Process for the synthesis of ammonium nitrite
AssigneeAllied Chemical Corporation
InventorRichard Ross Hertzog
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Abstract
Ammonium nitrite is commercially produced by contacting a gaseous stream containing nitric oxide, nitrogen dioxide and oxygen with an aqueous solution containing a basically reacting ammonium compound in an absorption system. However, at normal production rates, serious problems have been encountered because of the emission of unreacted nitric oxide which causes pollution of the atmosphere. It has now been found that by adding controlled supplemental quantities of nitrogen dioxide to the absorption system, nitrogen oxide emission is substantially reduced.
Claims5
In a process for producing ammonium nitrite by the absorption of a gas containing nitric oxide, nitrogen dioxide, oxygen and at least 65 percent by volume of inert gas in an absorption system with an aqueous absorbing solution containing a basically reacting ammonium compound selected from the group consisting of ammonium carbonate, ammonium bicarbonate, ammonium hydroxide and mixtures thereof, employing entering gas with at least 2.0 mol ratio of nitric oxide:nitrogen dioxide and employing absorbing solution having normality of at least 0.01 with respect to the basically reacting ammonium compound, the improvement which comprises adding supplemental nitrogen dioxide to said gas being absorbed in the absorption system in amount sufficient to maintain a nitric oxide:nitrogen dioxide mol ratio between 0.8 and 1.0 in the exiting gas, said supplemental nitrogen dioxide being added to said gas when the absorption of nitrogen oxides is 50 to 95 percent complete based on the nitrogen oxides in the entering gas.
Dependencies are inferred from the claim text.