Tube-side ammonia vaporizers offer powerplants an alternative method to vaporize both aqueous and anhydrous ammonia for use in selective catalytic reduction systems, in tube-side vaporizers, ammonia is forced through the tube side of a heat exchanger and the heating source is located on the shell side, Tube-side vaporizers provide such advantages as a consistent ammonia vapor composition, unlimited amount of superheat, and minimal amount of ammonia holdup.