WO2018044002A1 - Nitrogen oxide reducing solution using aldol wastewater, and method for preparing same - Google Patents

Abstract

The present invention provides a nitrogen oxide reducing solution using aldol wastewater, and a method for preparing same. The solution, which is used in selective non-catalytic reduction for nitrogen oxide, is prepared by means of aldol wastewater, thereby enabling easy reaction temperature control during operation. And by means of reducing the amount of urea or ammonia used, the solution requires lower preparation cost while providing excellent performance compared to an existing reducing solution preparation.

Description

Nitrogen oxide reduction solution using aldol wastewater and its manufacturing method

The present invention relates to a nitrogen oxide reduction solution for removing nitrogen oxides generated in an incinerator and a method for preparing the same, and more particularly, as a solution used for selective non-catalytic reduction for nitrogen oxides. Nitrogen oxide reduction using aldol wastewater, which is manufactured by using aldol wastewater, makes it easy to control the reaction temperature during operation and reduces the amount of urea or ammonia used to obtain excellent performance at a lower cost compared to conventional reducing solution materials. A solution and a method for producing the same.

Various incinerators, such as thermal power plants or waste dumps, emit exhaust gases. More than 90% of the nitrogen oxides (NOx) contained in these exhaust gases are nitrogen monoxide (N0), nitrogen dioxide (N0 ₂ ) and nitrous oxide (N ₂ O). When it is discharged as it is without any treatment, it becomes a representative environmental pollutant that causes air pollution. Nitrogen monoxide, for example, acts as a causative agent of acid rain, induces urban smog, and when absorbed into the human respiratory tract, is a harmful component that can lead to bronchitis and death when exposed to high concentrations, and nitrous oxide is a major cause of global warming. .

Nitrogen oxides are generated during high-temperature combustion of fossil fuels and require separate control to prevent air pollution.The control technology for these nitrogen oxides greatly reduces combustion concentrations by controlling combustion conditions and discharges them after combustion. There is a way to do post-processing before it is done.

However, the method of controlling the combustion conditions is not currently considered as an effective control method due to the limit of the reduced concentration and the enhanced emission allowance standard. Therefore, the selective catalytic reduction method using the catalyst which is a post-combustion treatment technology and the catalyst are not used. Two kinds of selective non-catalytic reduction methods are widely used.

The selective catalytic reduction using a catalyst is a method of converting nitrogen oxides into harmless nitrogen and water vapor by inducing a reaction between the adsorbent of the reducing agent and the nitrogen oxides at the active site of the catalyst surface. Although the selective catalytic reduction method has a high removal efficiency or more than a certain level, there is a problem in that the use period is short and the used catalyst must be disposed of.

On the other hand, the selective non-catalytic reduction method is a method of mixing the reducing agent containing urea water or ammonia water at several points in the middle of the exhaust path of the incinerator to reduce NO to N ₂ while directly spraying the exhaust gas. The selective non-catalytic reduction method has an advantage in installation / maintenance since it has a long service life and does not require much additional facilities than the selective catalytic reduction method. However, compared to the selective catalytic reduction method, the efficiency of reducing nitrogen oxides is low and the temperature range showing high removal efficiency of nitrogen oxides is narrowly limited to about 900 to 1,000 ° C., and thus the removal efficiency is significantly lowered and higher than this. In the case of increasing the combustion rate of the injected reducing agent causes a problem that the reduction reaction of nitrogen oxide is not properly induced.

In other words, in the case of the selective non-catalytic reduction method, the conversion rate is improved only within a narrow temperature range. If the urea water or ammonia water is directly sprayed on the exhaust gas, the temperature of the exhaust gas is drastically reduced, and thus the conversion rate is lowered and the temperature control during operation is reduced. Problems that are not easy arise.

In addition, urea water or ammonia water is an expensive material, and as the amount used increases, the manufacturing cost of the reducing solution increases accordingly.

Prior art literature

Patent Literature

(Patent Document 1) Domestic Registered Patent 10-0393322

The present invention has been made in view of the above-described conventional problems, to facilitate the control of the reaction temperature in the nitrogen oxide reduction treatment process by extending the reaction temperature range effective to convert NO to N ₂ , the amount of urea or ammonia used While improving the rate of conversion of NO to N ₂ and reducing the side reaction of NO to N ₂ O, while reducing the cost of production compared to conventional reducing solution materials using aldol waste water An object of the present invention is to provide a nitrogen oxide reducing solution and a method of manufacturing the same.

According to one aspect of the invention,

A nitrogen oxide reducing solution comprising 4.5 to 5.5 wt% of urea or ammonia, 45 to 55 wt% of aldol waste water, and 40.5 to 49.5 wt% of water, wherein the aldol waste water is N-butyraldehyde under a sodium hydroxide (NaOH) catalyst. Octanol (C ₈ ) using 2-ethylhexenal (C ₈ H ₁₆ O) mixture obtained by condensation reaction of (N-Butyraldehyde, CH ₂ (CH ₂ ) ₂ CHO) after aldol polymerization H ₁₇ OH) is a wastewater recovered by decanting the 2-ethylhexenal mixture in the process for producing H ₁₇ OH), Na + (sodium ion) 11, OOO ~ 13,000 mg / L, K ⁺ (potassium ion) 14 ~ 17 mg / L, CO ₃ ^{2 -} (carbonate ion) 7,600 ~ 9200 mg / L, OH - ( hydroxyl ions) 6,700 ~ 8100 mg / L, SO 4 2- ( sulfate ions) 300 ~ 360 mg / L, and HCO ₃ ^- ( Bicarbonate ion) to provide a nitrogen oxide reduction solution using the aldol waste water, characterized in that containing 5 ~ 7 mg / L.

According to another aspect of the present invention,

2-ethylhexenal (2-Ethylhexenal, C ₈ H) obtained by condensation reaction of N-Butyraldehyde (CH ₂ (CH ₂ ) ₂ CHO) with Aldol polymerization under sodium hydroxide (NaOH) catalyst ₁₆ O) recovering the aldol wastewater by decanting the 2-ethylhexenal mixture in the process of producing octanol (C ₈ H ₁₇ OH) using the mixture and the aldol wastewater, urea ((NH ₂ ) ₂ CO) or ammonia (NH ₄ OH) by mixing any one or more of the water and provides a method for producing a nitrogen oxide reduction solution using an aldol waste water comprising the step of preparing a nitrogen oxide reduction solution.

According to a preferred feature of the invention

Injecting ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ) and ferrous sulfate (FeSO ₄ ) into the recovered aldol waste water while irradiating ultraviolet (UV), characterized in that it further comprises the step of removing the odor.

According to the nitrogen oxide reduction solution using the aldol waste water of the present invention,

By an aldol effluent from waste water treatment unit of step height after the oxidation number of elements or mixed with ammonia, urea or transition while reducing the amount of ammonia improve the rate at which the nitrogen oxide NO converted to N ₂ and NO is a N ₂ O The side reaction is suppressed to have an excellent performance while reducing the production cost compared to the conventional reducing solution material.

In addition, by extending the reaction temperature range effective to convert NO to N ₂ , it is easy to control the temperature in the nitrogen oxide reduction treatment process compared to the conventional reducing solution material and there is an effect that can further improve the conversion rate.

1 is a schematic diagram of aldol polymerization and condensation reactions.

2 is a schematic diagram of an aldol wastewater recovery step in the octanol production step.

3 is a graph showing the NO conversion rate according to the temperature range of the nitrogen oxide reduction solution according to the embodiment of the present invention and a comparative example.

Figure 4 is a graph showing the N ₂ O production concentration according to the temperature range of the nitrogen oxide reduction solution according to the embodiment and the comparative example of the present invention.

Hereinafter, preferred embodiments of the present invention will be described. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the inclusion of any component throughout the specification means that it may further include other components, except to exclude other components unless specifically stated otherwise.

Nitrogen oxide reduction solution production method using the aldol waste water according to the present invention,

2-ethylhexenal (2-Ethylhexenal, C ₈ H) obtained by condensation reaction of N-Butyraldehyde (CH ₂ (CH ₂ ) ₂ CHO) with Aldol polymerization under sodium hydroxide (NaOH) catalyst ₁₆ O) recovering aldol wastewater by decanting the 2-ethylhexenal mixture in the process of producing octanol (C ₈ H ₁₇ OH) using the mixture, while irradiating ultraviolet (UV) ozone (O) ₃ ), injecting hydrogen peroxide (H ₂ O ₂ ) and ferrous sulfate (FeSO 4) into the recovered aldol wastewater to remove odors and in aldol wastewater, urea ((NH ₂ ) ₂ CO) or ammonia (NH ₄ OH) It comprises a step of producing a nitrogen oxide reduction solution by mixing any one or more and water.

1 is a schematic diagram of the aldol polymerization and condensation reaction, Figure 2 is a schematic diagram of the aldol wastewater recovery process in the octanol production process.

* The step of recovering the aldol waste water, ₂ -ethyl ethyl N-butyraldehyde (CH ₂ (CH ₂ ) ₂ CHO) by condensation reaction after Aldol polymerization under sodium hydroxide (NaOH) catalyst This may be done by decanting and recovering the hexenal (2-Ethylhexenal, C ₈ H ₁₆ O) mixture.

Conventional octanol (C ₈ H ₁₇ OH) manufacturers have been spending a lot of money to treat or dispose of aldol wastewater that is essential in the octanol manufacturing process. The present invention is to recover the aldol waste water generated in the octanol manufacturing process and use it as a nitrogen oxide reducing solution prepared by mixing it with urea ((NH ₂ ) ₂ CO) water or ammonia (NH ₄ OH) water. This provides the beneficial effect of enabling octanol manufacturers to reduce the cost of treating / disposing aldol wastewater.

The aldol wastewater has Na + (sodium ion) 11, OOO ~ 13,000 mg / L, CO 3 2- ( carbonate ion) 7,600 ~ 9200 mg / L, OH - ( hydroxyl ions) 6,700 ~ 8100 mg / L SO ₄ ^2-, and a (sulfate ions) 300 ~ 360 mg / L, Cl - ( chlorine ions) 41 ~ 51 mg / L, K + ( potassium ion) 14 ~ 17 mg / L, HCO 3 - ( bicarbonate ions) 5 ~ 7 mg / It contains L, and may contain 40 ~ 48 mg / L of other Nitrogen Chemicals and 5 ~ 6 mg / L of Suspended Solid.

The alkalinity of the aldol wastewater is 19,000 ~ 24,400 eq / l, CODcr (chemical oxygen demand due to potassium dichromate) may be 6,600 ~ 8,000 (mg / L).

Aldol wastewater recovered according to the present invention may include organic substances such as lactone (C12-Lactone), ethylhexanol-diol-butyrate, butyric acid and may cause odors The chromaticity needs to be corrected for the rejection of waste water recycling or for the improvement of the merchandise.

Accordingly, optionally, the method for producing a nitrogen oxide reduction solution using the aldol wastewater according to the present invention, while irradiating ultraviolet (UV), ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ) or ferrous sulfate (FeSO ₄ ) Injecting the recovered aldol waste water may further comprise the step of removing the odor.

UV irradiation, hydrogen peroxide or ferrous sulfate act as an ozone oxidant, and may irradiate only ozone with ozone or add one or more of hydrogen peroxide or ferrous sulfate to ozone. It is most effective for organic matter decomposition (maximum decomposition rate: 96%) and chromaticity correction (maximum removal rate: 100%) in a short time because it increases the amount of hydroxyl radicals.

The ozone injection flow rate may be 0.026 to 0.053 g / min, and when injected at 0.053 g / min or more, the removal rate of organic matter is slowed, so it is preferable to be injected at 0.053 g / min.

The injection concentration of hydrogen peroxide may be 5 ~ 25 mM, it is preferable to be injected at a concentration of 10mM at 10 Mm or more because the organic removal rate and color correction effect is not greatly improved. This is presumably because hydrogen peroxide forms radical peroxide at a concentration of 10 Mm or more, thereby decreasing the reactivity of the radical.

The injection concentration of ferrous sulfate may be 0.04 ~ 0.1 mM, it is preferable to be injected at a concentration of 0.1 mM, since the removal rate of organic matter is reduced rather than 0.1 mM. This is presumably because ferrous sulfate acts as a scavenger of radical hydroxide at a concentration of 0.1 mM or more.

Subsequently, in the method for preparing a nitrogen oxide reduction solution using the aldol wastewater according to the present invention, any one or more of aldol wastewater, urea ((NH ₂ ) ₂ CO) or ammonia (NH ₄ OH) and water are mixed to reduce the nitrogen oxide reduction solution. It comprises a manufacturing step.

The aldol wastewater refers to wastewater as it is recovered or optionally pretreated for odor removal.

Nitrogen oxide reduction solution according to the present invention is mixed with at least any one of 45 ~ 55 wt% of aldol wastewater, urea ((NH ₂ ) ₂ CO) or ammonia (NH ₄ OH) and 40.5 ~ 49.5wt of water Can be prepared.

Aldol wastewater recovered according to the present invention contains a large amount of metal ions such as Na + (sodium ion) and K ⁺ (potassium ion) to promote hydrolysis of urea or ammonia, CO ₃ ^2- (carbonate ions), OH ^(hydroxyl ions), and SO ₄ ^2- (sulfate ion), and HCO ₃ ^- (bicarbonate ions) and cycles to create a suitable pH optimum conditions and there is a large amount to a basic anion-containing urea or ammonia due to hydrolysis, such as NO -> N _{2 It} is assumed that the maximum conversion is increased, the effective conversion temperature range is extended, and NO-> N ₂ O side reactions are also suppressed.

Any one or more of urea ((NH ₂ ) ₂ CO) or ammonia (NH ₄ OH) may use 4.5 to 5.5 wt%, and when used below 4.5 wt%, the effect of NO-> N ₂ conversion is minimal, 5.5 The use of more than wt% does not increase the NO-> N ₂ conversion effect.

Aldol effluent can be 45 ~ 55 wt%, and compared to when using only the elements Using less than 45 wt% NO - even with the> N ₂ up conversion synergistic effect is not generated more than 55 wt% NO -> N ₂ up to Conversion rate increase does not increase.

Experimental Example

Nitrogen oxide reduction solution according to the embodiment and the comparative example of the present invention are as follows. Example is a nitrogen oxide reduction solution according to the present invention prepared by mixing 5% by weight of urea, 50% by weight of aldol waste water and 45wt of water, Comparative Example is a conventional nitrogen oxide reduction solution prepared by mixing 5% by weight of urea and 95wt% of water to be.

Figure 3 is a graph showing the NO conversion rate according to the temperature range of the nitrogen oxide reduction solution according to the embodiment and the comparative example of the present invention.

Current legislation regulates the NO-> N ₂ conversion of incinerators to be above 60%, so 60% will be referred to as the effective conversion rate.

As shown in FIG. 3, the maximum conversion rate of the nitrogen oxide reduction solution according to the comparative example is 82% at 964 ° C., and the effective conversion attainment temperature range is 900 to 1030 ° C., while the maximum conversion rate of the nitrogen oxide reduction solution according to the embodiment is obtained. The conversion is 93% at 936 ° C. and the effective conversion attainment temperature range is 800-1030 ° C.

In contrast to the comparative example, since the maximum conversion is improved by 11% from 82% to 93%, the present invention has an advantageous effect of reducing the amount of the nitrogen oxide reducing solution used by 11%.

In contrast to the comparative example, the effective conversion rate achieved temperature range is extended by approximately 200% from 120 ° C. (= 1030-900 ° C.) to 230 ° C. (= 1030-800 ° C.). It has an advantageous effect that can be facilitated.

Current legislation regulates the incineration NO-> N ₂ conversion rate, but is indifferent to the emissions of N ₂ O, another major source of fine dust. Although not preferred, when urea or ammonia is used as the nitrogen oxide reducing agent, NO-> N ₂ O side reactions also occur.

Figure 4 is a graph showing the N ₂ O production concentration according to the temperature range of the nitrogen oxide reduction solution according to the embodiment and the comparative example of the present invention.

As shown in FIG. 4, the N ₂ O production concentration is 90 ppm at 964 ° C. at which the maximum conversion rate of the nitrogen oxide reduction solution according to the comparative example is recorded, whereas the maximum conversion rate of the nitrogen oxide reduction solution according to the example is recorded. The N ₂ O production concentration at 936 ° C. is 6 ppm.

In comparison with the comparative example, since the N ₂ O production concentration is reduced by 93.3% from 90ppm to 6ppm, the use of the nitrogen oxide reduction solution according to the present invention can reduce the N ₂ O production rate by 93.3% compared with the conventional method. Exert.

It is intended that the invention not be limited by the embodiments described above but rather by the claims appended hereto. Accordingly, various forms of substitution, modification, and alteration may be made by those skilled in the art without departing from the technical spirit of the present invention described in the claims, which are also within the scope of the present invention. something to do.

Claims (3)

1. A nitrogen oxide reducing solution comprising 4.5 to 5.5 wt% of urea or ammonia, 45 to 55 wt% of aldol wastewater, and 40.5 to 49.5 wt% of water,

   The aldol wastewater is 2-ethylhexenal (2-Ethylhexenal) obtained by condensation reaction of N-butyraldehyde (N-Butyraldehyde, CH ₂ (CH ₂ ) ₂ CHO) after aldol polymerization under a sodium hydroxide (NaOH) catalyst. , Wastewater recovered by decanting the 2-ethylhexenal mixture in a process of producing octanol (C ₈ H ₁₇ OH) using a mixture of C ₈ H ₁₆ O).

   Na + (sodium ion) 11, OOO ~ 13,000 mg / L, K + ( potassium ion) 14 ~ 17 mg / L, CO 3 2 - ( carbonate ion) 7,600 ~ 9200 mg / L, OH - ( hydroxyl ions) 6,700 - ^{_{8100 mg / L, SO 4 2-}} ( sulfate ions) 300 ~ 360 mg / L, and HCO ₃ ^- (bicarbonate ions) from 5 to, the nitrogen oxide reduction using the aldol effluent being configured to contain a 7 mg / L solution.
2. 2-ethylhexenal (2-Ethylhexenal, C ₈ H) obtained by condensation reaction of N-Butyraldehyde (CH ₂ (CH ₂ ) ₂ CHO) with Aldol polymerization under sodium hydroxide (NaOH) catalyst ₁₆ O) decanting the 2-ethylhexenal mixture in the process for producing octanol (C ₈ H ₁₇ OH) using the mixture, and recovering the aldol wastewater; and

   Preparation of nitrogen oxide reduction solution using aldol wastewater comprising the step of mixing any one or more of aldol wastewater, urea ((NH ₂ ) ₂ CO) or ammonia (NH ₄ OH) and water to prepare a nitrogen oxide reduction solution Way.
3. The method of claim 2,

   Injecting ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ) and ferrous sulfate (FeSO ₄ ) into the recovered aldol waste water while irradiating ultraviolet (UV), further comprising the step of removing odors, aldol Nitrogen oxide reduction solution using wastewater.

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