Ammonia vaporization changes the state of ammonia from a liquid to a gas. Vaporized ammonia is important for use in industrial refrigeration and in pollution abatement technology, such as selective catalytic reduction (SCR) systems used to neutralize nitrogen oxides from large electric utility and industrial boilers.
Although ammonia is generally shipped and stored under pressure in its liquid form, it is most frequently used in its vapor state. Aqueous ammonia vaporization uses heat to evaporate an ammonia and water mixture. The liquid is mixed with atomizing air and dispersed into the vaporization chamber as a fine mist where it is heated until it vaporizes. The air, ammonia, and water vapor mixture is then transferred to the injection grid.
This blog post, the first in a Magnetrol® series on modular skid systems, explores skid configurations for vaporizing ammonia and discusses common level applications that impact skid functioning.
Why Choose Skids?
Throughout the process industry, modular fabrication has become a viable option to field construction for owner/operators, OEMs, and plant engineers. From zero site disruption during fabrication to plug-and-play commissioning, single- and multiple-skid systems have become more popular in recent years. Nearly any unit operation can be fabricated as a self-contained, modular skid system. While most skids are housed within an open structural framework, a skid maker can also fabricate the skid system inside a standard shipping container.
Anhydrous and aqueous ammonia are skid-configured for unloading, storage, transfer, vaporization, stripping, metering, injection, and urea-to-ammonia (U2A) conversion. Skids range from compact, single-process systems to multi-unit utility systems.
Level Measurement Solutions
Below are common level measurement applications for ammonia vaporization skids and level measurement solutions for these applications:
- Ammonia Storage Tanks: Pure ammonia is stored in a pressure vessel rated at 250 to 300 psig. Aqueous ammonia (70 to 80% water) is stored in a tank rated at 25 to 30 psig. For continuous level, the Eclipse® Model 706 guided wave radar transmitter or the Atlas or Aurora® magnetic level indicators are recommended. For point level, the Model A10/A15 single stage displacer switch is recommended.
- Mixing Tanks: The mixing tank uses an agitator for blending. Level controls trigger alarms in underfill and overfill incidents. For continuous level, the Pulsar® R86 non-contact radar transmitter or the Atlas or AURORA magnetic level indicators are recommended. For point level, the Echotel® Model 961/962 ultrasonic level switch or the Model T20 single stage float level switch are recommended.
- Vaporizer Liquid Level: Functioning as an essential safety measure, a level switch in a vaporizer can provide high liquid level alarm, overfill tank alarm, leak detection alarm, or low level alarm. For continuous level, the PULSAR R86 non-contact radar transmitter; the ECLIPSE Model 706 guided wave radar transmitter; or the ECHOTEL Model 355 ultrasonic transmitter are recommended. For point level, the ECHOTEL Model 961/962 ultrasonic switch for high/low alarm or the Thermatel® TD1/TD2 are recommended.
For more information on level measurement solutions for ammonia vaporization skids and other modular skid systems, download the modular skid systems brochure.