Attempts to minimize nitrogen oxide emission from diesel engine by using antioxidant-treated diesel-biodiesel blend.

The study represents a comprehensive analysis of engine exhaust emission variation from a compression ignition (CI) diesel engine fueled with diesel-biodiesel blends. Biodiesel used in this investigation was produced through transesterification procedure from Moringa oleifera oil. A single cylinder, four-stroke, water-cooled, naturally aspirated diesel engine was used for this purpose. The pollutants from the exhaust of the engine that are monitored in this study are nitrogen oxide (NO), carbon monoxide (CO), hydrocarbon (HC), and smoke opacity. Engine combustion and performance parameters are also measured together with exhaust emission data. Some researchers have reported that the reason for higher NO emission of biodiesel is higher prompt NO formation. The use of antioxidant-treated biodiesel in a diesel engine is a promising approach because antioxidants reduce the formation of free radicals, which are responsible for the formation of prompt NO during combustion. Two different antioxidant additives namely 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (MBEBP) were individually dissolved at a concentration of 1% by volume in MB30 (30% moringa biodiesel with 70% diesel) fuel blend to investigate and compare NO as well as other emissions. The result shows that both antioxidants reduced NO emission significantly; however, HC, CO, and smoke were found slightly higher compared to pure biodiesel blends, but not more than the baseline fuel diesel. The result also shows that both antioxidants were quite effective in reducing peak heat release rate (HRR) and brake-specific fuel consumption (BSFC) as well as improving brake thermal efficiency (BTE) and oxidation stability. Based on this study, antioxidant-treated M. oleifera biodiesel blend (MB30) can be used as a very promising alternative source of fuel in diesel engine without any modifications

Study of the oxidation stability and exhaust emission analysis of Moringa olifera biodiesel in a multi-cylinder diesel engine with aromatic amine antioxidants

In this study, the two most effective aromatic amine antioxidants N,N'-diphenyl-1,4-phenylenediamine (DPPD) and N-phenyl-1,4-phenylenediamine (NPPD), were used at a concentration of 2000 ppm. The impact of antioxidants on the oxidation stability, exhaust emission and engine performance of a multi-cylinder diesel engine fuelled with MB20 (20% Moringa oil methyl ester and 80% diesel fuel blend) were analysed at varying speed conditions at an interval of 500 rpm and a constant load. It was observed that, blending with diesel enhanced the oxidation stability of the moringa biodiesel by approximately 6.97 h, and the addition of DPPD and NPPD to MB20 increased the oxidation stability up to 34.5 and 18.4 h, respectively. The results also showed that the DPPD- and NPPD-treated blends reduced the NOx emission by 7.4% and 3.04%, respectively, compared to the untreated blend. However, they do have higher carbon monoxide (CO) and hydrocarbon (HC) levels and smoke opacities, but it should be noted that these emissions are still well below the diesel fuel emission level. The results show that the addition of antioxidant with MB20 also improves the engine's performance characteristics. Based on this study, MB20 blends with amine antioxidants can be used in diesel engines without any modification

Study of the oxidation stability and exhaust emission analysis of Moringa olifera biodiesel in a multi-cylinder diesel engine with aromatic amine antioxidants

In this study, the two most effective aromatic amine antioxidants N,N'-diphenyl-1,4-phenylenediamine (DPPD) and N-phenyl-1,4-phenylenediamine (NPPD), were used at a concentration of 2000 ppm. The impact of antioxidants on the oxidation stability, exhaust emission and engine performance of a multi-cylinder diesel engine fuelled with MB20 (20% Moringa oil methyl ester and 80% diesel fuel blend) were analysed at varying speed conditions at an interval of 500 rpm and a constant load. It was observed that, blending with diesel enhanced the oxidation stability of the moringa biodiesel by approximately 6.97 h, and the addition of DPPD and NPPD to MB20 increased the oxidation stability up to 34.5 and 18.4 h, respectively. The results also showed that the DPPD- and NPPD-treated blends reduced the NOx emission by 7.4% and 3.04%, respectively, compared to the untreated blend. However, they do have higher carbon monoxide (CO) and hydrocarbon (HC) levels and smoke opacities, but it should be noted that these emissions are still well below the diesel fuel emission level. The results show that the addition of antioxidant with MB20 also improves the engine's performance characteristics. Based on this study, MB20 blends with amine antioxidants can be used in diesel engines without any modification

Quality improvement of biodiesel blends using different promising fuel additives to reduce fuel consumption and NO emission from CI engine

Considering the low cetane number of biodiesel blends and alcohols, ignition promoter additives 2-ethylhexyl nitrate (EHN) and di-tertiary-butyl peroxide (DTBP) was used in this study at a proportion of 1000 and 2000 ppm to diesel-biodiesel-pentanol blends. Five carbon pentanol was used at a proportion of 10% with 20% jatropha biodiesel-70% diesel blends and engine testing was carried out in a single cylinder DI diesel engine. The fuel properties, engine performance, emission and combustion were studied and mainly the effects of two most widely used ignition promoter on the engine behaviour were compared and analyzed. Experimental results indicated that, the fuel properties like density (0.36–1.45%), viscosity (0.26–3.77%), oxidation stability (5.5–26.4%), cetane number (2–14.58%) are improved remarkably with a moderate change in calorific value for the pentanol and ignition promoter treated biodiesel blends depending on the proportion used and for different benchmark. The brake power (BP) is developed very slightly (0.66–1.52%), which is still below than that of diesel, however, the brake specific energy consumption (BSEC) decreased significantly (0.92–5.84%). Although mixing of pentanol increased the nitric oxide (NO) (2.15% than JB20) with reducing the hydrocarbon (HC), carbon monoxide (CO) and smoke, however, the addition of EHN and DTBP reduced the NO (2–4.62%) and smoke (3.45–15.5%) emissions showing higher CO (1.3–9.15%) and HC (5.1–17.87%) emission based on percentage of ignition promoter used. The NO emission from the peroxide ignition promoter treated fuel blends are consistently lower than those for the nitrate ignition promoter treated fuel blends at similar cetane level. The combustion pressure (CP) and heat release rate (HRR) of the ignition promoters added blends are improved showing advanced combustion pressure (0.11–0.53 bar) and lower heat release rate (0.82–2.29 J/°CA). In conclusion, it can be said that, pentanol and ignition promoters are promising additives for biodiesel blends for improving overall performance of a diesel engine

A comprehensive study on the improvement of oxidation stability and NO<inf>x</inf> emission levels by antioxidant addition to biodiesel blends in a light-duty diesel engine

Moringa oleifera oil, a non-edible biodiesel feedstock with high unsaturated fatty acid content, was used in this study. MB20 (20% Moringa oil methyl ester and 80% diesel fuel blend) was mixed with three antioxidants, namely, N,N′-diphenyl-1,4-phenylenediamine (DPPD), N-phenyl-1,4-phenylenediamine (NPPD) and 2-ethylhexyl nitrate (EHN), at a concentration of 1000 ppm. The effects of these antioxidants on the oxidation stability of biodiesel as well as on the exhaust emission and performance of a single-cylinder diesel engine were analysed. After the Rancimat test, oxidation stability was enhanced by the antioxidants in the order of DPPD > NPPD > EHN. Results also showed that DPPD-, NPPD- and EHN-treated blends reduced NOx emissions within 5.9-8.80% compared with those in the untreated blend because of suppressed free radical formation. Antioxidant-treated blends contained high amounts of carbon monoxide and hydrocarbon and showed improved smoke opacity, thereby indicating that emissions were below the diesel fuel emission levels. Results demonstrated that antioxidant addition to MB20 improves engine performance characteristics. This study shows that MB20 blends with antioxidants can be used in diesel engines without any modification

Experimental assessment of non-edible candlenut biodiesel and its blend characteristics as diesel engine fuel.

Exploring new renewable energy sources as a substitute of petroleum reserves is necessary due to fulfilling the oncoming energy needs for industry and transportation systems. In this quest, a lot of research is going on to expose different kinds of new biodiesel sources. The non-edible oil from candlenut possesses the potential as a feedstock for biodiesel production. The present study aims to produce biodiesel from crude candlenut oil by using two-step transesterification process, and 10%, 20%, and 30% of biodiesel were mixed with diesel fuel as test blends for engine testing. Fourier transform infrared (FTIR) and gas chromatography (GC) were performed and analyzed to characterize the biodiesel. Also, the fuel properties of biodiesel and its blends were measured and compared with the specified standards. The thermal stability of the fuel blends was measured by thermogravimetric analysis (TGA) and differential scan calorimetry (DSC) analysis. Engine characteristics were measured in a Yanmar TF120M single cylinder direct injection (DI) diesel engine. Biodiesel produced from candlenut oil contained 15% free fatty acid (FFA), and two-step esterification and transesterification were used. FTIR and GC remarked the biodiesels' existing functional groups and fatty acid methyl ester (FAME) composition. The thermal analysis of the biodiesel blends certified about the blends' stability regarding thermal degradation, melting and crystallization temperature, oxidative temperature, and storage stability. The brake power (BP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) of the biodiesel blends decreased slightly with an increasing pattern of nitric oxide (NO) emission. However, the hydrocarbon (HC) and carbon monoxides (CO) of biodiesel blends were found decreased

A comparative study of C<inf>4</inf> and C<inf>5</inf> alcohol treated diesel-biodiesel blends in terms of diesel engine performance and exhaust emission

Use of pure alcohols or alcohols blended with petroleum-based fossil fuel or biodiesel blends as engine fuel is an attractive alternative solution for internal combustion engines. This study conducted an experiments in a single cylinder, four-stroke, water-cooled, direct-injection diesel engine. Engine performance and emission characteristics of diesel-Alexandrian laurel biodiesel blends with 15 and 20 vol.% of n-butanol (C4) and pentanol (C5) as blending components were investigated and compared under different speed conditions. Results show that brake power and brake specific fuel consumption of the engine using C4 and C5 alcohols mixed with biodiesel blends were improved greatly than that using biodiesel. The emissions of hydrocarbon and carbon monoxide were extremely reduced with increasing nitric oxide and carbon dioxide, but carbon dioxide decreased at maximum speed. Finally, it can be conclude that, C5 alcohol is preferred than C4 alcohol because of its elevated performance and emission

Improving oxidation stability and NO<inf>X</inf> reduction of biodiesel blends using aromatic and synthetic antioxidant in a light duty diesel engine

Poor oxidation stability of biodiesel is now a major concern all over the world, especially due to its extensive utilisation in transport and industrialisation. Therefore, biodiesel needs better stability, in order to be sustainably utilised in the long term. The oxygen inhibitor antioxidant can counter the poor oxidation. In this experiment, 20% of Calophyllum inophyllum biodiesel (CIB20) was used as biodiesel feedstock. Three most effective antioxidants N, N'-diphenyl-1, 4-phenylenediamine (DPPD), N-phenyl-1, 4-phenylenediamine (NPPD) and 2-ethylhexyl nitrate (EHN) were used at a 1000 ppm concentration with CIB20. The oxidation stability, exhaust emission and performance of a single cylinder diesel engine were analysed and compared to those of diesel. From the results, it was concluded that there was no significant negative impact on biodiesel physiochemical properties, while the stability of biodiesel (CIB20) with the addition of antioxidants with tested blends increased. Among these three antioxidants, DPPD exhibits a better stability in biodiesel. The results shows that CIB20 produced an average of 5.23% lower brake power (BP), 7.84% less brake thermal efficiency (BTE) and 11.2% higher brake specific fuel consumption (BSFC), compared to pure diesel. However, by mixing the antioxidant with CIB20, the BP and BTE, increased while the BSFC slightly decreased. For exhaust emission, antioxidants reduced NOx by about 5.92%-8.83%, with an increment of hydrocarbon (HC) and carbon-monoxide (CO) for all blends. For this reason, CIB20 blends with aromatic amine antioxidants can be used in diesel engine without any engine modifications

Evaluation of oxygenated n-butanol-biodiesel blends along with ethyl hexyl nitrate as cetane improver on diesel engine attributes

In the present investigation, an attempt has been made to study the fuel properties, engine performance and emission of a diesel engine by mixing ethyl hexyl nitrate (EHN) with n-butanol-diesel-biodiesel blends. The engine test was carried out at full throttle opening in a single cylinder direct injection diesel engine. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis was done to evaluate the thermal properties of the test fuels. Experimental results revealed that the density, viscosity, and other properties are developed well. Notably, the cetane number of the blends increased 4.74% to 11.82% are promising. Alcohol along with cetane improver make the diesel-biodiesel blends thermally more strong. Moreover, introducing the EHN in the blends increased the carbon monoxide (CO) up to 16.64%, hydrocarbon (HC) emissions up to 27.46%, brake power (BP) up to 5.62% and brake thermal efficiency (BTE) up to 2.5% compared to the n-butanol added biodiesel blends. On the other hand, the brake specific fuel consumption (BSFC), nitric oxide (NO) and smoke reduced from 1.44% to 2.8%, 2.53% to 5.27% and 7.08% to 14.11% respectively with the addition of EHN into the n-butanol mixed biodiesel blends. Hence it can be concluded that the addition of cetane improver to oxygenated alcohol treated biodiesel blends is well efficient for a diesel engine

Influences of ignition improver additive on ternary (diesel-biodiesel-higher alcohol) blends thermal stability and diesel engine performance

Pentanol is a long chain alcohol produced from renewable sources and considered as a promising biofuel as a blending component with diesel or biodiesel blends. However, the lower cetane number of alcohols is a limitation, and it is important to increase the overall cetane number of biodiesel fuel blends for efficient combustion and lower emission. In this consideration, ignition improver additive 2-ethylhexyl nitrate (EHN) were used at a proportion of 1000 and 2000 ppm to diesel-biodiesel-pentanol blends. Experiments were conducted in a single cylinder; water-cooled DI diesel engine operated at full throttle and varying speed condition. The thermal stability of the modified ternary fuel blends was evaluated through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis, and the physic-chemical properties of the fuel as well as engine characteristics were studied and compared. The addition of EHN to ternary fuel blends enhanced the cetane number significantly without any significant adverse effect on the other properties. TGA and DSC analysis reported about the improvement of thermal characteristics of the modified blends. It was found that, implementing ignition improver make the diesel-biodiesel-alcohol blends more thermally stable. Also, the brake specific fuel consumption (BSFC), nitric oxides (NO) and smoke emission reduced remarkably with the addition of EHN. Introducing EHN to diesel-biodiesel-alcohol blends increased the cetane number, shorten the ignition delay by increasing the diffusion rate and improve combustion. Hence, the NO and BSFC reduced while, carbon monoxide (CO) and hydrocarbon (HC) emissions increased slightly