Effects of operating conditions on deNOx system efficiency in supercritical circulating fluidized bed boiler

The purpose of this work was to determine the impact of a operating conditions on the deNOx system efficiency.in a 966MWth supercritical circulating fluidized bed boiler. Experimental tests were carried out on a full-scale DeNOx system installed in the world’s largest once through supercritical circulating fluidized bed boiler. In this work, the effects of the following parameters were studied: flue gas temperature inside the separators between 636°C and 845°C, relative ammonia mass flow over the range 0.22-1.00 and three relative values of O2 concentration (i.e. 0.94, 1.0 and 1.13). The efficiency of deNOx system increases (ca. 53%) with increasing relative ammonia mass flow. A maximum DeNOx system efficiency (ca. 70%) was achieved at flue gas temperature in the range from 720°C to 790°C. In the case of all unit loads, deNOx system efficiency from 36% to 70% was observed and performs a standard emissions relate to permissible concentration of NOx in the flue gas.