Ammonia system design

[ingherrera]

I need some info about NH3 design, features...

Where can i get this info?, it could be a manual o a summary. I need a insulation desing for Ammonia pipes.

[TXiceman]

Several places to look.

Firsyt look in the ASHRAE Handbooks, there is a chapter on ammonia piping practices.

Next check out IIAR (International Institute of Ammonia Refigeration). I believe they have some Spanish language booklets.

Next check some vendors such as Vilter, Mycom or Hasegawa.

I don't have the web addresses, but you can easily do a Google Search.

Ken

[US Iceman]

I need a insulation desing for Ammonia pipes.

Installation or insulation design???

IIAR has a piping handbook that is pretty good for getting started. https://www.iiar.org/f-store.cfm

[Josip]

Hi, ingherrera

I need some info about NH3 design, features...

Where can i get this info?, it could be a manual o a summary. I need a insulation desing for Ammonia pipes.

What you need about insulation?

Best regards, Josip

[TXiceman]

Are you asking about installation or insulation for piping. ASHRAE Handbooks have a chapter in insulation of piping for generic insulation. As for specific insulation data, you will need to contact an insulation manufacturer for specific thickness and applications. You will need to decide about vapor barrier, insulation material (urethane, styrofoam, foam glass, wool, etc). Most of the work we do is with urethane. The insulation will also require a protective jacket of metal or vinyl.

Insulation thickness will be dependent on pipe temperature, ambient air movement and ambient wet bulb temperature.

All of the insulation manufacturers have design/installation guide handbooks.

Ken

[ingherrera]

I need to find the right insulation for a system. Here in Costa Rica a client installed a system five year ago, Sollie designed the system; about one year ago the insulation fault and small drops appeared at the bottom of the pipes. That’s why I am looking for guidelines for ammonia insulation.

[Andy P]

If the insulation was OK originally and then deteriorated then it sounds like it is the vapour seal which is at fault - probably the most common mistake when insulators work on cold systems. The cold pipe attracts moisture so if you don't put a waterproof barrier round the outside of the insulating material it will soak up like a sponge. Metal cladding doesn't count! (it is full of holes)

cheers
Andy P

[Josip]

Hi, Ingherrera

I need to find the right insulation for a system. Here in Costa Rica a client installed a system five year ago, Sollie designed the system; about one year ago the insulation fault and small drops appeared at the bottom of the pipes. That’s why I am looking for guidelines for ammonia insulation.

I am sorry to hear you have some problems with insulation. That is Dos Pinos. Can you, please, tell exactly what happen, can you send some photos about. Drops are water or PU. What system is that +3, -10, -35 or -45. Is that down in compressor room or upstairs in separator room or outside on the bridge?

In your documentation you can find all about insulation thickness for each system or I can send a copy to you. Send me PM with your email address.

The best is still the same you have on your plant, injected PU in aluminium cladding, but something strange happen there.

Best regards, Josip

[Josip]

Insulation thickness will be dependent on pipe temperature, ambient air movement and ambient wet bulb temperature.


Ken

agreed with all said

...and pipe DN

Best regards, Josip

[US Iceman]

This certainly sounds like insulation system failure, or poor installation techniques. Insulating pipes is an art, along with some science.

Obviously the vapor barrier has failed. This is the most critical part of insulation systems. It is not uncommon to find a metal jacket on exterior piping with screws used to hold the jacket in place. The screws puncture the vapor barrier and it is only a matter of time before the insulation is saturated.

Here is a link that shows some of the recommended installation techniques.
http://www.dow.com/PublishedLiteratu...ge=BasicSearch

And a link to other ideas to consider.
http://www.dow.com/styrofoam/na/dowpipe/library/

[Josip]

Hi,

I think I know the cause of the problem (not sure but we can discuss it), but still waiting for additional info from Ingherrera, about exact places of insulation faults.


Best regards, Josip

[ingherrera]

Hi

Thank you for all your advices.

The problems are in all liquid and gas pipes in lines -35 C and -45C.

[US Iceman]

but still waiting for additional info from Ingherrera, about exact places of insulation faults

ingherrera, I think the information Josip is wanting to hear about is where are the major problems with ice and water forming on the pipes. I know you said earlier the water was forming on the bottom, but that is the logical place to see the water.

I believe the locations Josip is thinking of are the insulation joints in the piping (next to valves, or fittings) and what I call "vapor stops".

A vapor stop is where the butt-end of the insulation terminates into a bare pipe (say next to a valve station, or at compressor suciotn valves).

I need to find the right insulation for a system.

I would make sure any type of glass fiber was not used for the insulation. This is only for hot service, not cold.

Just about any of the extruded foam insulations are OK.

[Samarjit Sen]

Since thread is on Ammonia System Design, I would like to aske you that if the system is a liquid overfeed system and there are a number of Evaporator units, then do one take seperate liquid lines from a liquid header. How do I design the header.Is it possible to provide me a sketch of the system.

I am really grateful to the engineers in the forum to have helped me to learn about Ammonia System which I have not been used to.It is a great forum.

With best wishes,

[TXiceman]

Samarjit Sen, best place for info on the piping is the ASHRAE Handbooks for ammonia piping practices. Next look for some old info from York, Frick and vilter.

you need to know the flow rate and size the lines accordingly for velocity and pressure drop.

Ken

[Samarjit Sen]

Thanks Ken, I will do just what you advised. I have been able locate some details and more I presume I will get from Ashrae.

[tjk2007]

Hi friends,

i need design details for Ice cream cold storages.Kindly give your tips and best weblinks