussed in this article.
•CuO-NiO/Al2O3 catalyst with palm oil used to synthesize green fuel.•GasTurb-13 data is validated engine performance model using green fuel.•GD10PME10 blend had the lowest TSFC, matching Jet-A1 ...efficiency at high speeds.•GD20OME30 has the lowest emissions (CO, and CO2) and temperature.•NOx rose with blends; GD10PME10 closest to Jet-A1. Optimized blends can cut NOx.
This study aims to assess the impact of using green fuel in place of biodiesel on the performance and exhaust emissions of air-breathing engines. GasTurb 13 is utilized to forecast the engine’s performance (kingTech 180 k turbojet engine). Catalytic deoxygenation of vegetable oils produces green diesel, offering an alternative to biodiesel. Physiochemical properties of GD blends (PME30GD20, PME20GD30, PME10GD10) were analyzed, and GasTurb-13 software predicted engine performance and emissions, validated with experimental data. The results show that GD10PME10 exhibited higher density (767.6 g/m3) than pure green fuel, while viscosity dropped by 53.85 % compared to PME. GD outperformed Jet-A1 by 0.74 % in heating value, with GD10PME10 having the highest at 42.63 MJ/kg. Engine performance measures included thrust, mass fuel flow, thrust-specific fuel consumption, and exhaust gas temperature. GD10PME10 showed a 12.5 % thrust increase and the lowest TSFC (95 g/kN.s) at 80,000 RPM compared to Jet-A1. GD20PME30 achieved the lowest EGT (550 °C) at the same RPM. Regarding emissions, GD20PME30 emitted the lowest CO (100,000 RPM, 150 ppm) and 0.5 % less CO2 (90,000 RPM) than Jet-A1. GD10PME10 produced the lowest NOx (12.5 ppm) at maximum speed, while Jet-A1 emitted the least NOx (7.5 ppm) at 120 k RPM. Overall, the data suggested that green fuel might increase the physiochemical properties of biodiesel blends, hence improving the fuel’s capacity to burn more effectively in aero-engines.
Due to the finite stock of fossil fuels and its negative impact on the environment, many countries across the world are now leaning toward renewable sources energies like solar energy, wind energy, ...biofuel, hydropower, geothermal and ocean energy to ensure energy for the countries development security. Biodiesel is one kind of biofuel that is renewable, biodegradable and has similar properties of fossil diesel fuel. The aim of this paper is to provide the substantial information on biodiesel to the researchers, engineers and policy makers. To achieve the goal, this paper summarizes the information on biofuel development, feedstocks around the world, oil extraction technic, biodiesel production processes. Furthermore, this paper will also discuss the advantages of biodiesel compared to fossil fuel. Finally, the combustion behavior of biodiesel in an internal combustion engine is discussed and it will help the researchers and policy maker and manufacturer. To determine the future and goal of automotive technology the study found that, feedstock selection for biodiesel production is very important as it associates 75% production cost. Moreover, the test of fuel properties is very important before using in the engine which depends on the type of feedstocks, origin country, and production process. Most of the researchers reported that the use of biodiesel in diesel engine reduces engine power slightly but reduces the harmful emission significantly. Finally, the study concludes that biodiesel has the potential to be used as a diesel fuel substitute in diesel engines to solve the energy and environment crisis.
In recent years, the approaches paid much attention to are adding nanoparticles in biodiesel-based fuels to overcome the disadvantages of biodiesel like high molecular mass, high viscosity, and ...pouring point, and low calorific value significantly affecting the spray, atomization, and combustion characteristics. Among the aforementioned nanoparticles, Cerium oxide (CeO2) nanoparticles show their advantages such as flexible capacity in valence transformation, large oxygen storage, and good thermal properties, CeO2 nanoparticles are thus believed to have a great potential to become an additive for the diesel engine. Indeed, in this review paper, the preparing methods and physicochemical properties of biodiesel-based fuels containing CeO2 nanoparticles were fully introduced. Furthermore, the effects of CeO2 on the atomization and micro-explosion of as-used fuels were also discussed in detail. More importantly, the combustion behavior, performance, and emission characteristics of diesel engines fuelled with biodiesel containing CeO2 nanoparticles were thoroughly analyzed. In general, the addition of CeO2 nanoparticles into biodiesel has demonstrated positive effects on reducing toxic emissions (soot, smoke opacity, NOx, CO, HC), enhancing thermal efficiency and brake power, and improving fuel consumption. However, the impacts of CeO2 nanoparticles on PM emission, human health, and the environment need to be further investigated in future researches.
•Preparing methods for CeO2-added fuels and their properties were introduced.•Effects of CeO2 nanoparticles on spray and fuel properties were mentioned.•Performance of engine fuelled with CeO2-added biodiesel was thoroughly analyzed.•Combustion and emission characteristics of diesel engine were discussed in detail.
Engine performance parameters, including fuel conversion efficiency (FCE), power, torque and specific fuel consumption (SFC), can be affected by variables such as ignition timing (IGT), injection ...timing (IT) and hydrogen volume fraction (H2%). In this paper an engine fueled with different H2/CNG blend rations from 0 to 50% volume under ignition and injection timing at different speeds were investigated. For model validation, the engine operating conditions were simulated using the AVL fire software and compared with experimental results. The statistical comparison showed that there was no significant difference between them. Also, a support vector machine (SVM) was used to study the engine's behavior according to the variables studied. The SVM model predicted the FCE, power, torque, SFC and CO with error of less than 4%. The Genetic Algorithm (GA) was used to find optimal IGT, IT and H2% values to achieve optimum engine performance. Therefore, the results showed that the optimum engine operating conditions depend on the engine speed. Also, the results showed that independent variables (IT, IGT and H2%) maximize the engine performance and minimize SFC and CO emission. So that the optimum use of hydrogen in this research at different engine speeds was between 20% and 30%.
•Effect of hydrogen fuel in direct injection engine was studied.•Use of HCNG fuel can improve engine performance and exhaust emissions.•The SVM model could predict the engine performance and CO with error of less than 4%.•Ignition timing, injection timing and hydrogen volume fraction at different engine speeds.
This study investigated the engine performance and emission characteristics of biodiesel blends with combined Graphene oxide nanoplatelets (GNPs) and 10% v/v dimethyl carbonate (DMC) as fuel ...additives as well as analysed the tribological characteristics of those blends. 10% by volume DMC was mixed with 30% palm oil biodiesel blends with diesel. Three different concentrations (40, 80 and 120 ppm) of GNPs were added to these blends via the ultrasonication process to prepare the nanofuels. Sodium dodecyl sulphate (SDS) surfactant was added to improve the stability of these blends. GNPs were characterised using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR), while the viscosity of nanofuels was investigated by rheometer. UV-spectrometry was used to determine the stability of these nanoplatelets. A ratio of 1:4 GNP: SDS was found to produce maximum stability in biodiesel. Performance and emissions characteristics of these nanofuels have been investigated in a four-stroke compression ignition engine. The maximum reduction in BSFC of 5.05% and the maximum BTE of 22.80% was for B30GNP40DMC10 compared to all other tested blends. A reduction in HC (25%) and CO (4.41%) were observed for B30DMC10, while a reduction in NOx of 3.65% was observed for B30GNP40DMC10. The diesel-biodiesel fuel blends with the addition of GNP exhibited a promising reduction in the average coefficient of friction 15.05%, 8.68% and 3.61% for 120, 80 and 40 ppm concentrations compared to B30. Thus, combined GNP and DMC showed excellent potential for utilisation in diesel engine operation.
•Influence of Graphene oxide nanoplatelets (GNPs) and dimethyl carbonate (DMC) were studied.•Surfactant sodium dodecyl sulphate (SDS) was used to stabilise the blend.•The best ratio of GNP to SDS was 1:4 for maximum stability in biodiesel.•Maximum reduction in BSFC and maximum BTE was observed for B30GNP40DMC10.•B30GNP120DMC10 fuel blend showed a maximum reduction of 15.05% in COF.
In order to enhance engine combustion and emissions, inclusion of nano additives containing hydrogen is recommended due to the high viscosity, poor calorific value, atomization, and vaporization ...issues of biodiesel. Transesterification was used to transform sunflower oil into methyl ester. Sunflower biodiesel of 20% by volume was blended with diesel fuel, and CeO2 nanoparticles of 100 ppm were added to blends. Hydrogen was introduced by 5 and 10 lpm from intake manifold. Diesel engine operated at 2000 rpm and loads of 15, 30, 45, and 60 N m. BSFC was decreased by 1.77%, 4.71%, and 7.19% but BTE was improved by 1.39%, 4.04%, and 7.01% when cerium oxide, 5, and 10 lpm hydrogen were added to B20, respectively. When methyl ester mixture was combined with nano additive and H2 at 5 and 10 lpm, respectively, EGT was reduced by 2.62, 4.77, and 6.73%. B20+ CeO2 and B20+ CeO2+ 5 lpm, and B20+ CeO2+ 10 lpm showed decreases of 46.51%, 56.59%, and 63.57% in CO emissions but the declines in NOx were 6.34, 13.6% and 20.71%, respectively compared to diesel oil. Inclusion of nano-doped hydrogen at 5 and 10 lpm reduced HC emissions by 12.09% and 28.57%, respectively, about diesel. Hydrogen addition of 5 and 10 lpm to CeO2-doped B20 improved the in-cylinder pressures by 3% and 3.52% but the maximum heat release rate increases were 3% and 3.52% respectively compared to diesel. Biodiesel from sunflower oil with 100 ppm CeO2 with hydrogen shows reductions in emissions and combustion enhancement.
Display omitted
•Nano additive improved heat transfer and thermal conductivity capabilities.•The addition of CeO2 shortened the ignition delay time compared to B20.•Burning fuels with H2 content releases more energy than fuels with a much LHV.•H2 addition enhanced ignition and combustion characteristics.•Increased gas diffusivity caused a decrease in BSFC due to the hydrogen ratio.
•Analysis of hydrocarbon and smoke exhaust emissions was performed.•Fuel mixture combustion parameters effect on thermal performance and emission.•Research focused on the use of biodiesel to run gas ...turbine engines.•Aspects of fuel blends, combustion chamber geometry and injection time.•This study focused on blend formulation through dual blends.
Current research focuses on finding environmentally friendly energy sources as an alternative to fossil fuels due to declining resources with increasing population growth. This study identifies and summarises recent studies into the effect of biodiesel blends on engine performance and provides a classification of the literature. This study also aims to clarify the incentives for using biodiesel and the challenges still faced by researchers. Articles on biodiesel fuel and its blends in diesel and gas-turbine engines were collated and filtered based on the blending methods (complete substitution without diesel or partial substitution). Biodiesel utilization in gas turbines and its competitiveness with Jet fuel performance is one of the things that this study touched upon. Despite that, the gaps in using biodiesel instead of Jet-A still exist in turbine engines, so settling the challenges of using biodiesel in the aviation sector could be through using additives or substitutes. A total of 72 articles were selected and divided into two groups: single biodiesel blends and dual blend biodiesel. The fuel used and the engine types were identified for all articles, and the emission results and engine performance when biodiesel was used. This study contributes to the development and research into the primary system (such as compressor, combustion chamber, or turbine), challenges, and the limitations of the current studies.
