Nitrogen Pipework for pigging system within EX environment

[D!v!ng]

Hi all,

I’ve come full circle on google, emailed manufactures/sellers with no successful response, in process, luckily came across this forum. As much of the information found has been is contradictory including use of copper (more so brass for fittings), galvanized and stainless steel

Handed a nitrogen generator and 5 x 500 litre galvanized receivers to feed multiple pigging systems within a modern EX (liquid solvent) factory that creates cleaning products.

In a nutshell, what material should my pipework be? (ideally brass + galvanized/ stainless steel)



More detail:

UK based. Max used pressure 6 bar

The pigging system is already in place is stainless steel, I’m simply just supplying the nitrogen inlet.

Going to use a ≥30mm solid pipe as a manifold line, teeing off ≥12mm solid pipes. With flexi to the generator, receivers and Inlets on flexi

I was looking at sicomat pipework (here), antistatic coated aluminum with nylon fittings. In my experience nylon can hold static charge, but learnt of Nylon types (PA6, PA12 etc) apparently PA6 is anti static, but again waiting for manufacturers/sellers to get back. Another issue with insulated fittings; I’ll have to earth across each one.

Flexi will be either NBR (compatibility charts) or “legris advanced polyamide calibrated" (what the manufacturer has used in the generator) Pretty sure it’s just PA12 tubing. So will have to be placed outside the EX zone.

Copper can not be used, as it creates CuN2 / CuN3 which is rapid oxidation. Which will affect the products.

 

[D!v!ng]

An update in case this helps any one else.

All Nylon including “legris advanced polyamide calibrated" can cause static.

In this circumstance, the nitrogen generator will be required to feed from outside the zone.

Galvanized and stainless steel are both fine for this circumstance.

 

[LittleInch]

What's the issue you're concerned about here?

Cleanliness or electrical earthing?

What staatic charge?

Velocity you're running at?

 

[btrueblood]

Are there concerns for particle generation (particulate in the line being carried downstream)? If not, galvanized pipe is likely ok (assuming no significant outdoor exposure, or concern for external rust). Basically, SS piping would stay cleaner (no zinc to flake/oxidize and turn to powder).

Not clear how you think copper nitrides will form in a pure nitrogen environment? Normally, nitrides are formed by exposing metal powders to high temperature ammonia, not nitrogen. Not a huge issue either way, copper prices being what they are these days.

 

[EdStainless]

We ran high purity N2 in both Cu and SS.
The Cu was heavy gauge (K) and brazed all of the joints.
The SS was a swaged system (VicPress).
Do you want to dissipate static or to be electrically conductive?

 

[D!v!ng]

What's the issue you're concerned about here?

Cleanliness or electrical earthing?

What staatic charge?

Velocity you're running at?

1. Atex / Ex hazard, as we use >99.5% solvents

2. In regards to what?

3. Any static at all, it's mandatory that everything is earthed.

4. N2 will be 150-300 litres/min

 

[D!v!ng]

Are there concerns for particle generation (particulate in the line being carried downstream)? If not, galvanized pipe is likely ok (assuming no significant outdoor exposure, or concern for external rust). Basically, SS piping would stay cleaner (no zinc to flake/oxidize and turn to powder).

Not clear how you think copper nitrides will form in a pure nitrogen environment? Normally, nitrides are formed by exposing metal powders to high temperature ammonia, not nitrogen. Not a huge issue either way, copper prices being what they are these days.

Only if the particles can create static. Quoting for SS and galvanized today. It's all indoor; very clean environment (for a factory).

Our chemist strictly doesn't want CuN2 / CuN3 touching the products. We create a lot of different products.

 

[btrueblood]

Um, I'd love to see him show you a copper nitride film formed from exposure of metallic copper to nitrogen gas (hint: he would need a high voltage supply to create a nitrogen ion beam).