9 replies to this topic

[stelu85]

Dear all,

 

as first approach i've been proposed to use a graphic exchanger as condenser of reaction vapours containing:

 

H2SO4

CH2Cl2

H2O

HCl

 

cleary is a good choice, but i'm looking for what could be the disadvantages of a normal shell & tube heat exchanger.

The previous one was made of Alloy 8020

 

regards

 

[breizh]

Hi, 

For reference : http://www.deltathx....eat-exchangers/

why do you want to replace your existing HX and change the material ? 

Graphite HX should be cheaper ....you need to find a reliable manufacturer of graphite HX  .

 

You may consider tantalum HX 

https://www.alfalava...-ppi00578en.pdf

my 2 cents

Breizh 

Edited by breizh, 03 August 2020 - 10:14 PM.

[stelu85]

Hi Breizh,

 

thatnks for your tips. Cannot find any disadvantages on graphite HX.

Both AISI 316L and Alloy 8020 had corrosion problems, therefore we would like to solve this issue.

 

Probably the best solution is the tantalum you proposed. I will take it into account, thanks

 

regards

[AndyChemEng]

We use graphite vapour condensers as standard at our facility and they are robust. We have cracked a couple over the years though which were down to poor maintenance work - over tightened bolts i believe.

[breizh]

Hi,

To add to my previous post , a brochure from Mersen :

https://www.mersen.c...ocks-mersen.pdf

 

Good luck

Breizh 

[stelu85]

really thanks both of you.

 

Andy, would you suggest the condenser typology you have? Alfa Laval suggests even graphite plate heat exchangers for this application.

[MikeCH]

Dear all,

 

as first approach i've been proposed to use a graphic exchanger as condenser of reaction vapours containing:

 

H2SO4

CH2Cl2

H2O

HCl

 

cleary is a good choice, but i'm looking for what could be the disadvantages of a normal shell & tube heat exchanger.

The previous one was made of Alloy 8020

 

regards

 

Graphite heat exchangers are more fragile. Too much mechanical forces from the connected pipework will damage your condenser. Proper specified bellows are important. Also take care about the material compatibility. These condensers are made out of graphite and a resin. If your chemicals affect the resin, it will swell up and you loose mechanical stability layer by layer. Often, small amines are problematic.

 

You can also consider silicon carbide. It shows great corrosion resistance against various chemicals. But take care about the seals between the tubes and the tube sheet. These seals (O-rings) have to be specified together with the manufacturer. You know about your chemicals and your process. The manufacturer knows about the mechanical design of his HX. 

 

If you can afford tantalum condensers, go for it. But usually they are too expensive.

 

Mersen as potential supplier was already mentioned. They offer Graphite, SiC and Tantalum. 

 

 

Cheers,

Michael

[breizh]

Hi,

another possibility .

You may consider  Tantalum coating on SS :

 

https://tantaline.co...eat-exchangers/

 

Agree with MIkeCH' comments about graphite condenser . 

As a consequence  you need to have a spare equipment in maintenance workshop in case of troubles . 

 

Good luck

Breizh

Edited by breizh, 10 August 2020 - 06:38 AM.

[stelu85]

ty for help, i'll go for different quotes and see what's best in a cost-benefit scheme.

[AndyChemEng]

Hi,

 

We use the graphite block design.

 

Tantalum, as breizh has mentioned, is an alternative and we also operate with these without issue but I am aware that the tantalum is pretty expensive.