The addition of Al2O3 nanoparticles to a diesel engine improves the efficiency of biodiesel (2023)

With population growth and economic growth, the world's demand for energy continues to grow. By 2040, energy demand in non-OECD countries will reach 64% of the 739 trillion British thermal units [1, 2]. Similar to Indonesia, domestic energy demand is expected to increase by an average of 3.5%. Demand for each type was dominated by heating oil, which grew on average by 2.8% annually. This is because fuel technology devices are still more cost-effective than those using other energy sources, especially in transport, industry, trade and energy [3].

In the field of transportation, the number of motor vehicles in Indonesia is increasing year by year. According to the data of the Central Statistical Office for 2021, the number of motor vehicles in Indonesia is 143,797,227 compared to 136,137,451 in 2020 [4]. This causes greenhouse gas (GHG) emissions. Actual greenhouse gas emissions in 2020 are 1.0504 billion tons of CO₂e[5]. The impact of greenhouse gases is a serious problem worldwide. One attempt to reduce vehicle emissions is the use of biofuels as environmentally friendly alternatives, such as biogas [6], bioethanol [7] and biodiesel [8]. Biodiesel has environmental benefits such as CO levels₂The emissions of the produced exhaust gases are 72% lower than in the case of diesel fuel, they are non-toxic, renewable, do not contain sulfur and are environmentally friendly [9]. Biodiesel is already used in many countries as a blend with diesel fuel. As of 2020, Indonesia uses a biodiesel called B30 (30% diesel/biodiesel blend) according to Presidential Decree no. 22/2017 [10, 11].

The use of biodiesel in vehicles also has many advantages, including improved combustion efficiency and reduced carbon monoxide (CO) emissions [12]. Biodiesel does not contain sulfur or aromatic compounds that contribute to the increase in exhaust emissions from diesel engines [13] and increases the cetane number, which shortens the ignition delay time [14]. Biodiesel blends, even biodiesel, after minor modifications can be used in diesel engines [15], and biodiesel improves lubricity, thus extending the life of engine components [16]. However, biodiesel has several disadvantages compared to diesel: low calorific value, low volatility and high viscosity [17]. Low volatility and high viscosity can lead to superdetonation [18].

Performance and emission studies of B30 biodiesel have already been investigated. This study compared several diesel fuels, including B30 biodiesel and diesel fuel. The results of this study showed that CO₂B30 biodiesel has lower emissions than diesel. This is due to the low sulfur content of B30. However, the power and torque seem to be lower than in the case of diesel oil [19]. This is due to the poor atomization of the fuel due to the high viscosity of biodiesel [20]. In other studies, it has been explained that the high viscosity of B30 increases the ignition delay compared to diesel [21].

One attempt to reduce the weakness of biodiesel is to use additives to overcome the high viscosity. Earlier studies used the addition of potassium hydroxide (KOH) added to biodiesel. Parsley oil with a viscosity of 14.9 mm was used for the tests²/s, with the addition of KOH the viscosity decreases to 4.77 mm²/Other. This value is in accordance with ASTM D6751 [22]. Viscosity value reduction was also performed using Ni/zeolite additives [23]. With a decrease in the viscosity value, the volatility value will be high [24]. The use of copper oxide₂The nanoparticle additive increases the calorific value by up to 6% compared to that without CuO₂Nanoparticle additives mixed with B20 biodiesel [25]. Using the same basic additives, nanoparticles and aluminum₂Europa₃Cylinder pressure and heat release rate were reported to be 6% and 13% higher for type B20 compared to B20 without Al₂Europa₃connection. In addition, specific fuel consumption was reduced by 7.3%, thermal efficiency was increased by 4.7%, and the calorific value of the highest concentration was increased by 6% compared to B20 without additives [26]. This is due to the high content of oxygen present in biodiesel blends and nanoparticles, where oxygen supports a better combustion process [27]. There are several types of nanoparticles, Al₂Europa₃Compared to other types, it is the best type due to the smallest size of the subsequent droplet and better reduction of fuel consumption [28].

Based on several previous studies, it can be concluded that the addition of nanoparticle additives can improve the properties of biodiesel. However, several parameters such as engine performance, combustion characteristics and smoke opacity are little discussed, especially when B30 is used. In this study, the addition of Al nanoparticles₂Europa₃B30 fuel is used to test engine performance, combustion characteristics and emissions. This test is designed to investigate combustion characteristics such as net heat release and cylinder pressure. Engine performance such as brake thermal efficiency and fuel efficiency. Check the transparency of the show.

Various test samples were used in the study, including biodiesel B30, B30+Al₂Europa₃30 ppm, B30+Al₂Europa₃50 ppm, B30+Al₂Europa₃70 ppm, B30+Al₂Europa₃90 ppm Each sample was tested on a diesel engine. GC-MS (Gas Chromatography and Mass Spectrometry) and FTIR (Fourier Transform Infrared Spectroscopy) were also performed to determine compound levels in the fuel samples.

2.1 Experimental device

A 3.5kW diesel engine was used in this study, and engine specifications are shown in Table 1. Using multiple sensors in the engine, the computer automatically collects engine performance and combustion efficiency data via the IC-Engine application. Engine loads of 3, 5, 7 and 9 kg were used at a compression pressure of 16:1. Use an OPA-100 connected to a computer to download emission turbidity data. Data were collected 3 times for each sample to reduce data collection errors. The scheme of the experiment is shown in Figure 1.

picture 1.experimental settings

Table 1.engine settings

The work presents the effect of mixing B30 with Al₂Europa₃The nanoparticles are then tested for engine performance, combustion efficiency and smoke opacity. GC-MS and FTIR tests are also available to determine compound levels in fuel samples. Table 3 shows the properties of fuel samples. All B30+Al grades with mixed viscosities₂Europa₃Increased compared to B30. Viscosity values ​​are in accordance with ASTM D6751.

Table 3.Properties of the fuel sample

3.1 Fourier transform infrared chromatography and gas chromatography-mass spectrometry

3.1.1 B30

Based on the functional groups, the chemical composition of B30 was analyzed by FT-IR as shown in Figure 3. The detection frequency is 3464.15 1/cm and the stretching area of ​​N-H and N bonds is between 1598.99-1531.48 1/cm in the amide region. The frequency of 2924.09-2854.65 1/cm has a C-H stretch in the alkane and alkyl region, frequencies of 1460.11-1375.25 1/cm and 721.38 1/cm are in the same region, but the type is a CH bond The C=O stretching in ketones and esters has a frequency of 1745.58 1/cm, a frequency of 1168.86 1/cm in the alcohol C-O stretching region and a C-I stretching frequency of 351.04 1/cm in the alkyl halide region.

The content of individual compounds in B30 fuel is shown in Figure 4. They contain 9-octadecanoic acid 6.67%, docosane 10.26%, dodecane 2.57%, eicosane 3.18%, heptadecane 3.29%, hexadecane 3.83 %, hexadecanoic acid 17.42%, naphthalene 2.18%, 3.05% nonadecane, 2.67% octadecane, 4.54% octadecane, 1.9% pentadecane, 9.36% pentadecane, 3.36% tetradecane , 1.74% myristic acid, tridecane 4.45%, 9,12-octadecanoic acid 3 0.90%, 10-octanoic acid 15.63%. and several other compounds less than 1%.

3.1.2 Aluminium B30+₂Europa₃nanoparticles

Chemical composition B30+Al₂Europa₃The nanoparticles based on their functional groups were analyzed by FT-IR as shown in Figure 5. The detection frequency is 3464.15 1/cm, which is the N-H stretching area of ​​the amide, and the frequency is 1602.85-1539.20 of the N-H region of the amide bond, and the frequency is 2924.09-2854.65 1/cm, corresponding to the C-H stretching of the alkane and alkyl regions. 1460.11-1375.25 1/cm is the C-H bonding region of alkanes and alkyls, frequency 1745.58 1/cm is the C=O stretching region of ketones and esters, frequency is 1168.86 1/cm is the C-O stretching region of alcohols, frequency is 356.83 1/cm is the alkyl halide in the stretching zone C-I.

The content of the B30+Al mixture₂Europa₃The nanoparticle fuel can be seen in Figure 6, i.e. these are the compounds: 13-octadecenoic acid 16.82%, docosane 2.86%, 9,12-octadecadienoic acid 2.95%, benzene 1.98%, biphenyl 1.12%, docosane 2.85%, dodecane 3.41%, eicosane 1.99%, eicosane 1.33%, hexadecane 5.48%, hexadecanoic acid 14.01%, naphthalene 16.58%, nonadecane 1.96%, octadecane 1.85%, octadecanoic acid 3.31%, pentadecane decanoate 1.15%, pentadecane cane 4.90%, tetradecane 1.31%, tetradecane 2.59%, myristic acid 1.18% and partly undecanoic acid 4, 7% 1.18% partly 4% undecane 1.18%, other contents below 1% compounds.

The FT-IR and GC-MS studies show that hexadecane (C16H34) is a compound affecting fuel quality, which is closely related to the determination of diesel fuel quality [29]. Cetane compounds are blended with nanoparticles to produce a 5.48% higher percentage of fuel compared to B30 which is around 3.83%.

photo 3.Biodiesel FTIR B30

Figure 4.GC-MS biodizel B30

Figure 5.Infrared spectrum B30+Al₂Europa₃nanoparticles

Figure 6.GC-MS B30+Al₂Europa₃nanoparticles

3.2 Fuel consumption indicator

Specific fuel consumption (SFC) is an important parameter reflecting engine performance [30]. Figure 7 shows the SFC for the motor load. With a load of 3 kg, the value of B30+Al₂Europa₃30 ppm is 43% less than B30, which has an SFC value of 0.71 kg/kWh. However, with a load of 5 B30+Al₂Europa₃70 ppm fuel has the lowest SFC value of around 25% compared to B30. With a load of 7 kg, the B30 fuel value has the highest SFC value compared to all B30+nano fuel blends, and the SFC value of B30 is approximately 25% higher than B30+Al₂Europa₃70 ppm of fuel oil. With a load of 9 kg, the value of SFC B30+Al₂Europa₃Fuel with 90 ppm content is the lowest at 0.23 kg/kWh, which is about 41% less than B30. Among all load variations, the SFC of pure B30 fuel was consistently higher than that of the B30+nano fuel blend. This is because the mixture of fuel and nanoparticles has a low viscosity value to prevent poor atomization. Due to the large size of the fuel droplets, poor atomization makes it difficult to burn the atomized fuel [31]. Air-fuel mixing and combustion are improved due to the presence of nanoparticles. Nanoparticles have reactive surfaces that contribute to their reactivity as potential catalysts. The presence of nanoparticles in biodiesel blends increases the surface area to volume ratio, resulting in better catalysis and better combustion, resulting in lower fuel consumption [32-34].

Figure 7.Specific fuel consumption at different engine loads

3.3 Net Heat Release

Net heat release (NHR) has a large impact on the course of the combustion process, and a high value of NHR will accelerate the time of fuel combustion, thus reducing fuel consumption [35]. Figure 8 shows the NHR to the crank angel under a 5 kg load. The NHR value of the B30 fuel was 21.02 J/deg, which is lower than that of the B30+nanoparticle fuel mixture. Top NHR B30+Al₂Europa₃34.54J/deg at 30ppm, B30+Al₂Europa₃50 ppm is 35.31 J/degree, B30+Al₂Europa₃70 ppm, i.e. 36.21 J/degree, B30+Al₂Europa₃90 ppm is 30.7 J/deg. The NHR is 41% higher than the NHR B30 value. This may be due to better fuel atomization, better fuel-air mixing, and a high surface-to-volume ratio of air-reactive nanoparticles. It should be noted that metal oxides are useful as fuel additives due to their thermal conductivity. The good thermal conductivity of the nanoparticles enables faster heat transfer in the fuel droplets, allowing the fuel to burn quickly. Smaller particle sizes are more effective in increasing the thermal conductivity of nanoparticles because the surface area to volume ratio of the particles increases with decreasing particle size [36-38].

Number 8.Net heat release at the angle of the knee

3.4 Cylinder pressure

The self-ignition process depends on the pressure and heat in the cylinder, the higher the cylinder pressure, the faster the fuel burns [39]. Figure 9 shows the relationship between cylinder pressure and crankshaft angle at an engine load of 5 kg. Compared to the higher blend of B30+ nanoparticles, the B30 fuel achieved a peak cylinder pressure of 43.27 bar. B30+Al cylinder pressure₂Europa₃30 ppm i 49,7 bara, B30+Al₂Europa₃50 ppm i 43,77 bara, B30+Al₂Europa₃70 ppm at 47.63 bar and B30+Al₂Europa₃90 ppm is 50.08 bar. mixture of fuel and aluminum₂Europa₃Nanoparticles increase cylinder pressure by 13%. This is due to the fact that the thermal conductivity of nanoparticles increases the rate of evaporation of fuel droplets, and a greater supply of fuel to oxygen, a higher surface-to-volume ratio and a low viscosity value enable rapid combustion of fuel in mixtures containing nanoparticles [40]. ].

Figure 9.The pressure in the cylinder at the angle of the crankshaft

3.5 Brake thermal efficiency

The thermal efficiency of braking (BTHE) is the ratio of the energy contained in the braking power to the energy of the input fuel in appropriate units [30]. The BTHE values ​​of the mixture of B30 concentration and nanoparticles at each load are shown in Figure 10. Under a load of 3 kg, the BTHE value of pure B30 reaches 14.54%, which is less than the value of B30+Al₂Europa₃30 ppm, of which the highest BTHE value is 25.06%. Motor load 5kg has BTHE B30+Al₂Europa₃70 ppm, which is more than all fuel blends with B30+ nanoparticles, and the BTHE value for B30 reached only 19.86%. The lowest BTHE B30 value was 23.11% with a load of 7 kg compared to the fuel mixture B30 + nanoparticles. With a motor load of 9 kg, the highest BTHE value is B30+Al₂Europa₃90 ppm As can be seen from all engine load changes, the B30 + nanoparticles fuel mixture has a higher BTHE value than B30. This is because nanoparticles increase cylinder pressure and reduce fuel consumption. The addition of nanoparticles helps to disperse fuel droplets and disperse injected fuel. Nanoparticles have reactive surfaces that contribute to their reactivity as potential catalysts. Air-fuel mixing and combustion are improved due to the presence of nanoparticles. The addition of nanoparticles improves the dispersion of fuel droplets and the dispersion of the injected fuel. The addition of smaller droplets of nanoparticles, lower fuel viscosity and larger effective fuel surface [41].

Figure 10.Thermal efficiency of the brake at various engine loads

3.6 Neprozirnost dima

Figure 11 illustrates the change in smoke opacity with load. Smoke transparency increases with engine load. It was observed that with a load of 3 kg, the smoke value of B30 fuel was about 79% higher than that of B30+Al₂Europa₃90 ppm Opacity value B30+Al₂Europa₃50 ppm under a load of 5 kg is 4.5%, about 65% less than B30 fuel. The percentage of opacity of each fuel was relatively constant and amounted to 5, 7 and 9 kg, where B30+Al₂Europa₃30ppm over all types of fuels. Compared to 50 ppm B30+Al, smoke values ​​for B30 fuel were approximately 64% higher at 7 kg load and 79% higher at 9 kg load₂Europa₃. All load variations show that the opacity values ​​of a fuel mixture containing B30+ nanoparticles are usually lower than those of B30 fuel. This can occur as a result of microbursts resulting in smaller and flammable fuel atomized droplets [42], better atomization [43], more molecular oxygen and lower carbon content in the fuel (compared to B30 in comparison), resulting in better combustion. Emissions are immediately reduced due to burning more fuel during the combustion process and shortening the combustion time for better combustion [33].

Figure 11.Exhaust gas opacity at various engine loads

The addition of nanoparticles improves diesel engine performance and emissions when mixed with B30 fuel. mixture of fuel and aluminum₂Europa₃Nanoparticles increase cylinder pressure by 13%. The net heat release is an increase of 41% compared to the NHR B30 value of 21.02 J/°. Changes in brake thermal efficiency under the influence of nanoparticles contained in B30. The BTHE value of the fuel mixture B30 + nanoparticles is higher than B30. Smoke values ​​from all load changes show that the fuel mixture with B30+ nanoparticles is lower than B30 fuel. Among all load variations, the SFC of the B30 fuel was consistently higher than that of the B30+nano fuel mixture.

The future regulatory implications of this research will be applied to biodiesel before it is sold to consumers. This research therefore contributes to reducing the impact of greenhouse gases on the environment and reducing the consumption of fossil fuels. In this work, the stability of the mixture of nanoparticles and B30 fuel was not investigated. As a suggestion for further research, the stability of nanoparticles should be investigated to determine how long a mixture of nanoparticles can be stable on fuel.