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Tycho
24-10-2014, 04:50 PM
Had some down time at the workshop today and thought I'd show the younger service technicians the dangers of purging ammonia in water.
the pretext was that everyone of them had heard stories of how someone had purged ammonia into a bucket, or tub of water and left them unattended, only to come back and find the water container empty a few hours later.

(purging ammonia into the ocean is illegal, and if you purge ammonia into a container with water it is to be treated as hazardous waste)

That's me in the video (I'm wearing safety goggles btw :))

https://www.youtube.com/watch?v=WMqvGIcuCkk

Poor quality since the guy who took the video sent it to me as an MMS video

Tycho
24-10-2014, 04:51 PM
it was inspired by this video, but I thought it would have a more permanent effect to show it live instead of "Oh yeah, I saw that on youtube once"

https://www.youtube.com/watch?v=vgBe0fsPcjk

Grizzly
24-10-2014, 05:31 PM
Hi Tyco.

Got a copy of the Sabroe Training video I see!
Incidentally I could not get your first attachment to run!
Grizzly

Tycho
24-10-2014, 06:18 PM
it's working here, can you try it again plz and let me know if the video plays?

Grizzly
24-10-2014, 06:28 PM
Sorry my friend.

I click the red cursor and here what I assume is the water and a thud. A imploding plastic bottle maybe?

I don't know because the run red line travels across the screen but the video does not run.
For me anyway!

Grizzly

Tycho
24-10-2014, 09:59 PM
https://www.youtube.com/watch?v=WMqvGIcuCkk&list=UU5vOz1PFjN5RF9zsus_ct9g

how about this?

Tycho
24-10-2014, 10:00 PM
No fun in listening to the bottle collapsing as it fills with water unless you can see it :)

RANGER1
24-10-2014, 10:22 PM
Can Tyco or anyone through practice or theory advise under what conditions the water can be sucked into system.
I had it suck into a compressor once when leaving a hose connected. The compressor was hot from running
& I believe cooled down while hose in water sucking it in.
You only do that once!
We had a guy working for us from the UK reckon it could be sucked into a condenser, can't say I've seen that though (purging air).

Grizzly
24-10-2014, 10:35 PM
Filled an RC911 once with about 200litres of water, by leaving a long 1/4" gauge line in the Barrel of water.
Which I was purging said isolated comp of it's ammonia into!
A more detailed version of events was posted by me sometime ago.
Needless to say when a comp or any "vessel is warm you have positive pressure / Temp.
Allow the purging vapour or it's pressure to drop sufficiently. Whoosh! That imploding plastic bottle.
Becomes the (in my case) the comp that was being purged. By the way that crack heard is supersonic.
Meaning the pressure change from positive to negative is that fast.

We have both been there and as you say once bitten twice shy!
Grizzly

Glenn Moore
24-10-2014, 11:52 PM
Hi guys
Back in my service days I spent a lot of my time on ammonia systems. Purging ammonia was the norm on nearly every job. When purging I found that irrespective where you purged from, if you opened the purge valve to quickly you could make the hose suck back. so when I purged I would hold the hose in the water and slowly open the purge valve and in most instances I could open the valve to a point that suckback occurred. At this point I would pull the hose out of the water and wait for the water to be ejected from the hose and ammonia start to blow. I then put the hose back in the water and close the valve down a little, but keeping my hand on the hose in case suckback restarted. Purging from a high pressure seemed to be easier to cause suckback than purging from a low pressure condition. Good subject
Look forward to others comments

Magoo
25-10-2014, 02:55 AM
Been there done that and got stung with a compressor and water in it, now put a hydraulic check valve in charge hose vent line, a simple in line check vav, no more suck back.

Grizzly
25-10-2014, 10:46 AM
Been there done that and got stung with a compressor and water in it, now put a hydraulic check valve in charge hose vent line, a simple in line check vav, no more suck back.

Hi Magoo.
Impressive and simple! Always the best.
Incidentally I have a Ammonia Manifold so I purge through this regulating the purge pressure to a very small flow rate. Especially as the back pressure drops, as the bubbles / turbulence begins to fade.
I lift the line out of the water.
I think it's fair to say You cannot leave a line purging unattended.

Incidentally Guys.
You may like to consider my alternative method. (Credit to my good friend and colleague Paul.)
If you have access to a Evaporative Cooling Tower.
Instead of purging through Water, place the purge line into the fan airstream, regulating with said manifold

Allow the vapour to be drawn into the Airstream and as it meets the Water spray it's dissolved. Perfectly safe and acceptable, with no Saturated water to deal with either.
Your very own water curtain on-site and no Fire Brigade needed!
Grizzly

Josip
25-10-2014, 07:46 PM
Hi, all :)

what to say ... just to add my experience .....

I usually, if possible, connect a hose to buster compressor and discharge the high pressure into low pressure system ... leaving about 0,3-0,5 bar pressure to discharge oil in case when changing oil ... for other works (replacing oil filter, coalescing elements, shaft seal) .... just come down to 0 bar ... need to repeat that few times to remove ammonia from oil .... then the rest just purge into air (this can last a little longer, but good to take a coffee break ...so far no problems ;)

.... at least I use also another high pressure compressor, but connection valve at suction to reduce pressure down to suction .... then release a small part of pressure into bucket with water and using the rest of pressure to drain the oil ... or slowly purge into air

... sometimes there is only one compressor so the bucket or drum with water is inevitable ;)

.... must say all my plants are in general industrial ammonia plants and taking some good care it is possible to do any job in a good way ... of course always attended ....

one, maybe strange thing for someone .... working with ammonia we use to be at least two person present to do the task ... maybe less money for each one of us, but for sure more safe and easier ...

Best regards, Josip :)

RANGER1
25-10-2014, 10:01 PM
In some cases we have to use a lot of water for different reasons.
To dispose of this water, someone puts it in a trailer, creates a small water leak & go for a long drive in the country :off topic:.

PS only if nearby drain, coral reef or river not available.

RANGER1
25-10-2014, 10:16 PM
I also made a mistake of pouring a very large container of liquid ammonia into a pit full of water.

We had to pump out a large ammonia water chiller system with time constraints, in the middle of the night.
System had to be pumped down into liquid receiver, only small pump down time due to this plant having many safeties not allowing it to run if pressure low etc (PHE evaporator).
On flooded evaporator PHE surge drum which was insulated, I drained what I thought was dead ammonia (ammonia with a lot of moisture in it).
When disposing of it into pit of water (where all reliefs are piped to) as I poured it in in one go I nearly killed myself if not through a heart attack, the violent reaction it had when it hit the water.

Of course after I did it I knew what an idiot I was.

It was liquid ammonia chilled down in a insulated vessel, it looked like water, did not smell, did not ice up much on outside of container due to very dry climate in winter.

Sometimes if you get a little complacent with this stuff it soon corrects your attitude, if you survive.

Grizzly
25-10-2014, 11:32 PM
Sometimes if you get a little complacent with this stuff it soon corrects your attitude, if you survive.

The wisest words I have read in a long time!
Grizzly

Tycho
16-02-2015, 10:39 PM
Hi guys
Back in my service days I spent a lot of my time on ammonia systems. Purging ammonia was the norm on nearly every job. When purging I found that irrespective where you purged from, if you opened the purge valve to quickly you could make the hose suck back. so when I purged I would hold the hose in the water and slowly open the purge valve and in most instances I could open the valve to a point that suckback occurred. At this point I would pull the hose out of the water and wait for the water to be ejected from the hose and ammonia start to blow. I then put the hose back in the water and close the valve down a little, but keeping my hand on the hose in case suckback restarted. Purging from a high pressure seemed to be easier to cause suckback than purging from a low pressure condition. Good subject
Look forward to others comments

Hi Glenn :)

Back then purging ammonia into any body of water was the norm, I remember my first supervisor telling me to "drop the hose in the ocean and keep the drain valve open until you hear crackling sounds in the hose, then come get me" I later learned that the crackling sounds in the hose was the supersonic sound of ammonia collapsing on itself as the hose was free of liquid... and that to go "come get me" meant to go to the truck and wake up the supervisor as he was not allowed to leave me since I was just an apprentice at the time, and even at that time I noticed that the supersonic crack of ammonia imploding and water going the wrong way in the hose happened at around 0.2-0.5 bar when there was only gas left to be purged.

as long as there was liquid to be purged, or as long as the pressure in the system was 0.2-0.5 bar (depending on the accuracy of the pressure gauge) there would be no suckback.

And after working 19 years with ammonia, I have never had suckback, mostly because back when it was legal to dump in the ocean I always had a 0.1 bar non return valve :D

But I have a good story :D A trawler, with an ammonia charge of 3.000 kg of ammonia were told to discharge their refrigerant charge back when it was legal to dump ammonia in the sea... so they did, connected a hose to their refrigerant pumps and dropped it over the side of the ship, and steamed from iceland back to norway, with the hose over the side, so when the ship came to norway the system was full of water :) (ooops)

Tycho
16-02-2015, 10:45 PM
Sometimes if you get a little complacent with this stuff it soon corrects your attitude, if you survive.

Thank you Ranger :)

I keep telling my guys to respect what they are doing, but don't be afraid of it, but if they make a mistake they will be corrected promptly"

I will steal your quote and use it as my own ;D