Design Considerations for Stirred Tanks

Another limitation of a boiling reactor is the effect of pressure on boiling point. A very tall reactor will have higher temperatures at the bottom that will typically give lower molecular weight polymer and higher polydispersity in the product. 

Field erection of stirred tanks is much more expensive than shop erection, and the maximum size of a stirred-tank reactor may be limited by the size that can be shipped. Thus plants immediately adjacent to water may be able to have larger reactors than plants accessed only by rail or road. Rail and road shipments limit reactor sizes to about 100 m. Much larger vessels are field-erected, but these designs are usually more suited as low-pressure storage tanks or fermentation reactors than as polymerization reactors that are typically rated for 10-20 atm pressure. 

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