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A nitric oxides (NOX) waste pollution control in industrial process and resource reclaiming method

A technology for waste gas treatment and nitrogen oxides, applied in chemical instruments and methods, separation methods, separation of dispersed particles, etc., to achieve good treatment effects, high investment ratio, saving space and investment

Inactive Publication Date: 2006-11-22
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At the same time, no secondary pollution sources such as waste water and waste gas are generated in the whole process

Method used

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  • A nitric oxides (NOX) waste pollution control in industrial process and resource reclaiming method

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Embodiment 1: adopt 56% nitric acid to make oxidizing agent to produce organic acid product, produce NO X Exhaust gas, flow rate 4.6m 3 / h, NO X The volume concentration is 75%, where NO and NO 2 About 2:1. The exhaust gas and air are mixed according to the volume ratio of 1:4 and then enter the absorption section. The operating pressure of the absorption section is 2.6atm, and 6-stage absorption is adopted. Three towers are connected in series, and each tower has 2 stages, such as figure 1 shown. Each stage is equipped with liquid distributor, stainless steel filler 3m, liquid collection box and other accessories. 6 levels of liquid circulation are 5m 3 / h. The diameter of the absorption tower is 0.4m. NO in exhaust gas X The emission concentration is 22ppm, and the rate is 0.12kg / h. Nitric acid (yellow-green) with a mass concentration of 48% flows out from the absorption section, and enters the enrichment tower with a diameter of 0.6m, a 12-layer sieve tray t...

Embodiment 2

[0032] Embodiment 2: Adopt the concentrated nitric acid of 62% to make oxidant to produce methanol catalyst, produce NO and NO 2 Gas, the ratio is about 1:1, the flow rate is 10.2m 3 / h. The exhaust gas and air are mixed according to the volume ratio of 1:3.5 and then enter the absorption section. The operating pressure of the absorption section is 4atm, and 4-stage absorption is adopted. Two towers are connected in series, and each tower has 2 stages. Each stage is equipped with a liquid distributor, stainless steel packing 4m, liquid collection box and other accessories, and the liquid circulation volume of the four stages is 80, 80, 55, 55m respectively 3 / h. The diameters of the absorption towers are respectively 0.6m and 0.4m. NO in exhaust gas X The emission concentration is 45ppm, and the rate is 0.2kg / h. Nitric acid with a mass concentration of 45% (yellow-green, dissolving part of NO) flows out from the absorption section X ), enter the enrichment section, the e...

Embodiment 3

[0033] Embodiment 3: adopt the concentrated nitric acid of 98% to make oxygenant to produce silver nitrate, produce NO 2 Gas, the flow rate is 32.50m3 / h. The waste gas and air are mixed at a volume ratio of 1:2.5 and then enter the absorption section. The operating pressure of the absorption section is 5 atm, and the absorbent is clean water. A single tower with 3 stages of absorption is adopted, with a tower diameter of 0.8m. Each stage is equipped with a liquid distributor, stainless steel packing 5m, liquid collection box and other accessories, and the liquid circulation volume of the three stages is 150m3 / h. NO in exhaust gas X The emission concentration is 32ppm, and the rate is 0.18kg / h. Nitric acid (colorless) with a mass concentration of 38% flows out from the absorption section, and enters the concentrated nitric acid flow process of this plant to produce 98%.

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Abstract

The invention relates to a method for treating and reusing waste gas containing nitrogen oxide generated in industrial process. It comprises following steps: mixing waste gas containing nitrogen oxide with air according to a certain proportion, plural serial adsorbing it in tower by introducing it from bottom of head tower, discharging it from top of tail tower, discharging generated hydrogene nitrate of low concentration from bottom of head tower, proceeding decompressing and thickening process in thickening tower, which includes bleaching and dewatering; hydrogen nitrate of low concentration is introduced from top of thickening tower, hydrogen nitrate of high concentration being 45-65% is discharged from bottom; supercharging nitrogen oxide extracted from thickening tower top with vacuum system, then introducing it into adsorbing process again; the water or diluted acid from thickening tower is used as adsorbent and is added from top of tail tower in adsorbing process and counter current contacts with gas in tower for mass transferring. The waste gas treatment effect is good, and the discharging concentration of nitrogen oxide in exhaust gas is less than 50 ppm; all the nitrogen oxide in exhaust gas is recycled to generate aqua fortis with mass concentration being more than 55%.

Description

technical field [0001] The invention patent belongs to NO X Waste gas environmental protection emission, renewable resources and circular economy technology fields. Background technique [0002] Nitric acid is commonly used in industrial processes as an oxidizing agent for the production of methanol catalysts, organic acids, and many fine chemicals. When nitric acid is reduced, 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. NO X Exhaust gas not only causes acid rain and acid fog, but also destroys the ozone layer, causing serious harm to the natural environment and human production and life. Therefore, NO X The absorption and recycling of nitric acid is an important part of environmental governance and various nitric acid industrial production, which is not only the need to realize the sustaina...

Claims

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Application Information

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IPC IPC(8): B01D53/56
Inventor 耿皎张志炳孟为民彭瑾
Owner NANJING UNIV
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