空气重介质振动流化床入料特性与操作参数的协同研究
Synergy of coal feed characteristics and operating parameters on the performance of vibrated air-dense medium fluidized bed
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摘要: 入料物性直接影响空气重介质流化床的分选效果,为此进行了不同粒度和不同可选性煤样的分选特性研究,考察了抛射强度、风量与入料特性的协同作用。结果表明:粒级对分选精度的影响显著,随粒级减小,Ep值变大,50~25,25~13和13~6 mm粒级难选煤最小Ep值分别为0.06,0.07和0.11 g/cm3;可选性对Ep值略有影响,50~25 mm粒级不同可选性煤样,易选、中等可选和较难选煤样最小Ep值分别为0.035,0.040和0.045 g/cm3。通过优化风量和抛射强度,分选精度明显提高,不同粒级或可选性煤样优化后的风量和抛射强度相近,均分别在140 m3/h和1.46左右。分析了气泡生成频率与床体振动频率的关系,揭示了振动改善流态化分选的作用机理。Abstract: The separation efficiency of an air-dense medium fluidized bed is directly affected by coal feed characteris- tics. So a systematic study had been carried out to investigate the effect of feed-coal particle size and different wash- ability on its separation characteristics. Moreover,the synergy between projectile strength,air volume and different coal feed characteristics on the separation characteristics was evaluated. The results show that the influence of feed-coal particle size on the separation accuracy is rather prominent. Ep values increase with the decrement of particle sizes. The minimum Ep values for 50-25,25-13 and 13-6 mm difficult-separation coals are 0. 06,0. 07 and 0. 11 g / cm3 , respectively. Washability has a slight effect on Ep . The minimum Ep values for easy-separation coal,moderate-separa- tion coal and more difficult-separation coal of 50-25 mm size ranges are 0. 035,0. 040 and 0. 045 g / cm3 ,respective- ly. Separation accuracy is dramatically improved by the optimization of air volume and projectile strength. The optimum operating process parameters of different coal feed characteristics range over which the separator can operate satisfacto- rily,are found that projectile strength and air volume are 1. 46 and 140 m3 / h,respectively. The mechanism of impro- ving fluidized separation by vibration was revealed by analyzing the relationships between initial bubbles frequency and vibration frequency in the vibrated air-dense medium fluidized bed.