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Method for circularly absorbing NOX and SO3 in nitrified tail gas by using sulfuric acid

A technology of acid cycle and tail gas, applied in chemical instruments and methods, separation methods, air quality improvement, etc., can solve the problems of low absorption rate, difficult wastewater treatment, high alkali consumption, etc., achieve simple equipment, reduce liquid alkali The effect of consumption and investment saving

Active Publication Date: 2013-10-16
福建康峰新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention mainly aims at the technical problems existing in the existing alkali absorption technology, such as low absorption rate, high alkali consumption, large amount of waste water, and difficult treatment of the generated waste water, and provides a method for absorbing NO in nitrification tail gas by using sulfuric acid circulation. X , SO 3 Methods

Method used

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  • Method for circularly absorbing NOX and SO3 in nitrified tail gas by using sulfuric acid
  • Method for circularly absorbing NOX and SO3 in nitrified tail gas by using sulfuric acid

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Embodiment 1

[0023] Use 98% concentrated nitric acid, 105% fuming sulfuric acid mixed acid to produce aromatic dinitrates, the production process is separate reaction of mononitration and dinitration, use 98% concentrated nitric acid, 105% fuming sulfuric acid mixed acid for dinitrification The waste mixed acid produced by nitrification and dinitration is commonly called semi-waste acid (the mass concentration of sulfuric acid is about 95-98%), and the semi-waste acid is used as the acid for mononitration after adding nitric acid dropwise. In order to utilize the half-waste acid, the half-waste acid can be used instead of the sulfuric acid to be recycled and absorbed, and the half-waste acid can be de-nitrated after being recycled and absorbed. The resulting NO X and SO 3 Exhaust gas, flow rate 80.6m 3 / h, NO X The volume concentration is about 85%, of which NO and NO 2 The ratio is about 1:1, SO 3 The volume concentration of the waste gas is about 6%. The waste gas and air are mixed ...

Embodiment 2

[0025] Use 98% sulfuric acid to absorb 98% concentrated nitric acid, 105% oleum storage tank breathing gas, and produce NO X and SO 3 Exhaust gas, flow rate 1.6m 3 / h, NO X The volume concentration is about 60%, of which NO and NO 2 The ratio is about 2:1, SO 3 The volume concentration is about 12%. The waste gas and air are mixed according to the volume ratio of 1:5 and then enter the absorption section. The first stage is absorbed by a 98% sulfuric acid tower, and the latter stage is absorbed by a lye tower. Each stage of the tower is equipped with liquid distribution Device and PTFE packing, liquid circulation tank and other accessories. Absorption liquid circulation volume is 5 m 3 / h, the diameter of the absorption tower is 0.4M, and the tower height is 3M. The sulfuric acid absorption and its accessories are made of carbon steel, and the lye absorption and its accessories are made of plastic. Sulfuric acid is sent to the top of the first-stage absorption tower to ...

Embodiment 3

[0027] Use 98% sulfuric acid to absorb NO produced when nitrates are neutralized X Tail gas, after the nitrification reaction is completed, after standing and stratifying, the nitrate containing mixed acid is obtained, which needs to be neutralized and washed to remove the mixed acid, and the produced NO X Exhaust gas flow 30m 3 / h, NO X The volume concentration is about 20%, of which NO and NO 2 The ratio of waste gas and air is about 1:1. The waste gas and air are mixed according to the volume ratio of 1:3 and then enter the absorption section. Two towers are connected in series. The first stage is absorbed by 98% sulfuric acid tower, and the latter stage is absorbed by lye tower. Equipped with liquid distributor and PTFE filler, liquid circulation tank and other accessories. Absorption liquid circulation volume is 10 m 3 / h, the diameter of the absorption tower is 0.5M, and the tower height is 3M. The sulfuric acid absorption and its accessories are made of carbon stee...

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Abstract

The invention belongs to the technical field of environmental protection and in particular relates to a method for circularly absorbing NOX and SO3 in nitrified tail gas by using sulfuric acid. The method comprises the following steps of: introducing air into the nitrified tail gas and mixing; and discharging the mixed gas after first-class absorption, second-class absorption and third-class absorption, wherein 90 to 98 mass percent sulfuric acid is used as absorption solution in the first-class absorption and the second-class absorption; the sulfuric acid after the first-class absorption is recycled; the sulfuric acid after the second-class absorption is returned to the first-class absorption; and alkali liquor is used in the third-class absorption. The NOX and the SO3 in the tail gas are absorbed to form reaction raw materials, namely nitric acid and the sulfuric acid, and volatile materials are dissolved by the sulfuric acid and are returned to nitration, so the using amount of the raw materials can be reduced under the condition of not increasing the kinds of absorption raw materials, simultaneously the technical problems of low absorption rate, high alkali consumption, a large amount of wastewater, difficult treatment of generated wastewater and the like in the conventional absorption method are solved.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, in particular to a method for absorbing NO in nitrification tail gas by circulating sulfuric acid X and SO 3 Methods. Background technique [0002] As we all know, when an aromatic ring with a passivating group is used for dinitration, oleum and concentrated nitric acid are often used to prepare a mixed acid for high-temperature nitration. In the process of mixed acid preparation and nitrification, tail gas of nitrogen oxides and sulfur trioxide will be produced. At present, the method of alkali circulation absorption is generally used to eliminate tail gas, but there are problems such as low absorption rate, large alkali consumption, large amount of waste water, and difficult treatment of the generated waste water. [0003] Chinese invention patent ZL02138494.0 discloses a method of using dilute nitric acid to absorb nitrogen oxides in tail gas in a single-stage cycle. This m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/78B01D53/60
CPCY02A50/20
Inventor 张位德吴永良吴向峰吴康周华真
Owner 福建康峰新材料有限公司