Novel green hydrochar production for renewable fuel substitutes, and experimental investigation of its usability on CI engine performance, combustion, and emission characteristics

Abstract

In the present work, green hydrochars from renewable sources (cellulose (HC-Cel), and glucose (HC-Glu) are obtained via the hydrothermal carbonization method. Then different dosages (100 ppm, and 200 ppm) of these nano-sized hydrochar particles are added to the waste cooking oil biodiesel (20 %) and diesel blends (80 %) with the aid of an ultrasonification process. The experiments are performed at an indirect injection, water-cooled, three-cylinder diesel engine. During the experiments, the engine runs at a fixed engine speed of 2000 revolutions per minute (rpm), and at different loading conditions (15-60 Nm with intervals of 15 Nm). Then the impact of hydrochar addition to the diesel-biodiesel blends under these operation parameters is discussed in terms of engine behaviors (combustion, performance, and environmental). Considering the engine performance outputs, the brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) metrics for B20 are firstly 9.74 % higher, and 9 % lower than D100. The addition of 100 ppm HC-Glu, 200 ppm HC-Glu, 100 ppm HC-Cel, 100 ppm HC-Cel, and 200 ppm HC-Cel to B20 decreased the BSFC values by 17 %, 21.9 %, 15.31 %, 22.76 %, and enhanced the BTE by 13 %, 16 %, 12.07 %, 16.7 %, respectively. On the other hand, significant drops of 27.45 %, 39.22 %, 18.63 %, and 30.39 % for Carbon monoxide (CO) emission, 7.80 %, 12.52 %, 9.11 %, and 11.54 % for Nitrogen oxide (NOx) emission, and 8.91 %, 19.80 %, 5.94 %, and 15.84 % for uHC emission are recorded for B20 + 100 ppm HC-Glu, B20 + 200 ppm HC-Glu, B20 + 100 ppm HC-Cel, and B20 + 200 ppm HC-Cel test fuels, respectively. In conclusion, this work proves that hydrochars are efficient green agents to improve the worsened engine combustion, performance, and emission characteristics of diesel-biodiesel binary mixtures.