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US 4,333,735 AGranted
Process and apparatus for measuring gaseous fixed nitrogen species
AssigneeExxon Research & Engineering Co.
InventorsJames E. Hardy, John J. Knarr
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AssigneeExxon Research & Engineering Co.
InventorsJames E. Hardy, John J. Knarr
Estimating the term…
Process and apparatus for measuring total fixed gaseous nitrogen species, including NH.sub.3, NO, NO.sub.2, 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 N.sub.2 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 NH.sub.3, through premature catalyzed reaction with NO and subsequent loss from the system as N.sub.2.
An improved process for measuring the total concentration of fixed nitrogen species, including NO, NO.sub.2, NH.sub.3 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:
An improved process for measuring the total concentration of fixed nitrogen species, including NO, NO.sub.2, NH.sub.3 and HCN, involving the steps of contacting a gaseous mixture, containing one or more of said species 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 by NO chemiluminescence and calculating therefrom said total concentration of gaseous fixed nitrogen species, in which the improvement comprises the combined steps of:
An improved apparatus for measuring the total concentration of fixed nitrogen species in a gaseous mixture, including NO, NO.sub.2, NH.sub.3 and HCN, involving a means for introducing said gaseous mixture into said apparatus, a catalytic converter for converting said fixed nitrogen species in said gaseous mixture at elevated temperature to NO and an NO detector for measuring the resulting NO concentration in which the improvement comprises the combined elements of:
An improved apparatus for measuring the total concentration of fixed nitrogen species in a gaseous mixture, including NO, NO.sub.2, NH.sub.3 and HCN, involving a means for introducing said gaseous mixture into said apparatus, a platinum gauze catalytic converter for converting said fixed nitrogen species in said gaseous mixture at elevated temperature to NO and an NO chemiluminescence detector for measuring the resulting NO concentration, in which the improvement comprises the combined elements of:
Dependencies are inferred from the claim text.