Experimental investigation of ammonia gas as hydrogen carrier in prunus amygdalus dulcis oil fueled compression ignition engine

The present study aims to utilize ammonia gas as a hydrogen carrier with prunus amygdalus dulcis (sweet almond oil)-fueled single-cylinder compression ignition (CI) engine. Due to the high viscosity of sweet almond oil, a transesterification procedure was used to convert it to biodiesel. The diesel fuel was completely replaced with biodiesel to assess the performance, emission, and combustion characteristics of the CI engine running at a constant speed of 1500 rpm under different load conditions. Poor performance and combustion were exhibited with biodiesel in comparison to diesel. Lower brake thermal efficiency with higher fuel consumption and lower nitrous oxides (NOx) emissions were observed with biodiesel in comparison to diesel. While hydrocarbon (HC), carbon monoxide (CO), and smoke emissions were higher with biodiesel, to further improve the performance, hydrogen gas was introduced at different flow rates (10–30 LPM). Hydrogen improved the brake thermal efficiency with reduced carbon emissions. At maximum load condition, with 30 LPM hydrogen brake thermal efficiency is improved by 15 %. However, NOx emissions were higher with hydrogen induction compared to base fuels at all load conditions. NOx emissions were increased from 1274 ppm with biodiesel to 1451 ppm with 30 LPM hydrogen addition at maximum load. Although hydrogen is one of the most promising techniques to improve the performance of biodiesel, its higher NOx emissions and safety aspects make its practical application questionable. Hence, ammonia gas was used as a hydrogen carrier, and tests were conducted in dual fuel mode with biodiesel at different flow rates. It is observed that performance parameters in ammonia dual fuel mode are on par with those of biodiesel with reduced carbon and NOx emissions. Hence, ammonia can be considered a viable option to replace hydrogen as its carrier to meet global energy demands and also for its safer use.