Critical Impeller Speed (NSG) for Solid Suspension in Sparged Stirred Vessels Fitted with Helical Coils

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• 作者：Bhaurao P. Nikhade ; Jacob A. Moulijn ; and Vishwas G. Pangarkar
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2005
• 出版时间：June 8, 2005
• 年：2005
• 卷：44
• 期：12
• 页码：4400 - 4405
• 全文大小：106K
• 年卷期：v.44,no.12(June 8, 2005)
• ISSN：1520-5045

文摘

An attempt has been made to investigate the effect of the presence of a helical coil, used inspecific cases to increase the heat-transfer rate, on the critical impeller speed (N_SG) for a solidsuspension in a sparged stirred tank reactor. It has been observed that the coil disturbs theflow pattern generated by the impeller, consequently affecting the critical impeller speed. Thecritical impeller speed increases with an increase in the superficial gas velocity (investigated inthe range of 0.52-9.74 mm s^-1). For the small-size solids (<150 m), typical of the industrialcatalyst size and the range of solid loading investigated (0.5-2 wt %), the six-bladed downflow-pitched (45) turbine was found to be the most efficient impeller in terms of power required fora solid suspension.