Ammonia-Free Catalytic Reduction System Utilizes Safe Urea Solution
Nationwide Boiler's ammonia-free CataStak-FT selective catalytic reduction (SCR) system utilizes the TRIM-NOX urea injection system under a license and supply agreement with Combustion Components Associates. The ammonia-free CataStak-FT SCR system utilizes a safe urea solution as an alternative to anhydrous ammonia. This system eliminates the need for end-users to store or handle ammonia, which typically requires a HAZMAT safety program if stored in volumes greater than 500 pounds.
Nationwide Boiler's demonstration test for the CataStak-FT SCR system was performed on an 800-hp (27,600 lb/hr) Cleaver-Brook firetube boiler, operating at 125 psig. During the testing period, several urea injection points within the shell of the boiler were evaluated to determine the optimal flue gas temperature needed for proper decomposition of urea to ammonia for the conversion of NOx to the formation of harmless nitrogen and water vapor.
Nationwide Boiler and CCA pursued several different approaches before determining the proper injection location points occurred following the second pass of the boiler, at a flue gas temperature of approximately 700° F. Initial NOx results indicated levels of only 1 ppm with less than 2 ppm, according to Larry Day, Nationwide's vice president of sales and marketing. After additional research and testing, Nationwide Boiler can now provide end-users with an SCR system without the use of ammonia, performing at NOx levels below 5 ppm.