DP level for anhydrous ammonia bullet


Thread Starter

Mladen Kojic

Dp transmitter is installed next to the lower tapping point and therefore wet leg is short as possible. In that way we have eliminate boiling of ammonia on wet leg side. Dry leg is significantly long (3.5 m)and as soon as outside temperature is below ammonia temperature we have condensation in dry leg. We are considering two options: 1) To fill impulse lines with suitable seal liquid. Question is what is suitable liquid that will not react with ammonia? 2) To install condense pot below the lowest point of dry leg –depending on the capacity of the pot dry leg could stay dry. Any advices on suitable seal liquid or any other solution?

Power Plant Engineer

This is a pretty common problem...we experience the same thing on our Level transmitter for our Steam Drum. Condensate Pots will work in your situation. A couple of other things that we do are: use two transmitters in a redundant setup, move the transmitter so that the dry leg runs uphill to the transmitter, and insulate and heat trace the dry leg. Good luck, I'm sure you'll get it.

David W. Spitzer

Mladen, Using dp for this level application will be difficult (at best). I suggest applying another technology. Regards, David W Spitzer, PE Copperhill and Pointer, Inc. http://www.icu.com/spitzer 845.623.1830 (phone/fax)

William L. Mostia, Jr

Two other solutions that come quickly to mind are remote seals(for the dry leg or both legs for that matter) and for the dry leg, a pressure repeater might be used. Bill Mostia ==================================================== William(Bill) L. Mostia, Jr. PE Principal Engineer WLM Engineering Co Independent I&E Consultant P.O. Box 1129 Kemah, TX 77565 USA 281-334-3169 E-Mail: [email protected]

Malvern Jones

With reference to your level measurement problem I would offer the following solution. Fit remote diaphagm seals to the transmitter. Install them as close to the process as passible. This will give you an offset as zero DP will be equal to a full tank. So reverse the output of the transmitter. There are other ways of solving this problem, but i have always found the above to work best. If you are interested Coulton Instrumentation are agents for Fuji Electric, and can offer a wide range of solutions. You can contact them on [email protected] or visit their web site at WWW.coulton.com

Larry Kolbert

While there may be some objections to the technology, an excellent solution to this measurement is a gamma ray level gauge. Non-contact, non-intrusive, minimal maintenance are benefits to consider. Several manufacturers offer this technology including ThermoMeasureTech. Check web site "www.ThermoMT.com":http://www.ThermoMT.com . L.Kolbert
Not sure if the application is the same but we use capacitance probe transmitters for measuring the level of liquid ammonia in surge drum vessels. Danfoss or Bosma probes I think?

S Henderson Instrumentation supv.

Have used this successfully on a couple of 4000 gal. Nh3 storage vessels for about 15 years now. The key is to mount high side to vessel lowest point and heat trace & insulate (we use a 1/2" line)the low side to keep the condensed Nh3 vaporized. Always ensure to utilize good quality valves for isolation etc.