Ammonia is commonly used as a fertilizer, an industrial coolant and reduces NOx emissions from combustion sources. In each case, thermal mass flow meters can be used for ammonia measurement, and Sage has uniquely addressed the issues associated with safely calibrating the instrument.
Ammonia as Fertilizer
Ammonia is one of the top five chemicals produced in the United States. Over 80% of the ammonia produced is used as fertilizer which provides nitrogen for plant growth. Ammonia can be used directly or combined with various salts to provide fertilizer in a bulk solid form.
Ammonia as Coolant
Another common use of ammonia is as a coolant for industrial refrigeration equipment. This is because ammonia is easy to liquefy with compressed and also it absorbs large amounts of heat when in the gaseous state.
Ammonia to Reduce NOx
The growing use of ammonia is for emission control of combustion sources. Ammonia is used for the reduction of NOx in either a selective catalytic reduction (SCR) system or a non-catalytic system. The NOx will react with ammonia to create nitrogen and water. The accurate measurement of ammonia gas flow is critical for the proper performance of the system to meet environmental requirements.
Ammonia Flow Measurement
Using thermal mass flow meters to measure ammonia flow does pose some difficulties. A major hurdle is calibrating the meter. Each meter must be calibrated on a flow bench using the actual gas to obtain the highest accuracy, yet due to safety concerns, a direct calibration using ammonia is not feasible. Thus Sage Metering calibrates using a substitute gas and makes adjustments based on modeling developed by Sage Engineering using the difference in thermal gas properties.