Process analysis of fine coal preparation using a vibrated gas-fluidized bed

• The process of fine coal dry preparation in a vibrated gas-fluidized bed (VGFB) was analyzed.
• Particle distribution characteristics of − 6 + 3 mm fine coal in a VGFB were experimentally investigated.
• Effects of several factors on separation performance were evaluated by using response surface methodology.
• A VGFB of fine coal had a satisfactory separation performance with an E value of 0.18.

Fine coal dry preparation becomes more and more significant for countries and regions which have insufficient processing water. Fine coal separation based on density segregation in a vibrated gas-fluidized bed (VGFB) does not use water and dense medium and has a good separation performance. This paper attempted to carry out a systematic process analysis of fine coal preparation in a VGFB. Particles distribution characteristics were experimentally studied and it was pointed out that a VGFB of fine coal having a periodic slugging behavior could obtain a good performance of density segregation. Furthermore, the effects of several operational factors on the stratification performance were studied using Box–Behnken response surface methodology (RSM) and the RSM analysis indicated that several factors including superficial air velocity, vibration intensity and bed height all had significant effects. Among these factors, the superficial air velocity behaved considerably more significant than others. Under the optimal operational conditions determined by the RSM analysis, the results of − 6 + 3 mm fine coal preparation in a VGFB showed that the yield and ash content are 76.68% and 25.15% as to the clean coal product, and 23.32% and 60.08% as to the gangue product, respectively. The probable error E value is 0.18, indicating a good performance of fine coal dry preparation in a VGFB.

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