Abstract
Teeter Bed Separators (TBS) are liquid–solid fluidized beds that are widely used in separation of coarse particles in coal mining industry. The coal particles settle in the self-generating medium bed resulting in separation according to density. Due to the existence of self-generating medium beds, it is difficult to study the sedimentation of particles in TBS through experiments and detection methods. In the present research, a model was built to investigate the bed expansion characteristics with water velocity based on the Euler–Euler approach, and to investigate the settling of foreign particles through bed based on the Euler–Lagrange approach in TBS. Results show that the separation of in TBS should be carried out at low water velocity under the condition of stable fluidized bed. Large particles have a high slip velocity, and they are easily flowing through the bed into the light product leading to a mismatch. The importance of self-generating bed on separation of particle with narrow size ranges are clarified. The model provides a way for investigating the separation of particles in a liquid–solid fluidized bed and provides suggestions for the selection of operation conditions in TBS application.
Highlights
Fluidization technology has been widely used in chemical reactions, mineral/coal separation and pneumatic conveying in the past few decades [1,2,3,4]
Teeter bed separator (TBS) is one of liquid–solid fluidized beds mainly applied to the separation of coal fines and mineral, desliming and tailings recovery [5,6,7,8]
It has been reported that new separators were well applied in mineral sand, low grade iron ore, chromite and coal fines in industry, as well as pyrite, phosphate ore, heavy minerals, electronic waste and hematite in laboratory and pilot plants [13,14,15]. Applications separating these materials have been illustrated the improvement for separation performance of TBS
Summary
Fluidization technology has been widely used in chemical reactions, mineral/coal separation and pneumatic conveying in the past few decades [1,2,3,4]. Several researches were attempted to model the particle separation based on convection-diffusion equation, CFD simulation and hindered particle settling model incorporated with operating and design variables [19,20,21] In these applications, the mechanism of the particle movement is the basic and most important for a good prediction and optimization of TBS. The effect of fluidized water velocity, flow patterns, operating conditions, fluid properties, particle properties, bed dimensions and the drag laws on the motion of binary particles were studied. Considering applicability of three numerical methods, we proposed that the pseudo-fluid method is suitable to simulate the fluidized bed composed of a large number of fine particles with less computational consumption. An attempt is made to study the change of bed characteristics with operating water velocity and the settling behavior of particles introduced to the bed based on a combination of the Euler–Euler and Euler–Lagrange approach.
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