Computational investigation of contraction behavior in a liquid-solid fluidized bed

Petroleum Science, Jan 2012

Contraction behavior of a liquid-solid fluidized bed has been investigated numerically. Based on a simple hydrodynamic model proposed by Brandani and Zhang (2006), a case study for solid particles with a density of 3,000 kg/m3 and a diameter of 2.5×10−3 m is simulated in a two-dimensional fluidized bed (0.50 m height and 0.10 m width). Due to the continuity of numerical computation, there is a transition region between two zones of different solid holdups when the liquid velocity is suddenly changed. The top, middle and bottom interfaces are explored to obtain a reasonable interface height. The simulated results show that the steady time of the middle interface is more close to Gibilaro’s theory and suitable for describing the contraction process of a phase interface. Furthermore, the effect of liquid velocity and particle diameter is simulated in the other two-dimensional fluidized bed (0.10 m height and 0.02 m width) where the solid particles are glass beads whose properties are similar to those of the catalyst particles used in the alkylation process. The results also show good agreement with Gibilaro’s theory, and that larger particles lead to a more obvious bed contraction.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2Fs12182-012-0188-7.pdf

Computational investigation of contraction behavior in a liquid-solid fluidized bed

Corresonding author. email: zhang ecei ed May Computational investigation of contraction behavior in a liuidsolid uidized bed Yao Xiuying 1 Guan Yanjun 1 Chang Jian 0 Zhang Kai 0 1 Jiang Jianchun 0 National ngineering Laboratory for iomass Power Generation qui ment , North China lectric Power ni ersity, ei ing 102206 , China National ngineering Laboratory for iomass Chemical tilization, Institute of Chemical Industry of orest Products, Chinese Academy of orestry , Nan ing 210042 , China 1 State Key Laboratory of Hea y il Processing, China ni ersity of Petroleum , ei ing 102249 , China Contraction beha ior of a liquid-solid fluidized bed has been in estigated numerically. ased on a simle hydrodynamic model roosed by randani and hang (2006), a case study for solid articles with a density of ,000 g m and a diameter of 2.5 10- m is simulated in a two-dimensional uidized bed (0.50 m height and 0.10 m width). Due to the continuity of numerical com utation, there is a transition region between two zones of different solid holdu s when the liquid elocity is suddenly changed. he to , middle and bottom interfaces are e lored to obtain a reasonable interface height. he simulated results show that the steady time of the middle interface is more close to Gibilaro's theory and suitable for describing the contraction rocess of a hase interface. urthermore, the effect of liquid elocity and article diameter is simulated in the other two-dimensional fluidized bed (0.10 m height and 0.02 m width) where the solid articles are glass beads whose roerties are similar to those of the catalyst articles used in the al ylation rocess. he results also show good agreement with Gibilaro's theory, and that larger articles lead to a more ob ious bed contraction. Liquid uidized bed; dynamic bed contraction; C D simulation - With increasingly stringent en ironmental rotection olicies, the roduction of gasoline with high octane alue, low olefins, and low sulfur content oses a great challenge to the oil re ning industry of China. o meet this challenge, no el catalysts and rocesses for roducing clean fuel ha e been roosed, e.g., the Hydrodesulfurization (HDS) and C4 alylation rocesses (Chang et al, 2009). HDS is a commonly used method for sulfur reduction of etroleum in refineries (Guo et al, 2010). Howe er, this rocess will cause a significant reduction of octane number due to the saturation of olens in nahtha from uid catalytic cracing, as well as the high hydrogen consumtion (Song, 200 ). n the other hand, al ylate is one of the few com onents that seems to a oid such restrictions (Hommeltoft, 2001 Meister et al, 2000) due to its low olatility, reacti ity and toicity (Platon and homson, 2005). he al ylation rocess is thus a romising method to roduce clean gasoline. At resent, de elo ment of an al ylation rocess using Initial and operating conditions p p p0 p0 H ave s s l l s H z s H t H 0 l g ave g (H 0 z) (z H0) l g (H t z) (z>H0) 3 Results and discussion 3.1 Prediction for response time LI U dLI d l 2 l1 dLI dt U A U dLsd U l l dL dt dL dt U l L U U U L L2 U 2 3.2 Determination of the interface height 3.3 Bed contraction h h 0.4 0.3 m , t igh 0.2 e H 0.1 0.0 z, m 3.4 The effect of particle diameter 4 Conclusions Nomenclatures C ds Fad g Greek letters Subscripts l s Acknowledgements


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2Fs12182-012-0188-7.pdf

Xiuying Yao, Yanjun Guan, Jian Chang, Kai Zhang, Jianchun Jiang. Computational investigation of contraction behavior in a liquid-solid fluidized bed, Petroleum Science, 2012, 93-99, DOI: 10.1007/s12182-012-0188-7