Design and Operating Experience of Selective Catalytic Reduction Systems for NO X Control in Gas

The design and operating experience of the Selective Catalytic Reduction (SCR) systems for denitrification of flue gas in utility and industrial gas turbine applications is presented. The paper will discuss the general SCR design approaches and the effects on the NOx removal efficiency of various design and operating parameters such as gas temperature, velocity and composition, NOx content, catalyst material and type, quantity of ammonia injected, acing, and pressure drop limitation. Two different types of ammonia injection methods (namely, anhydrous and aqueous ammonia injections) and attendant ammonia injection control schemes are described. A brief summary of SCR operating experience with power-generating gas turbines and process heaters/boilers concludes the paper.