Change NH4 to R134A

Dear Friends
A customer has the refrigeration plant close to production area. They manufacture spaguetties . They have had some leaks of ammonia in the ambient It makes the production people to hold prodution. They ask for change the refrigerant from NH3 to R135A or R22.
The refrigeration system was designed to cool water from 35°C to 18°C . It is formed for three screw compresors ,three evap condencers and three flooded shell and tube heat exchangers . The oil of the compressor are cooled by a thermosiphon system.
Could such ammonia system move to R134A or R22?
Could the heat exchange operated with R22 or R134A?
What about the oil coolers?
What about the compressors?
I appreciate your thought

Gwapa;
It CAN be done. 134a is probably not the best choice however.
22 is acceptable, but if you have leaks with NH3, you will still have leaks with 22.
Oil return and cleaning of the system is a big issue. What would have to be done depends on what you have installed.
Pipe sizes will likely be an issue.
You have to design a oil return system for 22, unless you pump very little oil into the system. Even then you have to pump out the accumulators on a regular basis.
I would probably look at repairing the system, rather than changing refrigerants.

The heat exchangers may be affected slightly, however any potential performance issues may not be noticed if there is excess surface area available.

For the most part, R-22 is similar to NH3 in performance.

The biggest issue is the potential chemical reactions that can occur when changing the refrigerants. This can be a big problem from some information I have seen!

My concern is; it would be better to find the reasons for the leaks and do something to eliminate 100% of them by finding the causes or other potential conflict that allow this happen.

Even accidental releases can be prevented. Here in the US there is a saying; Only you can prevent forest fires. The same applies to ammonia leaks. These give the industry a bad reputation.:(

NH3LVR, US Iceman, Wouldn't overall tonnage of systems have a decrease if changed to R22?

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Originally Posted by US Iceman

The biggest issue is the potential chemical reactions that can occur when changing the refrigerants. This can be a big problem from some information I have seen!:(

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US Iceman
Could you elaborate on the possible reactions? I would assume if we flushed with solvent and evacuated we would avoid this.

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Originally Posted by goodguy

NH3LVR, US Iceman, Wouldn't overall tonnage of systems have a decrease if changed to R22?

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Short answer-almost certainly. I would start with looking up the Compressor Tonnage on the two refrigerants.
But what is really needed is a complete design review. When I said it could be done I did not mean to imply it would be simple or easy.

We do have to remember that few of us sign the checks. If the Customer, or your Boss wants to go ahead with a project, it leaves you with very little choice. (I am NOT talking about unsafe systems here)

NH3LVR,

I'm going from memory from an article I quickly read several years ago. A system was using R-22 and was converted to ammonia at the owners request. All of the piping and other components were already industrial quality.

The problem was the residue R-22 reacted with the ammonia and created a powder which plugged up strainers and valve ports.

Apparently it was a real mess.

I will have to try to find the article to be more specific.

According your thought We could have the following topics to take in account.

1. System Capacity

• I checked the compressor capacity and it will reduce araund 10% which it would not be a problem
• What will be the water Cooler capacity? The overall heat transfer coeficient will remain the same?
• What will be the condenser capacity?

2. Equipments performs

• Will the screw compressors work fine without any modifications or we should change oil heat exchanger ,seals, oil pumps,othe parts?
• Flooded Water Cooler. How can we garantee the oil retour to the compressor?

3. Flushing the System

• We should flush all the system. How?
• Will a good vacuon procedure be enought?
• Acording with our dear friend US Iceman we could expect a chemical reaction betwenn R22 and NH4 with a powder which plug the filter etc.

4. Piping

• What do we make?
• The pressure lost are the same
• We should check the slops

5.- Instruments ans safety

• should some manometer be changed?
• what about the safaty Valves and the controls valves?

It is like a check list however there are good question to think and discous about?

Any thing you do , please be sure you change all rubber or any other elastomer to NEOPRENE , as R22 will EAT any other.

A leak is still a leak whether NH3 or R22 R134.

The customer by moving away from NH3 is going the wrong way.

Sure it smells when there is a leak, but that makes it easier to trace and also easier to put detection systems in place to monitor it.

NH3 is more environmemtally friendly and I have the impression that all this customer wants is to keep production going even if tonnes or R22 or R134 leak into the atmosphere.

Stick to NH3 and fix the leaks.

Paula

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They have had some leaks of ammonia

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Isn't the solution simply - fix the leaks!!!!!!!!!!!!!!!!!

The costomer has a proposal to install a leak detector .It is a very complex system, formed for

• a set of nh3 sensors
• Alarm
• blowers and ductwork
• Nh3 water scrubers
• The Hh3 - water solution will then realease to the atmosfere very far from the production room
• The cost of such system is aprox . 150000 US $ and still have the problem

I think (no sure) the ammonia is absorbed by the spagetti dough y change the characteristic and lost products

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Originally Posted by gwapa

I think (no sure) the ammonia is absorbed by the spagetti dough y change the characteristic and lost products

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Perhaps it would be better to use indirect cooling in the production spaces if this is where the problems occur.

I found the atached report in the WEB . This is a plant changed from R22 to HN3. After three year they reported a leak in a condenser. They did not report other issue.

The report was based on a RMP file for ammonia, which dealt specifically with a leak that occurred after ammonia was introduced into the system. They would not be required to address any other system problem that may have occurred.

I do not believe this is representative of what you want to accomplish.

At the minimum I would expect o-ring and seal problems plus extremely higher refrigerant costs to recharge the system.

I have a feeling that this effort will not provide the desired results.

Don't forget to compleetle redesign the oil return system.

Succes

When 134a was introduced in the 90`s into the refrigeration world, we suffered with a lot of problems according to the specific requirements of this refrigerant. A lot of leaks occured at points where we never expected problems, threaded joints, gaskets, o-rings, shaft seals. A lot of was related to the poe oil used with 134a. I think a conversion to 134a is to difficult and expensive. The oil seperator for expample will be to small. A conversion to R22 might be possible but i also heard of internal scale building due to a chemical reaction and this was just a small of R22 added to a evacutated NH3 system for leak testing. My recommendation? Stay with ammonia, it is really easy to get the unit leak free if you do it once right. What are the major potential leaks? Welded joints? Corrosion (what about the water content of the NH3 used). Cracking of joints? Vibrations? Sealed threads? Flanges/Gaskets. I am sure we can support you with the right information to get your units leak free.

Entropie / US ICEMAN / All friends

Thanks for your thought and sopports

hearing to you all I will recomend to the costumer to move all the refigeration system to another building. Located in a near place where the air does not allow to a possible leaks of ammonia goes to the producciton room.

We will keep the chilled water tank in its place and pump out to the chiller located in other building

To move every thing we have to buy a new water chiller in order do not stop produccion. Then we can move step by step all componets.

This alternative could cost aprox. 400.000 $ but I will be sure it will work, Beside I solve the problem from the roots

The conclution to my original post is that you all do not recomend move a system working with NH3 to either R22 or 134A due to many problems that can arise

I will like to kown what kind of product Will form NH3 and R22 anyway

Best regards to all of you

Spend a dim to save a penny? Best to simply fix the leaks, then moving it will not even be needed!

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Originally Posted by gwapa

I will like to kown what kind of product Will form NH3 and R22 anyway

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"A chemical analysis identified the material (a white very fine powder) as ammonium fluoride."

Hi I am new to RE but not new to industrial refrigeration have just came across this thread regarding changing refrigerants . Be careful.iCE MAN is correct regarding chemical reactions.
A few years ago I was asked to check a NH3 plant that giving problems.
The Plant’s basic function was to supply refrigeration to eight 14 plate plate freezers.
A leak had occurred on one of the flexible hoses to one of the plates. An inexperience service man had been called in to trace the leak and repair. After apparently replacing a faulty hose he decided to pressure test and used R22????.
On deciding the system was again sealed he returned to plate unit to service after a short vac out.
I attended the plant the next day on being told there was a liquid feed problem. Not being aware of the previous work we arranged to have the strainers checked on the liquid feed lines assuming the problem was oil but what we found confounded me originally because the filter unit was blocked up by what appeared to be a wax.:confused:
To cut along story short the compound was Ammonium Fluoride. (NH4F).
Chemical analysis eventually deduced the following.

R22 +R717 => Ammonium Cyanide + Ammonium Chloride + Ammonium Fluoride
CHFIF2 + 5NH3 _=> NH4CN + NH4CI + 2NH4F

In the presence of iron the above becomes
R22 +R717+Iron => Ammonium Ferro cyanide + Ammonium Chloride + Ammonium Fluoride + Hydrogen
6CHFIF2 + 28NH3 +Fe =>(NH4)4Fe(CN)6 + 6 NH4CI + 12NH4F + H2

I understand a similar reaction any of the HFC refrigerants will have an adverse reaction with ammonia. Don't go there.
Remember the source of the Iron is the components of your plant and piping systems.

Hi John,

Welcome to the RE forums. It's nice to have another industrial person on here. You added quite a bit more detail to the questions and for me that was very helpful.

We hope to see you here on a regular basis.

Best regards,
US Iceman

Hello US Iceman,

I had to convert an ammonia system to R 22. The main issue was cleaning the complete system properly so that there was no trace of ammonia. I had installed 2 nos. of TEV and other controls for the R 22 system and had removed the ammonia accumulator. The leakage were located and stopped. It was from the compressors shaft seal. The system has now been working for over 6years, and the customer is getting a better production. It is an Ice Plant.

If the system were to be converted from R 22 to Ammonia , then there are the problems of corrossion due to the chemical properties.

As you have stated earlier in this thread that R 22 has a lot in common with Ammonia and as such I too feel that it would be a better idea to convert it to R 22.

I have just returned and everything is fine.

Hi, gwapa :)

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Originally Posted by gwapa

Dear Friends
A customer has the refrigeration plant close to production area. They manufacture spaguetties . They have had some leaks of ammonia in the ambient It makes the production people to hold prodution. They ask for change the refrigerant from NH3 to R135A or R22.
The refrigeration system was designed to cool water from 35°C to 18°C . It is formed for three screw compresors ,three evap condencers and three flooded shell and tube heat exchangers . The oil of the compressor are cooled by a thermosiphon system.
Could such ammonia system move to R134A or R22?
Could the heat exchange operated with R22 or R134A?
What about the oil coolers?
What about the compressors?
I appreciate your thought

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That must be a big leak if you have a problem in the next area. What about doors inbetween...Seems they do not have any maintenance...or maybe complete plant was not properly installed...

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Originally Posted by Paulajayne

A leak is still a leak whether NH3 or R22 R134.

The customer by moving away from NH3 is going the wrong way.

Sure it smells when there is a leak, but that makes it easier to trace and also easier to put detection systems in place to monitor it.

NH3 is more environmemtally friendly and I have the impression that all this customer wants is to keep production going even if tonnes or R22 or R134 leak into the atmosphere.

Stick to NH3 and fix the leaks.

Paula

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Agree with above statement 100%.

Your client has a very dangerous mind. He has no scruples to poison so many people, but to run his production and to make profit:mad:

He is going to uninstall/discharge one good, natural and nature friendly refrigerant gas (instead to repair leaks) and to install/charge another refrigerant with properties, in all, far behind ammonia....R22, R134 and NH3 are similar but not the same and for all of us R22 and R134 are more dangerous then ammonia...

If I have a power I will forbid, for industrial cooling, to install anything but ammonia refrigeration plants except for some with very specialized requirements for another refrigerant...

Best regards, Josip :)

Hi Josip,

I fully agree to your views. You have seen the ammonia systems in our country . Ammonia is very good if properly installed. Till the time this is understood and the customers realise that paying a higher price to get a good system works out less expensive in the longer run, these sort of activities shall continue.

Ammonia requires proper maintenence which in most cases are absent as the users do not want to spend money for such work.

There are two issue in this thread

1. Could I change a NH4 system to R22 or 134A?
2. A NH4 system is the best when one fit all the leaks and we have a very good mantenance team.

According with your posts we have to clean the system very well and make a lot of modificatoons in order the new system work propely. I personally think it is risky and expensive. No Recomended

The second is to keep the system free of leaks.
It seems easy but who can garantee that!!!
As I mentioned before, the ammonia system is located in the same room of the dought production.
Also the atmosferic ventilation was made in a way that any leaks goes to the producction equipments pushed for the natural ventilation.
The reaction of the dought and ammonia is not allowed.
The Plant designed a system formed for a set of fan and ammonia scruber to evoid the ammonia get in touch with the dought.This solutions was not approved.Doe to the fact the risk is still there.
I think that the instalation of the ammonia system in the same room was a mistake and the best solutions would be to make a new room to relocate the ammonia system. It solves the problem for the rest of the plants life
Thanks to all of you

You yourself have answered the best solution. Ammonia is the best refrigerant although I am learning about it from the Forum and had used it about 4 times till now. The leakages are solely due to may be improper installation or poor maitenence.It is just like any other refrigerant.

Installing the ammonia plant within the production area and that too with proper ventilation system is very wrong.

The best solution is reinstall the complete plant in a seperate area with proper ventilation. Second thing is that ensure the proper installation with good quality valves and flanges are used. These will be far less expensive than going in for conversion .

Regarding the guarantee of leak proof, it is you who has to ensure that there will not be any leaks. Ammonia does not leak by itself. It leaks from loose conections and joints. Adopt Good Practice methods. You will be happy.

....what is NH4....:confused:
...why...
...ammonia is very good stuff,just holes is too big...

Dear Sinke
It war a mistake .I should say NH3 Ammonia

Thanks

wow that sounds like a whole lot of expense when you could just fix the leaks!
install ammonia detectors with ppm read out.
this will give peace of mind to workers,and advise that nh3 is harmless at low levels less than r22 and r134a which will either knock you cold without warning or kill from cancer.
in new zealand the TWA (time awaited average)exposure is 25ppm for 8 hours, this gives employers some way to keep workers on the floor.
give advise for actions to take during a leak it is not likely to rupture killing people instantly is it .
pipe all reliefs in a common line to a scrubber is a good idea too
r22 is so nasty i thought we were trying to eradicate it??