초록 ▼

Process and apparatus for measuring total fixed gaseous nitrogen species, including NH3, NO, NO2, HCN and organic amines in gaseous mixtures. The process involves catalytic conversion at elevated temperature of all fixed nitrogen species to nitric oxide, NO, followed by chemiluminescent measurement

Process and apparatus for measuring total fixed gaseous nitrogen species, including NH3, NO, NO2, HCN and organic amines in gaseous mixtures. The process involves catalytic conversion at elevated temperature of all fixed nitrogen species to nitric oxide, NO, followed by chemiluminescent measurement of the resulting NO concentration. The improvement features of the process are the use of a reduced pressure gaseous sample flow to prevent N2 poisoning of the heated platinum catalyst and a preheat step of the reduced pressure gaseous mixture in an inert, non-catalytic quartz preheater prior to catalytic conversion to prevent loss of some species, such as NH3, through premature catalyzed reaction with NO and subsequent loss from the system as N2.

대표청구항 ▼

An improved process for measuring the total concentration of fixed nitrogen species, including NO, NO2, NH3 and HCN, in a gaseous mixture involving the steps of contacting said gaseous mixture with a conversion catalyst at elevated temperature and in the presence of excess elemental oxygen and there

An improved process for measuring the total concentration of fixed nitrogen species, including NO, NO2, NH3 and HCN, in a gaseous mixture involving the steps of contacting said gaseous mixture with a conversion catalyst at elevated temperature and in the presence of excess elemental oxygen and thereby converting said fixed nitrogen species to NO and measuring the resulting NO concentration and calculating therefrom said total concentration of gaseous fixed nitrogen species, in which the improvement comprises the combined steps of: (a) reducing the pressure of said gaseous mixture to about 0.03 MPa or below; (b) preheating said gaseous mixture from step (a) to a temperature in the range of about 700°-1100°K in a non-catalytic preheat zone; and (c) contacting said preheated gaseous mixture from step (b) with said conversion catalyst at a temperature in the range of about 800°-1100°K. for a sufficient time to convert substantially all of said gaseous fixed nitrogen species to NO.