A study on alcohol acid compound mixed with biodiesel as alternative biofuel for diesel engine

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In order to reduce the harmful effects on the environment, researchers around the world must find ways to reduce emissions. For this reason, the EU allows the use of biofuel mixtures as fuel for internal combustion engines.

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International Journal of Mechanical Engineering and Technology (IJMET) Volume 10, Issue 03, March 2019, pp. 392–403, Article ID: IJMET_10_03_040 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=3 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed A STUDY ON ALCOHOL ACID COMPOUND MIXED WITH BIODIESEL AS ALTERNATIVE BIOFUEL FOR DIESEL ENGINE Chang Chun Xu and Haeng Muk Cho Division of Mechanical and Automotive Engineering, Kongju National University (KUN) 275, Budae-dong, Cheonan-si, Chungcheongnam-do 331-717, South Korea ABSTRACT In order to reduce the harmful effects on the environment, researchers around the world must find ways to reduce emissions. For this reason, the EU allows the use of biofuel mixtures as fuel for internal combustion engines. Therefore, an alternative has been made in this study. Since biodiesel is used in experiments for the effect of internal combustion engines on emission concentrations, it shows uncertain results. Due to the performance of biofuels, such as combustion delays, injection times, fuel types, etc., for this reason, researchers have tried to add some alcohol compounds to biofuels for investigation. Because biodiesel type of biofuel material has some FAME (fatty acid methyl ester), it has some effects, such as high density and low calorific value, although it has better emissions and reduced lubricity compared to pure diesel. But if biofuel additives and alcoholic acid compounds affect the biofuel diesel ratio and diesel injection time on combustion, performance and emissions. In this paper, emissions of CO, CO2, NOX and unburned hydrocarbons are measured. Key words: Alcoholic Acid Compound, Internal combustion engine, Exhaust emission, Performance and Biofuel. Cite this Article: Chang Chun Xu, Haeng Muk Cho, A Study on Alcohol Acid Compound Mixed with Biodiesel as Alternative Biofuel for Diesel Engine, International Journal of Mechanical Engineering and Technology 10(3), 2019, pp. 392–403. http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=3 1. INTRODUCTION During the operation of internal combustion diesel engines, a large amount of fossil fuel is consumed, so they pose a threat to the environment in terms of pollutant emissions. In the past few decades, the depletion and volatility of fossil fuels has led to a global concentration of energy to find and find alternative fuels. Biofuels are one of the liquid fuels that can be used in diesel engine vehicles. Whether the biofuel initially produced is produced directly from food crops by fermentation (eg bioethanol) or transesterification as biodiesel [1]. The second method of biofuel power generation is produced from agricultural products and some waste such as wood, straw, corn and specific biomass crops, thus avoiding global concerns about http://www.iaeme.com/IJMET/index.asp 392 editor@iaeme.com
Chang Chun Xu, Haeng Muk Cho food prices and scarcity. Due to their source derivatives, the important role of using this biofuel can replace the petroleum fuel of internal combustion engines. Since the main advantages of biofuels are regenerability, emissions from combustion and biodegradability [2]. The use of alcohol (ethanol, methanol) and its mixture with diesel is another current research model. When mixed with diesel, the alcohol, especially ethanol, becomes a hygroscopic mixture, causing the fuel injector to become clogged. The use of biodiesel in a diesel-ethanol mixture results in no stratification, paving the way for a ternary fuel mixture known as an alcohol-diesel-biodiesel mixture, and reports many work with alcohol-diesel- biodiesel fuel mixtures [1]. Due to the high viscosity, low volatility and flammable diesel properties, it is difficult to prepare a homogeneous premixed diesel/air mixture prior to ignition. Thus conventional diesel combustion processes are mixed controlled diffusion combustion, and high NOx and particulate matter can be generated due to high temperatures and locally enriched regions that can affect engine exhaust emissions. As with the researchers, it is important that the reduction in NOX and soot emissions form a fairly uniform charge prior to ignition. Therefore, by research, alcoholic acid compounds are widely used in various alcohol substitutes because of their improved volatility and latent heat. Therefore, the mixture can be displayed in the engine as ethanol - biodiesel - diesel and methanol - biodiesel - diesel. Even though various literatures focus on the development of ternary mixtures as alternative materials, these have several disadvantages, such as phase separation, reduced calorific value of mixtures with higher ethanol concentrations, and unreliability in storage and transportation. And the use of a mixture of biodiesel can add alcohol which is very useful for reducing the viscosity and density of biodiesel, which is higher than standard mineral diesel. And when the fuel is a diesel engine, the alcohol additive increases combustion efficiency and produces lower exhaust emissions. Compared to pure diesel, the oxygen content of ethanol and methanol is about 35% and 30% higher, and due to high oxygen and high carbon number, diesel engines can help diesel engines achieve higher complete combustion, thereby reducing ignition delay. As for the combustion effect, carbon monoxide and carbon dioxide emissions can be reduced due to high oxygen [3]. Alcohol is a liquid fuel that can be used in internal combustion engines [1]. The alcohol as a fuel additive can be combined with a proportion of petroleum-based diesel, biodiesel and diesel/biodiesel fuel mixtures to provide combustion as a fuel. At the same time, research on the application of alcohol/diesel/biodiesel fuel mixtures has been carried out in the literature. It has been pointed out that the viscosity and surface tension of the fuel and the alcohol as additives are reduced while improving atomization and increasing the oxygen content. On the other hand, low calorific value and cetane number, poor ignition quality, miscibility of the alcohol and its own stability problems can limit the use in diesel engines. Alcohol is used as an additive component of the fuel mixture in important processes to address fuel source problems. In previous studies, methanol and ethanol as lower alcohols have been studied as alternative fuels for diesel engines in the literature. Butanol and pentanol are good fuel additives or attractive alternative fuels for diesel engines [3]. They have many advantages over lower alcohols, such as higher cetane number and calorific value, and lower heat of vaporization. Therefore, recent research on the use of butanol and pentanol in diesel engines has increased [2]. Butanol, also known as n-butanol, n-butanol or butanol, is an alcohol that is available from renewable sources. It is colorless and transparent and immiscible with water. Butanol has a moderate non-permanent odor. It has been used as a solvent in the fields of plastics, cosmetics, coatings and foods, mainly for the production of isobutyl acetate. In addition, it http://www.iaeme.com/IJMET/index.asp 393 editor@iaeme.com
A Study on Alcohol Acid Compound Mixed with Biodiesel as Alternative Biofuel for Diesel Engine can be added to materials used for rust and abrasion. Butanol is a toxic alcohol. It tends to burn. The calorific value of butanol is lower than that of diesel, and the heat in diesel can be as high as 40%. In addition, the properties of butanol are very close to diesel fuel[3]. Pentanol is also known as n-pentanol, n-pentanol or pentanol. It can be made from renewable raw materials. Pentaerythritol has a higher cetane number and energy content than other alcohols. Up to 45% can be used by adding diesel fuel[8]. Worldwide, there are many studies on the analysis of engine performance, combustion and exhaust emissions characteristics of diesel engines using different fuels (eg biodiesel, diesel, biodiesel/diesel blends, alcohol/biodiesel/diesel blends, etc.). On the other hand, the number of studies on the use of butanol and pentanol in diesel engines is limited[8]. So some of these studies were summarized follow below: Zhu et al. [11] analyzed the emission and combustion characteristics of a four-cylinder four-stroke diesel engine fueled by a waste cooking oil biodiesel-pentanol mixture. They detected the onset of fuel combustion and removed the maximum exothermic crank angle from top dead center. As the proportion of pentanol in the fuel mixture increased, the pressure and heat release rate in the cylinder increased. Although the hydrocarbon (HC) and CO emissions of the fuel mixture have improved, NOx emissions are more severe. Atmanli et al. [12] used n-butanol and crude rapeseed, soybean, sunflower, corn, olive and hazelnut oil to make a vegetable oil- microemulsification of a diesel fuel mixture. 70% diesel fuel, 20% vegetable oil and 10% n- butanol mixture are fully loaded in a four-cylinder four-stroke turbocharged direct injection diesel engine with various engine speeds. The experimental results show that braking torque, braking power, braking thermal efficiency (BTE), braking average effective pressure (BMEP), exhaust gas temperature (EGT), HC and CO reduction, and braking ratio fuel consumption (BSFC), NO and CO increase compared to diesel fuel.Imdadul et al. [13] analyzed the addition of 10%, 15% and 20% of Tamani oil biodiesel and pentanol to diesel fuel and examined the engine performance of a single-cylinder water-cooled diesel engine operating with test fuel and Exhaust emissions. According to B20 fuel, BSFC values, smoke opacity, CO, HC and CO2 emissions of alcohol blended fuels decreased by 8.7, 21.2, 33.1, 43, 45 and 2.5%, respectively. However, thermal efficiency, braking power and NO emissions increased by 15%, 10.4% and 4.4%, respectively. Imdadul et al. [14] produced biodiesel from Tamani oil by transesterification and mixed 15% and 20% by volume with conventional diesel fuel. Butanol and pentanol in a ratio of 15% and 20% were added to the mixed fuel. All test fuels are placed in a single cylinder four stroke direct injection diesel engine. It was finally determined that adding alcohol would reduce BSFC values, increase braking power, NO and CO2 emissions, and reduce CO and HC emissions compared to B15 and B20 fuels.Ibrahim [15] studied the effects of 10% and 20% butanol addition in biodiesel-diesel fuel mixtures on engine performance, exhaust emissions and combustion characteristics of single-cylinder diesel engines. During the course of the study, the addition of up to 20% butanol resulted in certain changes in engine performance, exhaust emissions and combustion characteristics. On the other hand, they found that it was necessary to optimize the diesel engine using butanol, and the change in fuel type had no significant effect on the combustion period.Wei et al. [16] found that the addition of pentanol and fuzzy increase NOx emissions, and increased braking power, reducing CO and HC emissions.Mehta et al. [17] reported that by adding n-butanol to the mixture, HC emissions increased while CO and smoke emissions decreased.Kumar and Saravanan [18] comprehensively reviewed the use of higher alcohols in diesel engine applications. They point out that the replacement of diesel fuel in whole or in part with higher alcohols in compression-ignition engines has been found to be generally successful because higher alcohols reduce conditioning emissions and increase efficiency.Yilmaz et al. [19] studied the effects of adding 5%, 10% and 20% butanol to waste http://www.iaeme.com/IJMET/index.asp 394 editor@iaeme.com
Chang Chun Xu, Haeng Muk Cho cooking oil biodiesel on the performance and emission characteristics of indirect injection diesel engines. Compared to biodiesel fuels, it was determined that EGT and NOx emissions decreased with the addition of butanol, but CO and HC emissions increased. In addition, the fuel mixture has a higher BSFC value than diesel fuel.Ozer [20] compares the engine performance and exhaust emissions of diesel engines for diesel engines by adding 3, 5, 8 and 10% butanol to diesel at different engine loads. The results indicate that the BSFC increases due to an increase in the proportion of butanol in the fuel mixture. Although thermal efficiency and EGT are reduced. It has also been found that CO, NOx and smoke opacity are reduced, although CO2 and HC emissions are increased.Li et al. [21] have different emissions and combustion characteristics for single-cylinder direct-injection diesel engines under various engine loads and constant speeds of 1600 rpm, adding the effect of adding pentanol to biodiesel and diesel fuel. As a result of the experiment, a 40% diesel-30% biodiesel-30% pentanol mixture exhibited better combustion and emissions data as well as engine performance.Keskin et al. [22] tested diesel engine fuel with two different fuel mixtures. This shows that the use of a fuel mixture reduces engine torque and power values compared to conventional diesel fuel. In addition, they showed a slight increase in NOx emissions, but smoke opacity, CO and HC emissions decreased by 87.5%, 87.01% and 57.14%, respectively.Sahin et al. [23] studied the effect of n-butanol injection into diesel engine intake on engine performance and exhaust emissions under different engine loads. Therefore, in terms of engine characteristics, 2% n-butanol injection will be the optimum mixing ratio, and NOx emissions will be reduced by 0.58%, 0.31% and 17.38%, respectively. On the other hand, they show that the thermal efficiency increases by 1.01%.Tosun et al. [24] conducted experiments by adding 20% alcohol by volume to biodiesel produced from scrub oil. Engine power was found to increase by 2.4%, 10%, and 12.8% compared to biodiesel in experiments with methanol, ethanol, and butanol, and 26.36%, 20.85%, and 18.91, respectively, compared to diesel fuel. %. Compared with biodiesel, the engine torque values of methanol, ethanol and butanol blends increased by 1.2%, 3.4% and 6.1%, respectively, and were reduced by 20.53%, 18.81% and 16.67%, respectively, compared to diesel fuel. In addition, as the alcohol mixture is discharged, CO emissions are reduced and NOx emissions are increased. Atmanli [25] prepares a fuel mixture such as 50% diesel + 50% biodiesel, 40% diesel + 40% biodiesel + 20% different alcohol, and naturally inhales in a four cylinder at a constant engine speed of 1800 rpm. Testing and various engine loads are performed in indirect injection diesel engines. The paper concludes that the addition of propanol, butanol and pentanol increased CO emissions by 39.95%, 38.83% and 12.60%, respectively, but NOx emissions were reduced. Nanthagopal et al. [26] showed the effects of 1-pentanol and 1-butanol as additives and chlorophyll biodiesel on diesel engine characteristics under different engine loads. They point out that higher alcohol biodiesel blends have lower BTE and higher BSFC. Due to the cooling effect of higher alcohols, NOx simultaneously reduces CO, HC and smoke emissions from all higher alcohol blends. Babu and Anand [27] analyzed the performance, combustion and exhaust emissions behavior of diesel engines operating on biodiesel/diesel/n-pentanol or n- hexanol mixtures without engine modifications. They concluded that performance and combustion performance can be improved by adding higher alcohols to the biodiesel/diesel mixture. Among the higher alcohol blends, 85% biodiesel / 5% diesel / 10% pentanol fuel has the smallest CO, HC and filtered smoke. Dhanaseharan et al. [28] studied the effects of waste cooking oil biodiesel, diesel and n-pentanol ternary mixture on the combustion, performance and emission characteristics of fixed direct injection diesel engines with and without exhaust gas recirculation. It can be concluded that the ternary mixture produces less NOx and smoke emissions, but HC and CO emissions are found to be higher. In addition, they improved the BSFC after adding n-pentanol according to B50 fuel. Atmanli et al. [29] suggested that the ternary mixture contains 10% n-butanol / 20% cotton oil / 70% diesel fuel to meet the engine's http://www.iaeme.com/IJMET/index.asp 395 editor@iaeme.com
A Study on Alcohol Acid Compound Mixed with Biodiesel as Alternative Biofuel for Diesel Engine cold flow performance and provide satisfactory engine performance and emissions. Celebi and Aydin [30] prepared a binary mixture of butanol/safflower oil biodiesel/diesel fuel, including the volume basis of 5%, 10% and 20% butanol. They then performed a half load and a constant speed test at 1500 rpm on a four-cylinder four-stroke direct-injection diesel engine generator. The ternary mixture showed a reduction in emissions observed, with higher BTE and BSFC recorded at 1.5% and 6%, respectively, compared to diesel fuel. According to the various scholars' research above, most of the previous studies have focused on (a) increasing the impact of alternative fuel concentrations; (b) using the same percentage of different alternative fuels and (c) mixing the effects of different alternative fuels. Biodiesel adds a small amount of alcohol with the same oxygen concentration (but different fuels C, H and LHV). According to the author's knowledge and research, all of these studies were carried out with a mixture of different carbon (C) and hydrogen (H) percentages, different from the oxygen (O) content and the different low calorific value (LHV). Differences in C, H, O, and LHV do not allow for the establishment of similar conditions to compare engine performance and exhaust emissions during various fuel usage periods. Engine performance and exhaust emissions are affected by many factors, including the C/H ratio of the fuel, the oxygen content of the fuel, and the lower calorific value. In addition, under the same operating conditions, there is still a lack of research on the effects of lower alcohols (methanol and ethanol) and higher alcohols (butanol, pentanol and propanol) on the same engine. The effects of low-grade alcohols such as methanol and ethanol added to diesel, biodiesel and diesel biodiesel blends on engine performance, exhaust emissions and combustion characteristics were investigated. Research on diesel engines fueled with diesel, biodiesel or diesel-biodiesel fuel blends with butanol and pentanol fuels has been limited, especially in terms of the impact on fuel combustion characteristics and engine performance. Study engine performance (such as torque, power, BSFC, BTE, etc.), exhaust single-cylinder, four-stroke, water-cooled, direct-injection diesel engine emissions (such as CO, CO2, NOx, etc.) and combustion behavior (such as in-cylinder pressure and Heat release rate). 2. COMBUSTION CHARACTERISTICS Usually, the following parameters are usually selected in the research process to analyze the effects of alternative fuels on engine combustion characteristics and performance: in-cylinder pressure, heat release rate (HRR), ignition delay (ID), combustion duration (DOC), coefficient of variation ( COV)) Indicative mean effective pressure, brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE)[5]. The combustion process includes ignition delay (ID), uncontrolled combustion, controlled combustion, and late combustion. During the ignition delay, fuel is injected into the combustion chamber and evaporated by mixing with air. The ignition delay time is the time span between the start of fuel injection and the start of fuel ignition[7]. In other words, the ignition delay is the primary rate at which sudden pressure increases are observed. During this time, the physical and chemical processes required to prepare the fuel for combustion work. There is a temperature difference between the pressure of the fuel injected into the combustion chamber and the temperature at which the temperature is increased during compression. During the evaporation of the fuel, the temperature of the heat overflows the temperature difference. The heat extracted during this transfer process, to some extent, slows the increase in temperature and pressure within the cylinder. Other important parameters in diesel engine combustion analysis are start of injection (SOI), start of combustion (SOC), end of combustion (EOC), and combustion period (CP)[7]. http://www.iaeme.com/IJMET/index.asp 396 editor@iaeme.com
Chang Chun Xu, Haeng Muk Cho The ID is lowered due to an increase in the in-cylinder temperature due to an increase in engine load. For DOC, an increase in load results in fuel injection duration, air/fuel mixture formation, and increased fuel combustion [7]. Compared to diesel fuel, due to the alcohol, the lower cetane number of the mixed fuel and the higher latent heat of vaporization cause a decrease in the in-cylinder temperature and an increase in the ID. For DB, higher bulk modulus and higher biodiesel viscosity result in earlier combustion onset and lower ID. There are various reasons for using alcohol to reduce DOC in a blended fuel. First, the addition of alcohol to the mixed fuel results in a higher HRR in the premixed combustion stage caused by the longer ignition delay. Second, faster flame propagation of the alcohol can shorten the DOC. Third, the oxygen content of the alcohol can reduce the pyrolysis process and enhance oxidation during combustion, resulting in a shorter DOC. For BTE, the higher or similar BTE of the blended fuel (although the BSFC is increased) is due to lower fuel viscosity, improved fuel atomization and increased oxygen content, which improves the combustion process that converts the chemical energy of the fuel into fuel[12]. Useful engine work increases the BTE compared to ULSD. Among all the alcohols tested, methanol has the shortest chain and the lowest molecular weight, which results in easier ignition and better combustion, thus resulting in the lowest BSFC and the highest BTE[13]. Furthermore, the lowest boiling point of methanol in the tested alcohol results in a reduction in heat loss, thus resulting in a higher BTE. At lower loads, the lean fuel-air mixture produces lower combustion, which reduces brake thermal efficiency. As the load increases, fuel consumption increases to maintain a constant speed, which in turn increases the combustion temperature, causing the brake thermal efficiency to increase until the maximum limit is reached. After the maximum brake thermal efficiency is reached, incomplete combustion occurs due to the rich fuel mixture and reduced air fraction, which in turn reduces the brake thermal efficiency[5]. According to experiments, it was observed that the baking heat efficiency of diesel fuel was lower than that of biodiesel and fuel mixture. The brake heat efficiency in biodiesel is the highest. This may be due to the high oxygen content of the pressure. Higher concentrations of oxygen in biodiesel increase the combustion temperature, which in turn produces higher braking thermal efficiency than diesel. However, the addition of 1-butanol reduces the brake heat efficiency by absorbing more heat generated due to high heat of vaporization. As with higher mixtures, the brake thermal efficiency is lower than biodiesel, but these values are higher or closer to the brake thermal efficiency of the diesel engine. Due to the higher heat of vaporization, more heat is absorbed, which reduces the thermal efficiency of braking. The addition of 1-butanol reduces the cetane number, which reduces combustion efficiency, which is another reason to reduce the thermal efficiency of the brake. For the remaining fuel, specific fuel consumption was found to be higher due to the lower heating value. When 1-butanol is added to the diesel, the heat of vaporization increases. This, in turn, can absorb more heat during combustion and result in a further increase in specific fuel consumption at the same rating. This results in providing a greater amount of fuel mixture to maintain the same braking power. Therefore, biodiesel blends consume more fuel than diesel fuel. At low engine loads, the combustion temperature is low, so incomplete combustion occurs; on the other hand, under very high loads, the combustion temperature is high and the fuel/air ratio is richer, but there is not enough time to mix the fuel and air, resulting in incomplete combustion, BTE is reduced and BSFC is increased[20]. The exhaust gas temperature of diesel is lower than that of biodiesel. Diesel does not contain oxygen and produces a lower exhaust gas temperature. Due to the higher density and viscosity of biodiesel, poor atomization was observed in biodiesel combustion [23]. This in turn leads to incomplete or delayed combustion. Therefore, even after the expansion, the http://www.iaeme.com/IJMET/index.asp 397 editor@iaeme.com
A Study on Alcohol Acid Compound Mixed with Biodiesel as Alternative Biofuel for Diesel Engine combustion continues, which may raise the exhaust gas temperature. However, the 1-butanol mixed test fuel showed a lower exhaust temperature than biodiesel and was higher than the percentage of diesel. The heat of vaporization, oxygen content and viscosity (poor atomization) can affect the temperature of the exhaust gas. The 1-butanol/diesel blend has a higher oxygen content and is expected to have more heat inside the cylinder. However, due to the higher heat of vaporization, more heat is absorbed and the temperature of the exhaust gas is lower than the temperature of the biodiesel. As the engine load increases, more fuel is injected into the cylinders for combustion, which causes the in-cylinder temperature to rise and thus increase the EGT. As the engine load increases, more fuel is injected into the cylinders for combustion, which causes the in-cylinder temperature to rise and thus increase the EGT[20]. Figure 1 Brake thermal efficiency [3] Figure 2 Brake Specific Fuel Consumption [3] Figure 3 Exhaust Gas Temperature [3] 3. EMISSION CHARACTERISTICS Figure 4 shows that NOX decreases roughly with increasing load, which is consistent with other studies using diesel and DBE and diesel, DBu and DPe. Figure 4 also shows that all blended fuels (except for DB under all loads, DBPe of 28.5 Nm) resulted in a lower NOx reduction for all test loads than diesel fuel. At an average of five loadings, the NOX reductions using the blended fuel were 19.3% (DBPr), 14.2% (DBM), 11.7% (DBPe), 4.7% (DBE) and (DBBu), respectively, compared to diesel. There was an increase in NOX (5.8%). Although the combustion temperature has a large influence on the formation of NOx, it can be found from the above results that the length of the combustion duration (residence time) also has an influence on the formation of NOx[27]. http://www.iaeme.com/IJMET/index.asp 398 editor@iaeme.com
Chang Chun Xu, Haeng Muk Cho Reductions in NOx have also been reported in studies using ethanol, butanol and pentanol, and butanol and propanol. In addition, the increase in NOX using biodiesel has also been reported in many of the studies mentioned in the review articles[21][23]. Figure 4 Variation of NOX with engine loads. [1] Figure 5 shows the change in CO2 with engine load. It can be seen from Figure 5 that under different engine loads, the behavior of CO2 is almost similar to that of BSFC. It was also found that the lowest CO2 record was 199.5 Nm (which also had the lowest BSFC) and the highest CO2 was observed at 28.5 Nm of all tested fuels (which also had the highest BSFC). Figure 5 also shows that all blended fuels (except DB) can reduce CO2 compared to diesel fuel. References report similar trends in reducing carbon dioxide with ethanol and DBE. A slight increase was found in the reference and there was no significant CO2 effect. Compared to diesel, pure biodiesel (up 5.63%), DB50 (up 2.77%) and DB20 and DB10 (same) were used. In addition, DB has the same CO2 compared to diesel (a slight increase of 1.4% compared to the test). It can be inferred that only DBM is effective in reducing CO 2 by an order of 8.2% due to the lowest BSFC in all tested fuels. The effect of other blended fuels on carbon dioxide is almost similar to that of diesel [1][3]. Figure 5 Variation of CO2 with engine loads [1] In Figure 6, it can be seen that the effect of in-cylinder temperature rise and complete combustion as a consequence of engine load rise (except 256.5 Nm) on CO emissions reduction. At an average of five loadings, the CO reduction for all alternative fuels was DBM (23.9%), DB (11.3%), DBPr and DBBu (6.4%), DBPe (3.5%) and DBE (0.4% only), compared with diesel. Under low load, the lower combustion temperature (due to the higher cooling potential caused by latent heat of evaporation) affects the oxygen content of the blended fuel [29]. The effect of (complete combustion), which inhibits the CO oxidation http://www.iaeme.com/IJMET/index.asp 399 editor@iaeme.com
A Study on Alcohol Acid Compound Mixed with Biodiesel as Alternative Biofuel for Diesel Engine process, resulting in increased CO emissions from diesel. However, as the engine load increases, the effect of combustion temperature becomes weaker and the mixture can be seen at higher test loads. The CO emissions of fuels are lower than the CO emissions of ULSD[31]. Figure 6 Variation of CO with engine loads [1] Figure 7 depicts that an increase in load results in a decrease in HC for all tested fuels. At low engine loads, the combustion temperature is not sufficient to initiate complete combustion, resulting in an increase in HC emissions for all tested fuels. However, at higher loads, the combustion temperature is high enough to achieve more complete combustion, resulting in a lower HC of all tested fuels. Figure 7 shows that all blended fuels (regardless of ethanol of 85.5 Nm) can reduce HC from 85.5 Nm to the highest engine load (256.5 Nm). The increase in HC at the lowest load of a mixed fuel is similar to that of CO because the latent heat of vaporization of alcohol and biodiesel is higher than that of ULSD, resulting in incomplete combustion [27]. However, the effect of higher oxygen content in the blended fuel is the dominant factor for higher engine loads (from 85.5 Nm to 256.5 Nm), which leads to more complete combustion and increased unburned hydrocarbons at higher in-cylinder temperatures [30]. Some studies have also found that when using alcohol mixtures (such as DBE, DBBu and DBPe and BPn), THC increases at lower or even moderate loads and decreases at higher loads. In addition, other studies have found that using DE and DBE, DBPe and diesel mixed with ethanol or methanol can improve combustion quality compared to diesel fuel because of the higher oxygen content in the fuel and lower THC [28]. Among the average of the five engine loads, HC was reduced by DBM (24.3%), DBPe, DBPr and DB (12.3%) and DBE and DBBu (8.8%) compared to diesel fuel. Figure 7 Variation of HC with engine loads [1] http://www.iaeme.com/IJMET/index.asp 400 editor@iaeme.com
Chang Chun Xu, Haeng Muk Cho 4. CONCLUSIONS Recently, alternative fuels have become a prospect due to the rapid decline in fossil fuel reserves, rising oil prices, stricter emission regulations, increasing pollution of traditional fuels to the environment and concerns about energy security. These anxieties have led scientists to study alternative fuels. One of the most important alternative fuel sources for internal combustion engines is higher alcohols because of their environmental and economic advantages. 1-butanol and n-pentanol are higher alcohols and can be prepared from renewable feedstocks having a molecular structure of four and five carbons, respectively. The addition of 1-butanol slightly reduced brake thermal efficiency compared to pure biodiesel and reduced specific fuel consumption, exhaust gas temperature and emissions of all test gases such as NOx, CO and HC. In this survey, fuel characteristics indicate that alcohol treatment slightly reduced kinematic viscosity, density, calorific value, flash point and cetane number. However, the addition of alcohol to the biodiesel/diesel fuel mixture can reasonably improve low temperature performance. The 1-butanol and n-pentanol treated fuels have elevated BSFC values and are on average higher than diesel fuels. And the results are predicted due to the calorific value of the fuel sample. Most ternary mixtures have a lower BTE than diesel fuel. Compared to diesel fuel, the addition of n-pentanol and 1-butanol fuels significantly reduced CO emissions while observing a reduction in CO2 emissions from the fuel mixture. Due to the higher alcohol, the addition of n-pentanol is effective in reducing NOx emissions. In addition, the smoke opacity of the alcohol treated fuel mixture is reduced on average compared to diesel fuel. ACKNOWLEDGMENT This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (NRF-2019R1A2C1010557). REFERENCES [1] Meisam Ahmadi Ghadikolaei , Chun Shun Cheung , Ka-Fu Yung, Study of combustion, performance and emissions of diesel engine fueled with diesel/biodiesel/alcohol blends having the same oxygen concentration, Energy 157 (2018) 258-269. [2] Murat Kadir Yesilyurt , Tanzer Eryilmaz , Mevlüt Arslan, A comparative analysis of the engine performance, exhaust emissions and combustion behaviors of a compression ignition engine fueled with biodiesel/diesel/1-butanol (C4 alcohol) and biodiesel/diesel/npentanol (C5 alcohol) fuel blends. Energy 165 (2018) 1332-1351. [3] Jeya Jeevahan, G. Sriramanjaneyulu, R.B. Durairaj, G. Mageshwaran, Experimental investigation of the suitability of 1-butanol blended with biodiesel as an alternative biofuel in diesel engines. Biocatalysis and Agricultural Biotechnology 15 (2018) 72–77. [4] Sathaporn Chuepeng, Cholada Komintarachat, Interesterification optimization of waste cooking oil and ethyl acetate over homogeneous catalyst for biofuel production with engine validation. Applied Energy 232 (2018) 728–739. [5] M. Senthil Kumar*, S.V. Karthic, P. Pradeep. Investigations on the influence of ethanol and water injection techniques on engine's behavior of a hydrogen - biofuel based dual fuel engine. International Journal of Hydrogen Energy 43(2018) 21090-21101. [6] G. Ospina, Mohamed Y.E. Selim, Salah A.B. Al Omari, Mohamed I. Hassan Ali, Adel M.M. Hussien. Engine roughness and exhaust emissions of a diesel engine fueled with three biofuels. Renewable Energy xxx (2018) 1-8. http://www.iaeme.com/IJMET/index.asp 401 editor@iaeme.com
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