Vaporized ammonia is used in catalytic and noncatalytic reduction systems for emissions control in power plants. Ammonia is injected into the flue gas stream and acts as a reducing agent. The EPA mandates the reduction and control of these emissions, and ammonia is a key part of ensuring that a power plant is in compliance with EPA regulations. It is also used to enhance precipitator efficiency for particulate control. In order to keep the supply of ammonia readily available for usage and avoid spillage or accidents, a robust ammonia storage system with accurate level measurement must be in place.
Magnetrol® has produced an applications brochure for the power industry, detailing measurement challenges and solutions for each step of the power generation process. This blog post is part of an occasional series exploring each application in detail.
Level Measurement Challenges and Considerations
Pure ammonia is stored in a pressure vessel rated for 250 to 300 psig. Aqueous ammonia (70 to 80% water) is stored in a tank rated for 25 to 30 psig. Storage requirements for aqueous ammonia are three to four times that of pure ammonia. A level measurement device for ammonia storage tanks must be able to withstand pressure and still measure accurately. Accidental atmospheric release of pure ammonia vapor can be hazardous, so safety and environmental measures may be required which affect the level control selected.
Level Measurement Solutions
MAGNETROL has produced several level measurement solutions for ammonia storage tanks:
- For point level
Model A15 displacer-actuated switch
- For continuous level
Eclipse® Model 706 guided wave radar transmitter with 7XP coaxial probe
- For visual indication
Atlas™ or Aurora® magnetic level indicators can be supplied with switches or transmitters