Abstract
• Influence of operating condition on particle motion characteristics is studied. • The particle fluctuation indexes during motion process are analyzed. • The in-situ observation of particle behaviors below the burner plane is realized. • The change of maximum volatile frame area with initial particle size is discussed. • A time-scale comprehensive model of particle evolution is established. The characteristics of the coal particles in the entrained-flow gasifier are closely related to the stable operation of the gasifier. In this study, the particle motion and evolution characteristics in the impinging-flow zone were studied based on the bench-scale coal-water slurry (CWS) opposed multi-burner (OMB) impinging entrained-flow gasification platform and the radial imaging system below the burner plane. The visualization system was applied to obtain particle image sequences under different operating conditions. Image processing algorithms and statistical methods were used to calculate the particle parameters. The results show that the number of particles with small size increases with the rise of O/C ratio (elemental oxygen to elemental carbon). Particle movement is closely influenced by aerodynamic force and gravity, and there are velocity and direction fluctuations during the movement. The different types of particle ignition/oxidation behaviors based on size were described in detail and statistically distributed. The larger particle size and higher O/C ratio contribute to the larger maximum volatile flame area. A time-scale particle evolution model including heating-up, volatile oxidation and char oxidation was established. During particle evolution, the latter part of the volatile oxidation and the early part of the char oxidation overlap in a period of time.
Published Version
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