Hi Frens,

We are working on a 3" & 6" reactor lines connected at the topmost section of reactor that is almost at 100 meters height from the grade level. The lines needs constant support hangers at almost all locations on the platform (control station), so as to absorb the huge differential displacement between reactor & support structure. Note, there is an independent structure for the reactor & platform & it is no where connected to reactor. Hence, differential displacements.
The vertical displacement at constant spring supports is around +575 to +595 mm (vertically up) and operating loads is in the range of 2KN to 3.5KN maximum. We checked with almost all the spring vendors, no constant spring is available with this displacements values for the given loads (very less loads). Vendors suggest that we need higher loads atleast in range of 10 - 20KN for which they can design the spring for the given thermal displacements.
Can you please guide me the alternate supporting arrangement, where we can allow the thermal displacement upto 600mm & where loads at support location can be upto 3.5 - 5 KN range.

I have attached the Caesar II file (ver 2013 R1)& also the snapshot of the piping arrangement so as to have the better understanding of the problem.

Request you to provide an alternate solution (support type/supporting arrangement)for the constant springs.

One option which I came across is the counterweight balance arrangement mostly used in radiation & crossover section of SRT heaters. However, I dont have any idea on it. Incase, anyone has any idea, please share.

Thanks in advance for the time & efforts spent on the above.

Kindly check the temperature distribution of Reactor.
You can distribute the temperature profile to take the real effect.
so Upward thermal movement will be more realistic.

Hi Adi,

Already checked & confirmed with mechanical as well process, entire reactor's operating temp is at 549ºC. The reactor is Continuous Catalytic Regeneration (CCR) Reactor.
As far as process input are concerned, we were unsuccessful in all our attempts to get some relief on temp.
For same process input, we qualified all big bore lines mainly 42" dia using constant springs, for which spring vendor customised few of those springs so as to accomodate loads/displacements/space requirements. However, as per vendor there are no such springs available/can be customised for huge displacements upto 595mm with constant loads of 2KN. Hence, looking for an alternate to constant spring support.
There is an alternate support namely counterweight support - basically a rope & pulley arrangement that has counter wieght on one side so as to support the pipe on other side, which shall allow the pipe thermal movement with constant load throughout the operating conditions. However, I have never used it & hence don't know its reliability of operation for such critical lines at high temperatures & that too at higher elevations. Experts please share your experience/opinion on the above case.

Thanks.

Dear Piyush,

As you have said that you have qualified big bore lines connected to same equipment using high load , high displacement consatnt springs .

I have not came across situation that you are facing .

As an option , is it possible to support two or more lines on one constant spring by making special arrangement of pipe shoe .

Try it , if it works .

Thanks Mahesh,
Your suggestion is good. However, not all lines are running together or parallel that can be combined. Also, re-routing the lines also is not a solution, as there are specific process requirements mentioned on P&IDs for the max distance (3 mtrs) between the reduction gas heaters (mounted on topmost part of reactor - 3nos) & the nozzles on Reactor top. However, in my calculation, i have exceeded their max requirement by 1 mtr, which can be tackled seperately.