We are thinking of putting together a reclaim/pump out unit for ammonia. Anybody have suggestions in relation to major pump downs and tie ins etc.
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We are thinking of putting together a reclaim/pump out unit for ammonia. Anybody have suggestions in relation to major pump downs and tie ins etc.
Scott,
Have a look at the www.howe.com website if your are trying to put a pump out machine together.
Hi Scott:)
Pump out systems are not commonly used in the UK, but I have sugested this to the tech department of the company I work for.
You would need a connection after all three control solinoides, liquid Wet Return and Hot gas, with an isolating valve and a pipe connection into the top of a common header, flowing back to the pump-out compressor. For our jobs, mainly packaged units I was thinking of a common header with a flexible hose with an isolation valve at the loose end of the hose which could be connected to a number of isolation valves by means of a union, at various useful points on the packaged unit.
Hope this helps. Regards. Andy:)
G,Day Andy,
The thought was to have a self contained unit that we could connect to acces points through out the system such as you describe.
Like you I are not aware of too many systems that imploy this idea with the exception of very large plants that are piped with pump out lines to a dedicated compressors similar to those available from Howe.
With tie ins to wet gas lines, condensers etc the practise of purging remaining liquid and gas into drums of water and then running the diluted solution to waste is not desirable, particularly with OHSW and EPA regs being as they are.
Many factories have been evacuated or environmental disasters caused by poor blow down practises yet equipment designed for this type of work seems to be hard to find.
regards
Scott
G Day Scott
I was thinking of using a small bitzer open compressor, possibly a direct drive unit mounted on top on a 50 -75 litre liquid receiver, with a suction accumulator fitted.
Small enough to be semi- portable, but large enough to recover a bottle of gas at a time. A connection could be made to the bottom of the accumulator for fitting a hand liquid pump and a high level shut off switch to stop the compressor and warn of the need to pump out trapped liquid.
Regards. Andy
Andy,
A little Bitzer or Bock would be spot on and a slop pot would be essential. Finding a suitable condenser would possibly be the sticking point. We thought of a air cooled condenser mounted over the skid or a watercooled condenser connected to the existing plants condenser sump via a small portable pump.
regards
Scott
I have pumped down many old plants with no pump out provisions.
I used a 40 gallon Vessel built on a trailer with a level switch and solenoid valve to control flow and 2 weed burners attached to the vent on top and wasted the Nh3 while it burned off. No stink, No EPA probs. and it was a pretty flame at night.
Dangerous? Ya have to control the beast!
yeah, small & open type comp would be a good choice.
may be a pre-chilled cylinder would be better option to store the pump-out refrigerant.
added with weighing machine to control the amount of refrigerant charged to the cylinder/s.
give it some thoughts.
Hi,
please remember that when you pump the amonia in a tank is sted of to an other point in the ref.plant you wil need a condensor to make the discharge gas liquid or you wil get high pressure problems.
Greetz Art
Scott.Quote:
Originally Posted by Scott B
No disrespect meant, but I find myself slightly bemused / bewildered by your reason for wanting a reclaim unit for Ammonia.
Yes if you create large amounts of diluted ammonia. You may well be presented with the dilemma of how to dispose of it. Pouring it onto a hard surface ( say tarmac.. without drainage) and letting it evaporate is favourite.
Provided you control the release of it's gaseous vapour and avoid drainage pollution. Is a perfectly acceptable situation or has it become an offence to release Natural Substances.
I agree there are many situations where it is far harder to remove all traces of Ammonia from a system than a ***** one. Many managers and Engineers cannot accept that it takes usually 2 to 3 times longer. Not that difficult to understand when you realise that *****s expand 2-300 times by volume. But Ammonia expands 800 times by volume.
Or more simply put the same amount of liquid creates nearly 3 times the amount of vapour.
And we all know how difficult it is to remove vapour.
One trick I have perfected is to use BSP OR Metric hydraulic fittings to 10mm pneumatic plastic hose.
This is fed through my Ammonia Manifold to a remotely placed (preferably old Vacuum pump).
So having isolated the relevant valve / valves. and pumped the system down, several times if necessary. I use the pump to suck the remaining vapour out of the area to be worked on.
Apart from the occasional whiff from vapour trapped in oil etc. All is usually sweet.
Sometimes careful use of an electric hot air gun can aid liquid removal.
So back to 1 of my original points releasing Ammonia into the atmosphere always was and still should be acceptable. But as with all practises only if done safely and correctly.
I am not getting at you Scott but you do make the comment that I have underlined.
So as a experienced Ammonia Engineer I felt before the H&S Brigade start to dictate I would put the Sensible and reasonably practical argument forward!
Yes you can buy Ammonia reclaim units in U.K. Polar Pumps make one.
Got one not that Impressed. I will stick to controlled use of water and an old Vacuum P ump thanks!
So far the largest amount I have removed using a slightly modified version of what I have described is 400kg. I took 3/4 std working days mind.
Also I would like to point out that many thousands of tons of Ammonia is poured onto sub standard hay a year to improve it's feed quality I believe.
So the only Issue with Ammonia from our point of view is what the people working with it do or are trained to do.
I will stop my rant now but please guys why do we always accept what the misinformed ( not you Scott) tell us. Don't forget We all have skills that are in short supply. Anyone can say you can't do that. Not so many are willing to tell you how you can.
PS IT WORK WELL IN A RAIN STORM.. GODS OWN AMMONIA ABSORBER!
Grizzly.
Wow Grizzly. What got your fur ruffled?:D
Your comment about releasing ammonia directly to atmosphere is OK as far as I'm concerned, but then again you have to cognizant of the prevailing bureaucracy rules. The US rules are you have to report any leak greater than 100 pounds that occur within 24 hours. That is to atmosphere, and, someone could insist an intentional discharge is unlawful.
Sure, NH3 is biodegradeable but the stink alarms everyone to call the newspapers.
Personally, I think the best way to get rid of small quantities of ammonia is to use a flare (similar to what Ponca Dave mentioned)
Iceman and everyone else sorry about the rant only my buddy and close work colleague. In fact he is our second Ammonia Engineer. Him and I do all the Ammonia works in our region.Quote:
Originally Posted by US Iceman
Anyway he was admitted to hospital last week and as a consequence will be off work for at least 1 month likely more!
Which has led to the old chestnut from my managers of what tasks I should tackle on my own and when it becomes necessary to have a second Engineer present. Then there is the oh does the second Engineer have to be "ticketed"? CAN'T WE JUST give you one of the other lads!
To explain my colleague and I have always insisted on the 2 of us being present whenever we open up a system. Once it's been made safe don't mind working on the plant on our own. Yes we have both many times in the past opened systems etc etc on our own. But the modern work ethic dictates risk assessments and safe practises etc.
So we have adopted the afore mentioned of having the 2 of us together whenever WE deemed it necessary. I have other colleagues in other regions that for instance deem it necessary to have 2 men when charging.
So last week people realised that a lot of the forthcoming work we have would need 2 of us. So the old chestnut came out of "CANT YOU JUST" (to be read - on your own)"
So sorry to anyone if offended put it down to A BAD WEEK.. Still worried about my mate!
Do any of you guys out there operate a similar system?
With regard to my original post I think you may of misunderstood or I haven't made what I was trying to say clear.
IF Ammonia is released into water and that water is constantly replenished the solution is so weak that there is virtually no smell. If you get it wrong and it turns milky grey the concentration is to high and you definitely has a problem. what i should of said is it is possible through controlled use of water to virtually eliminate any smell and totally neutralise the ammonia liquid or vapour that you wish to dispose of.
Surely even in the U.S. Controlled purging of a system is allowed and can't be classed as a leak?
I know people get scared when they smell ammonia rightly so! All I am trying to say (badly I think) is that
Why would people ban it's use or the safe disposal of it. When if carried out properly no harm is done?
When I say about discharging the remaining vapour with a vacuum pump. I only mean the minute amount left once all the liquid has been boiled off and the system pumped down. Once again harmless if carried out in a safe and correct manor!
This is not meant as a rant I am just trying to explain and I would Value anyones input on how they cover manpower wise various maintenance tasks.
Grizzly
NO harm done Grizzly. Your comments were not taken in a negative way.
But, what you are pointing out is terribly important. I like the buddy system you and your associate use. More should be following that for safety reasons.
The damn bean counters are trying to hard to justify savings at the expense of the people doing the work. They don't understand the ramifications of the work or what can happen. They only see extra expense. (Now I'm getting on my soap box:D.)
What you are describing is a common requirement for any ammonia system. Barring any differences in the installation of the system, it seems reasonable we should be able to develop a common procedure for pump outs and blow downs, which are two different tasks.
When the people wrote our safety requirements they included the 100 pound leak rate in 24 hours as a mandatory reporting requirement to the authorities. However, I think there is no clear cut definition of what this actually means.
I have heard stories where an inspector looks at purchases of ammonia over some time and says that means you have lost refrigerant and did not report it. With any system having purgers you know you will loose some ammonia anyway. Is it a leak? No...but some can try to construe it to mean that.
These are serious issues and I suspect common to all of us who work with ammonia systems.
I am often faced with maintenance on ammonia systems where pump-outs are necessary, and there are times when a compressor simply isn't available. In those cases I use a water powered eductor valve (venturi valve) to evacuate that part of the system. Water passing through the eductor valve creates a suction and the water absorbs the ammonia. I am able to reduce the pressure down to 20-25 inches of mercury using this method.
The down side to this is that you end up with some stinky water, but with a little forethought you can keep the volume of water minimized.
I cannot even begin to express how strongly I recommend all ammonia people to utilize these valves, but ANYONE that requires a vacuum should also have one on hand. Eductors may be powered by compressed air, steam, or water. They are amazing. Do yourself a favor and look into them!
This is the best way I feel to do this. We used this last fall to evacuate a system or for the occasional tie-in.Quote:
Originally Posted by Oregon Jim
Yeah, the water can get stinky and you also have to watch out for burning the grass.:o
Picture this if you can...
A small water pump that draws suction from a barrel or some similar vessel. This water pump will discharge through the eductor valve and the flow will return from the eductor valve back into the barrel. This eductor valve creates the needed vacuum for your system, and your dirty water is contained in your vessel so that you may dispose of it at your convenience.
Yep, that would work although you are guaranteed to have stinky water as the ammonia will concentrate in it.;)
But it keeps the grass from burning though.:cool:
Jim/ IcemanQuote:
Originally Posted by Oregon Jim
This Method is new to me, but sounds very promising.
I presume it would only be practical for the
times when you need to evacuate larger amounts?
Although if you were site based presumably you could have a permanent rig set up?
Does anyone know of a commercial set-up were I can get details?
Thanks Grizzly
PS I assume that with this method there is no chance of creating "reverse pressure" and sucking the water back into the plant?
Been there! Managed to suck a 205ltr drum of water back into a compressor. Not reccomended and that's another Story!
We use a check valve with the eductor to prevent water from being sucked back into the system.
I use this frequently during our maintenance season when our refrigeration system is down, and I am just as likely to use it for pumping down a small part of the system as well as larger areas.
I have been busy with the off-season maintenance of my NH3 systems and have used my eductor valve frequently over the last couple of weeks while working on a low pressure ammonia receiver and ammonia pumps.
I was able to use my ammonia pumps to move most of the liquid NH3 to another low pressure receiver, and then used hot gas pressure to transfer the remaining liquid from the LPR. I then used an ammonia compressor to evacuate pressure from the receiver, isolating it once a vacuum was established. I vented the receiver to the atmosphere while cutting away old piping and valves and during times when welding was taking place, but kept a slight vacuum on the receiver throughout the rest of the procedure (replacing relief valves, installing new pump seals, etc.) to completely eliminate worries of ammonia concentrations in my working area. The down side to this procedure is that water flowing through the eductor valve absorbs a great deal of ammonia vapor, so disposing of the water may be an issue for some, especially if you do not evacuate your system well before you begin using the eductor. In my case, we have a good water treatment at our facility to monitor and control our wastewater stream.