KR20020081940A - Method of nitric oxides reduction and soot treatment by using hydrogen peroxide solution, alcohol or hydrogen peroxide solution /alcohol mixture - Google Patents

Abstract

PURPOSE: A method for NOx reduction by using hydrogen peroxide solution, alcohol or hydrogen peroxide solution/alcohol mixture is provided, which can remove effectively NOx and soot contained in exhaust gas stream of various burners and diesel engines. CONSTITUTION: The method comprises the steps of spraying mixture of hydrogen peroxide of 1 to 15 wt.% concentration, water and alcohol of 1 to 1.5 wt.% concentration at a weight ratio of 1-7.5:1-7.5:85-98 through reagent spraying nozzles(3) to exhaust gas coming from a combustion chamber(1) and containing nitrogen oxide (NOx) at 400 to 800 deg.C at a reactor(2); spraying water through water spraying nozzles(6) to condensate at a cooling tower(5).

Description

METHODS OF NITRIC OXIDES REDUCTION AND SOOT TREATMENT BY USING HYDROGEN PEROXIDE SOLUTION, ALCOHOL OR HYDROGEN PEROXIDE SOLUTION / ALCOHOL MIXTURE}

The present invention relates to a method for reducing and treating nitrogen oxides in exhaust gas. More specifically, the present invention relates to a method for reducing and treating nitrogen oxides contained in a large amount in the atmosphere of exhaust gas of various burners and diesel engines using hydrogen peroxide water, alcohol or a mixture of hydrogen peroxide water and alcohol.

As a conventional chemical treatment method for treating nitrogen oxides, a method of injecting ammonia or cyan (commonly known cyanide) solution into the exhaust gas has been mainly used in burners and industrial furnaces. There is no chemical treatment. In addition, as a method of reducing particulate matter, commonly referred to as soot, a filter called a diesel particle filter (DPF) is gradually being expanded, but it is difficult in terms of economics and durability.

Conventional nitrogen oxide reduction method using ammonia is characterized by the fact that nitrogen oxide concentration is minimized near 1400K (1127 ℃), so that almost all nitrogen oxides are decomposed. However, since exhaust gas temperature should be about 1127 ℃, it is practically impossible in a burner factory. Problem occurs, such as reheating, resulting in enormous energy loss. In addition, ammonia itself is a toxic material, corrosive and difficult to store.

Cyanide is also very toxic in itself, so there is a very high risk of personal injury in case of leakage and requires great care in storage. After use, cyan sublimates and isocyanic acid condenses at low temperature in the nitrogen oxide reduction device and remains as a poison.

In addition, the nitrogen oxide reduction method using platinum catalyst can decompose nitrogen oxide at a relatively low temperature (about 800 ° C), but the configuration of the device is very complicated, the installation cost and the cost of the catalyst are very expensive, and the exhaust gas has a large capacity (that is, , High concentrations of nitrogen oxides), there is a problem that can not be used.

On the other hand, in the case of nitrogen oxide discharged from the diesel engine, the reduction device is not yet applied in the country, and in the case of foreign countries, there is a method using a catalyst, but the cost is high and short life. In addition, in the case of the smoke reduction method DFP, there is a problem that the cost is high, the engine efficiency is lowered due to the increase in the pressure of the exhaust gas pipe and the durability is poor.

Accordingly, an object of the present invention is to provide a method for efficiently removing and treating nitrogen oxides and soot from exhaust gases of various burners and diesel engines using hydrogen peroxide water, alcohol or a mixture of hydrogen peroxide water and alcohol.

1 is a process schematic diagram of the present invention,

2 is a process schematic diagram showing an example in which the present invention is applied to a diesel engine,

3 is a perspective view showing a nitrogen oxide and a soot treatment system used in the embodiment of the present invention,

4 is a graph showing the amount of residual NO according to the temperature change during the injection of hydrogen peroxide, methanol and hydrogen peroxide + methanol,

5 is a graph showing the amount of residual NO according to the initial NO concentration change when hydrogen peroxide, methanol and hydrogen peroxide + methanol injection;

6 is a graph showing the amount of residual NO according to the change in injection amount of hydrogen peroxide, methanol and hydrogen peroxide + methanol;

7 is a graph showing the amount of NO according to the residual oxygen concentration change when hydrogen peroxide, methanol and hydrogen peroxide + methanol injection;

8 is a graph showing the amount of SO ₃ remaining according to the temperature change during the injection of hydrogen peroxide, methanol and hydrogen peroxide + methanol;

9 is a graph showing the amount of SO ₃ remaining according to the initial SO ₃ concentration change during hydrogen peroxide, methanol and hydrogen peroxide + methanol injection;

10 is a graph showing the amount of CH ₄ remaining according to the temperature change during the injection of methane and hydrogen peroxide + methane,

11 is a graph showing the amount of CH ₂ Cl ₂ remaining according to the temperature change during the injection of CH ₂ Cl ₂ and hydrogen peroxide + CH ₂ Cl ₂ ,

12 is a graph showing the amount of remaining C ₆ H ₆ and CO according to the temperature change during the injection of C ₆ H ₆ and hydrogen peroxide + C ₆ H ₆ ,

It is a graph which shows the result by NO concentration reduction simulation using a computer.

Explanation of symbols on major parts of drawing

1 .... combustion chamber 2 .... reactor

3 .... Reagent Jet Nozzle 4 .... Reagent Tank

5 .... cooling tower 6 .... water jet nozzle

7 .... Waste Storage Feet 8 .... Cylinder Block

10 .... Muffler 11 .... Incinerator

12 .... Variable swing burner 13 .... Hydrocarbon injection

14 .... Injecting sprays (hydrogen peroxide, etc.) 15 .... Exhaust duct

20 .... Bends

According to one aspect of the invention,

Applying hydrogen peroxide water, alcohol or a mixture of hydrogen peroxide and alcohol to exhaust gas containing nitrogen oxides (NOx) at 400-800 ° C .; And

Thereafter, applying water to condense into an aqueous solution;

Provided is a nitrogen oxide reduction and treatment method comprising a.

According to another aspect of the present invention,

Applying hydrogen peroxide, alcohol or a mixture of hydrogen peroxide and alcohol to the rear of the combustion chamber in which exhaust gas containing nitrogen oxides (NOx) is discharged; And

Thereafter, applying water to condense into an aqueous solution;

Provided is a nitrogen oxide reduction and treatment method comprising a.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The method of the present invention relates to a method for reducing and treating nitrogen oxides and soot contained in exhaust gas by using hydrogen peroxide water, alcohol or a mixture of hydrogen peroxide water and alcohol.

The present inventors have found that nitrogen oxides, in particular nitrogen monoxide (NO) and hydrogen peroxide water, alcohols or mixtures of hydrogen peroxide water and alcohols react to change nitrogen oxides to nitrogen dioxide and are easily reduced.

According to the method of the present invention, hydrogen peroxide (H 2 O 2 (aq.)), Alcohol or a mixture of hydrogen peroxide and alcohol is applied to the exhaust gas containing nitrogen oxide to be treated at 400-800 ° C. Hydrogen peroxide, alcohol or a mixture of hydrogen peroxide and alcohol (hereinafter referred to simply as 'nitrogen oxide treatment agent') may be applied in any form to the exhaust gas containing the nitrogen oxide to be treated, and preferably mist Is sprayed with.

When spraying the hydrogen peroxide, alcohol or a mixture of hydrogen peroxide and alcohol, the appropriate temperature is 400-800 ° C., more preferably 550-800 ° C. and most preferred is 700 ° C. When the nitrogen oxide and the hydrogen peroxide water, alcohol or a mixture of hydrogen peroxide water and alcohol react, the conversion of NO ₂ to NO ₂ in the above temperature range is shown.

The reaction mechanism of the hydrogen peroxide, alcohol or a mixture of hydrogen peroxide and alcohol with the nitrogen oxide contained in the exhaust gas in the above temperature range is as follows.

In the above temperature range, hydrogen peroxide is decomposed as follows to generate hydroxyl groups.

H ₂ O ₂ → 2OH

However, at this time, H ₂ O ₂ is not converted to 100% OH, and the conversion rate of the hydrogen peroxide solution to the hydroxyl group is the highest at 850 K (577 ° C.) under atmospheric pressure.

Thereafter, water and HO ₂ are present in the hydrogen peroxide (H ₂ O ₂ ) and the OH group reaction.

H ₂ O ₂ + OH → H ₂ O + HO ₂

On the other hand, typically 90-95% of the nitrogen oxides (NOx) generated in the combustion process is NO and the remainder is the NO ₂ or N ₂ O, when contacting the exhaust gas containing nitrogen oxides such as aqueous hydrogen peroxide HO ₂ And NO react and NO, which occupies most of the nitrogen oxides, is converted to NO ₂ according to the following reaction formula.

HO ₂ + NO → NO ₂ + OH

The content of hydrogen peroxide in the hydrogen peroxide water is preferably 1-15% by weight. This is because the inclusion of too little hydrogen peroxide lowers the NO ₂ conversion, and the inclusion of too much hydrogen peroxide can corrode the piping by the acidity of hydrogen peroxide and can be economically expensive. More preferred hydrogen peroxide content is 0.5-3% by weight.

In general, exhaust gases emitted from burners, diesel engines or industrial furnaces contain nitrogen oxides (NOx) such as nitrogen monoxide (NO) in large amounts. The exhaust gas exits the exhaust pipe after the combustion process and is discharged to the atmosphere through a stack. At this time, the exhaust gas temperature in the exhaust pipe immediately after the combustion chamber of the burner or industrial furnace is about 900 ° C. Therefore, the exhaust gas containing nitrogen oxides (NOx) is injected by injecting hydrogen peroxide (H ₂ O ₂ (aq.)), Alcohol or a mixture of hydrogen peroxide and alcohol into an exhaust pipe immediately after the combustion chamber (at 400-800 ° C.). In contact with the gas, the exhaust gas temperature is slightly lowered to maximize the chemical reaction of NO and OH so that most of the NO is converted to NO ₂ by the reaction as described above.

Alcohols and mixtures of hydrogen peroxide water and alcohols can also be used for nitrogen oxide treatment. When alcohol is used, H ₂ O ₂ is formed as in Scheme 4 below, and then reacted as in Schemes 1 to 3 to remove nitrogen oxides.

OH + OH → 2OH

In the formula, OH is attributable to alcohol.

2OH → H ₂ O ₂

If a mixture of hydrogen peroxide and alcohol is used, it is also reacted with nitrogen oxides as in the above schemes.

It is preferable that the alcohol used in the present invention contains 1-15% alcohol, and if the concentration is lower than this, the soot increases in the exhaust gas, and if it is higher than this, activation of chemical reaction more than necessary, i.e. This is because the additional combustion reaction increases the concentration of nitrogen oxides.

In the case of a mixture of hydrogen peroxide and alcohol, the mixing weight ratio is 1-7.5: 1-7.5: 85-98 weight ratio of hydrogen peroxide: water: alcohol, preferably 1-5: 5 in terms of both optimization and cost minimization of the reaction. -10: 94-85 weight ratio is good. Alcohols suitable for the present invention are methanol and ethanol, and in particular, methanol is a preferred alcohol for the present invention because methanol is most easily decomposed into CH ₂ , OH ₂ , and the like at low temperatures.

In addition, other soot components, such as other RH based, ie hydrocarbon based components, are also removed simultaneously by the process of the invention. That is, the hydrocarbon-based fuel represented by RH is removed with CO ₂ by reacting with OH or HO ₂ during nitrogen oxide treatment by the method of the present invention.

The reactant is then condensed into an aqueous solution by subsequently spraying water on the reactant converted in this manner. Since NO ₂ has a property of dissolving well in water, an aqueous solution of NO ₂ containing is easily obtained by spraying water.

Hydrogen peroxide, alcohol or a mixture of hydrogen peroxide and alcohol can be applied directly to the rear of the combustion chamber in which exhaust gases containing nitrogen oxides (NOx) are released. More specifically, it may be directly applied to the rear end of the combustion chamber and the start portion of the exhaust pipe. The temperature of the rear end of the high temperature combustion chamber is about 400 to 800 ° C. The nitrogen oxide treatment agent is directly applied to the rear end of the combustion chamber in which exhaust gas is emitted, preferably sprayed to react with the nitrogen oxides as described above.

The aqueous solution containing NO ₂ obtained by spraying the water can be stored for post-treatment. NO ₂ containing aqueous solution is generally and collected by storing in the pit, the pit is in the aqueous solution to move in the horizontal direction bending as shown in reference numeral 20 of the second to be described later so as to fall by a load of the NO ₂ contained in the aqueous solution was obtained from the other exhaust gas components It is desirable to allow easy separation.

The pit used in the present invention is preferably made of heat-resistant plastic or stainless steel that does not corrode in the strong acidity of the NO ₂ -containing aqueous solution.

Furthermore, the collected NO ₂ -containing aqueous solution may then be decomposed by wastewater treatment using microorganisms. Wastewater treatment using the microorganism is a general microbial wastewater treatment known in the art that NO ₂ is used as food for microorganisms to be decomposed.

The method of the present invention may be applied to a system as shown in FIG. 1 in one embodiment. Exhaust gases emitted from combustion chamber 1 , such as burners or industrial furnaces, react with H ₂ O ₂ (aq.) And / or alcohols injected from reactant injection nozzles 3 connected to reactant tank 4 in reactor 2 . The reactant is then transferred to cooling tower 5 and reacted with water sprayed by the water jet nozzle 6 to convert it into an aqueous solution. The aqueous solution is collected in a waste storage pit located at the bottom of the cooling tower, and when a certain amount is collected, the water is treated in the same manner as microbial wastewater treatment.

Furthermore, when applied to a diesel engine, it is preferable to preheat the hydrogen peroxide water before injection to prevent excessive temperature drop in the exhaust pipe during the hydrogen peroxide water injection. Preheating of the hydrogen peroxide water can be achieved, for example, by attaching a reactant tank containing hydrogen peroxide to the engine cylinder block as shown in FIG. 2. In this case, the method of the present invention can be applied to a system as shown in FIG. As shown in FIG. 2, the reactant injection nozzle 3 connected to the reactant tank 4 containing H ₂ O ₂ (aq.) And / or alcohol is attached to the engine cylinder block 8 . The injection nozzle is also located at the beginning of the exhaust pipe 9 to allow the exhaust gases and reactants to react during the injection. The reactant is then reacted with water sprayed by the water jet nozzle 6 to be converted into an aqueous solution and collected in an exhaust reservoir 7 . Nitrogen oxides and the remaining exhaust gas are exhausted through the muffler 10 to the exhaust pipe.

The method of the present invention can be applied to heating, combustion and incineration plants in any plant using burners and to any mechanical device (e.g. automobiles and ships) equipped with diesel engines.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example

3 shows the experimental apparatus used in this example. Exhaust duct 15 was connected to incinerator 11 with variable swing burner 12 , hydrocarbon (CH ₄ , CH ₂ Cl ₂ ) injection at 13 , methanol and hydrogen peroxide injection at 14 and exhaust gas measurement at 15 . . In FIG. 3, the unit of length is m.

The variable swing burner 12 is a 300 kW (259,200 kcal / h) boiler simulator device, with 15% hydrogen peroxide, 15% methanol for methanol, and 15% methanol for hydrogen peroxide. Was mixed in a 7.5: 7.5: 85 weight ratio. The injection and exhaust gas were reacted for 0.5-3.2 seconds. This was inverted from the reaction time and the total distance of 14m. The exhaust gas flow rate was 4.375-28m / s, the temperature range of the reactor was 600K-1100K, the temperature drop rate was 188K / s in the reactor, and the exhaust was exhausted at the point of 500K. Gas was collected.

Example 1

Under these conditions, the initial NO concentration [NO] i was 200 ppm and the reaction zone temperature was 650-1100K, with hydrogen peroxide (15% solution), methanol (15% solution) and hydrogen peroxide + methanol (hydrogen peroxide: methanol: water = 7.5: 7.5: 85) was sprayed at the inlet of the exhaust pipe 300 ppm each, and the residual NO amount according to the temperature change was measured and shown in FIG. 4. The residual oxygen concentration after the reaction was 3.8% (air ratio 1.22).

Hydrogen peroxide, methanol, and hydrogen peroxide + methanol mixtures all significantly reduced NO.

Example 2

Under these conditions, the initial NO concentration [NO] i is 80-500 ppm, and the reaction zone temperature is 780 K, with hydrogen peroxide (15% solution), methanol (15% solution) and hydrogen peroxide + methanol (hydrogen peroxide: methanol: water = 7.5: 7.5: 85) were injected at the inlet of the exhaust pipe at 300 ppm each, and the residual NO amount according to the change of the initial NO concentration, that is, [NO] i was measured and shown in FIG. 5. The residual oxygen concentration was 3.8% (air ratio 1.22).

In case of spraying hydrogen peroxide solution (15% solution), the residual NO amount was 6.4 ppm at 80 ppm with low initial NO concentration, and the residual NO amount was 20 for 200, 300, 400, and 500 ppm, respectively, regardless of the initial NO concentration. 10, 30, 40 and 50 ppm levels were maintained.

When the hydrogen peroxide + methanol solution was sprayed, the residual NO amount was 1.6 ppm at 80 ppm with low initial NO concentration, and the residual NO amount was 8, 12 for 200, 300, 400 and 500 ppm, respectively, regardless of the initial NO concentration. 4, 16 and 20 ppm were maintained.

When methanol was injected, the amount of remaining NO decreased in inverse proportion to the initial NO concentration.

Example 3

Under the above conditions, the initial NO concentration [NO] i was 200 ppm and the reaction zone temperature was 780 K, with hydrogen peroxide solution (15% solution), methanol (15% solution) and hydrogen peroxide + methanol (hydrogen peroxide: methanol: water = 7.5: 7.5: 85) is injected from the exhaust pipe inlet while changing to 1, 1.5 and 3 times (ie, 200, 300 and 600 ppm) of [NO] i, respectively, and the remaining amount of NO according to the change amount of each injection is measured and FIG. Shown in The residual oxygen concentration was 3.8% (air ratio 1.22).

The higher the concentration of the injection to the NO concentration, the better the reduction effect of NO. When the concentration of the injection was three times that of [NO] i, it showed the best reduction effect of NO.

Example 4

Under the above conditions, the initial NO concentration [NO] i was 200 ppm and the reaction zone temperature was 780 K, with hydrogen peroxide solution (15% solution), methanol (15% solution) and hydrogen peroxide + methanol (hydrogen peroxide: methanol: water = 7.5: 7.5: 85) was injected at the inlet of the exhaust pipe at 1.5 times (ie, 300 ppm) of [NO] i, respectively, and the residual NO amount according to the residual oxygen concentration change was measured and shown in FIG. 7.

The NO reduction effect was excellent in order of residual oxygen concentration up to 1.5% in order of methanol, hydrogen peroxide + methanol, and hydrogen peroxide solution. In the case of residual NO amount was about 30ppm.

Example 5

Under these conditions, the initial NO concentration, [NO] i is 200 ppm, the initial SO ₃ concentration, [SO ₃ ] i is 100 ppm and the reaction zone temperature is 650-1100K, hydrogen peroxide (15% solution), methanol (15% solution). ) And hydrogen peroxide + methanol (hydrogen peroxide: methanol: water = 7.5: 7.5: 85) are each injected at the inlet of the exhaust pipe at 1.5 times (ie 450 ppm) of [NO + SO ₃ ] i and remain with the temperature change of the reaction zone. The concentration of SO ₃ was measured and shown in FIG. 8. The residual oxygen concentration was 3.8%.

Was most effective solid at 810K in case of injecting a hydrogen peroxide residual SO3 concentration is 180ppm was, was most effective solid at 780K in aqueous hydrogen peroxide + when the injection of methanol remaining SO ₃ concentration was 90ppm, and if the injection of methanol Was most effective near 970K and the residual SO ₃ concentration was 132ppm.

Example 6

Under the above conditions, the initial NO concentration [NO] i is 200 ppm, the initial SO ₃ concentration [SO ₃ ] i is 30, 60 and 100 ppm and the reaction zone temperature is 780 K. Hydrogen peroxide (15% solution), methanol (15% solution) ) And hydrogen peroxide + methanol (hydrogen peroxide: methanol: water = 7.5: 7.5: 85) were injected at the inlet of the exhaust pipe at 1.5 times (ie 345, 390 and 450 ppm) of [NO + SO ₃ ] i and the initial concentration of SO ₃ The residual SO ₃ concentration according to the change of [SO ₃ ] i was measured and shown in FIG. 9.

Hydrogen peroxide + methanol was the most effective in reducing SO ₃ , followed by methanol and hydrogen peroxide. If the initial SO ₃ concentration is high, the amount of SO ₃ decreased in proportion to it.

Example 7

Under these conditions, the initial NO concentration [NO] i was 200 ppm, the initial CH ₄ concentration [CH ₄ ] i was 45 ppm and the reaction zone temperature was 650-1100K. The hydrogen peroxide solution (15% solution) was [H ₂ O ₂ ] / [NO + CH _4] 1.5 times of i (i.e., 367.5ppm) and methane is injected in parallel the number of methane or methane and hydrogen peroxide alone at the exhaust pipe inlet with 300ppm and represents the residual CH ₄ concentration of the reaction zone temperature to 10 It was. (300 ppm injection rate when methane alone injection, 50:50 injection weight ratio when injection of methane and hydrogen peroxide in parallel).

When the methane alone was injected, the residual methane concentration began to decrease above 850 K, and hardly remained above 970 K. On the other hand, when hydrogen peroxide and methane were sprayed in parallel, the residual methane concentration began to decrease near 680K, showing the best effect near 890K.

Example 8

Under these conditions, the initial NO concentration, [NO] i is 200ppm, the initial CH ₂ Cl ₂ concentration, [CH ₂ Cl ₂ ] i is 37ppm and the reaction zone temperature is 650-1100K so that the hydrogen peroxide solution (15% solution) is [ _{H 2 O 2] / [NO} + CH 2 Cl 2] 1.5 times of i (i.e., 355.5ppm) and CH ₂ Cl ₂ is solely injected CH ₂ Cl ₂ in the exhaust pipe inlet with 300ppm or CH ₂ Cl ₂ and the hydrogen peroxide solution Concurrent injection and residual CH ₂ Cl ₂ concentration according to the temperature of the reaction zone are shown in FIG. 11 (injection amount 300ppm when CH ₂ Cl ₂ alone injection, injection weight ratio 50:50 when CH ₂ Cl ₂ and hydrogen peroxide parallel injection).

When CH ₂ Cl ₂ was sprayed alone, the residual CH ₂ Cl ₂ concentration began to decrease above 750K and showed the best effect near 1100K. In contrast, when hydrogen peroxide and CH ₂ Cl ₂ were sprayed in parallel, the residual CH ₂ Cl ₂ concentration began to decrease near 660K, showing the best effect near 1010K. At this time, the CO produced as an intermediate reactant was generated from 750K, but decreased after forming a maximum concentration near about 810K, showing a minimum concentration at 1010K.

Example 9

Under the above conditions, the initial NO concentration [NO] i was 200 ppm, the initial C ₆ H ₆ concentration [C ₆ H ₆ ] i was 17 ppm, and the reaction zone temperature was 650-1100K, and the hydrogen peroxide solution (15% solution) was [H _2]. 1.5 times of O ₂ ] / [NO + C ₆ H ₆ ] i (i.e. 325.5 ppm) and 300 ppm of C ₆ H ₆ , injecting C ₆ H ₆ alone or C ₆ H ₆ and hydrogen peroxide in parallel at the inlet of the exhaust pipe. Residual C ₆ H ₆ concentration according to the reaction zone temperature is shown in FIG. The concentration of CO was also shown as an intermediate reactant (injection weight of 300 ppm of C ₆ H ₆ alone, and injection weight ratio of 50:50 for the simultaneous injection of C ₆ H ₆ and hydrogen peroxide).

When C ₆ H ₆ was sprayed alone, the residual C ₆ H ₆ concentration began to decrease above 850K and showed the best effect near 990K. In contrast, when hydrogen peroxide and C ₆ H ₆ were sprayed in parallel, the residual C ₆ H ₆ concentration began to decrease near 660K, showing the best effect near 930K.

Example 10

Under the above conditions, the NO concentration reduction was simulated using a computer. Initial NO concentration, [NO] i is 200ppm and reaction zone temperature is 650-1100K, hydrogen peroxide (15% solution), methanol (15% solution) and hydrogen peroxide + methanol (hydrogen peroxide: methanol: water = 7.5: 7.5: 85) is assumed to be injected at the inlet of the exhaust pipe at 1.5 times [NO] i (ie 300 ppm) (residual oxygen concentration is assumed to be 3.8%). FIG. 13 shows the results of the chemical dynamic calculation of the residual NO concentration change according to the reaction zone temperature (all assumed to be in gaseous state).

Hydrogen peroxide and hydrogen peroxide + methanol gas showed similar NO reduction and were most effective in the temperature range of 650-980K. Methanol alone showed NO concentration reduction at 850-1050K and was most effective at 900-950K.

Through the present embodiment it can be seen that the optimum reaction conditions of the present invention based on the initial NO concentration of 200ppm, the temperature of 780K, the residual oxygen concentration of more than 3% and H ₂ O ₂ and / or methanol injection concentration of 450ppm.

The method of the present invention can effectively remove nitrogen oxides and soot contained in the exhaust gas by using hydrogen peroxide water or a mixture of alcohol and hydrogen peroxide water, and the handling is safe and inexpensive. In addition, the method of the present invention can be easily applied to various combustion furnaces and diesel engines.

Claims (12)

Applying hydrogen peroxide water, alcohol or a mixture of hydrogen peroxide and alcohol to exhaust gas containing nitrogen oxides (NOx) at 400-800; And Thereafter, applying water to condense into an aqueous solution; Nitrogen oxide reduction and treatment method comprising a. Applying hydrogen peroxide, alcohol or a mixture of hydrogen peroxide and alcohol to the rear of the combustion chamber in which exhaust gas containing nitrogen oxides (NOx) is discharged; And Thereafter, applying water to condense into an aqueous solution; Nitrogen oxide reduction and treatment method comprising a. The method according to claim 1 or 2, wherein the hydrogen peroxide water has a hydrogen peroxide content of 1-15% by weight. The method of claim 1 or 2, wherein the alcohol has an alcohol content of 1-15% by weight. The method according to claim 1 or 2, wherein the mixture of hydrogen peroxide and alcohol has a mixed weight ratio of hydrogen peroxide: water: alcohol of 1-7.5: 1-7.5: 85-98. The method of claim 2, wherein the temperature at the rear end of the combustion chamber is 400-800. 7. The method of claim 1 or 6, wherein the temperature is 550-800. The method according to claim 1 or 2, further characterized in that the preheating is carried out before the injection of the hydrogen peroxide water, alcohol or a mixture of hydrogen peroxide water and alcohol. The method of claim 1 or 2, wherein the condensed aqueous solution is collected in a pit that is bent so that the aqueous solution moving in the horizontal direction is lowered by a load. 10. The method of claim 9, wherein the pit is made of heat resistant plastic or stainless steel. The method of claim 1 or 2, wherein the alcohol is methanol. The method of claim 9, further comprising the step of decomposing the collected aqueous solution by wastewater treatment using microorganisms.