Patent ID: 6165435
Filing Date: 2000-12-26
Classification: C01B

Abstract:
In a process for producing nitric acid by oxidizing ammonia gas to form dinitrogen tetroxide gas, reacting the dinitrogen tetroxide with water in an absorption zone to form aqueous nitric acid and nitric oxide gas, removing a nitric acid/nitric oxide stream from the absorption zone and feeding the stream into a nitric acid bleaching zone, removing impurities from the nitric acid in the bleaching zone to form nitric acid product and adding supplemental oxygen gas to one or more of the reaction streams to increase nitric acid production and/or strength,the improvement which comprises injecting the supplemental oxygen into a nitric acid-containing process stream to form a gas bubble/liquid mixture therein comprising a fine dispersion of gas bubbles having diameters of less than about 0.1 mm and thereby providing increased interfacial surface between the gas bubbles and the liquid mixture.