Mechanism of Achieving a Dense Downer: Modeling and Validation

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• 作者：Hengzhi Chen ; Hongzhong Li ; and Shiyu Tan
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2006
• 出版时间：May 10, 2006
• 年：2006
• 卷：45
• 期：10
• 页码：3488 - 3495
• 全文大小：160K
• 年卷期：v.45,no.10(May 10, 2006)
• ISSN：1520-5045

文摘

A pressure balance model for a circulating fluidized bed (CFB) unit that incorporates a downer has beenproposed. A comparison of the operation stability between a CFB downer and a CFB riser showed that,although only one critical operating gas velocity exists in the CFB riser for a given riser solids flux, there canbe many critical gas velocities for the operation of a CFB downer. Therefore, it is possible to achieve highsolids concentration in a CFB downer if appropriate operating conditions are used. Parameters that affect thesolids concentration in the CFB downer have been studied using the model and have been validated withexperimental data obtained from a special CFB unit that incorporates a downer. Measures to increase thesolids concentration in the downer have been proposed.