The issue of recovering ammonia emitted from the breathing valve of the ammonia tank

If the design strength of the equipment is sufficient, can the set pressure for discharge be increased, and the set pressure for vacuum be decreased? Solving the problem at its source to reduce emissions is the best approach.

All the breather valves I’ve come across are connected directly to the atmosphere; I’ve never seen ones that require exhaust followed by direct recycling. Ammonia tanks are usually placed outdoors, with at most a canopy provided over them. If the volume of gas released through the breathing valve during unloading is substantial, it is recommended to install an exhaust fan to channel that gas into an open tank through pipes. Would this be better?

When connecting to a torch or incinerator, it is still best not to breathe ammonia into the air.

The atmospheric environment in the park is acidic; whenever a tank truck arrives to unload ammonia, the ammonia gas released from the breathing valve reacts with the air, and from a distance it appears as blue smoke, similar to that of a fire.

It’s definitely not good; better avoid taking the torch

I’m not sure what the specific design is for a pressure-free container. I asked a few companies, and it seems that they all discharge directly into the atmosphere.

Your ammonia tank is presumably a tank for storing ammonia solution; it operates at atmospheric pressure, so it’s normal to install a vent valve. However, when loading ammonia solution into the tank, ammonia gas evaporates and escapes, causing an irritating odor in the surrounding area. If this gas reacts with acidic gases, blue smoke may be produced. One approach is to install a negative pressure tube at the top of the tank (the vent valve remains in place, and the negative pressure should not be too high); this tube can be activated during unloading to draw out the gas and discharge it into water, thereby recovering the ammonia. Another option is to avoid using a vent valve and instead use an inverted U-shaped liquid seal (using water, with a valve installed at the top of the inverted U shape); the valve is closed during unloading, allowing the ammonia gas in the tank to dissolve into the water, and it is opened during loading to allow air to enter. This method may not necessarily meet design requirements and is provided only as a reference.

Currently, it may not be permitted to install a breathing valve on the ammonia storage tank in terms of design; our ammonia system does not have such a valve, and it is connected directly to the flare system. I wonder if you use some kind of preservation device when unloading liquid ammonia – we use compressors and various pipelines for this purpose. When the pressure in the tank truck is high during unloading, the pressure from the tank truck is used to transfer the material into the storage tank. After some time, when the pressure in the tank truck drops below that in the storage tank, the compressor is used to pump the gas from the tank into the tank truck in order to increase its pressure and facilitate unloading.

Compared to chemical companies, our organization is quite simple. We are ammonia tanks. Currently, every time ammonia is unloaded, the green smoke appears, from a distance, as if there’s a fire.

Breather valve with recovery device? It’s a good question; breathing can involve the use of activated carbon. But this raises another issue: the replacement of activated carbon, as well as determining whether the activated carbon has become ineffective, are both problems. Therefore, there is still a long way to go in addressing the recycling issue.