Biodiesel Combustion Research Articles

Prediction and Simulation of Biodiesel Combustion in Diesel Engines: Evaluating Physicochemical Properties, Performance, and Emissions

Environmental and energy sustainability concerns have catalyzed a global transition toward renewable biofuel alternatives. Among these, biodiesel stands out as a promising substitute for conventional diesel in compression-ignition engines, providing compatibility without requiring modifications to engine design. A comprehensive understanding of biodiesel’s physical properties is crucial for accurately modeling fuel spray, atomization, combustion, and emissions in diesel engines. This study focuses on predicting the physical properties of PODL20 and EB100, including liquid viscosity, density, vapor pressure, latent heat of vaporization, thermal conductivity, gas diffusion coefficients, and surface tension, all integrated into the CONVERGE CFD fuel library for improved combustion simulations. Subsequently, numerical simulations were conducted using the predicted properties of the biodiesels, validated by experimental in-cylinder pressure data. The prediction models demonstrated excellent alignment with the experimental results, confirming their accuracy in simulating spray dynamics, combustion processes, turbulence, ignition, and emissions. Notably, significant improvements in key combustion parameters, such as cylinder pressure and heat release rate, were recorded with the use of biodiesels. Specifically, the heat release rates for PODL20 and EB100 reached 165.74 J/CA and 140.08 J/CA, respectively, compared to 60.2 J/CA for conventional diesel fuel. Furthermore, when evaluating both soot and NOx emissions, EB100 displayed a more balanced performance, achieving a significant reduction in soot emissions of 34.21% alongside a moderate increase in NOx emissions of 45.5% compared to diesel fuel. In comparison to PODL20, reductions of 20.4% in soot emissions and 3% in NOx emissions were also noted.

Emission analysis of combustion of cashew nutshell biodiesel in a toroidal combustion chamber: an experimental study

Emission analysis of combustion of cashew nutshell biodiesel in a toroidal combustion chamber: an experimental study

Effect of air supply on combustion and emission characteristics of biodiesel in industrial furnace

Effect of air supply on combustion and emission characteristics of biodiesel in industrial furnace

Enhancing reactivity-controlled compression ignition engine performance: A response surface methodology approach with ammonium hydroxide-waste cooking oil biodiesel optimization

The focus on ammonium hydroxide, biodiesels and their combustion technology has garnered significant attention in pursuing carbon-neutral and carbon-free fuels to address greenhouse gas emissions (GHG) and mitigate global warming. Low-temperature combustion (LTC) has been introduced as an alternative method to conventional compression ignition (CI) combustion. Reactivity controlled compression ignition (RCCI) can be achieved by introducing highly reactive waste cooking oil methyl ester (WCOME) oil directly into the manifold in intervals of 10% energy and injecting low-reactive ammonium hydroxide at 20%–50%. Utilizing the response surface methodology (RSM) approach, it was determined that for optimal operation in RCCI mode, an ideal ammonium hydroxide energy sharing (AHES) of 43% would account for the varying parameters and their effects on emissions and performance. The results of the experiments predicted a brake thermal efficiency (BTHE) of 34.85% and a brake specific energy consumption (BSEC) of 10.69 MJ/kWh. Meanwhile, a notable decrease in exhaust emissions was observed for HC, CO, CO2, NO x and smoke by 41.54%, 38.89%, 48.89%, 51.27% and 65.80% respectively when compared to conventional biodiesel combustion (CBC). The experimental result at maximum load operation with an AHES of 50% indicates that RCCI combustion led to an increase in thermal efficiency from 30.36% to 35.42%, and the in-cylinder pressure and heat release rate dropped from 83.42 bar to 59.64 bar and 78.68 kJ to 60.92 kJ, respectively. There was a significant reduction in HC, CO, CO2, NO x and smoke emissions recorded as 58.76 ppm, 0.11%v, 1.61%v, 442 ppm and 6.64 N, respectively, compared to CBC.

Experimental study on macro spray, combustion and emission characteristics of biodiesel and diethyl carbonate blends

Experimental study on macro spray, combustion and emission characteristics of biodiesel and diethyl carbonate blends

Assessing the Effect of Aluminium Oxide Nanoparticle Additives on Biodiesel Combustion in Marine Diesel Engines

Abstract The increases in annual ship exhaust emissions have prompted the shift towards adopting alternative energy sources. Biodiesel is a suitable substitute fuel for marine engines that does not necessitate engine alterations. Biodiesel is renewable, environmentally friendly, and plant-based with biodegradable properties. The fuel is also non-toxic and oxygenated and shares similar characteristics with diesel fuel. Nonetheless, biodiesel fuel exhibits slightly reduced performance compared to diesel primarily due to its lower energy content. This study aims to evaluate the combustion attributes of a marine diesel engine employing palm biodiesel fuel incorporated with aluminium oxide (Al2O3) nanoparticle additives. A B20 biodiesel fuel was blended with 50, 100, and 150 ppm Al2O3 nano additives. The engine combustion parameters, in-cylinder pressure, heat release rate (HRR), mass fraction burned, and ignition delay were analysed and compared to the B20 fuel without additives. Adding Al2O3 nano additives to the B20 biodiesel blend improved the engine combustion characteristics. The optimal performance was recorded by the blend incorporating 150 ppm nanoparticles. The in-cylinder pressure and HRR peaks also improved by 5.41 to 15.1% and 4.69 to 16.9%, respectively, compared to the other B20 fuel blends. Furthermore, the B20 mixed with Al2O3 documented a more rapid mass fraction burned rate, resulting in a shorter ignition delay of approximately 5 CA°. In addition, the amount of oxygen in biodiesel blended with Al2O3 nano additives has improved engine combustion compared to B20 fuel. The present study demonstrated that adding Al2O3 nano additives to palm biodiesel fuel significantly enhanced engine combustion attributes, thus highlighting its potential to reduce reliance on petroleum-based fuels and provide sustainable fuel alternatives for marine diesel engines.

Experimental study on the effect of combustion and emission performance of biodiesel–ammonia dual-fuel engine

Experimental study on the effect of combustion and emission performance of biodiesel–ammonia dual-fuel engine

Evolution of collisional condensation of biodiesel combustion particulate matter in engine exhaust pipe

To investigate the evolution of biodiesel combustion particulate matter (PM) within the engine exhaust system, PM samples were analyzed from diesel fuel, soybean oil methyl ester (SME), catering waste oil methyl ester (WME) and palm oil methyl ester (PME) at various locations along the engine exhaust pipe, and a gas-solid two-phase flow model of exhaust gas and PM was developed using the coupled computational fluid dynamics-discrete element method (CFD-DEM). The results indicate that the average primary particle diameter of biodiesel PM is smaller than that of diesel PM at the same position within the exhaust pipe, and it exhibits an increasing trend with respect to the iodine value of biodiesel. The adhesion forces of diesel, SME, WME, and PME PM at 0 m downstream from the exhaust pipe were measured as 9.83 nN, 16.74 nN, 26.54 nN, and 34.31 nN, respectively. The biodiesel PM with higher mass density readily formed structurally stable particulate agglomerates at the inlet of the exhaust pipe. With an increase in exhaust flow velocity, there was a corresponding rise in particle collision frequency. The initial agglomeration probability of particles exhibited an increase followed by a subsequent decrease. The normal overlap of particle collisions decreased with an increase in the Young's modulus of the particles, thereby reducing the likelihood of adsorption and adhesion during particle collision and hindering the formation of a greater number of particle aggregates.

Production and testing of mahua oil-based biodiesel synthesized through heterogeneous catalyst using experimental and numerical method.

A two-step treatment of mahua oil was conducted to synthesize mahua biodiesel using heterogeneous biomass-based catalyst derived from mahua shell. Mahua oil having higher free fatty acid (FFA) content (about 19%) was esterified to reduce the FFA content up to 1%. The esterification process was carried out using 200mL mahua oil, 5:1 molar ratio (methanol:oil), and 2.25 weight% of H2SO4 at a temperature of 60°C for 3h. Post esterification, a set of 16 experiments were created using a Box-Behnken design (BBD)-based response surface methodology (RSM) approach to conduct the transesterification of the esterified oil. Molar ratio, catalyst loading, reaction temperature, and reaction time were the four input variables chosen for the design of experiments. The optimized conditions for maximum biodiesel yield (87.7%) were found to be 14.88 molar ratio, 3.578% catalyst loading, 69.7°C reaction temperature, and 81.9min reaction time. The Diesel RK engine simulation tool which was experimentally validated for baseline diesel fuel was used for numerical simulation of mahua biodiesel. The performance, combustion, and emission behavior of mahua biodiesel analyzed using numerical simulation presented the sustainability of mahua biodiesel as an alternate fuel.

An image-processing method based on regional separation-parameter coupling for the stability analysis of biodiesel flame

Flame stability is vital to obtain good combustion performance. Therefore, the development of flame stabilization technologies and stability evaluation methods has always received considerable research attention. However, the existing evaluation methods have low precision, which makes it difficult to accurately assess the flame stability. To address this issue, we proposed an effective flame state evaluation method in this study. We conducted relevant combustion experiments, and applied the proposed method to evaluate the flame stability of biodiesel. Furthermore, we established a numerical evaluator of the flame state based on a regional separation-parameter coupling image-processing method. This numerical evaluator combines the statistical characteristics of six flame parameters, which we derived from the flame images. The experimental results suggested that the proposed method can be used to determine some characteristic parameters that cannot be obtained by traditional methods, such as oscillation frequency and propagation velocity. Notably, these characteristic parameters are important for the evaluation of flame stability. At an oxygen concentration of 24 % and fuel pressure of 0.5 MPa, we subdivided the combustion state of biodiesel into stable, relatively stable, unstable, and extinguished states. We observed that by decreasing the airflow rate from 0 to 12.50 m3/h, the flame color changed from orange to green, then blue, and finally to yellow-green. We also observed, contraction and spreading in the flame highlight region. The color space analysis revealed that the larger the blue-to-red ratio, the more complete the combustion, which led to a blue flame. Overall, the proposed evaluation method provides a useful guide for regulating the combustion of biodiesel. Furthermore, these result can be generalized to assess the combustion states of other fuels.

The Combustion and Emission Characteristics of Corn Oil Biodiesel with Titanium Oxide (TiO2) Nano-additive

This experiment produced biodiesel from corn oil through transesterification. Fuel mixture proportions were changed to assess engine performance and reduce fossil fuel emissions. This study examined brake power, mean effective pressure, mechanical efficiency, brake thermal efficiency and indicated thermal efficiency, and emissions such as hydrocarbons, carbon monoxide and NOx. 20% of corn oil was blended with diesel to make biodiesel. The fuel characteristics of the corn oil methyl ester matched ASTM standards. Experimental results were obtained by operating a single-cylinder four-stroke diesel engine under various load conditions. Titanium oxide nanoparticles in the biodiesel reduced HC and CO engine emissions whereas, there was an increase in CO2 and NOx emissions. Combustion parameters such as cumulative net heat release rate and fuel line pressure decreased whereas, cylinder pressure and net heat release rate increased; the sample BD20 + 100 ppm TiO2 sample exhibited appreciable results.

A Circular Economy Approach to Convert Waste Dairy Scum Oil into Biodiesel for the Development of Sustainable Environment

The present study is an effort to examine a technique for evaluating the expenses associated with the production of biodiesel from waste dairy scum oil in Pakistan, to create an economic assessment of this option. A survey was conducted on ten dairies in Gujrat to encourage them participation in the biodiesel supply chain. The survey aimed to collect data on waste dairy scum creation, disposal methods and quantity, as well as purchase cost. The waste dairy scum oil was extracted by solvent extraction method. Acetone solvent has been used to extract the waste dairy scum oil. A two-step acid treatment was done to reduce the FFA value of WDSO from 4.6 to 0.98 mg KOH/g. The independent variables of the transesterification process parameters including catalyst concentration, methanol to oil ratio, temperature, speed, and reaction time were kept 0.25 w/w, 8.50:1, 57.50℃, 600 rpm, and 1h respectively. The maximum biodiesel yield at these operating parameters was observed 93%. The economic feasibility of the conversion of WDSO into biodiesel was assessed using the information obtained from the surveys conducted by the different dairy’s owners. Approximately 70% of diaries produced scum and wanted to convert this waste dairy scum into biodiesel. The net biodiesel production cost was found to be 171 rupees. The logistic cost of biodiesel produced from the WDSO was found to be 22 rupees. The overall cost of 1L biodiesel would be 193 rupees. A two-way sensitivity analysis was performed to determine the profit of the conversion of the WDSO into biodiesel. The environmental analysis revealed that the emissions like CO, HC, and NOx significantly reduced during the combustion of biodiesel as compared to conventional diesel.

Effects of surface functional groups on the wettability of biodiesel combustion particulate matter

This paper investigates the impact of particle surface functional groups on the wettability of particulate matter (PM) emitted from biodiesel engines. Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectrometry (XPS), and Contact Angle Measurement techniques were employed to detect and analyze PM generated from combustion of diesel, soybean oil methyl ester (SME), palm oil methyl ester (PME), and waste edible oil methyl ester (WME) biodiesels. The results showed that PM derived from biodiesel exhibited a higher content of aromatic nuclei compared to that from diesel. The surface of the PM displayed significantly elevated levels of C–OH functional groups in comparison to CO functional groups, and the relative proportion of C–OH and CO functional groups on the biodiesel-derived PM surface decreased with an increase in biodiesel iodine value. The contact angles of the PM to the diesel droplets were less than 20°, and the PM is highly lipophilic. The wettability of the PM with both water and diesel droplets increased as the relative content of C–OH and CO functional groups rose. Moreover, it was observed that biodiesel-derived PM exhibited superior wettability towards water and diesel droplets when compared to its diesel counterpart, thereby enhancing its susceptibility to wetting by diesel droplets.

Cofiring of renewable biodiesel fuels inside natural gas flame for enhancement of thermal properties of flame and NOx reduction

AbstractThis 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%.

Analysis of Calophyllum Inophyllum Biodiesel Combustion with Variations of Magnetic Field Strength

The problems facing the world today are limited fossil fuels and increasing global warming due to fuel emissions. Therefore, there is a need to transition from fossil energy to alternative energy that is environmentally friendly and renewable. Biodiesel is an alternative material that can be used as a substitute for diesel fuel. This research aims to improve the combustion quality of calophyllum inophyllum biodiesel using the magnetic field influence method. The combustion test method uses a Bunsen burner and variations in magnetic strength of 4000 gauss, 8000 gauss and 12000 gauss are given. The equivalent ratios used in combustion analysis are 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1:1.1, and 1:1.2. The fuel and air flowing in the Bunsen pipe are heated to a constant temperature of 250°C for the fuel evaporation process. Then the resulting flame was analyzed for its combustion characteristics with RGB color variables, laminar burning velocity, and flame height. The research results show that the stronger the magnetic field effect, the more optimal the combustion quality will be. This is indicated by the increasingly strong magnetic field effect exerted on the flame, causing the red color intensity to decrease, the laminar burning velocity to increase, and the flame height to decrease. This is because the magnetic field can influence the movement of O2 molecules and cause a change in the orientation of the hydrocarbon from para to ortho. As a result, diffusion combustion becomes minimal and the combustion reaction becomes faster.

Evaluation of the effects of oxygen enrichment on combustion stability of biodiesel through a PSO-EMD-RBF model: An experimental study

<abstract> <p>In this study, we processed the flame images of biodiesel combustion in industrial furnaces, classified and evaluated flame states using digital image processing techniques, and proposed a combustion stability index (CSI) using the particle swarm optimization (PSO) algorithm. In order to more accurately predict the combustion stability under different oxygen concentrations, we proposed a method that combines the Multi-Input Radial basis function neural network (RBF-NN) with empirical mode decomposition (EMD). Initially, the EMD method was employed to decompose the original time series of CSI. Subsequently, a decomposition model incorporating initial parameters and CSI was established using the radial basis function. The results of the computations indicate that the EMD-RBF-NN model significantly outperforms existing models in enhancing the accuracy of CSI.</p> </abstract>

Numerical simulation of the combustion chamber and performance analysis of microalgae-based biodiesel/diesel-powered CI engine: An axisymmetric flow approach

This study presents a comprehensive analysis of the combustion chamber characteristics of a variable compression ratio compression ignition engine powered with microalgae biodiesel/diesel and their impact on engine performance and emissions. Both numerical and experimental methods have been employed to study the problem. A computational fluid dynamics method is used to study the axisymmetric flow in the cylindrical combustion chamber. Numerical simulations are obtained by solving time-independent steady, incompressible Navier-Stokes equation in a two-dimensional cylindrical coordinate system. Fluid flow characteristics, such as velocity vector field, streamlines, and pressure distribution are presented for different biodiesel blends. The velocity vector field analysis shows that biodiesel blends exhibit high velocities near the axisymmetric wall region. Swirl motion generated near the outer periphery of the combustion chamber influences the flow patterns. The experimental study involves the engine performance and its emissions. Due to the increase of biodiesel blend ratios in B20 (20% biodiesel and 80% diesel), B40 (40% biodiesel and 60% diesel), B50 (50% biodiesel and 50% diesel), and B100 (100% biodiesel), the brake thermal efficiency (BTE) decreases for a given brake power. B20, B100, and diesel exhibit 32.87%, 29.15%, and 34.45% BTE respectively. Higher brake-specific fuel consumption is obtained at no-load engine operations due to incomplete combustion of fuel. B20, B40, B50, and B100 show reductions of 16.04%, 20.85%, 25.66%, and 32.08% CO, respectively, as compared to diesel. HC emissions are very low for all biodiesel blends, while B20 exhibits a decrease of 7.35% HC compared to diesel. However, NOx emissions increase with the biodiesel blend ratio, with B100 exhibiting a 22.56% increase in NOx compared to diesel. Smoke emissions decrease with an increase in the biodiesel blend ratio, while B20 shows a 4.64% reduction. Results show that B20 offers a favorable balance between emissions reduction and engine performance. This study determines the biodiesel combustion characteristics and insights for the practical implementation of biodiesel blends in the transportation and energy sectors.

Characterization of Biodiesel and Diesel Combustion Particles: Chemical Composition, Lipid Metabolism, and Implications for Health and Environment.

Biodiesel, derived from alkyl esters of vegetable oils or animal fats, has gained prominence as a greener alternative to diesel due to its reduced particle mass. However, it remains debatable whether biodiesel exposure has more severe health issues than diesel. This study performed high-resolution mass spectrometry to examine the detailed particle chemical compositions and lipidomics analysis of human lung epithelial cells treated with emissions from biodiesel and diesel fuels. Results show the presence of the peak substances of CHO compounds in biodiesel combustion that contain a phthalate ester (PAEs) structure (e.g., n-amyl isoamyl phthalate and diisobutyl phthalate). PAEs have emerged as persistent organic pollutants across various environmental media and are known to possess endocrine-disrupting properties in the environment. We further observed that biodiesel prevents triglyceride storage compared to diesel and inhibits triglycerides from becoming phospholipids, particularly with increased phosphatidylglycerols (PGs) and phosphatidylethanolamines (PEs), which potentially could lead to a higher probability of cancer metastasis.

Investigating the fractal dimension of flame fronts of the biodiesel-diesel blends combustion in atmospheric conditions and engine cylinders: An experimental study

The fractal dimension of the flame front is an important parameter that quantifies the degree of flame folding and twisting as well as the instantaneous mass burning rate. Due to the geometric nature of flame surface folding, the fractal approach is also considered one of the most appropriate methods in power law modelling. Although biodiesel fuel is an important renewable fuel, studies on the fractal dimension of the flame during the combustion of biodiesel and its blends are limited. To address this research gap, combustion assays of biodiesel-diesel mixtures were systematically conducted within a coaxial diffusion burner and a diesel engine. High-resolution images of the evolving combustion flames were captured using a high-speed video camera. Digital image processing was applied to facilitate the extraction of key features from these images. Through the differential box counting (DBC) method, the fractal dimensions of the flame fronts were derived. A comprehensive analysis was carried out, revealing the influence of various parameters on the flame's fractal dimensions, including the biodiesel-diesel blend proportion, blend temperature, engine operational speed, and air flow rate. The results highlight that the fractal dimension undergoes a non-monotonic variation as biodiesel content increases. Specifically, the combustion of B25 blend exhibited the minimum fractal dimension, while the B100 blend showed the maximum. Further, in engine environments, peak fractal dimensions were observed to occur earlier at higher speeds (2200 r/min) with an increase in the biodiesel ratio. These insights not only bridge a critical knowledge gap in power-law modeling for biodiesel combustion but also offer a quantitative understanding of how blend ratios and engine conditions affect flame fractal properties.

Effect of phospholipids on the oxidative reactivity and microstructure of soot particles from Jatropha biodiesel combustion

Excessive phosphorus content can aggravate the formation and emission of particulate matter (PM) during biodiesel combustion, which can lead to the performance degradation of automobile exhaust catalytic converters and make it difficult to control pollutant emissions. However, the influential mechanism of phosphorus in biodiesel on PM formation is not clear yet. Therefore, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy are used to study the formation, oxidation characteristics, and nanostructures of soot particles produced from Jatropha biodiesel (JB100) combustion under different phospholipid (PE:phosphatidylethanolamine, main phospholipid type in JB100) contents. The results show that with increasing PE content in JB100, the amount of soot particles first increases and then decreases. When the PE content is 400 ppm, the amount of soot particles is the largest, almost 13.40% higher than that produced from neat JB100. Further, the activation energy (AE) of soot oxidation first increases and then decreases with increasing PE content. The apparent AE is the largest (131.40 kJ/mol) at 400 ppm. Furthermore, when the PE content is 400 ppm, the strength of oxygen-containing functional groups in the soot particles is the weakest, and the ratio of nanocrystal height to polycyclic aromatic hydrocarbons (PAHs) interlayer spacing (Lc/d002) (4.396), the average lattice spacing of PAHs (0.367 nm), and the ratio of D1 and G peaks integral intensity (ID1/IG) (2.566) are minimum. This verifies that the PE content in JB100 can affect the strength of active oxygen-containing functional groups and the size and structure of PAHs in the soot particles and that the oxidative reactivity of soot particles is lowest at 400 ppm.