×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

We are about to carry out tightness

We are about to carry out tightness

We are about to carry out tightness

(OP)
We are about to carry out tightness test of a Diesel Hydrotreater reaction section for newly constructed plant. The op.pr. is 125 kg/cm2 range.

To carry out tightness test of this system with NITROGEN, Make-up gas and Recycle gas compressors can provide max upto 42 kg/cm2 g pressure because of constraint on discharge temp with higher disch. pr. The valves on compressor for nitrogen service are also not designed for higher pressure.

We are planning to carry out tightness test with Nitrogen upto 42 kg/cm2 g pr. and then inject Hydrogen to carry out tightness test upto about 100 kg/cm2 g pressure.
However, our client is asking us to carry out tightness test with NITROGEN only up to 100 kg/cm2 g pressure which is not possible with the compressor in the plant.

I would like to know if someone has an exp for carrying out tightness test with Nitrogen only under these conditions. Is it really required to carry out tightness test above 42kg/cm2g pr with nitrogen?

Thnx in adv.

Nirav Kholiya
nirav-kholiya@enc.ltindia.com
www.lntenc.com

RE: We are about to carry out tightness

I am glad I live a long way from this plant. This is a high pressure (in my opinion) to be carrying out a pnumatic test. I would avoid it if possible, and use Diesel or fuel oil ..I am presuming that this is a hydrotest you are doing and not a sensitive leak test. If its a sensitive leak test I would opt for a lower pressure using helium....maybe more costly but lots less dangerous

RE: We are about to carry out tightness

(OP)
Thanks for reply Aybee,
I am not talking about hydrotest. The hydrotest was done during mechanical works.
At present, we are talking about the 'leak test' of the system before commissioning. As you said, helium would be the better choice, but we don't have provision for that as the quantity of the gas required will be huge for the entire plant.

RE: We are about to carry out tightness

I think using Hydrogen is not a great Idea. Secondly if you are checking the leak tightness of the whole system (All items in one stroke) you have a problem for gettig the required volume of inert Gas. Why don't you split your test scheme so that you are able to check in sequence and use the inert gas.

You are constraining yourself by using available resourse. You may hire a compressor to suit your pressure that is if the test is specified in your Purchase or contract document.

I suggest you make a detailed test procedure and get the same approved by local safety body and your consultant before venturing into such high pressure test.

Why don't you reason out with your process licensor and consultant and try offering Vacuum testing instead of High pressure test or other NDT leak testing methods.

How do you intend to check the leak?if there is a leak. Soap solution at each joint? At this pressure you're mentioning  you're sure to miss any leak as the solution would jet off. Do you intend to check the raise or fall in pressure. If so then it is not leak test.

As per general engineering convention Leak test are generally low pressure test.

Any way i would be glad, if you let know as to what you did at the end.

Good Luck

RE: We are about to carry out tightness

Nirav,
After reaching 42 kg/cm2g pressure, you can inject Nitrogen from HP Nitrogen cylinders.... and I am sure you won't need many cylinders...

Before pressurising with Nitrogen, ensure that vacuum is held for atleast one hour(I am sure you're talking next step of this but...), there should not be any increase in pressure.

Once Hydrogen is put, it being smaller atom, it is possible that you will have leaks.. some can need even replacement of flange-gasket. Hot bolting(brass spanners,spark proof/pneamatic spark proof) is solution.

And be prepared for surprise leak when after no leaks were found (even during the course H2-pressure leak test and startup circulation) the moment you put oil in the reactor circuit. We had fire from CFE's at this point... !

All the best..
SAA

RE: We are about to carry out tightness

So, it appears, it  is an established norm to carry out such high pressure test by inducing H2. This is really new to me. There has to be some approved document based on some safety standard or local law, could some one give further information

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close