Factorial Tests on Process Operating Conditions and Bed Fines on the Circulating Fluid Bed Performance

详细信息    查看全文

• 作者：Lawrence J. Shadle ; James Spenik ; Angela Sarra ; and John Ontko
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2004
• 出版时间：July 21, 2004
• 年：2004
• 卷：43
• 期：15
• 页码：4166 - 4173
• 全文大小：122K
• 年卷期：v.43,no.15(July 21, 2004)
• ISSN：1520-5045

文摘

A cold-flow circulating fluid bed (CFB) was operated using coke breeze with a packed-bedstandpipe over a range of riser and standpipe air flows. The bed materials were selected tosimulate solids flow in a CFB gasifier (carbonizer) but are generally relevant to most CFBprocesses. CFB tests were conducted primarily in the transport mode with sufficient gas velocityto achieve a uniform axial riser pressure profiles over most of the riser height. The independentvariables tested included the riser gas velocity, aeration at the base of the standpipe, andconcentration of fines (average particle size). The solids inventory and riser outlet pressure weremaintained constant. Factorial tests were conducted in randomized order and in duplicate toprovide and an unbiased estimate of the error. Fines were tested as a blocked variable. The gasvelocity, standpipe aeration, and relative amount of fine particles were all found to be significantfactors affecting both the riser solids holdup and solids flux. The riser pressure drop and masscirculation increased at the higher level of fines contrary to some earlier reports in the literature.The riser pressure drop was fitted using the general linear model (GLM), which explained morethan 98% of the variation within the data, while a GLM for the mass circulation rate explainedover 90%. The uncertainty of process operating variables was characterized independentlythrough a series of duplicated flow proving experiments.