Fuel spray and flame characteristic of biodiesel blend for CFB coal-fired steam power plant start-up process

Abstract

This study aims to obtain the spray and flame characteristics of biodiesel blend fuel used in the ignition system of a Circulating Fluidized Bed (CFB) coal-fired steam power plant. Characterization of the chemical composition, physics of fuel, handling of biodiesel in handling system to the burner, and the characterization of combustion in the burner simulator are studied. The primary data in this study is the data from the combustion trial results in the burner simulator, while the secondary data is in the form of operation data and power plant design data. Biodiesel has properties close to diesel oil and allows use in blending to a specific ratio. The result shows that the spraying angle of biodiesel and blends are narrower than the B0 condition, and the distance of flame become shorter along with the increase in biodiesel content. These phenomena can cause the burner difficult to ignite, which can be overcome by adjusting the igniter position into the fuel spray distribution zone. Because biodiesel is easily oxidized, it is necessary to maintain the fuel lines kept clean, primarily when the system is not operating for a long time. Biodiesel has a higher viscosity and density than petroleum diesel which can cause problems with the injection start-up burner. The use of biodiesel fuel requires more stringent handling, adding filters, isolating fuel oil tanks from rainwater and humid air, and replacing materials that are not compatible with biodiesel in pipe fittings and gasket.