A device and method for treating nitrogen oxides generated from cyclohexanone oxime waste water

Abstract

The application provides a device and method for treating nitrogen oxides generated in cyclohexanone oxime wastewater, wherein the device comprises a blower, a tail gas absorption tower, a first circulating pump and a condenser; the air inlet of the blower is aligned with yellow smoke gas generated in the process of treating cyclohexanone oxime wastewater, and the air outlet of the blower is connected to the bottom of the tail gas absorption tower; the bottom of the tail gas absorption tower is connected to the top of the tail gas absorption tower through a circulating pipeline, and the circulating pipeline extends into the tail gas absorption tower and is connected to a liquid distributor; the first circulating pump and the condenser are sequentially arranged on the circulating pipeline; the circulating pipeline is connected with an input pipeline near the top of the tail gas absorption tower, the input pipeline is used for inputting dilute nitric acid solution, and the circulating pipeline is provided with an output pipeline between the condenser and the top of the tail gas absorption tower. The application realizes atomic recycling and utilization, reduces total nitrogen in wastewater, is economic and environmentally friendly, has good sustainability, and can reduce the treatment cost of wastewater.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical preparation, and in particular to a device and method for treating nitrogen oxides generated in cyclohexanone oximation wastewater. BACKGROUND

[0002] Toxic and harmful nitrogen oxide yellow smoke gas is often generated in the treatment process of wastewater generated in the cyclohexanone oximation process of caprolactam production, which not only pollutes the environment, but also is very harmful to the health of on-site workers. Moreover, the wastewater is difficult to treat due to high total nitrogen content, which has been a technical difficulty and pain point in the industry.

[0003] Currently, the treatment method for nitrogen oxides generated in the treatment process of cyclohexanone oximation wastewater usually adopts alkali absorption method or solid catalyst absorption method. Although both methods can effectively absorb nitrogen oxides, they have the following problems:

[0004] 1. High treatment cost

[0005] Using the alkali absorption method will produce inorganic salt accumulation, which needs to be cleaned regularly, and will also produce a certain amount of wastewater into the biochemical treatment device, which needs to add a composite carbon source to treat the wastewater, increasing the consumption cost of the composite carbon source, increasing the wastewater treatment cost, and also increasing the operating load of the biochemical treatment device.

[0006] Using the solid catalyst absorption method, the solid catalyst is expensive and has a large loss during use.

[0007] 2. Low atomic economic utilization rate

[0008] Neither the alkali absorption method nor the solid catalyst absorption method can realize the recycling of nitrogen atoms, and the atomic economic utilization rate is low.

[0009] Therefore, how to reduce the total nitrogen of oximation wastewater under the premise of effective absorption of nitrogen oxides, improve the atomic economic utilization value, realize green recycling and recycling, and save the treatment cost is an important direction for long-term development of the industry. SUMMARY

[0010] In order to solve the above problems of the prior art, the present application provides a device and method for treating nitrogen oxides generated in cyclohexanone oximation wastewater, which reduces the treatment cost and improves the atomic economic utilization rate.

[0011] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0012] In a first aspect, the present application provides a device for treating nitrogen oxides generated from cyclohexanone oximation wastewater, comprising a blower, a tail gas absorption tower, a first circulating pump and a condenser, the air inlet of the blower is aligned with yellow smoke gas generated in the process of treating cyclohexanone oximation wastewater, and the air outlet thereof is connected to the bottom of the tail gas absorption tower;

[0013] The bottom of the tail gas absorption tower is connected to the top of the tail gas absorption tower through a circulating pipeline, and extends into the tail gas absorption tower and is connected to a liquid distributor, the first circulating pump and the condenser are sequentially arranged on the circulating pipeline, the circulating pipeline is connected with an input pipeline at a position close to the top of the tail gas absorption tower, the input pipeline is used for inputting dilute nitric acid solution, and the circulating pipeline is provided with an output pipeline at a position between the condenser and the top of the tail gas absorption tower.

[0014] The present application has the advantages that: the method of countercurrent absorption of nitrogen oxides with dilute nitric acid is used to eliminate the yellow smoke generated in the process of treating wastewater, and the dilute nitric acid generated by absorbing nitrogen dioxide in the nitrogen oxides into water can be reused, realizing atomic recycling and utilization, reducing total nitrogen in wastewater, being economic and environmentally friendly, and being sustainable; at the same time, without the need for expensive solid catalysts, the total amount of wastewater generated is also reduced, the consumption of composite carbon sources is reduced, and the treatment cost is reduced.

[0015] Optionally, it also comprises a ceramic membrane filter, an oximation production wastewater storage tank, a pH adjusting storage tank, a static mixer, a stirring mixer, a Fenton reaction tank and a biochemical tank, the wastewater outlet of the ceramic membrane filter is connected to the water inlet of the oximation production wastewater storage tank, the water outlet of the oximation production wastewater storage tank is connected to the water outlet of the pH adjusting storage tank, and the water inlets of the static mixer and the stirring mixer are connected to the water outlet of the pH adjusting storage tank, the water outlet of the static mixer is connected to the water inlet of the stirring mixer, the water outlet of the stirring mixer is connected to the Fenton reaction tank, and the water outlet of the Fenton reaction tank is connected to the water inlet of the biochemical tank.

[0016] The air inlet of the blower is aligned above the Fenton reaction tank, and the output end of the output pipeline is connected to the top of the ceramic membrane filter.

[0017] Optionally, the output pipeline is connected with a dilution pipeline, and the dilution pipeline is used for inputting desalted water.

[0018] According to the above description, the output solution is diluted to a suitable concentration by desalted water for recycling.

[0019] Optionally, the output pipeline is also provided with a control valve.

[0020] In a second aspect, a method for treating nitrogen oxides generated from cyclohexanone oximation wastewater is provided, comprising the following steps:

[0021] S1, the yellow smoke gas generated in the cyclohexanone oximation wastewater treatment process is blown into the bottom of the tail gas absorption tower by the air blower;

[0022] S2, the dilute nitric acid solution enters the liquid distributor in the top of the tail gas absorption tower through the input pipeline, and the dilute nitric acid solution is sprayed through the liquid distributor to perform countercurrent absorption on the yellow smoke gas, and the reaction heat is removed through the condenser;

[0023] S3, the dilute nitric acid solution generated after the absorption is output through the output pipeline and circulated back to the ceramic membrane filter for membrane tube cleaning.

[0024] Optionally, the mass concentration of the dilute nitric acid solution sprayed into the tail gas absorption tower is 15%-30%.

[0025] Optionally, the absorption temperature of the tail gas absorption tower is 15-20℃, and the pressure is 0.1-0.3MPa.

[0026] Optionally, it further comprises the steps of:

[0027] The wastewater after cleaning the ceramic membrane filter is collected in the oximation production wastewater storage tank, and the wastewater in the oximation production wastewater storage tank is mixed by the second circulating pump and concentrated sulfuric acid in the pH adjusting storage tank through the third circulating pump and input into the static mixer for mixing, adjusting the pH of the wastewater to be acidic, and then input into the stirring mixer for secondary stirring and uniform mixing.

[0028] The wastewater after uniform mixing in the stirring mixer is added to the Fenton reaction tank for reaction, the treated wastewater reaches the discharge standard and is discharged into the river.

[0029] The technical effects corresponding to the nitrogen oxide treatment method of the cyclohexanone oximation wastewater provided in the second aspect are referred to the related description of the cyclohexanone oximation wastewater nitrogen oxide treatment device provided in the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structure schematic view of the cyclohexanone oximation wastewater nitrogen oxide treatment device of the embodiment of the present application.

[0031] Figure 2 It is a flowchart of the cyclohexanone oximation wastewater nitrogen oxide treatment method of the embodiment of the present application.

[0032] MARKED FOR EXPLANATION:

[0033] 1, air blower; 2, tail gas absorption tower; 3, first circulating pump; 4, condenser; 5, circulating pipeline; 6, liquid distributor; 7, input pipeline; 8, output pipeline; 9, ceramic membrane filter; 10, oximation production wastewater storage tank; 11, pH adjustment storage tank; 12, static mixer; 13, stirring mixer; 14, Fenton reaction tank; 15, biochemical tank; 16, dilution pipeline; 17, control valve; 18, second circulating pump; 19, third circulating pump. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solutions, the exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more clearly, thoroughly understood and the scope of the present application can be completely conveyed to those skilled in the art.

[0035] Example 1

[0036] The existing alkali absorption method or solid catalyst absorption method has the problems of high treatment cost and low atomic economic utilization rate. Therefore, the present embodiment uses the method of countercurrent absorption of nitrogen oxides by dilute nitric acid to eliminate yellow smoke generated in the production wastewater treatment process, solving the existing problems. The specific improvements are as follows:

[0037] Please refer to Figure 1 A device for treating nitrogen oxides generated in cyclohexanone oximation wastewater, comprising an air blower 1, a tail gas absorption tower 2, a first circulating pump 3, a condenser 4, a ceramic membrane filter 9, an oximation production wastewater storage tank 10, a pH adjustment storage tank 11, a static mixer 12, a stirring mixer 13, a Fenton reaction tank 14 and a biochemical tank 15.

[0038] Among them, the wastewater outlet of the ceramic membrane filter 9 is communicated with the water inlet of the oximation production wastewater storage tank 10, the water outlet of the oximation production wastewater storage tank 10 is communicated with the water outlet of the pH adjustment storage tank 11 through the second circulating pump 18, and the water outlet of the pH adjustment storage tank 11 is communicated with the water inlet of the static mixer 12 through the third circulating pump 19, the water outlet of the static mixer 12 is communicated with the water inlet of the stirring mixer 13, the water outlet of the stirring mixer 13 is communicated with the Fenton reaction tank 14, and the water outlet of the Fenton reaction tank 14 is communicated with the water inlet of the biochemical tank 15.

[0039] In the present embodiment, concentrated sulfuric acid is introduced into the pH adjustment storage tank 11 for pH adjustment, and the pH of the wastewater in the static mixer 12 is between 2-5.

[0040] The air inlet of the air blower 1 is aligned with the upper part of the Fenton reaction tank 14, and is aligned with the yellow smoke gas generated in the cyclohexanone oximation wastewater treatment process, and the air outlet is connected to the bottom of the tail gas absorption tower 2. The bottom of the tail gas absorption tower 2 is connected to the top of the tail gas absorption tower 2 through a circulating pipeline 5, and extends into the tail gas absorption tower 2 and is connected to a liquid distributor 6. A first circulating pump 3 and a condenser 4 are sequentially arranged on the circulating pipeline 5. An input pipeline 7 is connected to the circulating pipeline 5 near the top of the tail gas absorption tower 2, and is used to input dilute nitric acid solution. An output pipeline 8 is arranged on the circulating pipeline 5 between the condenser 4 and the top of the tail gas absorption tower 2. The output end of the output pipeline 8 is connected to the top of the ceramic membrane filter 9.

[0041] The output pipeline 8 is connected to a dilution pipeline 16, which is used to input desalted water to dilute the dilute nitric acid solution in the output pipeline 8 to a suitable concentration before being input into the ceramic membrane filter 9 for cleaning.

[0042] The output pipeline 8 is also provided with a control valve 17, so that the treated solution is output after being absorbed for several cycles.

[0043] As shown in Figure 1 The tail gas absorption tower 2 is also provided with a tail gas discharge pipeline for tail gas discharge.

[0044] The working principle of this embodiment is referred to Embodiment Two.

[0045] Embodiment Two

[0046] A method for treating nitrogen oxides generated in cyclohexanone oximation wastewater, comprising the following steps:

[0047] S01, collect the wastewater after cleaning the ceramic membrane filter 9 in the oximation production wastewater storage tank 10. The wastewater in the oximation production wastewater storage tank 10 is mixed by the second circulating pump 18 and the concentrated sulfuric acid in the pH adjusting storage tank 11 through the third circulating pump 19 into the static mixer 12 to adjust the pH of the wastewater to be acidic, and then input into the stirring mixer 13 for secondary stirring, and mix uniformly.

[0048] In this embodiment, the concentrated sulfuric acid adjusts the pH of the wastewater in the oximation production wastewater storage tank 10, so that the pH of the wastewater in the static mixer 12 is between 2-5.

[0049] S02, the wastewater mixed uniformly in the stirring mixer 13 is added to the Fenton reaction tank 14 for reaction. The treated wastewater that meets the standard is input into the subsequent biochemical tank 15 for treatment, and is discharged into the river after meeting the discharge standard.

[0050] S1, the yellow smoke gas generated in the cyclohexanone oximation wastewater treatment process is blown into the bottom of the tail gas absorption tower 2 by the air blower 1.

[0051] Wherein, the blower 1 is set above the Fenton reaction tank 14 to absorb the toxic and harmful yellow smoke gas generated in the upper part of the Fenton reaction tank 14 to the tail gas absorption tower 2 for treatment.

[0052] Wherein, the main components of the yellow smoke gas are:

[0053] NO2: 1000-1500 mg / m 3 ; NO: 200-300 mg / m 3 ; N2O: 0-100 mg / m 3 .

[0054] S2, the dilute nitric acid solution enters the liquid distributor 6 at the top of the tail gas absorption tower 2 through the input pipeline 7, and the dilute nitric acid solution is sprayed through the liquid distributor 6 to absorb the yellow smoke gas in countercurrent, and is circulated and absorbed multiple times through the circulation pipeline 5, and the reaction heat is removed through the condenser 4.

[0055] In this embodiment, the mass concentration of the dilute nitric acid solution is 15%-30%, such as 18%, 23%. In this embodiment, the absorption temperature of the tail gas absorption tower 2 is 15-20℃, and the pressure is 0.1-0.3MPa, such as the absorption temperature is 16℃, and the pressure is 0.18MPa. Wherein, the condenser 4 cools the solution in the circulation pipeline 5 to below 20℃.

[0056] Wherein, the nitrogen monoxide in the nitrogen oxide is oxidized to nitrogen dioxide to be dissolved in the dilute nitric acid solution, and since new nitrogen monoxide is generated in the absorption process, multiple absorption is required to reduce the concentration of nitrogen oxide in the gas to the expected target.

[0057] S3, the dilute nitric acid solution generated after absorption is output through the output pipeline 8 and recycled back to the ceramic membrane filter 9 for membrane tube cleaning and recycling.

[0058] Wherein, the concentration of nitrogen oxide in the gas after absorption is less than 80 mg / m 3 , and the absorption effect reaches more than 98%.

[0059] Wherein, the dilute nitric acid solution is recycled back to the ceramic membrane filter 9 through the output pipeline 8 for membrane tube cleaning, realizing the recycling of nitrogen oxide absorption.

[0060] In summary, the above embodiment adopts the method of countercurrent absorption of dilute nitric acid to nitrogen oxide to eliminate the yellow smoke generated in the production wastewater treatment process, which has the following advantages:

[0061] (1) Reduce the total nitrogen content, reduce the cost of wastewater treatment: compared with alkali absorption method, the total amount of wastewater is reduced, and the consumption of composite carbon source is reduced; compared with solid catalyst absorption method, no expensive solid catalyst is needed; thereby the treatment cost is reduced.

[0062] (2) High atomic economic utilization rate: after the nitrogen dioxide in the nitrogen oxide is dissolved in water and absorbed, the generated dilute nitric acid returns to the oximation production process for cleaning the membrane tube, atomic recycling and utilization are realized, the total nitrogen of the wastewater is reduced, it is economic and environmental protection, and sustainability is good.

[0063] (3) Optimize the process: no by-product salt precipitation is generated, manual intervention cleaning is not needed, and the process is simplified.

[0064] (4) Green and environmental protection: the generation of toxic and harmful gases in the cyclohexanone oximation wastewater treatment process is eliminated, and the health of on-site workers is ensured.

[0065] In the description of the present application, it should be understood that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0066] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0067] In the present application, unless otherwise specifically defined and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature, can be directly above or obliquely above the first feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature, can be directly below or obliquely below the first feature, or only indicates that the horizontal height of the first feature is lower than that of the second feature.

[0068] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0069] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can modify, modify, replace and modify the above-described embodiments within the scope of the present application.

Claims

1. A device for treating nitrogen oxides generated from cyclohexanone oxime wastewater, characterized in that, The application relates to a device for treating yellow smoke gas generated in a cyclohexanone oximation wastewater treatment process, which comprises a blower, a tail gas absorption tower, a first circulating pump and a condenser. The bottom of the tail gas absorption tower is connected to the top of the tail gas absorption tower through a circulating pipeline, and extends into the tail gas absorption tower and is communicated with a liquid distributor; the first circulating pump and the condenser are sequentially arranged on the circulating pipeline; an input pipeline is connected to the circulating pipeline near the top of the tail gas absorption tower, and is used for inputting dilute nitric acid solution; and an output pipeline is arranged on the circulating pipeline between the condenser and the top of the tail gas absorption tower. The device further comprises a ceramic membrane filter, an oximation production wastewater storage tank, a pH adjusting storage tank, a static mixer, a stirring mixer, a Fenton reaction tank and a biochemical tank; the wastewater outlet of the ceramic membrane filter is communicated with the water inlet of the oximation production wastewater storage tank; the water outlet of the oximation production wastewater storage tank is simultaneously communicated with the water outlet of the pH adjusting storage tank and the water inlet of the static mixer; the water outlet of the static mixer is communicated with the water inlet of the stirring mixer; the water outlet of the stirring mixer is communicated with the Fenton reaction tank; and the water outlet of the Fenton reaction tank is communicated with the water inlet of the biochemical tank. The air inlet of the blower is arranged above the Fenton reaction tank, and the output end of the output pipeline is communicated with the top of the ceramic membrane filter.

2. The apparatus for treating nitrogen oxides generated from cyclohexanone oxime waste water according to claim 1, wherein A dilution pipeline is communicated with the output pipeline, and is used for inputting desalted water.

3. The device for treating nitrogen oxides generated from cyclohexanone oxime waste water according to claim 1, wherein A control valve is further arranged on the output pipeline.

4. A method for treating nitrogen oxides produced from cyclohexanone oxime waste water, characterized by, The device comprises the following steps: S1, yellow smoke gas generated in a cyclohexanone oximation wastewater treatment process is blown into the bottom of a tail gas absorption tower through a blower; S2, dilute nitric acid solution is input into a liquid distributor in the top of the tail gas absorption tower through an input pipeline, the dilute nitric acid solution is sprayed through the liquid distributor to perform countercurrent absorption on the yellow smoke gas, and the dilute nitric acid solution is circulated and absorbed for multiple times through a circulating pipeline, and reaction heat is removed through a condenser; S3, after absorption is completed, the generated dilute nitric acid solution is output through an output pipeline and circulated back to a ceramic membrane filter for membrane tube cleaning; The device further comprises the following steps: Wastewater after the ceramic membrane filter is cleaned is collected in an oximation production wastewater storage tank, the wastewater in the oximation production wastewater storage tank is mixed in a static mixer through a second circulating pump and concentrated sulfuric acid in a pH adjusting storage tank, the pH of the wastewater is adjusted to be acidic, and the wastewater is secondarily stirred in a stirring mixer and uniformly mixed; The uniformly mixed wastewater in the stirring mixer is added into a Fenton reaction tank for reaction, the treated wastewater is input into a subsequent biochemical tank for treatment, and the treated wastewater is discharged into a river after reaching a discharge standard.

5. The method of claim 4, wherein the method is characterized by: The mass concentration of the dilute nitric acid solution sprayed into the tail gas absorption tower is 15%-30%.

6. The method of claim 4, wherein the method is characterized by, The absorption temperature of the tail gas absorption tower is 15-20 DEG C, and the pressure is 0.1-0.3 MPa.

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