Soot formation characteristics in a lab-scale turbulent pulverized coal flame with simultaneous planar measurements of laser induced incandescence of soot and Mie scattering of pulverized coal

Laser diagnostics of pulverized coal combustion in O2/N2 and O2/CO2 conditions: velocity and scalar field measurements

“…The presence of Mie signal together with the absence of OH PLIF signal, combined with the high-intensity LII signal in this region, reflects the lack of oxygen in these globally rich mixture conditions (φ bulk = 2.3) and consumption of any remaining oxygen by the devolatilized hydrocarbons and coal particles breaking through the main flame. As observed before (Hayashi et al 2013), the low concentration of oxygen and the high temperatures enhance soot formation greatly. This is also reflected in the increased Mie scatter from soot particles in the center of the product region further downstream at high coal-loading rates.…”

“…A slit is used to eliminate the lowenergy regions of the laser sheet, and a homogeneous laser energy profile is obtained in the imaging area. The laser energy is optimized to achieve maximum LII signal intensity (Hayashi et al 2013). The shot-to-shot variation of laser energy is <2.5 % of mean energy, which eliminates the shot-to-shot energy correction of LII images.…”

“…Coal-based thermal power plants provide almost 28 % of world's primary energy consumption and a 36 % of all CO 2 Hayashi et al 2013) have been made in very small laboratory diffusion flames using methane as a carrier, which demonstrated the feasibility of the diagnostics and interpretation. Other studies (Smith et al 2002) have used Mie scatter as a qualitative index for flame structure.…”

Numerical analysis on effect of furnace scale on heat transfer mechanism of coal particles in pulverized coal combustion field

“…In Central Research Institute of Electric Power Industry (CRIEPI), new models such as the TDP model for detailed devolatilization modeling [10,11] and the RD model for detailed char combustion modeling [12] have been developed to improve the accuracy of the simulation of coal combustion. Since the development of new models require various experimental data to validate the simulation results, various studies have been conducted using test facilities in CRIEPI such as the studies for the combustion characteristics of sub-bituminous coal [13,14], the combustion characteristics of high ash coal [15,16], the hydrogen sulfide formation in coal combustion field [17], the soot formation characteristics in coal combustion field [18], the influence of combustion condition and coal properties on physical properties of flay ash [19] and the detailed flow field in the coal combustion test furnace [20]. Experimental data from the facilities are also beneficial for the understanding of the coal combustion phenomena and the evaluation of coal brands for using in actual scale boiler.…”

Numerical investigation of reaction kinetics of coal volatiles with a detailed chemistry and its simplification

“…Many experimental approaches have been performed to clarify the combustion physics in the coal flame (Makino and Kimoto, 1994;Yi-guo and Jian-ming, 2011;Moon et al, 2013;Hwang et al, 2005;Hayashi et al, 2013). Although the experimental researches have brought enormous advances in understanding the combustion field, our knowledge of the physics taking place within the system is limited due to the difficulties in the direct observation of this two-phase reacting flow.…”