Catalytic denitrification control process and system for combustion flue gases

摘要

A control process and system for catalytic denitrification of NOx containing flue gases derived from a fuel combustion unit such as a gas turbine by ammonia addition to the flue gas upstream of a catalytic denitrification unit. The ammonia addition rate is controlled based on a basic signal which is generated based on functional parameters including the fuel being burned, its combustion temperature, flue gas flow rate, ammonia flow rate and the catalytic activity, so as to inject initially into the flue gas stream less ammonia than is theoretically required. Then the NOx concentration in the exhaust gas downstream of the catalytic unit is compared with the appropriate standard, the ammonia quantity initially being added is further adjusted until the NOx concentration is gas emitted to the atmopshere is reduced sufficiently to meet local clean air standards while avoiding unsatisfactory excess ammonia injection and system oscillation.