Hastalloy or C/S PTFE for Hypo 1

[PeterPiper]

I am in the process of designing a pipe run for sodium hypochlorite, 14/15%, ambient temp, up to 6bar.g., about 150m long.

I am considering 1" PTFE lined carbon steel or small bore 1/4" hastalloy-c276. Does anyone have any advice for the most ecomical material for a hypo line or experience of use of these ,aterials for hypo duty.

Best regards,

Pete.

 

[josephn16]

Hastalloy is probably the most expensive way to go. I would suggest, if the line size is 1", go with PP lined CS. It's a bit cheaper then TFE lined, and it will handle the hypo easily.

Maybe someone else will know for sure, but you may be able to get away with PVC, which would be the cheapest way to go, but without time to go through the conditions, I'm not sure. I am sure that I have provided hypo lines in PVC before. If I get a chance, I will take a look at the conditions and see if it will be OK for your application.

If you can go with 1/4" line size, why not 316SS or PVC tubing? There may be a compatibility issue with SS, but I am not entirely sure.

 

[butelja]

Titanium is the (metallic) material of choice for hypochlorite. Its pricing is similar to that of Hastelloy C-276. Don't even consider stainless steel, as it is totally incompatible.

 

[PeterPiper]

Thanks for the input.

Do you have any contact for Titanium tubing, 1/4" and 1/2" to supply in the UK?

Regards,

Pete.

 

[butelja]

I am in the USA and haven't worked with any UK suppliers, but I found the following from a web search using Titanium AND UK.

AirCo Metals
Falcon Business Park
Ivanhoe Road
Hogwood Lane Estate
Finchampstead
Berkshire
RC40 4QQ
Tel: +44 118 973 0509
Fax: +44 118 973 1031

http://www.airco-metals.com

 

[vnmarkande]

PVC is good enough & cheapest material for the above service. This can also withstand quite a bit of pressure.

Yes, SS (whether 304 or 316 ) totally unsuited for above service.

 

[ghopkins]

PVC will work for 10-20 years and much, much cheaper than titanium - and more readily available. No issues with pressure rating or finding fittings either.

Greg

 

[josephn16]

Yes, PVC will do fine, just make sure the piping won't be outdoors, because PVC has some UV issues, and won't last the 10-20 years it should if exposed to sunlight on a regular basis.

Thanks to everyone for the input on the SS, I wasn't sure, I just knew that I have never seen it done.

 

[sam01]

Current wastewater treatment plants use PVC or CPVC piping to convey sodium hypochlorite at 15% solution. This is the most economical choice.

 

[DeltaCascade]

Have you considered diluting the bleach with a carrier water stream, like what is done for educting chlorine gas into potable water or cooling water, etc, streams?

 

[duphus]

The PVC option mentioned earlier is a good one. If you have a need for a more robost system that maintains a high degree of external chemical resistance, you can fibreglass wrap the pvc.

 

[cynwrig]

First question is always " How long is this line required - 1,10, 20 years? You can get away with rubber hose if it is for short term, irregular use! Why not ask your Hypo supplier - they handle this chemical every day and deliver to a wide variety of users. But do tell them the average AND maximium usage conditions. The latter statement goes for any materials selection. Chlorides only react with Austenitic St.St's above well documented conditions.

 

[PeterPiper]

FYI,

We used Ti tube, fully welded with pulled bends and the spec changed to U-PVC either end, at valves, drain points and pressure relief. Although the fittings are expensive where the spec changes overall it was the cheapest option.

PeteRJ