The experimental investigation on the impact of n-octanol in the compression-ignition engine operating with biodiesel/diesel fuel blends: exergy, exergoeconomic, environmental analyses

The use of alcohol with traditional diesel fuel in diesel engines reduces environmental damage. When the ternary mixtures obtained by adding biodiesel to diesel-alcohol fuel mixtures are used without making any changes in the compression-ignition (CI) engine, there is no significant problem in terms of performance and emissions. This research dealt energetic, exergetic, and environmental evaluation for a CI engine fueled with blends created using diesel/biodiesel/n-octanol at a constant speed of 1500 rpm and different loads (25, 50, 75, and 100%). Performance and emission values were recorded in the tests. Economic and environmental analyses were realized by using the data obtained in these tests in thermodynamic relations. The losses and efficiency of the engine were computed in the energy analysis. The highest thermal efficiency was found to be 40.6% in B20 and B20OCT5 at full load, while the lowest one was observed to be 15.77% when the engine fueled with B100 at 25% load. In the exergy analysis, exhaust exergy, exergy destroyed, and entropy generation were determined. Thermal and exergy efficiencies were parallel in all fuels depending on the load. The highest exergy efficiency was calculated to be 30.4% for B20 and B20OCT5 at full load. Lower exergy destruction was acquired for diesel fuel at full load in comparison with B20OCT20, B20OCT15 and B20OCT10. CO2 emission of fuels was used in exergy-based environmental analysis. The lowest environmental cost was determined as 3.85 $ month(-1) at 25% load in B20OCT10. The highest power cost was achieved to be 10.61 $ MJ(-1) at 25% load when the engine was run on B20OCT20. The cost of exergy losses at 25% load was computed to be 3.67 $ h(-1) for B20OCT20. While the increase in alcohol content in the blends caused a decrease in harmful pollutants, it is not economical due to the expensive pump prices. To conclude, it is to be clearly indicated that due to systematic thermodynamic, economic, and environmental analyses and the usage of n-octanol as a long-chain alcohol in the CI engine with blending diesel and biodiesel, this paper goes beyond previous efforts in the literature.

Automated summary

This study evaluated the energy, exergy, and environmental aspects of a CI engine fueled with diesel/biodiesel/n-octanol blends. The results showed that the use of these blends can reduce environmental damage without compromising engine performance and emissions.