Study Of Separation Mechanism And Structure Characteristic Of Radial-inlet Cyclone Separator In Syngas Preliminary Purification Process

This study is motivated by research interest in preliminary purification of syngas from entrained-flow gasification process. The study object is radial-inlet cyclone separator that is the key equipment used in syngas preliminary purification process. The multiphase flow field, separation efficiency and their relations with structure characteristics have been studied by experimental and numerical simulation. The detailed contents are as follows:1. The process of liquid drop impacting on the plate has been studied. The edge characteristics of liquid film formed by different kinds of liquid droplets impacting on plate have been investigated. And the edge liquid droplet, finger droplet and satellite droplet have been inspected. The relationshipn between spread diameter and time has been summarized.2. The distribution of liquid film in radial-inlet cyclone separator has been investigated by self-design double-parallel probe based on changeable resistance. It's found that the liquid film thickness distribution along the wall is dissymmetry and shows spiral path. The coverage area of the liquid film increases with the gas velocity and its distribution uniformity is improved. The increase of the liquid flow rate leads to the increase of liquid film thickness at first. While after the maximum point the current of rotary motion are weakened, and the thickness decreases with fluid flow rate because of gravity.3. The particle concentration distribution in radial-inlet cyclone separator has been studied. Most particles centralize near the wall, and along the radial direction of cylinder section the particle concentration can be divided into particle trapping area and particle separation area. In the trapping area the particles detach the gas flow and deposit on the wall, in the separation area the particle concentration is low and uniform.4. The particle folw field in radial-inlet cyclone separator has been investigated by introducing "holdup". And particle average residence time has been studied. The "holdup" increases with inlet gas velocity, particle concentration, vent-pipe diameter and inlet angle. The particle average residence time increases with vent-pipe diameter and decreases with inlet angle.5. The pressure drop of radial-inlet cyclone separator has been investigated. The gas-solid pressure drop increases with gas velocity, and decreases with vent-pipe diameter and inlet angle. Compared with the effect of particle concentration on the pressure drop, the liquid concentration has a larger influence on the pressure drop. The pressure drop decreases with liquid concentration obviously. And it increases with gas velocity at low liquid concentration. On the contrary, it decreases with gas velocity at high liquid concentration.6. The separation efficiency of radial-inlet cyclone separator has been studied. There exists a critical separation particle diameter. The particle larger than the critical separation diameter can not be separated under centrifugal force. The particle will remain movement at some section, finally separated under gravity. This will lead to the local wall abrasion of cyclone separatorThe critical separation particle diameter decreases with gas velocity and increases with cone diameter. And the critical separation particle diameter for lower density particle is larger under the same condition.7. The multiphase flow field of radial-inlet cyclone separator has been simulated. The effects of configuration parameters and operation conditions on the flow field have been studied. The high efficiency design proposal for radial-inlet cyclone separator is proposed according to analyzing separation efficiency and pressure drop. It's found that the optimum height rate of cylinder and cone is 1, the choice of inlet position should give consideration to "top dust ring" and short circuit flow. Necking design for vent-pipe and small cone bottom diameter are favorable for separation efficiency.