Spectroscopic analysis of crude rapeseed oil flame

Abstract

Utilizing crude vegetable oils in all types of heat engines can be a part of sustainable economy in the future. Focusing on their local usage, they can possibly compete with fossil fuels. Furthermore, to keep the pollutant emissions at the lowest possible level, the feedback control of the equivalence ratio is essential. Regarding the harsh environment of the combustion chambers, optical flame diagnostics is a potential tool. Therefore, in order to examine its feasibility, the comparison of flame emission spectroscopy (FES) of rapeseed oil with standard diesel oil was carried out at atmospheric conditions in a lean premixed prevaporized (LPP) burner at 15 kW of firing power. The well-known chemiluminescence intensity ratios of OH*, CH*, and C 2 * at 516 nm (C 2, 516 *) were investigated. A further significant peak was found at 554 nm in case of rapeseed oil firing, which probably corresponds to C 2 * (C 2, 554 *). The corrected chemiluminescence intensity ratios as a function of air-fuel equivalence ratio are shown in the current work. It was found that these ratios involving C 2 * at either 516 or 554 nm show less sensitivity to the pressure of atomizing air than OH*/CH*, therefore they are more suitable for diagnostics and for the control of the equivalence ratio of liquid fired burners.

Flame emission spectroscopy measurement of a steam blast and air blast burner

“…Finally, the uncertainty of the positioning system of the spectrometer is 1 mm both horizontally and vertically. Further details of the spectrometer can be found in the literature [36,37].…”

Droplet dynamics and size characterization of high-velocity airblast atomization

“…Our previous combustion studies revealed that atomization characteristics considerably affect the flame shape, pollutants, and chemiluminescence emissions (Józsa and Kun-balog, 2015;Józsa and Sztankó, 2016;Kun-Balog and Sztankó, 2015). In order to analyze both local and global spray characteristics, the plain-jet airblast atomizer was examined in cooperation with the Brno University of Technology.…”

Evaporation of Renewable Fuels in a Lean Premixed Prevaporized Burner

“…Therefore, the presented method is conservative. More details about the experiments related to this burner can be found in the literature (see, e.g., [9,13]). …”

“…In practical devices, the combustion power demand is given rather than the fuel flow rate. Consequently, SMD calculations were carried out keeping 15 kW of firing power, which comes from the previous experimental studies [9,13].…”

“…Volatility is also of importance, which usually grows with the length of the carbon chain. The temperature of combustion air was set to a constant value of 700 K, also based on the previous measurement series [9,13]. Table 3 contains the atomization and evaporation characteristics of the investigated fuels at 700 °C and atomization gauge pressure of 0.818 bar (critical pressure ratio, hence maximum investigated value), 0.333 bar (between the limits of the investigation by atomizing air exit velocity), and 0.053 bar (minimum investigated value).…”