Experimental Study On Separating Fine Lignite By Using Hot Air Vibration Fluidized Bed

Lignite is a sort of low-quality coal with a great reservoir, In connection with theurgent need for the large-scale exploitation of low-quality coal, and treating thelarge-scale exploitation as the study target, here conducting research on dryingpreparation, and this provides a theoretical basis of dry upgrading for China’slow-quality coal. Also it has certain directive significance to practical productionoperations. For its characteristics of high moisture, the lignite in fluidized bed wouldbond into a group easily; here we study the separation by adding the hot air into theVibration fluidized bed.This paper gives a brief introduction of the present situation on the research oflignite resource, and shows the distribution of lignite resource and upgradingtechnology, drying characteristics, the current situation of preparation research, etc.Then it summarizes the associated study about vibration fluidized bed and coal dryseparation. We focus on the study of3-1mm fine lignite, especially the research onseparating mechanism of3-1mm lignite in the vibration bed. Also this paper studiesits fluidization characteristics and separating characteristics in the vibration fluidizedbed, Finally, we study how the hot Air vibrating fluidized bed influences on thefluidization characteristics and separating characteristics of3-1mm fine lignite.This paper discussed the separation characteristics of vibration fluidized bedthrough many methods. With the increase of fluidization number, the separationefficiency increase firstly and then decrease. We get the best separating effect whileN=1.1~1.2. This study presents that the density is not the only factor which affects theseparation of3-1mm fine lignite, and the particle size also effects on the separatingoperation. The separating operation is influenced by density and particle size at thesame time. Meanwhile the experimental study shows the significant inhibitory effectson separation of water content, and it is found that3-1mm fine lignite has the bestseparation effect in fluidized bed.By vibration fluidized bed system platform, we study the effects of vibrationparameters and lignite physical properties on fluidization characteristics in the coldstate, also, we study the effect law of frequency, amplitude and fixing vibrationstrength on separating characteristics, the range test: the frequency of f=10~40Hz,amplitude of A=1~4mm, the separation effect is evaluated by the degree of segregation.we found that: with the increase of frequency, the minimum fluidization velocity decreases, S decreases, the separating effect is poor, with the increase of amplitude,the minimum fluidization velocity increases gradually, separation performanceincreases gradually, the vibration strength is fixed at4, while changing the frequencyand amplitude at the same time, the separation results keep consistent with the abovefrequency and amplitude; With the increase of ash content, the minimum fluidizationvelocity increases, with the increase of water content, cohesion of the particlesreinforce in the bed, so the fluidity is declined.After the test in a hot air vibration fluidized bed, we found a consistent influencelaw with cold state of the frequency and amplitude on fluidization characteristics, butcompared with the cold state, the bed pressure drop fluctuation at this time, S of thehot air vibrating fluidized bed is greater than the value of the cold state in the sameexperimental conditions, this shows that hot air is a significant role in promoting theseparation of3-1mm fine lignite, this is because the hot air promotes the fluidizationof bed layer. According the Preliminary research, we find that the amplitude andfrequency have great fluency on drying lignite，but the drying effect changes littlewhile the frequency of f>20Hz and amplitude of A>2mm.