KR100891231B1 - Reduction Reagent Solution For Restricting Production of Nitrous Oxide - Google Patents

Abstract

The present invention relates to a reducing solution material used to suppress the production of nitrous oxide (N ₂ O) discharged from a combustion furnace, and more particularly, to a reducing solution material in which a small amount of urea and NaOH are added and mixed with a manure extract. It is very effective in reducing nitrogen oxides in the exhaust gas discharged from the combustion furnace and suppressing the production of nitrous oxide.

Nitrous oxide, manure extract, urea, NaOH

Description

Reduction solution for inhibiting the production of nitrous oxide {Reduction Reagent Solution For Restricting Production of Nitrous Oxide}

1 is a graph showing the amount of N ₂ O produced according to the change of reaction temperature when spraying only urea solution.
2 is a graph showing the amount of N ₂ O produced according to the change in reaction temperature when NaOH was added to the urea solution.

The present invention relates to a reducing solution preparation used in a selective non-catalytic reduction process, and more particularly, to a selective non-catalyst reducing solution preparation prepared by adding urea and metal ions to a manure waste.

Nitrogen oxide (NOx) contained in exhaust gas is composed of more than 90% nitrogen monoxide, nitrogen dioxide and nitrous oxide, and is a representative environmental pollutant that causes global warming and air pollution. Nitrous oxide has various sources, but the amount of nitrous oxide produced by the burning of fossil fuels is increasing. Nitrous oxide removal is generally used interchangeably as a technique for removing nitrogen oxides, and a method using a catalyst that is a combustion post-treatment technique has been most frequently used.

As a technique using a catalyst, a technique using carbon monoxide in a metal oxide catalyst prepared from hydrotalcite [patent 10-0654885], and a method of simultaneously removing NO, NO ₂ and N ₂ O with a multistage catalyst layer. -0088774], a method using zeolite as a catalyst [public patent 10-2004-0010605], a method using an iron-supported zeolite [public patent 10-2004-0015066], using a catalyst supporting potassium and sodium in ferrierite US Pat. No. 6,682,710 B1, US Pat. No. 6,872,372 B1, and the like to remove N ₂ O using hydrocarbons in iron-supported zeolites. The technology using the catalyst is generally high efficiency, but has the disadvantage of having to install a separate facility at the rear of the facility and to continuously replace the expensive catalyst. In addition, there is a disadvantage that another NOx control technique should be used to remove NO and NO ₂ discharged simultaneously with N ₂ O generation. Therefore, if the catalyst is not used in the nitrogen oxide removal technology and the N ₂ O production can be suppressed, it can be a better reduction technology.

A technique that can reduce nitrogen oxides without using a catalyst is a selective non-catalytic reduction process, which can reduce nitrogen oxides by spraying urea solution, ammonia water or cyanuric acid at high temperature. However, although urea, ammonia and cyanuric acid used as NOx reducing agents all have an efficient part for removing NOx, N ₂ O is generated due to the nitrogen component of the reducing agent introduced.

In order to solve this problem, there is a technique using a hydrolysis agent (US Patent No. 5,543,123), a technique using an ammonium carbamate [US Patent No. 4,997,631] as a technology for reducing N ₂ O, nitrous oxide is decomposed at high temperature There is a thermal treatment method [US Pat. No. 5,048,432] which reheats nitrous oxide in gas discharged from a circulating fluidized bed combustion furnace to 920 ^° C. or more. However, this technique can reduce the N ₂ O but presents problems such as narrow temperature window, high price, low NOx removal efficiency, or increased NH ₃ emission concentration.

Thus, the present inventors to solve the above problems, the width has been developed a wide temperature range, new N ₂ O produced a reducing solution for reducing material can maintain a high NOx reduction ratio, and at the same time suppressing generation of N ₂ O in. That is, the present inventors added a small amount of metal ions and urea to the solution extracted from the livestock manure to be treated as waste to complete a reducing solution having excellent effect of suppressing the production of N ₂ O in the high temperature region of 700 ° C to 1,100 ° C. According to the invention, thereby inhibiting the generation of N ₂ O N ₂ O by being converted to metal ions in the solution reduced materials and N ₂ O in the exhaust gas is the reaction with N _2. That is, the present invention added a small amount of metal ions, such as Na, Li, K, to the livestock waste causing the waste treatment and wastewater treatment problems, thereby completing a reducing solution material having high efficiency of removing nitrogen oxides in the exhaust gas.
An object of the present invention is to provide a reducing solution material that can suppress the production of N ₂ O in a wide temperature range by using manure that causes waste treatment or waste water treatment problems.

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The reducing solution preparation of the present invention comprises a solution extracted using livestock manure as a main component, and a small amount of a metal compound (for example, NaOH) and urea [(NH ₂ ) ₂ CO] are added and mixed with the extract. At this time, the manure extract content of the total weight of the reducing solution, such as pig meal, pig meal, shaft meal is 1 to 95% by weight, the content of the metal compound is 0.1 to 5% by weight, urea [(NH ₂ ) ₂ CO] is 5 It is preferable that it is-50 weight%.
First, the manure extract is stirred with a stirrer for 24 hours at room temperature by mixing water to 1 to 50% by weight (or pig meal, shaft meal) using a stirrer, filtered under reduced pressure to extract the suspension without floating Get in the state.
In addition, the metal compound is preferably a metal compound containing metal ions such as Na, Li, Fe, Zn, Ba, K and Mg. Examples of such metal compounds include NaOH.

Referring to the process for producing a reducing solution preparation according to the invention of such a configuration in detail as follows.

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First, in order to prepare the manure extract, the system powder (or pig meal, shaft meal) is mixed with water at 1 to 50% by weight and stirred using a stirrer at room temperature for 24 hours. The stirred slurry is filtered under reduced pressure to obtain an extract free of suspended solids. 10 to 90% by weight of water, 5 to 50% by weight of urea and 0.1 to 5% by weight of NaOH were added to 1 to 95% by weight of the extract to complete the final reducing solution preparation.

The reducing solution preparation for reducing nitrogen oxides according to the present invention not only enables the reduction of nitrogen oxides and the suppression of nitrous oxide production in the temperature range of 700 ° C. to 1,100 ° C., but also reduces secondary pollution such as soil pollution or water pollution by manure waste. It is very effective in preventing environmental pollution.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

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Example 1

After adjusting the ratio of the system to water at 1: 1, the mixture was stirred while keeping it in contact with air at room temperature for 24 hours. After the stirring was terminated, the solution was filtered through a 300 μm mesh, and the filtrate was again operated by 1,800 rpm for 20 minutes using a centrifugal separator. The powdered extract extract, urea [(NH ₂ ) ₂ CO], and NaOH were mixed in a mass ratio of 94: 5: 1, respectively, to prepare a final nitrogen oxide reducing solution material.
Comparative Example 1
A reducing solution was prepared using 95 g of water and 5 g of urea.
[Experimental method]
A reactor made of a high temperature refractory (Castable) and SS304 conduit of 0.2m in diameter and 6m in length and using an LPG burner was prepared. Flue gas and about 500 ppm of nitrogen oxide were supplied into the reactor, and the reducing solution material prepared in Example 1 and Comparative Example 1 was sprayed through a nozzle installed at the side of the reactor.
At this time, the internal temperature of the reactor was adjusted to 750 ℃ to 1,050 ℃. After the reaction was completed, the flue gas inside the reactor was sucked through the sampling tube, and the change in N ₂ O concentration was measured using a gas analyzer, and the results are shown in FIGS. 1 and 2.
As can be seen from FIGS. 1 and 2, it can be seen that the reducing solution preparation of Example 1 more effectively reduces the N ₂ O concentration at the reaction temperature of 750 ° C to 1,050 ° C.

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Reducing solution material according to the present invention is excellent in the NOx removal efficiency at 700 ℃ ~ 1,100 ℃, it is possible to obtain the effect of suppressing the production of N ₂ O. In addition, the reducing solution material of the present invention has the additional advantage of being economical and preventing environmental pollution because it is manufactured using livestock waste. Therefore, the reducing solution material of the present invention can be widely used as a reducing agent for NOx purification while suppressing the production of N ₂ O in various industrial facilities.

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Claims (2)

As a reducing solution for reducing NOx and suppressing N ₂ O production by using a selective non-catalytic reduction process, A reducing solution for inhibiting the production of nitrous oxide comprising 94% by weight of manure extract, 5% by weight of urea [(NH ₂ ) ₂ CO] and 1% by weight of NaOH. delete

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