Avoid Costly Design Mistakes

Common errors keep plants from getting the most reliable and suitable vessels

By Chip Eskridge, Jacobs, Mike James, DuPont, and Steve Zoller, Enerfab

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and 60° configurations but mechanical
cleaning may be harder.
Click on illustration for a larger image.

The 45° or 90° pattern is selected if shell-side mechanical cleaning is required. Such a pattern also requires a removable bundle. The 45° is more common than the 90° because it provides more shell-side flow disturbance, which improves heat transfer. A 90° pattern is used to reduce pressure drop at the expense of duty and often is employed in boiling service to enable better vapor disengagement.

Make the right choices
In today’s chemical industry, too many engineers given the task of specifying welded equipment such as vessels, heat exchangers and tanks aren’t well versed in what’s necessary to develop an economic design that provides suitable safety and performance. Myriad choices must be made — and each will incrementally add to the final cost and schedule. When looking for savings, cutting the wrong corners may turn out to be very costly over the equipment’s service life.

Chip Eskridge is a principal engineer with Jacobs, Louisville, Ky. Mike James is a senior consultant, materials engineering, for DuPont, Houston. Steve Zoller is director of fabricated equipment for Enerfab, Cincinnati. Reach them via e-mail at chip.eskridge@jacobs.com, Michael.M.James-1@USA.dupont.com and Steve.Zoller@enerfab.com.

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