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Method for producing nitric acid

A technology of nitric acid and absorption zone, applied in the direction of nitric acid, chemical instruments and methods, nitrogen oxides/oxo acids, etc., can solve the problems of not being disclosed, and achieve the effect of improving color quality

Inactive Publication Date: 2004-07-14
PRAXAIR TECH INC
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But these patents do not disclose any practical advantages of these methods when gas and liquid are mixed in the production of nitric acid

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  • Method for producing nitric acid
  • Method for producing nitric acid
  • Method for producing nitric acid

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Embodiment Construction

[0073] All patent applications, patents and literature cited in this specification are incorporated by reference in their entirety.

[0074] The method of the present invention is accomplished using an in-line gas dispersion device capable of forming gas bubbles with a diameter below about 0.1 mm. A preferred device is an in-line sonic stripper, such as that available from Praxair and described in US Patent 5,302,325. The online gas dispersing device of US Patent No. 5,302,325 can accelerate part of the gas / liquid mixture to supersonic velocity and then decelerate the mixture to subsonic velocity. Acoustic shock waves are formed in the mixture in such a way that very fine bubbles are created which raise the interface surface between gas and liquid.

[0075] Oxygen can be introduced into the aqueous nitric acid wherever there is such a stream in the production process by the method of the present invention, particularly anywhere between the cooler / condenser chain 10 and the fi...

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Abstract

A process is described for producing nitric acid involving 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 involves injecting the supplemental oxygen into a nitric acid-containing process stream to form a gas bubble / liquid mixture in the stream, the mixture forming a fine dispersion of gas bubbles having diameters of less than about 0.1 mm. According to the invention, increased interfacial surface is created between the gas bubbles and the liquid mixture to facilitate removal of impurities from the liquid phase and shifting of the reaction.

Description

technical field [0001] This invention relates to a process for the production of nitric acid, and more particularly to methods for removing impurities produced by the process, and for increasing nitric acid production or reducing supplemental oxygen requirements. Background technique [0002] The industrial production of nitric acid is based on the ninety-year-old Ostwald method, which is subdivided into three main process steps: [0003] I: ammonia oxidation [0004] <chemistry num="001"> <chem file="99126938_cml001.xml" / > < / chemistry> (1) [0005] II: Oxidation of Nitric Oxide and Dimerization of Nitrogen Dioxide [0006] <chemistry num="002"> <chem file="99126938_cml002.xml" / > < / chemistry> (2) [0007] <chemistry num="003"> <chem file="99126938_cml003.xml" / > < / chemistry> (3) [0008] and [0009] III: Absorption of dinitrogen tetroxide [0010] ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B21/38C01B21/26C01B21/40
CPCC01B21/262C01B21/40C01B21/38
Inventor D·F·埃切加赖A·A·M·维洛索M·L·瓦格纳
Owner PRAXAIR TECH INC
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