"The original THERMAL DeNOx installations involved positioning a gridwork of pipes in the flue gas stream for injecting a mixture of NH3 and carrier air or steam. In the most recent designs, the injection grids have been replaced by wall injectors which offer numerous advantages such as higher performance, lower costs, better load following, and lower maintenance. Also, the development of a fundamental kinetic model of the process chemistry and a three-dimensional flow model have provided significant process optimization capability. One application of THERMAL DeNOX incorporating the most recent technology involves a 440,000 lb/hr boiler generating steam and power in a Japanese chemical plant. In this installation, 70% deNOx was achieved through utilization of the optimized design techniques at d cost approximately 20% of a comparable selective catalytic reduction facility. Other advantages of the most recent technology include the ability to deal more successfully with particulate-laden flue gas streams and methods of minimizing or eliminating effects from ammonium salts in the exhaust flue gas. In its present form, THERMAL DeNOX. offers a highly developed, practical means of achieving deep NOx reduction in all types of stationary fired equipment."