Uniform purging of resins in contact bed purge vessels
Resin storage vessels such as bins, silos, and tanks often double as purge vessels, in which products are purged of volatiles or polymerization reactions are controlled. Processing is achieved by gas flowing among resin particles or pellets. Problems associated with these purge vessels include typic...
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Published in | Polymer engineering and science Vol. 39; no. 9; pp. 1802 - 1811 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Hoboken
Wiley Subscription Services, Inc., A Wiley Company
01.09.1999
Wiley Subscription Services |
Subjects | |
Online Access | Get full text |
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Summary: | Resin storage vessels such as bins, silos, and tanks often double as purge vessels, in which products are purged of volatiles or polymerization reactions are controlled. Processing is achieved by gas flowing among resin particles or pellets. Problems associated with these purge vessels include typical bin flow problems such as flow stoppages due to arching or ratholing, erratic discharge, particle segregation, and flooding or flushing. In addition, purging may be non‐uniform or incomplete, and cross contamination between grades may occur. These problems are often the result of either a funnel flow pattern, where some of the material in the vessel moves while the rest remains stationary, or a non‐uniform velocity profile, where some parts of the vessel flow much faster than others. Also, the location and the manner in which gas is injected into the vessel contents affect the uniformity of exposure of polymer particles to the gas. This paper describes methods of designing purge vessels to eliminate stagnant regions. Also, velocity gradients of solids in mass flow vessels (where all of the material is in motion whenever any is withdrawn) are discussed. Considerations of the gas introduction schemes that do not disturb the resin flow patter are also described. |
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Bibliography: | ArticleID:PEN11574 istex:A5B6579E4E9E811CF0F49D552050D3E882B00F08 ark:/67375/WNG-VM8J25KH-P |
ISSN: | 0032-3888 1548-2634 |
DOI: | 10.1002/pen.11574 |