Emulsifier-free Water-in-Diesel emulsion fuel: Its stability behaviour, engine performance and exhaust emission

Emulsion fuel is an unconventional fuel for diesel engines, which can be used without modifications in the engine. The benefits of an emulsion fuel include lowering the emissions of nitrogen oxides (NO
 x
 ) and particulate matter (PM) which are harmful to health and cause diesel engines to suffer. This paper explains in detail the effect of water in the emulsion fuel on the emissions of NO
 x
 , PM, carbon monoxide (CO), hydrocarbon (HC), smoke and exhaust temperature. Experimental results from various researchers show a decrease in the NO
 x
 and PM emissions simultaneously. However, the results with the increasing water percentage in emulsion fuel are not consistent for HC and CO emissions. The water content in emulsion fuel affects the combustion and reduces the peak temperature in the combustion chamber. On the other hand, microexplosion phenomenon occurs and causes an increase in the volatility of diesel fuel which improves the combustion efficiency.

Effect of emulsion fuel on engine emissions–A review

Recent progress on mixing technology for water-emulsion fuel: A review

Investigation of emulsion and effect on emission in CI engine by using diesel and bio-diesel fuel: A review

The nitrogen oxide (NOx) release of diesel engines can be reduced using water in diesel emulsion fuel without any engine modification. In the present paper, different formulations of water in diesel emulsion fuels were prepared by ultrasonic irradiation. The water droplet size in the emulsion, polydisperisty index, and the stability of prepared fuel was examined, experimentally. Afterwards, the performance characteristics and exhaust emission of a single cylinder air-cooled diesel engine were investigated using different water in diesel emulsion fuels. The effect of water content (in the range of 5%–10% by volume), surfactant content (in the range of 0.5%–2% by volume), and hydrophilic-lipophilic balance (HLB) (in the range of 5–8) was examined using Box-Behnken design (BBD) as a subset of response surface methodology (RSM). Considering multi-objective optimization, the best formulation for the emulsion fuel was found to be 5% water, 2% surfactant, and HLB of 6.8. A comparison was made between the best emulsion fuel and the neat diesel fuel for engine performance and emission characteristics. A considerable decrease in the nitrogen oxide emission (−18.24%) was observed for the best emulsion fuel compared to neat diesel fuel.

Performance and emission characteristics of a diesel engine operating on different water in diesel emulsion fuels: optimization using response surface methodology (RSM)

In general, water-in-diesel (W/D) emulsion reduces both particulate matter and nitrogen oxides gas emissions level in diesel engine application as compared of using conventional diesel fuel. W/D emulsion was usually produced by addition of water into the diesel fuel with a slight quantity of surfactant at high speed of propeller mixing. The studies examine the result of several aspects on emulsion stability. Investigated variables are type of surfactant, mixing speed and mixing time. Surfactant used are span 80 and many type of glycerines which have been derived from a corn oil, palm oil, soy oil, rice bran oil and sunflower oil. The results show that the type of surfactant gives a big impact on the stability period of the emulsion fuel. The higher mixing speed and less water percentage increase the stability period of W/D emulsion fuel. Optimum mixing time is 5 minutes for W/D emulsion fuel which using Span 80 as surfactant with mixing speed of 2500 rpm.

A.B. Aiman

Papers

Stability Studies of Water-in-Diesel Emulsion