Bifurcation Behavior and Efficient Pure Hydrogen Production for Fuel Cells Using a Novel Autothermic Membrane Circulating Fluidized-Bed (CFB) Reformer: Sequential Debottlenecking and the Contribution
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- 作者：Zhongxiang Chen and Said S. E. H. Elnashaie
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2004
- 出版时间：September 1, 2004
- 年：2004
- 卷：43
- 期：18
- 页码：5449 - 5459
- 全文大小：217K
- 年卷期：v.43,no.18(September 1, 2004)
- ISSN：1520-5045
文摘
I am pleased to contribute, together with my Ph.D. student Zhongxiang Chen, this paper to the Ind.Eng. Chem. Res. special issue for Professor John Grace of the University of British Columbia inrecognition of his many contributions to subjects of interest to readers in this journal. I have knownJohn since the early 1970s (over 30 years now) when we were both studying for our Ph.D.'s in theU.K. (he was in Cambridge, and I was in Edinburgh). Since then, we have always been in close contact.I visited him at McGill and British Columbia Universities, and he visited me at King Saud and AuburnUniversities, and we cooperated in the development of novel fluidized-bed reformers (e.g., Adris, A.;Grace, J.; Lim, C.; Elnashaie, S. S. E. H. Fluidized Bed Reaction System for Steam Hydrocarbon GasReforming to Produce Hydrogen. U.S. Patent 5,326,550, Jun 1994; Canadian Patent 2,081,170, Dec2002). This was our first explicit application of the sequential debottlenecking methodology, althoughJohn has used the approach implicitly in many cases to develop novel processes. He is running theFluidization Research Center (FRC), which he established in 1997 at the University of BritishColumbia (UBC) and which is funded by Mitsubishi Chemical Corporation (MCC), the Natural Scienceand Engineering Research Council of Canada (NSERC), and a number of other government andindustrial sponsors. The contributions of Professor Grace to fluidization and fluidized-bed reactorsare outstanding. Recently, he edited the excellent proceedings for the 7th International Conferenceon Circulating Fluidized Beds, Niagara Falls, Ontario, Canada, May 5-8, 2003, and contributedexcellent papers to it. I would like to congratulate John for his latest award of the Innovation andScience Council of British Columbia for 2003. He was accorded this prestigious award fordistinguishing himself-as an educator, researcher, and innovator-in his 35-year career as a leadingauthority on fluidization and chemical reaction engineering. I would like also to congratulate himfor his recovery from his latest operation and wish him a fast and safe complete recovery. If youwant to know more about the outstanding achievements of Professor John Grace, I advise you tovisit his Web site at the University of British Columbia, Canada (http://faculty.chml.ubc.ca/jgrace/).The present paper is an investigation of the bifurcation behavior of a novel circulating fluidized-bed(CFB) autothermic reformer. I have learned a lot about CFBs from the excellent work of ProfessorJohn Grace. My Ph.D. student Zhongxiang Chen and I are happy to contribute this paper to thisspecial IECR issue in the honor of this excellent academician.-Said S. E. H. ElnashaieThe multiplicity of steady states (static bifurcation behavior, SBB) in a novel circulating fluidized-bed (CFB) membrane reformer for the efficient production of hydrogen by steam reforming ofheptane (model component of heavy hydrocarbons) is investigated. The present paper highlightsthe practical implications of this phenomenon on the behavior of this novel reformer with aspecial focus on hydrogen production. Two configurations are considered and compared. Onehas catalyst regeneration before gas-solid separation, and the other has catalyst regenerationafter gas-solid separation. The multiplicity of the steady states prevails over ranges of a numberof design and operating parameters with significant impacts on the performance of the reformer.The basis of process evaluation is focused on the net hydrogen production. The dependence ofthe behavior of this autothermal CFB is shown to be quite complex and to defy the simple logicof nonautothermal processes. The unit can be a very efficient hydrogen producer provided thatits bifurcation behavior is well understood and correctly exploited.