Bursting heat transfer jackets due to thermal variation

In my company, each reactor has a jacket through which steam, cooling water & Brine (-30 deg. celsius ,CaCl2) is passed for process heating or cooling. this resuls in the jacket piping being subjected to excessive thermal variation. Also , Brine ( CaCl2) is highly corrosive to MS piping. Could you help me regarding the choice of material that I must use for these jackets and the type of weld joints.

Thanks
mgindia@indiatimes.com

 

[butelja]

Alternating steam / water service is pretty severe by itself, but can usually be handled by a carbon steel half-pipe jacket with full penetration welds (NOT fillet weld only). Stainless steel is not good due to chloride stress cracking in steam/water service, and even more so with the CaCl2 present. Would it be possible to have separate zones of a half pipe jacket and/or internal coil dedicated to each service?

A plain jacket with large corrosion allowance could work, but will result in a very heavy expensive vessel.

Don't even consider a dimpled jacket. These WILL FAIL in alternating steam / water service. Thermal shock and/or waterhammer breaks the dimple welds. These will not always cause external leaks, and can crush the inner vessel if enough dimple welds fail.

 

Although more expensive as an initial investment, what about the exotics such as AL6XN? Anyone know?

 

[MJCronin]

mgindia,

A couple of comments here, I believe, are necessary...

- Is a "brine", a highly corrosive liquid, the best choice for a heat transfer fluid ? This does not sound like a good choice to me. Many chemical companies use a glycol liquid for jacketed vessels in heating and cooling service.

- The use of steam in a vessel jacket will lead to "hot spots" and venting problems. Usually, an injection heater that will mix steam with water is a better solution for a heating system design. ( Go to the PICK Heater website

http://www.pickheaters.com

or see "Chemical Engineering Progress" magazine - June 1997 issue)

- What the heck is "MS" piping ?? Main Steam ?

Keep us informed....


MJC

 

[rustbuster1]

I'm betting MS stands for mild steel.
As MJC points out, some of the design decisions in this arrangement seem doomed from the start. Maybe this is a better case of what not to do than a system with the hope of some convenient remedy.