A NITROGEN DIOXIDE MONITOR BASED ON NONDISPERSIVE VISIBLE OPTICAL DETECTION

The problem addressed in this project is the need to monitor oxides of nitrogen(NOx, ie NO and NO2) levels in the combustion gases of stationary sources suchas power plants in order to facilitate on-line control of the scrubbers that willbe used to remove those pollutants. Since the measurements are in the parts permillion range, simpler and less expensive instruments than those currently used,such as chemiluminescent analyzers, may be advantageous. The proposed innovationis to use recently available light emitting diode (LED) light sources and fiberoptic components to realize an NOx monitor working on the gas-filter correlationprinciple. The Phase I effort will consist of: 1) building a prototype in theproposed configuration, and measuring its sensitivity and response tointerferents; 2) determining by experiment and modelling an optimized design,specifically optimizing the filter design and the coupling of light from thesources into the fibers; and 3) testing the feasibility of real time computercontrol of ozone titration of NO to NO2. The Phase II effort will be to builda prototype instrument which would be capable of continuous automated monitoringof NOx at ppm levels in industrial environments.