Pragmatic investigation of the effect of ether additives on biodiesel combustion to reduce NOx and other harmful emissions

Abstract

• Adding ethers to the TB10 has reduced the NO x , CO, and CO 2 emissions compared to TB10. • The addition of DME10 to TB10 showed reduced CO by 22.3 % and 45 % compared to diesel and TB10. • At 100% load, TB10DEE10, TB10DME10, and TB10TME10 blends showed increased NOx by 10.6%, 6.8%, and 8.32%, respectively. • The ether-TB10 blend shows lower BTE compared to both diesel and TB10. • TB10DME10 showed reduced BSFC by 0.6 % and 11 % compared to diesel at 25 % and 50 % load condition. The addition of oxygenated additives such as ethers has shown better results with improved combustion and reduced emissions. Ethers have a lower viscosity and higher oxygen concentrations that can improve combustion and have lower calorific value, which can control the cylinder temperature. Hence, three ethers: diethyl ether (DEE), Diethylene Glycol Dimethyl Ether (DME), and Tri-propylene-Glycol Monomethyl ether (TME) were selected as biodiesel additives to conduct engine tests for reducing NO x and CO emissions. These three ethers were added at 10 % volume to the Tucuma B10 blend, and the results were compared with diesel, TB10, and TB20. The performance, combustion, and emission characteristics were investigated through engine tests conducted at 2400 rpm with varying loads of 25 %, 50 %, 75 %, and 100 %. The study found that adding oxygenated additives into the TB10 blend has led to a decrease in both CO and NO x compared to the TB10 blend alone. However, the NO x was higher for the ether-TB10 blends than diesel. At full load, TB10DME10 reduced CO emissions by 22.3 %, 45 %, and 38 %, compared to diesel, TB10, and TB20, respectively. Also, TB10TME10 showed reduced NO x by 8.5 %, 5.2 %, 6.62 %, and 0.12 % compared to TB10 at 25 %, 50 %, 75 %, and 100 % loads, respectively. Peak pressure values for ether blends were lower than diesel but higher than TB10 and TB20. The study concluded that the TB10DEE10 has shown better results in reducing CO, NO x , and BSFC and improved BTE. The study recommends a detailed computational fluid dynamics study to investigate more combustion aspects of ether blends. In addition, further investigation on oxidative stability, tribological behaviour, and cold flow performance of the ether blends is much needed.

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