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振动流化床分选细粒煤的稳定性与操作因子优化

Fluidization stability of vibrated fluidized bed and optimization of operating factors for fine coal separation

  • 摘要: 为定量研究振动能量的引入对普通空气重介流化床流化特性、分选效果的具体影响,在实验室振动空气重介流化床(直径120 mm,高度350 mm)上,对宽粒级(0.3~0.074 mm)磁铁矿粉加重质进行流化特性研究,试验表明:在最优操作条件下实验室振动空气重介流化床与普通流化床相比,振动能量的引入降低了分选床体内加重质的起始流化气速,床体密度波动标准差由0.045 9 g/cm3减小到0.028 1 g/cm3。利用响应面法结合正交试验得到振幅A、频率f、流化气速V、加重质静床高H四种操作因子对振动流化床的密度波动影响显著性为:A>V>f>H。在A=1 mm、V=1.2Umf(Umf为流化床起始流化气速)、f=10 Hz、H=80 mm的最优操作条件下对细粒(6~1 mm)永城烟煤进行分选试验表明,与普通流化床相比,振动空气重介流化床可能偏差由0.141 g/cm3减小为0.111 g/cm3。

     

    Abstract: In order to study the effects of the vibration energy on the fluidization characteristics and separation performance of air dense medium fluidized bed, the fluidization characteristics of wide sized magnetite powder ( 0.3 ~ 0. 074 mm) were investigated with the gas-solid fluidized bed ( diameter 120 mm, height 350 mm),t he results showed that the introduction of the vibration energy could reduce the critical fluidized velocity, and the standard deviation of bed density fluctuations reducing from 0.0459g/ cm3 to0.028 1 g 1 cm3. Under the optimal operation conditions, comparing with the conventional fluidized bed. The response surface method was co mbined with orthogonal experiment to study the importance of four various factors: amplitude A, frequency f, gas velocity V and static bed height H. The results indicate d that the significance of four various factors was A>V >f >H. Under the optimal operation conditions ofA= 1 mm, V= 1. 2Umf, f= 10 Hz, H = 80 mm, the experiments were conducted to separate Yongcheng Fine Bituminous Coal ( 6 ~ 1 mm) . Comparing with the conventional fluidized bed, the probable error E value of vibrated air de nse medium fluidized bed was reduced from0. 141 g/ cm3to0.111 g1 cm3.

     

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