I have 26" pipe connected to reactor equipment and sulphur condenser. Pipe conected vertically with in-line pressure balanced expansion joint installed in between. The idea of using inline pressure balance is to reduce get rid of pressure thrust because advantage of spring several spring assembly and their tie-rod that would act to balance the pressure thrust and wouldn't be transmitted to the nozzle. Line having Max Ope. Temp is 390 degC and Design Pressure is 3.5 bar.

I have some discussion with the vendor regarding spring assembly stifness (axial, lateral and bending stifness) and incorporate to Caesar calculation. The things that i'm going to ask in vendor catalog, they still give pressure thrust value (-3503 N) while EJ having 3 spring assemblies(2 flow bellows and 1 balancing bellows), pressure thrust can be assumed become 0 (zero) as a result of those balancing bellows installation? CMIIW

Another query, i build expansion joint as per tools provided by Caesar. I clicked EJ tools and select type, rating, pressure. Since i'm using in-line pressure balanced in the short pipe that is straight line connected between equipment, i have modified the support given by caesar. I've provided 30 mm gap in axial stop since i have nozzle of reactor and sulphur condenser in between. Not provided gap will result a huge force because it would be having 3 anchor in the straight line. Please advice about what i have done by giving 30 mm GAP in axial stop for build EJ in caesar.

thx in adv.
-piper-

http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Number=48711#Post48711

pls go to above link, i made some typo on this.

thx

Hi ,

It looks like you are doing the sulphur recovery unit.The large size and high temp. pipe connected between the reactor and condenser straight. Before I have met the same problem like this , I tried to use expansion joint to reduce the huge thermal force imposed on reactor and sulphur condenser nozzle. However , our client didn't agree to use EJ for sulphur unit !!
We just make a big stress model inculding 3 reactors , 9 heat exchangers , and other auxiliary equipments. Sometimes we need to use spring hangers for some of these equipments and need to check all the external load imposed on these nozzles. This is indeed a large stress work , and need each disciplines to solve together.

By the way , I have asked our client why they didn't agree to use EJ ? They said they have the same plant located in other area and still works without any EJ !! Even we show them the worst case without any EJ used , they didn't accept any flexible element to add.

Maybe if there are other difference experiences for you all members , you can share here and give us some other advice~

This is actually expansion plant and there is previous plant to have the same configuration. The client didn't have any further issue with EJ installation, however they restrict the EJ specification requirement. They asked vendor to give double convolutions with rings in between plus cover. Providing also instrument for early leak detector.

I had arrived with the same idea by using constant spring support for equipment. However, the chamber equipment that having 26" pipe connect to the same reactor as well, hence really tricky having many equipment with constant hanger since all of them act as a sliding.

Appleapple – When we developed the EJ modeler, we did not automate an ILPB EJ because they are so rare. There are two ways to model an ILPB joint:
1) The easiest way is to model it as a weld end, single zero length EJ and an outlet weld end. The axial and lateral spring rates should be per the manufacturer, the angular and torsional SRs should be infinitely large (10E7) and the effective ID should be set to zero. See attached picture.

2) An in-depth model can be created where you would model each of the three / four bellows and then enter restraints spanning from the inlet to the backside of the balancing bellows and then from the outlet to the front side of the balancing bellows. In this case, the bellows data would be the data for the individual bellows.
Also, please remember that an ILPB joint will only absorb axial and lateral movements.

HI,
CCCKKKK,
I have been facing exactly opposite problems ,I have the same equipment to equipment line config.,from reactor to exchanger nozzle going straight vertical upward,I suggested to put equipment exchanger on springs to which client accepted also but mechanical not ready to accept the responsibility of exchanger design on springs? dont know why?can anybody share if they have used such type of design -providing exchanger on springs to take the piping expansion (the equipment total weight is around 8 tonne-10 tonne,will be requiring big ton springs to support)
How ever client having existing line working with untied bellow for 8.5 barg pressure,240 deg C temp & size -30"? not sure how thrust load is taken care of?

Hi raj123 ,

1.For example,
As you may know , it is often useful to provide Reboiler on springs to take
the piping expansion. There are a lot of cases appiled in refinery plants.
From my personal viewpoint , the issue of exchangers supported with springs is no certain problem. Maybe you need to discuss with your mechanicl engineers clearly.

2.Regarding the existing line working with untied bellow for 30", 8.5 barg & 240C temp ; what I can think is that the operating pressure was kept around 0.4~0.6 barg normally and this will result in the thrust force 26kN only~