Post combustion methods for control of NO x emissions

This paper is a review of stack gas treatment methods for the control of NO x emissions. Particular emphasis is placed on status of development and factors affecting the performance of the processes. Catalytic, noncatalytic, and scrubbing processes are compared on a uniform engineering basis. Most of the active process development work is taking place in Japan. The three leading stack gas treatment techniques for NO x control are catalytic reduction with ammonia, noncatalytic reduction with ammonia, and direct scrubbing of NO with simultaneous absorption of SO 2. The wet processes are much less developed than the dry processes.