7/30/2019 Article in Chemical Industry Digest-March 2013

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Chemical Industry Digest. March 2013

CMY K 

Pipe Routing

The authors present the advantages of using dyke

bellows in tank farms and discusses this in the context ofone of their projects. Instead of anchoring of pipes in

dyke wall, they recommend use of dyke bellows to satisfy

pump nozzle loads in case of process & space con-

straints.

Use Dyke Bellows in Tank Farm Area toaddress Process and Space Constraints

Avinash Kadam, Sudhir Bhise

Authors

Avinash Kadam (M.Tech., IIT Delhi) is currently

head of Stress-Support Group Aker Powergas,

Pune. He has 10 years of experience in stressanalysis. He has previously worked for Lurgi,

Samsung Engg (S. Korea), Hyundai offshore Engg

(S. Korea).

Sudhir Bhise (B. E. Mech, VJTI Mumbai)

is freelance consultant and trainer. He has 15

years of experience in stress analysis. He has

worked for reputed organisations such as Tata

Consulting Engineers, Uhde India, Aker Powergas,

Pune.

Introduction

As projects get more complex and space isa limitation, piping engineers face a chal-lenging task to fulfill all requirements of 

safety and functionality of piping under givenconstraints. In this project, there were eight tankswith eight pumps in an area of 24.5 m x 50.5 m.Each tank size was 8.5m, which left limited spaceto plan pumps and piping connected betweenpumps and tanks. All these tanks were enclosedin a dyke wall to satisfy safety norms of industry

to avoid spillage in case of leakage of tanks. Linesrunning from tank to pump have to cross dykewalls. To meet the requirement of a spill proof dyke wall and provision of sufficient flexibilityto piping, we used the concept of Dyke Bellows.

Layout details

Typical layout for tank farm area, layout con-sisted of tanks and pumps (Fig 1). Pumps werelocated outside dyke wall. At a location wherepipe penetrated dyke wall, a barrier puddle flangewas provided.

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7/30/2019 Article in Chemical Industry Digest-March 2013

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Chemical Industry Digest. March 2013

CMY K 

Pipe Routing

When puddle flange is usedin dyke wall, the puddle flangeacts as an anchor restricting alldegrees of freedom. From above

layout, it is clear that there is littlespace available both inside andoutside the dyke wall to provideflexibility using bends to bring

 bo th tank and pump no zz leloads within vendor allowablelimits. This situation also createshigh forces and moments on tankand pump nozzles.

Dyke bellows

Provision of dyke bellows in suchsituation is a good solution for all stressanalysis problems. Here, one end of bel-lows is clamped on service pipe and an-other end on pipe sleeve which is in-serted in dyke wall (Fig.2). Sleeve size iskept one size higher than service pipe.Also, these bellows act as a dyke wallsealant, in case of failure of tank. Thisconstruction allows the pipe to movefreely inside the sleeve eliminating theanchoring effect of puddle flange. When

used for pump system in tank farm area,this helps to reduce pump and tanknozzle loads.

As bellows do not come in contactwith the service fluid, except when thereis spillage, it will have good service life.Minimum specifications for dyke bel-lows should consider the following:

1. Material of bellow

2. Small end size

3. Large end size

4. Clamp material for both sizes

5. Length

6. Fluid service (in case of tank spillage)

7. Expected displacements (axial & lateral)

Fig 1. Tank farm layout: A total of eight tanks with pipe rack in between to lay pipes.

All pumps are closely spaced, leaving minimum space to route suction lines from tank

to pump.

Requirement of bellow (with clamps) to allow pipe expansion and avoiding anchor at dyke

wall.

Fig 2. In the above scheme presented, we satisfy all requirement by using

dyke bellows which is cost effective technical solution and easy to install.

Pipe

Clamps

Bellow

Dyke wall

Pipe sleeve

Fig.3 Dyke Bellow

Summary

Dyke bellows offer a good techno-economic solution for relieving stress of pipes crossing walls without unnec-essarily altering the piping route. At the same time, it maintains the integrity of the dyke wall.

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