Liquid Ammonia 1

[ChipFuller]

We are starting a new process using liquid ammonia. The tanks are 2' diameter x 7'long. We are bring the tanks into our process bay and then hooking up the tank. We have brought a trunk line next to the tank to ventilate any ammonia gas. Our plant industrial hygiene now wants us to install a permenant ammonia monitor that ties into the PLC to alarm operators plus install a shroud around the tank connections. We will be operately this tank remotely but his concern is connecting and reconnecting hoses which will be 1-2 times a day. What's industry practice?

Thanks

 

[Montemayor]

ChipFuller:

Industry practice depends on the plant, the management philosophy, personnel needs/demands/unions, operating requirements, and a lot of other factors - just as in your plant operations. The present situation is that EPA and OSHA have no standards, rules, guidelines, or regulations on Ammonia connections or leak monitoring limits (except where it concerns spills and fugitive emissions) to my knowledge. There are literally hundreds of thousands of piped, process connections existing in the US alone - and nothing is done to monitor, inspect or regulate the screwed, flanged or hosed connections that are in storage tank areas, overhead pipe racks, on sleepers, inside process buildings, with or without expansion facilities, etc. In fact, I personally know that protection against liquid ammonia expansion betweeen two block valves is strictly up the owner and his PSM routine within the plant. There are no laws to "protect" you from spilling liquid NH3 or hurting someone - the involved plants must take a pro-active role in seeing to it that the operation is safe. Only AFTER an incident is the government able to step in - not BEFORE. This is unfortunate and it leaves the employees and personnel with the decision of plant/labor management.

I believe there is concern for the multiple times the liquid NH3 connections have to be made, and I personally agree that there is possibility for fugitive emissions or leakage. A monitoring system is a step in the right direction, but operability has to be respected and maintained; otherwise, a more serious accident can take place. Your safety department and your operators should be involved and allowed to work this problem out in concert with a total safety concern. In this specific example, I can attest to the fact that it should be very simple to detect fugitive NH3 emissions (if that is what you're after). A simple, metal shroud around the immediate area where the connections are should be ample to allow detection and also leave safe and ample room for operations and access. It is fortuitous that NH3 has such strong and pungent properties that a "sniffer" can easily pick up the ppms. This helps in not having to totally enclose the area and simply getting by with a shroud. I believe this will work and I would go with this first.

Art Montemayor
Spring, TX

 

[EGT01]

Try a search on the web for ammonia technical data manuals. Here's a couple of links...

http://www.ammoniapro.com/techincal_information.htm

http://www.rmtech.net/technical_information.htm

I found the Tanner Industries Storage and Handling Booklet very informative. Besides listing some guidelines they list some "industrial" references that you may want to review - Pamphlet G-2 from the Compressed Gas Association, 29 CFR 1910.111 US Code of Federal Regulations, Pamphlet ANSI K61.1, Ammonia Data Book from the International Institute of Ammonia Refrigeration.

I'm not sure what you mean by trunk line to ventilate any ammonia gas or what the shroud is but if you have an ammonia monitor in the area where you are disconnecting hoses that contained ammonia you most likely will get an alarm every time you disconnect a hose so I don't see a value in that. Not sure what happens to your hose after disconnecting but I could imagine even residual traces of ammonia in the hose could set off the monitor. I wonder if there isn't a better way to handle your ammonia delivery to the process so you are not having to handle the hose connections so much.

 

[MJCronin]

Chip,

I agree with EGT01,

(I am assuming you are talking about anhydrous ammonia, not aqua ammonia)

I also feel that a reading of Pamphlet ANSI K61.1, and the Ammonia Data Book from the International Institute of Ammonia Refrigeration is the best next course of action.

There are many industrial/process facilities that safely use ammonia and I feel that this process may benefit from a "more conventionally configured" and larger bulk distribution system. (You say that hoses must be hooked up twice per day ?)

Be aware that theft of anhydrous ammonia (by meth drug labs) is a big deal in certain parts of the US

http://yosemite.epa.gov/opa/admpress.nsf/0/65da877d5a2af424852568b9006124f1?OpenDocument

The US EPA also has requirements about handling and reporting on ammonia storage and usage. Beyond a certain stored weight, EPA requires a "Risk Management Plan"

http://yosemite.epa.gov/oswer/ceppoweb.nsf/vwResourcesByFilename/A-Toc.PDF/$File/A-Toc.PDF

My thoughts only.....

MJC