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Resourceful treatment method for nitrogen oxide waste gas in precious metal purification process

A treatment method and technology of nitrogen oxides, which are applied in the fields of nitrogen oxides/oxyacids, gas treatment, chemical instruments and methods, etc., can solve the problems of many absorption towers and increase equipment investment, etc., and achieve high absorption efficiency. secondary pollution and ensure the effect of up-to-standard discharge

Pending Publication Date: 2021-06-15
CHINA NAT OFFSHORE OIL CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the equipment not only has more absorption towers, which increases equipment investment, but also has the disadvantage that the alkali absorption tower produces secondary waste water

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0069] This embodiment provides a method for recycling nitrogen oxide waste gas in the precious metal purification process. The nitrogen oxide waste gas to be treated is the high concentration nitrogen oxide waste gas generated during the purification and recovery process of the precious metal platinum mesh catalyst. The maximum flow rate is 150m 3 / h, which contains NO, HCl, Cl 2 , air, water vapor, etc., among them, NO X The content is 8333mg / m 3 (NO accounts for more than 95%), HCl content is 500mg / m 3 , Cl 2 The content is 300mg / m 3 , the resource processing method includes:

[0070] The nitrogen oxide exhaust gas with a volume ratio of 1:4 is oxidized with air, the temperature of the oxidation reaction is controlled <30°C, the oxidation residence time is 120s, and the oxidation degree of nitrogen oxides in the mixed gas obtained by the oxidation reaction is 75%;

[0071] The mixed gas obtained by the oxidation reaction is contacted with the primary absorption liqui...

Embodiment 2

[0077] This embodiment provides a method for recycling nitrogen oxide waste gas in the precious metal purification process. The nitrogen oxide waste gas to be treated is the high concentration nitrogen oxide waste gas generated during the purification and recovery process of the precious metal platinum mesh catalyst. The maximum flow rate is 150m 3 / h, which contains NO, HCl, Cl 2 , air, water vapor, etc., among them, NO X The content is 8333mg / m 3 (NO accounts for more than 95%), HCl content is 500mg / m 3 , Cl 2 The content is 300mg / m 3 , the resource processing method includes:

[0078] The nitrogen oxide exhaust gas with a volume ratio of 1:5 is oxidized with air, the temperature of the oxidation reaction is controlled <30°C, the oxidation residence time is 120s, and the oxidation degree of nitrogen oxides in the mixed gas obtained by the oxidation reaction is 80%;

[0079] The mixed gas obtained by the oxidation reaction is contacted with the primary absorption liqui...

Embodiment 3

[0085] This embodiment provides a method for recycling nitrogen oxide waste gas in the precious metal purification process. The nitrogen oxide waste gas to be treated is the high concentration nitrogen oxide waste gas generated during the purification and recovery process of the precious metal platinum mesh catalyst. The maximum flow rate is 150m 3 / h, which contains NO, HCl, Cl 2 , air, water vapor, etc., among them, NO X The content is 8333mg / m 3 (NO accounts for more than 95%), HCl content is 500mg / m 3 , Cl 2 The content is 300mg / m 3 , the resource processing method includes:

[0086] The nitrogen oxide exhaust gas with a volume ratio of 1:3 is oxidized with air, the temperature of the oxidation reaction is controlled <30°C, the oxidation residence time is 120s, and the oxidation degree of nitrogen oxides in the mixed gas obtained by the oxidation reaction is 70%;

[0087] The mixed gas obtained by the oxidation reaction is contacted with the primary absorption liqui...

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Abstract

The invention relates to a resourceful treatment method for nitrogen oxide waste gas in a precious metal purification process. The method comprises the following steps: carrying out oxidation reaction on the nitrogen oxide waste gas and an oxidant, and sequentially carrying out countercurrent contact on mixed gas obtained by the oxidation reaction with primary absorption liquid and secondary absorption liquid, wherein the initial state of the first-stage absorption liquid is water, and the initial state of the second-stage absorption liquid is a hydrogen peroxide solution with the concentration of 27.5-35 wt%,; in the normal state, taking the first-stage reaction liquid and the second-stage reaction liquid as the first-stage absorption liquid and the second-stage absorption liquid respectively for cyclic absorption, intermittently gathering part of the second-stage reaction liquid and the first-stage reaction liquid as first-stage absorption liquid for cyclic absorption, so the concentration of nitric acid in the first-stage reaction liquid can be increased to 40 wt% or above for recycling, only a fresh hydrogen peroxide solution needs to be supplemented in the whole process, up-to-standard emission of nitric oxide can be guaranteed, secondary pollution sources such as waste water and waste gas are not generated, and high-concentration nitric acid can be obtained.

Description

technical field [0001] The invention relates to the technical field of waste gas treatment, in particular to a method for recycling nitrogen oxide waste gas during the purification process of precious metals. Background technique [0002] Nitric acid is a strong oxidizing and corrosive monobasic inorganic acid. It is an important chemical raw material and is often used as an oxidizing agent in industrial processes. However, nitrogen oxides (mainly NO and NO 2 , collectively referred to as NO X ), which will form yellow or brown smog in the air, commonly known as "yellow dragon", which is one of the important sources of air pollution at present. Nitrogen oxide exhaust gas not only causes acid rain and acid mist, but also destroys the ozone layer, causing serious harm to the natural environment and human production and life. Therefore, the absorption and recycling of nitrogen oxide waste gas is an important part of environmental governance and industrial production of vario...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/56B01D53/75B01D53/76B01D53/78B01D53/14C01B21/40
CPCB01D53/56B01D53/75B01D53/76B01D53/78B01D53/1493B01D53/1418C01B21/40B01D2251/11B01D2251/106B01D2251/2067B01D2252/103B01D2258/025
Inventor 昃彬段煜洲曾兆强刘欣薛扬李志宋雪微甄军
Owner CHINA NAT OFFSHORE OIL CORP