Abstract
An experimental investigation was conducted to disclose the outcomes of oxygenate mixture as additives in Jatropha biodiesel on the performance, combustion, and emission characteristics of a direct injection compression ignition engine. The experiments were conducted in an instrumented single-cylinder, air-cooled, four-stroke, direct-injection diesel engine, equipped with data acquisition system, AC alternator, and an electric loading device. Four oxygenate additives, namely, Ethylene Glycol (C2H6O2), Di methyl Carbonate (C3H6O3), 2-Butoxyethanol (C6H14O2), & Propylene Glycol (C3H8O2) were selected and nine different combinational oxygenate test fuels were prepared attaining ratios of 1, 2, and 4% volume of oxygenates with biodiesel. A significant reduction of emissions such as CO by 60%, Unburned HC by 11%, and smoke emissions by 27% were observed. Substantial improvement in brake thermal efficiency by 6% was observed, while NO emission increased marginally by 4%.
TopHighlights
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Four oxygenates namely, Dimethyl Carbonate (C3H6O3), Ethylene Glycol (C2H6O2), Propylene Glycol (C3H8O2) and 2-Butoxyethanol (C6H14O2) were selected as fuel additives.
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Ratios of 1, 2 and 4% volume of oxygenates were blended with Jatropha biodiesel.
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The brake thermal efficiency for oxygenates dispersed test fuels was substantially improved compared to that of neat biodiesel operation.
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The oxygenate-dispersed test fuels reduced CO emission by 60%, Unburned HC emission by 11% and smoke emission by 27%.
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The addition of oxygenates as additives in biodiesel resulted in enhanced performance and emission characteristics of a diesel engine.
TopIntroduction
Biodiesels are conceived as substitute fuels for petroleum products. Various efforts are established to examine the potency and suitability of the fuel. Biofuels have received more attention than other renewable fuels, as it has better fuel properties than those of petroleum fuel and suppress the environmental pollution. Lower emissions (aldehydes, polycyclic aromatic hydrocarbons and carbon monoxide), lower toxicity and sulphur dioxide emissions are the advantage of biodiesel fuel, having some of the disadvantages such as higher fuel consumption, lower calorific value, higher nitrous oxide (NOx) emissions, low stability and higher freezing point than diesel fuel. Blending biodiesel with additives significantly eliminates the disadvantages of it (Prabu and Anand, 2018). An additive for the fuel has to be selected carefully based on its functions. The commonly used additives in fuel are listed in Table 1.
Table 1. The commonly used additives in fuel
| S.No | Types of Additives | Function |
| 1 | Anti-Foam Agents | Reduce foaming during tank filling |
| 2 | Antioxidants | Inhibit oxidation, reduce precipitate and gum formation, extend storage life, |
| 3 | Biocides | Inhibit fungi and bacterial growth, prevent fuel filter plugging |
| 4 | Cetane Number Improver | Improves ignition quality by increasing cetane number, easy start of engine, reduces white smoke |
| 5 | Cloud Point Depressants (Suppressants) | Reduces temperature at which paraffin solubilize |
| 6 | Demulsifiers / Dehazers | Increase the rate of water separation from the fuel |
| 7 | Detergents / Dispersants | Improves spray patterns and clean injectors |
| 8 | Lubricity Improvers | Improve lubricity, better injector and pump lubrication |
| 9 | Metal Deactivators | Deactivate copper compounds in fuel and promotes longer storage life |
| 10 | Nanoparticles | Enhanced surface area to volume ratio improves the evaporation characteristics. |
| 11 | Oxygenates | Improves the oxygen content in the fuel |
| 12 | Pour Point Depressants | Improve cold-flow properties and low temperature operability |
| 13 | Rust Preventors | Reduce formation of rust in fuel systems and storage tanks |
| 14 | Smoke Suppressants | Reduce exhaust smoke and promote more complete combustion, |
| 15 | Stabilizers | Inhibits oxidation and extends storage life |
Key Terms in this Chapter
DMCPG1: Biodiesel + 0.5% Propylene glycol + 0.5% Dimethyl Chloride
EGBE1: Biodiesel + 0.5% Ethylene Glycol + 0.5% 2-Butoxy Ethanol
CO: Carbon Monoxide
DMC: Dimethyl Chloride
HC: Hydrocarbon
NO: Nitric Oxide
DMCBE2: Biodiesel + 1% 2-Butoxy ethanol + 1% Dimethyl Chloride
EGT: Exhaust Gas Temperature
ASTM: American Society for Testing and Materials
Btd: Before Top Dead Centre
DMCBE1: Biodiesel + 0.5% 2-Butoxy ethanol + 0.5% Dimethyl Chloride
EGBE2: Biodiesel + 1% Ethylene Glycol + 1% 2-Butoxy Ethanol
EGBE4: Biodiesel + 2% Ethylene Glycol + 2% 2-Butoxy Ethanol
DMCPG4: Biodiesel + 2% Propylene glycol + 2% Dimethyl Chloride
BSFC: Brake Specific Fuel Consumption
BE2: Butoxy ethanol
FFA: Free Fatty Acid
DMCPG2: Biodiesel + 1% Propylene glycol + 1% Dimethyl Chloride
BTE: Brake Thermal Efficiency
Bmep: Brake Mean Effective Pressure
DMCBE4: Biodiesel + 2% 2-Butoxy ethanol + 2% Dimethyl Chloride