Abstract:
The mixer is an important part of the purification system of coal gasification syngas. However, the adhesion of fly ash particles on the wall of the mixer can cause clogging, resulting in a lowered syngas purification efficiency and compromising the gasification efficiency of the gasifier leading to economic losses. In this paper, the deposition characteristics of gasification fine ash particles in the mixer are numerically simulated by using the particle deposition critical velocity model, and the influence of different particle sizes, gas flow rate and mixer structure on particle deposition is studied. At the same inlet gas velocity, the deposition rate of gasified fine ash on the inner wall surface of the mixer generally tends to decrease with the increase of particle size, especially for particles of 5—13 μm; deposition per unit area of 1 μm particles on the surface of wall4 is the largest. While the deposition rate of different particle sizes varies with the gas flow rate, it generally decreases, and the change of the distance
H from the outlet face of the water pipe to the end face of the indented casing mouth has minimal effect on the deposition rate of particles in the mixer. Mixer C is a structure that can effectively avoid clogging near the indented face.