Experimental assessment of cork based Botryococcus braunii microalgae blends and hydrogen in modified multicylinder diesel engine

Abstract

The extended research in using non-edible sources for production of biodiesel has been a boon in today’s need for an alternative fuel. However, the advanced biodiesels have helped to be an alternative fuel to tackle the fossil fuel shortage, the further improvements are needed in the composition of biodiesels. The present research paper gives the detailed explanation about the conversion of the Botryococcus braunii microalgae oil into biodiesel. In addition to the biodiesel blends, hydrogen was added to the injection system as secondary fuel. The addition of hydrogen in biodiesels will reduce the emission of unwanted pollutants. The hydrogenation increases the cetane number of the biodiesel and reduces the free fatty acids to improve the fuel quality. Experimental tests were conducted at full load condition by varying the engine speed from 1000 rpm to 3000 rpm. The hydrogen supply was provided constantly by allowing 5 L per minute into the BB (Botryococcus braunii) biodiesel. The varied proportions of biodiesel was BB0 (Diesel 100 %), BB10 (Botryococcus braunii biodiesel 10 %+Diesel 90 %) and BB20 (Botryococcus braunii biodiesel 20 %+Diesel 80 %) assisted with hydrogen to form BB0H5, BB10H5 and BB20H5. Blends were tested in a multi cylinder, naturally aspirated, compression ignition diesel engines. The different characteristics of the biodiesel with hydrogen in terms of performance, combustion and emission were calculated. The highest engine torque was reported when engine speed was maintained at 1500 rpm. BB10H5 reported the maximum engine torque of 282 Nm followed by BB20H5 and BB0H5. All the blends with hydrogen enrichment reported the highest thermal efficiency and reduced brake specific fuel consumption. Compared to plain diesel, the hydrogen added biodiesel significantly reduced the harmful gas emissions meanwhile the performance qualities were improved. However, there is no sign of reduction in the NOx across various engine speed due to the high cylinder temperatures at higher engine speeds.