Chilling sulfuric acid

[NoNickName]

I've been asked to submit a proposal for a sulfuric acid chiller.
Other than using a PHE in Hastelloy, I would like to verify whether it is possible to directly cool it by DX evaporator. I came across http://www.edmeston.com/ and am waiting an answer from them
Anyone any experience on this application?

[US Iceman]

I worked on one of these applications many years ago for a proposal, but the project was canceled. So I don't have any operating success stories to share with you.

I believe this was considered "lethal service", so very specific construction features are required. TEMA (Tubular Exchangers Manufacturers Association) has certain construction methods for this.

Using a PHE does have some risks. Even with welded cassettes you still have the potential for sudden spraying if a cassette gasket blows. he only alternative I am aware of for this is a "spray shield" over the top of the PHE.

I looked at flooded shell & tube and PHE's. I don't know of any reason why a DX cooler would not work as long as it is constructed properly.

[Paulajayne]

What sort of quantites are you looking at?
How is the H2SO4 stored?
Is it a production line?

Perhaps a small cold store might be the way to go?

Paula

[NoNickName]

It is an in-line chilling facility of 51% acqueous solution of h2s04.
I don't know how it is stored. I think with PTFE or Hastelloy pipes. It has to be cooled from 60°C to 30°C, for a capacity of 300kW.

[US Iceman]

It has to be cooled from 60°C to 30°C, for a capacity of 300kW.

At those temperatures you could probably use an evaporative cooler, which would use less energy than a refrigeration system. It might be something to consider... Unless you don't make evaporative coolers.

[NoNickName]

Yeah, supposed so, but the problem is that
1) the plant is in Libya, where db is in excess of 45°C, although wb and dp are very low.
2) There's no water to waste in cooling tower. They use the little water they have for drinking

[Renato RR]

Sea water?Sewage water?

Best regards,
Renato

[NoNickName]

Guys, life's hard, and I need to sell my chillers. Anyway, I can't push the customer to pump sea water for 10 kms into the desert, or to use sewage water (there are no sewages in the desert)

[US Iceman]

Guys, life's hard, and I need to sell my chillers.

That's what I expected. Everyone has to eat and you have to sell products or services to do that.

A couple of comments:

If you put the acid on the shell-side of a DX chiller this could be more expensive than the acid on the tube-side of a flooded chiller.

Acid on the shell side means everything except the heads has to be Hastelloy. On the other hand, if the acid is on the tube-side only the tubes, tubesheets, and heads have to be Hastelloy.

Either way this will be an expensive chiller to build. Another issue may be ability to work with the Hastelloy. If it's anything like titanium there may be a learning curve to deal with.

[NoNickName]

I checked, and Titanium is not suitable, and a PHE in titanium has a 52 weeks delivery time.
The only way I see is a completely hastelloy s&t evaporator.

[US Iceman]

I checked, and Titanium is not suitable,...

I did not mean to suggest the use of titanium for this application. I only meant I have heard working with titanium is difficult and Hastelloy may be just as bad. I don't know about this for sure, but was just offering some free advice on things to be careful of.

You may be able to get base materials with cladding also.

Here is some information on explosion cladding:
http://www.highenergymetals.com/bonding_animation.htm

http://www.idlind.com/metalcladding.html

You could get the heads, baffles, and tubesheet cladded. Just some ideas to consider.

Here is some information on working with Hastelloy that may be helpful.
http://www.haynesintl.com/pdf/h2010.pdf

[US Iceman]

I just happened to think of another possibility you could use: falling film chillers. Just buy the plates and assemble into a package. Now you can do this with TXV's and any one of your normal refrigeration units suitable for the desert ambient.

Install the plates in a box where the metal panels are a simple Hastelloy sheet with a spray bar above the plates.

Depending on the load for each plate you could use either a single TXV with a distributor (one distributor tube for each plate) or separate TXV's on any number of parallel circuits.

Here is a link to some information:
http://us.tranter.com/phe/PDFs/PCC-5.pdf

They also make the plates in Hastelloy!

This would reduce your financial exposure to working with Hastelloy, except for the coil inlets and outlets (the actual refrigerant connections). A lot less trial and error as I see it.

[taz24]

I carried out maint and repairs to an acid plant a while back.
The acid was used to treat aluminium and needed to be cooled do to the heat gained through electrolosis.
The plant was farley standard but the acid was cooled by chiled water that was chiled in a shell and tube evap. The acid / water heat exchanger was made from plastic and was quite big in physical terms.
It stood in a frame that measured at least 2.5mtr tall by 1.5 mtr wide and 3mtr long.
It was a hugh system and time has faded my memory about the specifics sorry.

taz.

[US Iceman]

I have seen something similar to this for a plating process. A chilled water system provided the cold water. The cold water was pumped to heat exchange plates or tubing that surrounded the acid tanks. That seemed to work OK too.

[taz24]

I have seen something similar to this for a plating process. A chilled water system provided the cold water. The cold water was pumped to heat exchange plates or tubing that surrounded the acid tanks. That seemed to work OK too.

I remember the heat exchanger being 50 glass tubes inside plastic pipes each one section was about 2.5 mtr long and with bends that had conections on them. These bends took them round to the next section.
It was a large glass and plastic pipe in pipe heat exchanger.

taz.

[frank]

You could also use a standard chiller and buffer type vessel with the acid circulated through a primary coil inside the buffer vessel, similar to how a primary coil is inserted into a calorifier.

[NoNickName]

Thanks everybody. I now gathered more info, and will work through it.

[w.l.ong]

hello,
i have fews customer in making aluminium,
what we use in here is s&t DX chiller barrel..
the tube is make from stainless steel (forget 304 or 316)
or maybe titanium,
the s&t is from taiwan..i can order it....
if you need more info i can check for you....


regards.
w.l.ong