Effect of agitation on the characteristics of air dense medium fluidization  

作　　者：Wang Yanan Luo Zhenfu Huang Ge Ren Baojin 

机构地区：[1]School of Chemical Engineering and Technology, China University of Mining & Technology

出　　处：《International Journal of Mining Science and Technology》2016年第3期383-387,共5页矿业科学技术学报（英文版）

基　　金：financial support by the National Key Programs for Fundamental Research and Development of China(No.2012CB214904);the National Natural Science Foundation of China(Nos.51174203,51134022)

摘　　要：In order to study the effect of agitation on the characteristics of air dense medium fluidization, we designed and constructed an agitation device. Analyses were then conducted on the fluidization characteristics curves, the bed density stability and the average bubble rise velocity Uaunder different agitation conditions. The results indicated that a lower bed pressure drop(without considering lower gas velocity in a fixed bed stage) and higher minimum fluidized velocity are achieved with increasing agitation speed.The height d(distance between the lower blades and air distribution plate) at which the agitation paddle was located had a considerable effect on the stability of the bed density at 9.36 cm/s < U < 10.70 cm/s. The higher the value of d, the better the stability, and the standard deviation of the bed density fluctuation r dropped to 0.0364 g/cm^3 at the ideal condition of d = 40 mm. The agitation speed also had a significant influence on the fluidization performance, and r was only 0.0286 g/cm^3 at an agitation speed of N = 75 r/min. The average bubble rise velocity decreased significantly with increasing agitation speed under the operating condition of 1.50 cm/s < U–U_(mf)< 3.50 cm/s. This shows that appropriate agitation contributes to a significant improvement in the fluidization quality in a fluidized bed, and enhances the separation performance of a fluidized bed.In order to study the effect of agitation on the characteristics of air dense medium fluidization, we designed and constructed an agitation device. Analyses were then conducted on the fluidization characteristics curves, the bed density stability and the average bubble rise velocity Uaunder different agitation conditions. The results indicated that a lower bed pressure drop（without considering lower gas velocity in a fixed bed stage） and higher minimum fluidized velocity are achieved with increasing agitation speed.The height d（distance between the lower blades and air distribution plate） at which the agitation paddle was located had a considerable effect on the stability of the bed density at 9.36 cm/s 〈 U 〈 10.70 cm/s. The higher the value of d, the better the stability, and the standard deviation of the bed density fluctuation r dropped to 0.0364 g/cm^3 at the ideal condition of d = 40 mm. The agitation speed also had a significant influence on the fluidization performance, and r was only 0.0286 g/cm^3 at an agitation speed of N = 75 r/min. The average bubble rise velocity decreased significantly with increasing agitation speed under the operating condition of 1.50 cm/s 〈 U–U_（mf）〈 3.50 cm/s. This shows that appropriate agitation contributes to a significant improvement in the fluidization quality in a fluidized bed, and enhances the separation performance of a fluidized bed.

关 键 词：Agitation Fluidized bed Bed pressure drop Minimum fluidization velocity Bed density Bubble 

分 类 号：TD92[矿业工程—选矿]