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Tycho
01-08-2017, 08:11 PM
We have a fish factory that has asked for NH3 scrubbers for all their ventilation, because they are close to a populated area.

They have had a blowout (faulty service valve that wouldn't close), and it caused a massive evacuation.

I've read about ammonia scrubbers, where there is a water/sulfuric acid mix that is circulated as a mist and when ammonia gas comes in contact with this mix.

All the information I can find is for large industrial process plants, does anyone have any experience with this, or any more information?

Would be much appreciated :)

Segei
03-08-2017, 12:03 AM
Long time ago I worked on LPG gas carrier vessel. To protect the crew in case of gas leak, air inlet of supply ventilation had very sensitive sensor which shut off the fan. Additionally we had NH3 scrubber on suction side of air supply fan. Scrubber was black plastic box size 2mx2m2m with recirculation pump and nozzles. I don't remember about any acid added to the water.
It is not clear for me what fish factory want to do. Do they want to put scrubbers on all exhaust fans?

RANGER1
05-08-2017, 10:40 AM
Tycho,
If still around, maybe this company can help.
There are come contact details on the bottom.

I would imagine this incident was looked into & had some safety recommendations.
Sometimes a screw on ball valve can be useful to use in a number of maintenance situations.
I would use one if valve was suspect, I wanted to close very quickly if something went wrong, like transferring liquid ammonia or high pressure ammonia.
With oil draining would definitely use one & in most cases mandatory.
So basically review all procedures, I'm sure you are on to it.

http://www.eurammon.com/sites/default/files/attachments/05_ecologically_sound_disposal_methods_in_ammonia_technology_en.pdf

I like these ones, as can screw onto anything threaded.

http://ph.parker.com/us/en/liquid-drain-ball-valve

Tycho
09-11-2017, 05:59 PM
Tycho,
If still around, maybe this company can help.
There are come contact details on the bottom.

I would imagine this incident was looked into & had some safety recommendations.
Sometimes a screw on ball valve can be useful to use in a number of maintenance situations.
I would use one if valve was suspect, I wanted to close very quickly if something went wrong, like transferring liquid ammonia or high pressure ammonia.
With oil draining would definitely use one & in most cases mandatory.
So basically review all procedures, I'm sure you are on to it.

http://www.eurammon.com/sites/default/files/attachments/05_ecologically_sound_disposal_methods_in_ammonia_technology_en.pdf

I like these ones, as can screw onto anything threaded.

http://ph.parker.com/us/en/liquid-drain-ball-valve

Thanks, the eurammon link lead me to this: http://wet-scrubber.com/scrubber-application/ammonia-gas-scrubber/ and this is kind of what they were asking for.

The incident where they had a blowout, what happened was that a service technician was going to check the standpipe for the level indicator on the high side receiver (old type danfoss AKS 41) for oil because of weird readings.

The service valve was a danfoss SNV8 CD10-3/8, it was mounted in the bottom of the standpipe, spindle down, and it was fitted with an Ermeto blanking plug and nut on the outlet side
15029

He undid the cap on the valve and checked that it was seated in the closed position, then he undid the nut for the blanking plug a few turns and tapped it a few times to unseat it, checked by hand that the plug was loose and unseated.
undid the nut, but the blanking plug was still in the groove, so he held his hand under it and tapped it with his wrench.
and *pooof* 10 bar high pressure liquid ammonia makes it's appearance in a rush.

(and no, it wasn't me)

This was during commissioning, so what had happened was probably that the plug and nut had been put on the valve early on and the guy that put it on didn't close the valve.
All SNV valves from danfoss come from the factory half way open, so during the commissioning some dirt had collected in the valve, enough for it to not leak when he checked if the plug was loose but still had the cap on and then when he tapped it off, it all came loose.

I always remove the o-ring from these plugs, because it's there to keep the groove and threads clean, not to prevent leaks :)

And I also never install any valves with the spindle pointing down :D