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Peter_1
12-04-2006, 01:19 PM
Perhaps an interesting link:
http://www.hantech.com/documents/PDF/WaterInAmmoniaSys.pdf

Andy
12-04-2006, 08:03 PM
Hi Peter:)
found this link interesting myself. Draining ammonia and boiling it off to leave just the water to drain:)

Kind Regards. Andy:)

US Iceman
12-04-2006, 08:36 PM
This sort of technology has been around for a long time. Some of the US industrial refrigeration manufacturers used to make a device called an ammonia re-generator, which did the same thing.

Using this in connection with the refrigerated purgers though is a NEW thing. A darn good idea I think.

US Iceman
12-04-2006, 10:08 PM
After reading the post made by Peter I found another source of information that might be interesting to some of you.

http://docnav.grasso-global.com/DocNav_Eng/Sources_e/DBo_e/ca0512_Bro_GAD__-gbr_08-05.pdf

SteveDixey
12-04-2006, 10:56 PM
One thing I could never nail our supplier on was for them to state how much water was in a system.

We had a plate freezer connection break, and it was doused with water sprays while pulling a vacuum :mad:

Anyway, rust scale started to appear in various places and the oil recovered suddenly went very black. :eek:

BOC indicated that it would cost a pile of money to take a big enough sample so all we ended up doing was decanting a 50 kilo sample off the liquid pump take-off and sending it away to BOC. It came back that after pulling off the ammonia, they found about 100ml of water in the cylinder. Doing a similar test ourselves by draining 10 kilo into a jug and leaving it to boil off, I got a result of 2%.

Tried to see how much was in the recovered oil. Took a 100ml sample, left it to stew for a day in a warm engine room, and then heated it on a hot-plate to around 80c and measured reduction in volume. We reckoned about 10% of the recovered "oil" was water. :confused:

We put a heater tape on the oil recovery pot, and that started to produce about 50ml per week on average, as water emerging out of the drain before the oil came, plus of course what was entrained in the oil.

One contractor suggested using standard high capacity dryer cores in the liquid line from the condenser, and just keep changing them until water stopped appearing in the oil pot.

So, how can you accurately cost and therefore justify the cost of installation?

Steve

US Iceman
13-04-2006, 03:30 AM
So, how can you accurately cost and therefore justify the cost of installation?

In the link Peter posted there were some curves that listed the difference in suction pressure that had to be maintained based on the amount of water. Page 2 Steve.

If the ammonia is diluted with water, the suction pressure has to ran lower to provide the same temperature as before (without the water).

The difference in power required at the lower temperature is your savings. This reacts the same way as if the suction line pressure drop is too high.

Lower suction pressure to maintain the same temperature.


We had a plate freezer connection break, and it was doused with water sprays while pulling a vacuum :mad:

I had something similar happen on an R-22 system. Not much fun to fix I'll say.

Johnny Rod
13-04-2006, 09:16 AM
Analysis of ammonia isn't exactly a laugh a minute, we can do it ad hoc but it's not very straightforward. In the IIAR bulletin no. 108 there is a simple method for measurement of gross water contamination in ammonia, if you have the equipment, but it ties down the evaporation temperature of your sample etc. for a more accurate number. Can't say I've tried it though.

I'm not really up on ammonia systems, but what sort of driers were going to remove the water? If it were a fluorocarbon system, this approach is common but arguably not great because of the amount of water in the system compared to the amount a drier cartridge is capable of removing.

Given about 70% of the cost of owning a chiller is electricity, I would have thought the pound notes add up. The alternative of replacing the charge has to include disposal, drum rental, time taken to recover and recharge (how big is your recovery unit?), and the nail in the coffin is usually the lost production time.

US Iceman
13-04-2006, 02:44 PM
...but what sort of driers were going to remove the water?

I'm not sure either.

I cannot imagine any desiccant would be more hygroscopic than ammonia.

SteveDixey
13-04-2006, 07:07 PM
I'm not sure either.

I cannot imagine any desiccant would be more hygroscopic than ammonia.

I think the reasoning was that at the condenser outlet, the liquid would not be as "wet" with water as in the LP side, so water would be absorbed there, plus you'd never get oil through a dessicant drier on the LP side. I'm sure I read in the Danfoss product book somewhere that you could use their cores for ammonia.

Steve

SteveDixey
13-04-2006, 07:15 PM
If the ammonia is diluted with water, the suction pressure has to ran lower to provide the same temperature as before (without the water).

The difference in power required at the lower temperature is your savings. This reacts the same way as if the suction line pressure drop is too high.

Lower suction pressure to maintain the same temperature.

I did understand that, but on a 1.4MW system with 5 freezers it was a nightmare trying to get consistent and steady readings to get any meaningful comparisons. In the end, we could not secure the time from production to conduct any meaningful tests and we gave up. It was impossible trying to convince managers who's sole understanding of refrigeration is "it gets cold" and who then wittered when it "wasn't cold enough".

Yes, we sometimes had to pull 0.73bar(a) to get a -40c suction temp, but that could be production winding up the production rate when our backs were turned:mad:

Steve

US Iceman
13-04-2006, 07:31 PM
It was impossible trying to convince managers who's sole understanding of refrigeration is "it gets cold" and who then wittered when it "wasn't cold enough".

This is a very common and old problem. No one wants to deal with the issues, no one will give you the time, and no one certainly wants to spend any money.

I think the only reasonable way to estimate this would be based on your sampling described earlier. Take your best estimate on water content, find out what the deviation in saturation temperatures would be, & then provide some "estimate" of the power difference between the two suction temperatures.

I will have to check into the Danfoss driers. I was not aware of these.

Thanks for the information Steve.

US Iceman
13-04-2006, 08:20 PM
Here is a link I found that provides some additional information and methods.

http://www.airgasspecialtyproducts.com/default.aspx?PID=1744

There are some other interesting sources of information on this linked site also.

Chopper
13-04-2006, 10:33 PM
We at York have had a water, dirt and oil unit on our portfolio for while now. They are portable to a certain extent, but would be a sensible addition to any ageing large NH3 plant. Once installed, our engineers drain them as part of there routine maintenance.
They are of very simple design consisting of a vessel with a sample/fill line from the bottom of the pumped liquid line and a suction line into the wet return. It uses 2 Danfoss PM valves, 1 with a solenoid pilot to take the vessel to suction pressure during filling and the other on a CVP to maintain the vessel at 2 C sat during "boiling". The liquid/sample is heated by a coil with glycol pumped through it and heated by a electric heating element.
Very simple and effective.
I'll look out the drawings and post them for you guy's reference, but its holiday time till Tuesday so the only place I'll be going is the pub!:)
Steve, I know what you mean about getting a consistent sample,especially on a large plant with multiple evaporators!:o The only way i have managed to get any level of consistency was to sample it when the plant is operating at full load and has been for a while.

Regards

Chopper

Andy
14-04-2006, 07:35 PM
I think the reasoning was that at the condenser outlet, the liquid would not be as "wet" with water as in the LP side, so water would be absorbed there, plus you'd never get oil through a dessicant drier on the LP side. I'm sure I read in the Danfoss product book somewhere that you could use their cores for ammonia.

Steve

What about driers on the discharge line:confused:

Kind Regards. Andy:)

SteveDixey
14-04-2006, 08:03 PM
What about driers on the discharge line:confused:

Kind Regards. Andy:)

Pipeline velocity was the reason I believe, plus all the discharge vapour lines are way up in the air, and the discharge main is 4"nb.

Condenser discharge was accessible and it was easy to install either a by-pass when changing cores, or put two cores in parallel so when one was out of service one was on-line.

Steve

US Iceman
14-04-2006, 09:48 PM
What about driers on the discharge line:confused:

I have seen this tried once in an R-22 semi-hermetic system with disastrous results. The compressors kept failing on a regular basis.

After many compressors were replaced by a previous firm, the company I was working at the time got the call.

The owner of the firm took me on the call to see this.

When the previous company replaced the compressors they also changed the drier cores. Apparently, the high gas velocity was eroding the drier cores and turning them into sand like grit.

The only time I have ever seen something like this.

SteveDixey
15-04-2006, 10:19 AM
I have seen this tried once in an R-22 semi-hermetic system with disastrous results. The compressors kept failing on a regular basis.

Apparently, the high gas velocity was eroding the drier cores and turning them into sand like grit.

I always wondered what happened to the inevitable loose bits that seemed to appear when you put a new drier in:eek:

Back to subject, I also was shown a NH3 cold-store plant that had been fited with Zwicky basket type filters to remove the rust particles that the water caused

Steve

Peter_1
15-04-2006, 10:42 AM
I'll look out the drawings and post them for you guy's reference, but its holiday time till Tuesday so the only place I'll be going is the pub!:)

I'm interested Chopper.

Andy
15-04-2006, 10:53 AM
I have seen this tried once in an R-22 semi-hermetic system with disastrous results. The compressors kept failing on a regular basis.

After many compressors were replaced by a previous firm, the company I was working at the time got the call.

The owner of the firm took me on the call to see this.

When the previous company replaced the compressors they also changed the drier cores. Apparently, the high gas velocity was eroding the drier cores and turning them into sand like grit.

The only time I have ever seen something like this.
If the cross sectional area was increased the velocity would go down:confused:

Apparently driers will remove more moisture on the discharge line, but drier cores only come in certain sizes, too small for all but the smallest systems.
I have seen pot driers made up, this would be a vessel filled with dried desicant beads, with a filter on the outlet. This would be the way to go, especially for drying on R22 systems that have high moisture content.

Kind Regards, Andy:)

US Iceman
15-04-2006, 03:54 PM
Hi Andy,


Apparently driers will remove more moisture on the discharge line

I was under the impression that the driers worked better when they were in the coldest liquid line. Can you provide some background on this Andy?

I'll try to dig up some information also.

Attached is a large liquid line drier assembly we used on a very large R-22 system some years ago.

The piping is 6" Schedule 40. The three valves are provided for bypass purposes to change the drier cores. The pumpout fitting is on the bottom.

The reason for all of the piping is to provide a uniform flow rate into each drier shell. It is piped in reverse-return to provide equal pressure loss and flow.

AMARNATH JHA
15-04-2006, 04:45 PM
Perhaps an interesting link:
http://www.hantech.com/documents/PDF/WaterInAmmoniaSys.pdf

Really very interesting.
Thanks
AMARNATH JHA

US Iceman
16-04-2006, 04:21 AM
I'm sure I read in the Danfoss product book somewhere that you could use their cores for ammonia.

I did check the Sporlan website for their drier information. They do have ammonia driers, so I'm sure Danfoss has something similar.

I stand corrected. :o

Learn something new everyday. :D Thanks for bringing that up Steve.

esawee
01-02-2008, 11:30 PM
Hellow
I want to seperate NH3 from the water by heating with 2 bar pressure.
Can you help me by explaning how to do it .
Thanks

Josip
01-02-2008, 11:45 PM
Hi, esawee :)

Welcome to RE forums...


Hellow
I want to seperate NH3 from the water by heating with 2 bar pressure.
Can you help me by explaning how to do it .
Thanks

......:confused:....seems you have some problem and looking for help ;), but you must explain much more all about your problem to us to be able, somehow, to help you.....

Best regards, Josip :)

esawee
01-02-2008, 11:57 PM
Thank you Mr. Josip for your reply
Yes I have problem
I have water saturated by NH3
I want to seperate the NH3 from the water by heating
NH3 will evaporate before the water but the water will evaporate also ,
I want to collect the water and take it away from the generator.
can you help me to do it.
Thanks

Ponca Dave
04-02-2008, 04:21 AM
The grasso filter I tried Ice Man and the filter material dissolved and went into the system.
Batch capture and boil off is the way to go.
dedicate an evap, flood it with liquid and slowly
Let the stink evaporate off and drain out the water.
I have gotten as much as 2 gallons of h2O/batch from an old Krack unit we used for that purpose.
A vessel with out tubes works best though.
and collect the refrigerant from the coldest liquid point. Thats where the water is.

esawee
04-02-2008, 04:54 PM
The grasso filter I tried Ice Man and the filter material dissolved and went into the system.
Batch capture and boil off is the way to go.
dedicate an evap, flood it with liquid and slowly
Let the stink evaporate off and drain out the water.
I have gotten as much as 2 gallons of h2O/batch from an old Krack unit we used for that purpose.
A vessel with out tubes works best though.
and collect the refrigerant from the coldest liquid point. Thats where the water is.
Dear sir
do you have any drawing as pracical not theorotical to do this way???
Thanks alot

Ponca Dave
09-02-2008, 05:37 AM
Dear sir
do you have any drawing as pracical not theorotical to do this way???
Thanks alot
I manufactured what I called H2Out. It consisted of a 12" dia vessel inside a 14" vessel. The 12" was the liquid container and the 14" enveloped it.
A solonoid valve was activted and then shut off by a Hanson float switch. the Liq. container was connected to intermediate suction with a valve left open except for maintainence so it can be filled quite full.seperation velocity is necessary for that line size.
A hot gas sol was opened when the float stopped the liquid feed and entered between the vessels. condensed gas was bled through an expansion valve to the same suction. My 1st controls were Radio Shack thermisters and transistors. I eventually went to better controls on the market.
The Trick is to evaporate, not boil off the NH3.
The process took about 10 hours/batch depending on the final temp set point. (the higher that set point the less stink but more time. I used 35 deg above
suction temp. I took the liquid feed off a tee I put in the gauge line of a LPR pump (1/4" line)
The water migrates to the coldest point due to vapor pressure. Basic facts:
1 Batch it
2 cold liquid
3 evaporate vs boilng
4 be patient
It took anywhere from weeks to 3 months to clean up depending on the contamination.
My only complaint was form a plant in MN.
He said it quit getting water out after 6 weeks.
My reply: Add more water.
LaRoche IND sells a test kit but it is tedious and ambient humidity can affect the results.
press/temp comparison is easier.
I will find the drawing and post it.

esawee
08-03-2008, 02:53 PM
Thanks alot Mr.Ponca Dave for your replay , I am waiting for the drawings.
Regards