8 replies to this topic

[Art Montemayor]

Before you do anything else, please read the following thread in the Industrial Safety Forum:

http://www.cheresour...?showtopic=1054

There are many other threads in this website - especially this Profession Industrial Form - which deal with and discuss the hazards attached to the utilization of Nitrogen in or around industrial processes. For example, refer to the last two postings on:

http://www.cheresour...?showtopic=1036

As I've stated many times before, the temptation to employ N₂ as an instrument air substitute is always present but you should also be aware of the potential tragic hazards it carries. I say this with personal experience since I was fortunate in avoiding a very tragic asphyxiation incident early in my career. It also involved using N₂ as an instrument air substitute. Four operators in an enclosed control room full of pneumatic instrumentation almost asphyxiated due to this oversight. I've never forgotten this incident that ocurred when I was starting up a plant in Geel, Belgium around 1970 and I swore I would never allow such an incident to ever become possible in my career again.

Bear in mind that inherently Nitrogen is going to be far more expensive to consume than compressed instrument air. The waste Nitrogen from your air separation column is probably close to atmospheric pressure so it has to be compressed with a compressor to be usable. So you really don't even have an economic advantage or reason for using it. The only way you can justify it is if it is available as a disposable, impure stream at the required pressure or if you are going to employ it only for a brief period while you get your instrument air supply back on stream. You fail to explain your reasons or detailed plans on the utilization of Nitrogen as an instrument fluid --- but regardless of your reasons or plans, an accident can still happen within a short period.

I strongly advise you to NOT go forward with this idea. 13 Nm³/min of air is a hell of a lot of instrument air. Your Nitrogen costs are going to be expensive. But more importantly, your safety risks are going to be what I consider as unacceptable. You can go bankrupt and go on with your life. However, you can never bring back deceased workers back to life.

[Art Montemayor]

The original post states the source of the Nitrogen as being an air separation plant. As such, the Nitrogen product will be 100% absolutely dry since it will have undergone cryogenic distillation and comes out as the overhead product of the Low Pressure Column.

I don't believe any water content or dewpoint will be detected on this Nitrogen source.