Study of the Influence of Biodiesel in Soot Emissions of Diesel Laminar Diffusion Flames

Abstract

In this work the presence of soot in laminar diffusion of diesel and blends diesel/biodiesel flames were investigated in the following proportions: 5, 10, 20 and 50% of biodiesel. The technique of laser-induced incandescence (LII) was used for the soot detection. Horizontal mapping were performed at two heights (80 and 260 mm above the burner) to investigate the distribution of soot along the studied flames. The experiment was performed with a pulsed Nd:YAG laser with the wavelength of 1064 nm. The results have shown that the soot emission decreases as the amount of biodiesel increases in the blends. Keywords: laser-induced incandescence, soot, biodiesel, combustion IntroductionDiesel engines are currently the largest source of power generation in the planet. They are widely used in quite different areas, as transportation and mining machinery. They are popular due to their high efficiency, low-cost and durability if compared with gasoline and other automotive fuels.1,2 Nevertheless, diesel engines also presents another remarkable feature: they are largely responsible by the emission of soot, one of most pollutants of environment. 3 Soot is basically formed by particles of impure carbon, with diameter from 10 to 50 nm. Due to its small size, soot particles can penetrate in the lung alveolus of human beings causing serious respiratory and cardiac diseases. 4 Besides health and ecological issues, soot also plays an inconvenient role in the energy generation from combustion processes. [5][6][7] In general, the presence of soot diminishes the overall efficiency of the combustion processes. Soot production is associated to the cracking reactions of hydrocarbon chains that generate carbon solid clusters. These reactions are carried out in gaseous phase and compete directly with the mechanism of oxidation of hydrocarbons that are responsible to the energy release. 8It means that soot is preferentially formed in fuel-rich and high temperature combustion flames, as diffusive flames. These flames are largely used as industrial energy sources. In diffusive flames, as the fuel is burned using only the oxygen available from surroundings, soot presence is higher than the other kind of flames, like premixed ones In some specific applications, like boiler devices, however, a moderate amount of soot is desirable, as its presence increases the heat transfer rate.7 Soot is also quite important in the production of carbon black, which is employed as active filler in rubber products and as component of printing paints.Among the strategies to reduce soot emission from diesel engines, recently a vegetable fuel, known as biodiesel, has been developed. 9 Biodiesel is a kind of biofuel made by alkyl esters from long-chain fatty acids derived from vegetable oils or animal fat. Biodiesel shows a better flammability if compared to other biofuels, and can replace the diesel oil, or diesel/biodiesel blends, in compression ignition engines without significant changes. 10It also presents the following advantages over pure diesel: there are no a...

Environmental Impacts of Biodiesel Production Cycle from Farm to Manufactory: An Application of Sustainable Systems Engineering

“…During this process, the amount of electricity, diesel, steel (used equipment), and copper (electric motors) was investigated. The indirect release of environmental pollutants caused by these inputs was estimated using EcoInvent international databases available in SimaPro 8.1 software [32], and the direct release of pollutants from the workforce was calculated using the method developed by (Nguyen and Hermansen [41].…”

“…The results posited that the total amount of carbon dioxide gas absorbed during the entire biological life cycle of rapeseed biodiesel is much greater than its emission, and biodiesel produced from rapeseed is an environmentally compatible energy source. The results of studies performed by Kumar Agarwal et al [3] and Tolomelli Luiz et al [32] showed that the use of diesel fuel and its combustion in the engine create large amounts of PM 2.5 particles suspended in the air. Examining different studies shows that there is no comprehensive research on the biodiesel production process cycle from different sources (different oils).…”

Qualitative and Quantitative Characterisation of Major Elements in Particulate Matter from In-use Diesel Engine Passenger Vehicles by LIBS

“…Generally speaking, these emission standards do not concern an additional compounds or chemical elements contained in the exhaust emissions or exhaust vapour [10], PM, [11], black carbon/carbon black (BC/CB) [12], or in the soot [13], formed by the diesel or biodiesel [14], from combustion engines [15]. Nevertheless, chemical elements adsorbed by carbonous particles present significant volumetric as well as mass fraction of the total Diesel Particulate Matter (DPM) or soot emission contents.…”