Investigating particle and volatile evolution during pulverized coal combustion using high-speed digital in-line holography

Characterisation of the combustion behaviours of individual pulverised coal particles entrained by air using image processing techniques

“…For example, the experiment results of the combustion characteristic of single coal particles in a laminar flow field explored by Köser et al [7] provided certain data support for the simulation results of Farazi et al [8]. Among various experimental studies, thermogravimetric analysis (TGA) [9] and visualisation methods [10][11][12][13][14][15][16][17][18][19][20][21] are the most commonly utilised to analyse the combustion behaviours of single solid fuel particles. However, the TGA method can only obtain the mass loss variation parameters of the fuel.…”

“…In the volatile combustion phase (about 1-20 ms), Ao and Ac, increase rapidly at the beginning and reach the maximum at 8 ms and then decrease to the minimum quickly. In this phase, the area of the combustion zone could increase to approximately 10 times bigger than that of the char particle [11,16,21]. Ap increases gradually after experiencing a short-lived decreasing period (22-26 ms, after the devolatilisation phase).…”

“…The support vector machine and deep learning algorithms were adopted to establish an automatic system for the identification of the rank of coal based on the morphological features of the burning coal particle [19]. Wu et al [20] and Yao et al [21] obtained particle images from three directions and realised a multi-angle comprehensive analysis of burning coal particles utilising digital in-line holography. However, there is still much information contained in these digital images that have not been attended, such as displacement, structure, time, texture, etc., for the quantitative analyses of combustion behaviours of coal particles.…”

Time-Series Temperature Measurement during Combustion of Volatile Matter and Coal Char of a Single Pulverized Coal Particle via Magnified Two-Color Pyrometry with Blue Backlit Imaging

“…14,16−18 Wu et al 19 demonstrated that digital in-line holography has the capacity to simultaneously measure reacting multiphase objects in hostile environments. Yao et al 16 used high-speed digital in-line holography to visualize and quantify the evolution of particles and volatile matter during pulverized coal combustion. Shaddix and Molina 14 showed that the soot cloud size and temperature are strongly affected by the oxygen content of the bulk gas and the use of N 2 versus CO 2 diluent.…”

“…Since the temperature gradient in a drop tube furnace (DTF) is lower than that in a practical coal-fired power plant, high temporal and spatial resolution measurements are required to reveal the time series of soot formation under high heating rate conditions. Although optical or laser measurement methods are useful for measuring soot formation, insufficient in-depth data have been obtained via the optical measurement of single pulverized coal particles. ,− Wu et al demonstrated that digital in-line holography has the capacity to simultaneously measure reacting multiphase objects in hostile environments. Yao et al .…”