Evaluation of Dimethyl Carbonate as Alternative Biofuel. Performance and Smoke Emissions of a Diesel Engine Fueled with Diesel/Dimethyl Carbonate/Straight Vegetable Oil Triple Blends

Investigation and prediction on emissions and performance of CI engine employing binary and ternary blends with Karanja oil, used cooking oil, and Dunaliella salina oil

Massive consumption of fossil fuels and alarming environmental degradation are motivating researchers to learn about alternative fuels. Straight vegetable oils are an alternative to fossil fuels to meet the standards. Microalgae is also a viable carbon-neutral alternative to depleting conventional fuel sources, a solution to the industrial requirement of organic consumables and an option for a green and sustainable economy for biofuels. In the present study, lipid was extracted from Karanja seeds and Dunaliella salina biomass. These were used to prepare different binary and ternary fuel blends with conventional reference diesel fuel with different proportions along with used cooking oil with their concentrations ranging from 10 to 20% (v/v). The influence of these blends on performance and emissions characteristics in CI engines has delved at varying engine loads from 0 to 100%. The binary blend with Dunaliella salina oil has increased the performance characteristics while decreasing all the major emission parameters compared to reference diesel fuel and shows a significant improvement among binary blends. Ternary blends with Dunaliella salina oil, on the other hand, have improved performance while lowering emission parameters when compared to reference diesel fuel and demonstrate a substantial improvement across ternary blends. For predicting the performance and emission characteristics of binary and ternary blends, an artificial neural network-based model was developed. The optimum blends, OB6 (90% RDF, 10% DO) and OB8 (80% RDF, 10% DO, 10% UCO), improved BSFC by 10.71%, BTE by 14.23%, and reduced BSEC by 12.45% at full load. Emissions were generally reduced, with CO2 decreasing by up to 39.39%. The simulation results demonstrated that the created 4-7-7 model was capable of accurately predicting the performance and emission characteristics of various alternative fuel blends and indicating a stronger correlation between the predicted and observed values, having a high correlation coefficient of 0.9974. Binary and ternary blends with straight vegetable oils improved CI engine performance and pollutants compared to reference diesel fuel, indicating they have the potential to replace conventional fuels for sustainable development.

Effect of adding dimethyl carbonate and gasoline to diesel fuel + corn oil blend on performance and combustion characteristics of a diesel engine

Diesel fuel and corn oil are mixed in the 80:20 volumetric ratio. Dimethyl carbonate and gasoline are added to diesel fuel + corn oil blend in 4:96, 6:94, 8:92, and 10:90 volumetric ratios to obtain ternary blends. Effects of ternary blends on the performance and combustion characteristics of a diesel engine are investigated under different engine speeds (1000-2500 rpm). 3D Lagrange interpolation method is applied to measured data of dimethyl carbonate blends to predict the engine speed, blending ratio, and crank angle giving maximum peak pressure and peak heat release rate. On average, dimethyl carbonate blends and gasoline blends show 4.3642-12.1578% and 1.0323-8.6843% reduction in effective power, and 1.4938-3.4322% and 4.3357-8.7188% reduction in effective efficiency, respectively, relative to diesel fuel. On average, there is a reduction in cylinder peak pressure (4.6701-7.3418%; 4.0457-6.2025%) and peak heat release rate (0.8020-4.5627%; 0.4-1.2654%) for dimethyl carbonate blends and gasoline blends, respectively, compared to diesel fuel. Because of low relative errors (1.0551% and 1.4553%), 3D Lagrange provides well accuracy in the prediction of maximum peak pressure and peak heat release rate. On average, dimethyl carbonate blends produce less CO (7.4744-17.5424%), HC (15.5410-29.5501%) and smoke (14.1767-25.2834%) emissions, compared with diesel fuel.

Advanced Biofuels from ABE (Acetone/Butanol/Ethanol) and Vegetable Oils (Castor or Sunflower Oil) for Using in Triple Blends with Diesel: Evaluation on a Diesel Engine

From a technical and economic point of view, our aim is to provide viable solutions for the replacement of fossil fuels which are currently used in internal combustion diesel engines. In this research, two new biofuels composed of second-generation vegetable oils (SVO),used oil sunflower (SO) or castor oil (CO), and the ABE blend (acetone/butanol/ethanol) were evaluated. ABE is an intermediate product from the fermentation of carbohydrates to obtain bio-butanol. Besides, the ABE blend exhibits suitable properties as biofuel, such asvery low kinematic viscosity, reasonable energy density, low autoignition temperature, and broad flammability limits. Diesel/ABE/SVO triple blends were prepared, characterized and then, tested on a diesel engine, evaluating power output, consumption, and exhaust emissions. The power output was slightly reduced due to the low heating values of ABE blend. Also, engine consumed more fuel with the triple blends than with diesel under low engine loads whereas, at medium and high loads, the fuel consumption was very similar to that of diesel. Regarding exhaust gas emissions, soot wasnotably reduced, and nitrogen oxides (NO_x) and carbon monoxide (CO₂) emissions were lower or comparable to that of diesel, while the CO emissions increased. The use of these biofuels allows the replacement of high percentagesof diesel without compromising engine power and achievinga significant reduction in pollution emissions. Furthermore, a notable improvement in cold flow properties of the fuel blends is obtained, in comparison with diesel.

Biodiesel Is Dead: Long Life to Advanced Biofuels—A Comprehensive Critical Review

Many countries are immersed in several strategies to reduce the carbon dioxide (CO2) emissions of internal combustion engines. One option is the substitution of these engines by electric and/or hydrogen engines. However, apart from the strategic and logistical difficulties associated with this change, the application of electric or hydrogen engines in heavy transport, e.g., trucks, shipping, and aircrafts, also presents technological difficulties in the short-medium term. In addition, the replacement of the current car fleet will take decades. This is why the use of biofuels is presented as the only viable alternative to diminishing CO2 emissions in the very near future. Nowadays, it is assumed that vegetable oils will be the main raw material for replacing fossil fuels in diesel engines. In this context, it has also been assumed that the reduction in the viscosity of straight vegetable oils (SVO) must be performed through a transesterification reaction with methanol in order to obtain the mixture of fatty acid methyl esters (FAMEs) that constitute biodiesel. Nevertheless, the complexity in the industrial production of this biofuel, mainly due to the costs of eliminating the glycerol produced, has caused a significant delay in the energy transition. For this reason, several advanced biofuels that avoid the glycerol production and exhibit similar properties to fossil diesel have been developed. In this way, “green diesels” have emerged as products of different processes, such as the cracking or pyrolysis of vegetable oil, as well as catalytic (hydro)cracking. In addition, some biodiesel-like biofuels, such as Gliperol (DMC-Biod) or Ecodiesel, as well as straight vegetable oils, in blends with plant-based sources with low viscosity have been described as renewable biofuels capable of performing in combustion ignition engines. After evaluating the research carried out in the last decades, it can be concluded that green diesel and biodiesel-like biofuels could constitute the main alternative to addressing the energy transition, although green diesel will be the principal option in aviation fuel.