RE: High temperature Piping in Refineries

From: <Mooney>
Date: Thu Oct 04 2001 - 13:18:00 EDT

I agree ,do not use expansion loops directly on a pump suction due to turbulence caused by ell's ,. suggest you provide straight pipe 5- 10D into suction just as std design practice. Maybe a better way of describing is to use offset pipe lengths to relieve stresses. referring to loops was meant as general term for flexibility that is easily misunderstood as a full loop.

On hot lines into multiple pumps suct/Disch I have placed guides in series and spring cans to keep loads below allowable. but to reduce the forces across these restraints a loop or offset length is required. Many times balancing between high moments and low stress and vice versa. There is no cookbook that covers all recipes to resolve stress, especially when many vendors say 0 loads allowed.

Kevin Mooney

-----Original Message-----
From: Udhayakumar, Jayapalan [mailto:JUdhayakumar@mcdermott.com] Sent: Thursday, October 04, 2001 3:37 AM To: 'PipingDesign@yahoogroups.com' Subject: RE: [PipingDesign] High temperature Piping in Refineries

My wishes to all,

In My experience ,

1. Having expansion loop at suction side of rotating equipments are not advisable ( cold pull, no way, please let me know if you happen to experience any where ).Generally suction piping should have minimum number of bends so that friction losses shall be very minimum. selecting spring supports or suitable expansion bellows are the best & workable solution.
2. Discharge is concern , expansion loop is preferable for offsite pipe routing ( other than plant ). For inside plant and equipments, spring supports are preferable.

Over and above, Negotiations can be made to pump vendors to accommodate additional nozzle loads to some extent.

Cold pull could be the last ( better avoid ) option for offsite pipe routing.

This is my opinion.

Please feel free to add / disagree,

Regards,

J.Udhayakumar

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Received on Thu Oct 04 13:18:00 2001