Assessment of the efficiency of biofuel use in the operation of marine diesel engines

The object of research is the process of operation of marine diesel engines using biodiesel fuel. The subject of research is the process of experimental determination of the optimal concentration of biodiesel fuel in a mixture with fuel of petroleum origin. At the same time, a simultaneous maximum increase in environmental and minimum decrease in the economic parameters of the operation of a marine diesel engine should be ensured. The studies were carried out on Hyundai Heavy Industries 5H17/28 marine diesel engines. Three such diesel engines were part of the power plant of a specialized marine ship with deadweight of 9600 tons. The study was aimed at determining the concentration of biofuel in a mixture with diesel fuel, which provides the best environmental performance of a diesel engine. The fuel supply circuit to the first diesel did not change and the diesel was operated on RMB30 fuel. Two other diesel engines were operated on a fuel mixture – RMB30 fuel and B99.9 FAME biofuel. The content of biofuel in the mixture varied in the range of 5–20 %. The main quantities measured during the experiment were the concentration of nitrogen oxides and the volumetric content of carbon monoxide in the exhaust gases, as well as the specific effective fuel consumption. By switching groups of consumers, the operation of diesel engines was carried out at the same load, the support of which was required during the experiment. The load on diesel engines during the experiments varied in the range of 55–85 % of the nominal value. The operation of diesel engines in each of the studied modes was carried out for at least 1.5–2 hours, during which the main parameters were measured and the obtained values were averaged. It has been established that the use of biofuel increases the environmental friendliness of the marine diesel engine: – by 7.6–26.61 % (depending on the diesel loading and the content of biofuel in the fuel mixture), the emission of nitrogen oxides with exhaust gases is reduced; – by 3.8–23.6 % (depending on diesel loading and biofuel content in the fuel mixture) reduces the emission of carbon oxides with exhaust gases. It has been also determined that when using biofuel, there is an increase in the specific effective fuel consumption by 0.5–8.65 %, which reduces the efficiency of a diesel engine. The optimal composition of the fuel mixture containing biofuel is proposed to be determined experimentally for each diesel load, taking into account its environmental and economic indicators.