Anhydrous Ammonia Venting 4

[PSP113]

We are installing an anhydrous ammonia tank in our coal burning power plant to inject for flue gas conditioning. My question has to do with the loading by truck of the product. The tank will be at 600 kPag (14°C) to 815 kPag (22°C), so when we fill the tank, the truck driver will equalize the pressure between holding tank and truck tank and then fill. After he is done, there will be approximately 8 kg of liquid in the fill line, which will then need to be vented. I have heard of putting the hose into a bucket of water and allowing the ammonia to flash in there, reducing vapor exposure. Does anyone have experience with this? How do you determine the amount of water required?

 

[Chance17]

I once used a stainless steel portafeed (4'x4'x4') that was 75% filled with 10% NaOH solution.
The portafeed was located about 10-feet from the ammonia truck station.
Small diameter (1/4") stainless steel tubing from vapor hose and liquid hose bleeds were inserted below the liquid level.
When ammonia odor was detected (about once a year), a fork lift transported the portafeed to an ecology sewer.
The contents were dumped and replaced with fresh solution.

 

[BenThayer]

you might consider venting the connection to your end user which i assume will be somewhere on the vent gas system. this will cause autorefrigeration but with a bit of encouragement, the liquid would boil off in just a few minutes. then you would have very little vapor to vent off for the final disconnect.

i doubt you want to bother with the money to install a recovery compressor to compress it and return it to your storage.

i am not sure that NaOH would be a good thing. NH3 reacts with water to make NH4OH and is itself a high pH, basic solution. we used to use NaOH to drive NH3 from a wastewater stream.

it would seem that you would be better with an acidic solution.

 

[Compositepro]

Ammonia is highly soluble in water. You have to be careful that you do not suck water up the line into the ammonia hose. And caustic would reduce solubility of ammonia in water as Ben says.