KR101762922B1 - Regular Flow Adjustment Device and Method with Blade in DeNOx Facilities - Google Patents

Abstract

The present invention relates to a denitrification apparatus and an denitrification method in which an ammonia injection apparatus is installed, and more particularly, to a method and apparatus for minimizing the emission of NOx, which is a contaminant contained in combustion gases generated in a facility using fossil (solid, The present invention relates to a denitration facility and a method for calculating an optimum ammonia injection ratio through a CFD analysis and controlling the amount of ammonia corresponding to the calculated value through a variable damper.

Description

Technical Field [0001] The present invention relates to an apparatus and method for regulating the flow of ammonia and NOx in a denitrification plant,

The present invention relates to a denitrification apparatus and an denitrification method in which an ammonia injection apparatus is installed, and more particularly, to a method and apparatus for minimizing the emission of NOx, which is a contaminant contained in combustion gases generated in a facility using fossil (solid, The present invention relates to a denitrification facility used for the purpose

The analysis of the flow change inside the Duct due to the increase / decrease of the combustion gas amount according to the power fluctuation of the power plant is performed, and the actual flow is confirmed by measuring the flow velocity, NOx concentration and ammonia concentration in the duct, The present invention relates to an apparatus and method for denitrating NOx and NH3 that adjusts the ratio of NOx and NH3 at all times by adjusting the variable value at all times even if a change occurs in the internal flow due to the change in output, .

Generally, when a combustion material is burned in a combustion apparatus such as a trash incinerator or a large boiler, organic nitrogen in the combustion material reacts with oxygen, and nitrogen oxides such as NO, NO2, and NO3, which are commonly referred to as NOx, are produced. The above-mentioned nitrogen oxides are typical air pollutants and cause pollution problems such as causing acid rain when they are released into the air.

Such as waste incinerators, large boilers, and engines, are strictly regulated by laws and regulations in relation to the emission of nitrogen oxides. Therefore, it is common that means for removing nitrogen oxides are provided in the flue gas exhaust system.

SCR (Selective Catalytic Reduction), which is one of techniques for reducing nitrogen oxides in combustion gases, is one of the technologies for reducing nitrogen oxides in combustion gases. In the catalyst, a reducing agent such as NH3, CO, hydrocarbons Is used to convert NOx to N2. The SCR is classified into a hydrocarbon reaction method and an ammonia reaction method depending on a reducing agent. The ammonia reaction method is a method in which ammonia is injected into a combustion gas and a combustion gas in which ammonia is mixed is passed through a catalytic reactor to cause nitrogen oxides to react with ammonia to turn into nitrogen gas and steam. An example of the chemical reaction formula of nitrogen compound and ammonia is as follows.

4NO + 4NH3 + O2? 4N2 + 6H2O

6NO + 4NH3? 5N2 + 6H2O

4NO + NO2 + 2NH3? 2N2 + 3H2O

6NO2 + 8NH3? 7N2 + 12H2O

The above reaction converts NOx into harmless N2.

A technique relating to an apparatus for removing nitrogen oxide from a combustion gas has been proposed in Korean Patent No. 0899105 (ammonia tuning method applied to a flue gas exhaust apparatus, hereinafter referred to as prior art).

The above-mentioned prior art relates to a technique for removing nitrogen oxides (NOx) by adding an appropriate amount of ammonia to a combustion gas discharged from a large combustion facility such as a waste incinerator or a boiler of a power plant, , A flow rate measurement unit, an ammonia injection unit, a catalyst reaction layer, and a downstream gas measurement unit to decompose NOx in the exhaust gas into nitrogen and water.

In the prior art, a separate regulating valve was further needed to optimally control the amount of ammonia injected into the large flue for discharging flue gas to effectively remove nitrogen oxides in the flue gas without leaving excess ammonia In addition to the inconvenience of the user having to manage the regulating valve to obtain the optimum amount of ammonia, the power plant does not always operate at a constant output (constant exhaust gas volume) but the output varies from time to time, The change of the flow field occurs due to the change. As the ratio of NOx and ammonia is changed, unreacted ammonia flows out to the downstream of the denitration facility, which causes clogging and corrosion of the equipment located in the downstream portion.

Korean Patent No. 0899105 (ammonia tuning method applied to flue gas exhaust apparatus)

As described above, since the flow rate of the combustion gas discharged from the combustion gas duct of the large-sized combustion apparatus is not fast, the combustion gas flowing through the inside of the duct is not well mixed with each other, There is a problem that the flow rate is changed when the output is changed and the ratio of NOx to ammonia is not always constant.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above, and it is an object of the present invention to provide a fluid flow analysis program (CFD) which compares the analysis result with a measured actual flow, The ratio of ammonia and nitrogen oxide concentration is constantly controlled through variable viscosity.

The present invention relates to a denitration facility 1000 for denitrifying NOx contained in a combustion gas and includes a duct 100 in which a combustion gas A flows and a bent portion 120 is formed in an intermediate portion of the duct 100, An inlet 200 formed at the front end of the duct 100 for injecting the combustion gas A from the outside and an inlet 200 formed at the middle of the duct 100 for supplying ammonia B to the combustion gas A injected through the inlet 200 A variable wool 500 formed in the bent portion 120 and operated under the control of the control unit 400 and an outlet 700 formed at the lower end of the duct 100 .

The control unit 400 controls the angle of the variable wing 500 by measuring and comparing the analysis result with actual flow and concentration and the duct 100 controls the flow of the combustion gas A and the ammonia B, And a plurality of fixed wings 600 for uniforming the wings.

The control unit 400 includes a flow measuring unit for measuring the flow of the combustion gas A and the ammonia B, and a concentration measuring unit for measuring the concentration.

(EN) Disclosed is a method of denitrifying a NOx contained in a combustion gas in a denitration facility using denitrification in a denitration facility. The method includes the steps of injecting a combustion gas from the outside (S1), ammonia (S3) for measuring the concentration of NOx and ammonia in the combustion gas, a CFD analysis step (S4) for analyzing an internal flow at an initial set condition, a flow obtained from the CFD analysis step (S6) in which the mixed gas of which the concentration is controlled by the variable chemistry is chemically reacted (S6), and the gas which has been reacted is discharged to the outside And a discharging step S7.

If the concentrations of ammonia and NOx are not the same, ammonia that has not reacted with NOx flows out to the downstream portion and reacts with other compounds contained in the combustion gas to produce a new ammonia compound having adherence and corrosiveness. Will cause clogging of equipment (Duct, AH, etc.) and corrosion on equipment structures.

The denitration facility according to an embodiment of the present invention maintains the concentration of NOx contained in the combustion gas and the concentration of ammonia injected at the same ratio to prevent the ammonia from reacting with other compounds contained in the combustion gas, Or corrosion can be prevented. In addition, by preventing the clogging or corrosion of the equipment, it is possible to prevent the entire facility from being stopped or the loss caused by not operating the equipment in advance.

1 is a perspective view of a denitration facility according to an embodiment of the present invention;
2 is a cross-sectional view of a denitration facility in accordance with an embodiment of the present invention.
3 is a cross-sectional view illustrating operation of a variable wing in a denitration plant according to an embodiment of the present invention.
4 is a cross-sectional view illustrating the flow of gas in a denitration facility according to one embodiment of the present invention.
5 is a flowchart showing a denitrification process in a denitration plant according to an embodiment of the present invention.

Hereinafter, the technical idea of the present invention will be described more specifically with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It should be understood that variations can be made.

Hereinafter, the technical idea of the present invention will be described more specifically with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the technical concept of the present invention, are incorporated in and constitute a part of the specification, and are not intended to limit the scope of the present invention.

The present invention relates to a denitration facility (1000) in which ammonia (B) is injected to minimize NOx emissions, which are pollutants contained in combustion gas (A) generated in facilities using fossil fuels such as power plants.

The denitrification apparatus 1000 according to an embodiment of the present invention calculates an optimum flow design value using a CFD program and compares the measured flow design value with the actually measured value to calculate NOx and ammonia B using the variable wing 500. [ The concentration ratio of < / RTI > And to prevent clogging or corrosion of the denitration facility 1000 caused by the ammonia (B) compound generated when the ratio is not constant.

FIG. 1 is a perspective view of a denitration facility 1000 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a denitration facility according to an embodiment of the present invention. 1 and 2, the denitration facility according to an embodiment of the present invention will be described in more detail.

Referring to FIGS. 1 and 2, a denitration facility 1000 according to an embodiment of the present invention has a shape of a duct 100, and a bent portion 120 is formed in a middle of the duct 100.

An injection port 200 is formed in the front end of the duct 100 for injecting combustion gas A generated in a facility using fossil fuel into the duct 100. The combustion gas A generated in the external facility is introduced into the duct 100 through the injection port 200. [

The injection port 200 is preferably formed of an appropriate material that does not react with NOx, and is a tube into which a combustion gas A, i.e., a combustion gas A containing NOx is injected.

The combustion gas A flowing through the injection port 200 flows inside the duct 100 and moves to the bent portion 120.

In the duct 100, an ammonia supply unit 300 is formed in the middle. The ammonia supply unit 300 is for artificially injecting ammonia (B) gas to minimize the discharge of NOx contained in the combustion gas A to thereby remove NOx. Since NOx in the combustion gas (A) affects environmental pollution as a contaminant, it is important to remove NOx. In order to remove NOx, it is reacted with ammonia (B) to produce another substance, that is, a harmless substance.

The combustion gas A injected into the injection port 200 flows along the duct 100 and is mixed with the ammonia B supplied from the ammonia supply unit 300 formed in the middle of the duct 100. NOx and ammonia in the combustion gas do not normally react with each other but react with each other through a catalyst. This process occurs in the catalyst processing unit 800 described later. The catalyst processing unit 800 will be described later. In addition, when the ammonia (B) is injected through the ammonia supply part 300, it is appropriate to inject it into the gaseous state.

The reaction formula when the NOx in the combustion gas (A) reacts with the ammonia (B) injected by the catalyst is as follows.

1) 4NO + 4NH3 + O2? 4N2 + 6H2O

2) 6NO + 4NH3? 5N2 + 6H2O

3) 4NO + NO2 + 2NH3? 2N2 + 3H2O

4) 6NO2 + 8NH3? 7N2 + 12H2O

1) reacts with four molecules of ammonia (B) gas injected with four molecules of NO (nitrogen monoxide) contained in the combustion gas A and one molecule of oxygen inside the duct 100 to form a nitrogen gas N2, 4 molecule and water vapor (H2O) 6 molecule.

2) shows a reaction formula in which six NO molecules (nitrogen monoxide) contained in the combustion gas (A) react with four injected ammonia (B) gas molecules to generate five nitrogen gas molecules and six water vapor molecules will be.

3) reacts with two molecules of ammonia (B) gas injected with four molecules of NO (nitrogen monoxide) and four molecules of NO2 (nitrogen dioxide) contained in the combustion gas (A) to form two molecules of nitrogen gas (N2) (H2O) < / RTI >

4) reacts with 8 molecules of ammonia (B) gas injected with 6 molecules of NO2 (nitrogen dioxide) contained in the combustion gas (A) to generate 7 molecules of nitrogen (N2) gas and 12 molecules of water vapor (H2O) Lt; / RTI >

When NOx in the combustion gas (A) is reacted with ammonia (B) gas at a constant rate as described in the above reaction formula, no remaining ammonia (B) remains after the reaction, that is, unreacted ammonia (B). It is important that the reaction is carried out at a constant rate so as not to cause unreacted ammonia (B). This is because, when the unreacted ammonia (B) is present, it reacts with other compounds contained in the combustion gas (A) to create a new material, clogs the facility, or causes corrosion, .

In order to prevent the unreacted ammonia B from being generated by reacting the combustion gas A injected from the injection port 200 with the ammonia B supplied through the ammonia supply unit 300, The program calculates the ideal flow of each gas.

CFD program is a computational Fluid Dynamics (CFD) program that combines fluid dynamics and numerical analysis to obtain an approximate solution to nonlinear partial differential equations that are difficult to solve mathematically. The denitrification system according to an embodiment of the present invention analyzes the characteristics of the flow and predicts an optimal design using one of the fields of CFD (CFD), which is a field of code application.

In this case, the most effective position is found by using the simulation using the CFD, since the variable cost is installed in various positions in the variable position.

CFD is able to know the flow (flow rate, chemical species) at each site by creating drawings of the same size as the existing denitrification equipment and entering the flow conditions after forming the grid. However, since CFD is a calculated result, it is necessary to compare the analytical result with the actual measurement result in order to improve the accuracy, and to select the most appropriate calculation formula or coefficients in which the deviation occurs, It will fit.

 The next step is to create a drawing that includes the variable interest at the location where the variable interest is expected to be appropriate, and find the most appropriate variable wise installation location by repeating the calculation.

That is, after calculating the reaction ratio condition for the optimal reaction between NOx and ammonia (B) in the combustion gas (A) through the CFD, the flow of the actually measured combustion gas (A) and ammonia (B) Lt; / RTI > That is, the flow of the combustion gas (A) and ammonia (B) is finely adjusted by providing the variable wing (500). The variable wing 500 will be described later.

A flow measuring unit (not shown), a concentration measuring unit 900, and a variable wing 500 are provided in the duct 100.

The flow measuring unit (not shown) and the concentration measuring unit 900 are provided to measure the concentration and the flow for each section.

The flow measuring unit is for measuring the flow of combustion gas A and ammonia B flowing in the duct 100 and may be formed anywhere in the duct 100. That is, the flow of the combustion gas A and the ammonia B is measured and the measured value is transmitted to the controller 400. The controller 400 controls the variable wing 500 according to the measured flow So as to have a flow for an appropriate reaction.

The concentration measuring unit 900 is for measuring the concentration of the combustion gas A and the ammonia B and may be formed anywhere inside the duct 100. For example, they may be formed at the front end, the middle end, and the end end of the duct 100, respectively, and may be disposed in another appropriate space to measure the concentrations of the combustion gas (A) and ammonia (B). Although the duct 100 according to an embodiment of the present invention is shown to have one concentration measuring unit 900 at each of the front end, the middle end, and the end end, the present invention is not limited thereto. .

3 is a cross-sectional view illustrating the operation of the variable wing 500 in the denitration facility 1000 according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating the flow of gas in the denitration facility according to an embodiment of the present invention . 3 and 4, the variable wing 500 is configured such that the NOx in the combustion gas A injected through the injection port 200 and the ammonia B supplied through the ammonia supply unit 300 react It plays a role of fine control of the flow in order to make the ammonia (B) unreacted react completely and does not occur.

The NOx and ammonia (B) contained in the combustion gas (A) are measured by the flow measuring unit, and the variable flow rate (500) is measured to match the calculated value for the existing calculated complete reaction .

That is, by controlling the flow of the combustion gas (A) and the ammonia (B) by changing the rotation or the angle of the variable wing (500), the flow of NOx contained in the combustion gas (A) , Is adjusted to match the flow conditions for the complete reaction calculated by CFD, thereby making it possible to minimize unreacted ammonia (B).

It is also possible that the variable wing 500 is manually adjusted by the user, and that the variable wing 500 is automatically adjusted by the control unit 400.

At the end of the duct 100, a fixed blade 600, a catalyst processing unit 800, and an outlet 700 are formed.

The fixed wing 600 is provided to uniformize the flow, and serves to once again control the flow adjusted by the variable wing 500. That is, the NOx and ammonia (B) in the combustion gas (A) adjusted by the variable wing (500) are controlled to have more accurate flow.

The catalytic treatment unit 800 is the same as that used in a conventional denitrification facility, and is a place where ammonia (B) with a constant flow is chemically reacted with NOx to decompose into N2 gas and water vapor. The catalyst treatment unit 800 is a well known technique used in a normal denitrification facility, and a description thereof is omitted here.

The outlet 700 is formed at the end of the duct 100 where the N2 gas and the water vapor C which are harmless gases generated by the denitration treatment in the catalyst treatment unit 800 are discharged to the outside.

FIG. 5 is a flowchart illustrating a denitration process in the denitration facility 1000 according to an embodiment of the present invention. Referring to FIG. 5, a denitration process of the denitration facility 1000 according to an embodiment of the present invention will be described.

The denitration method of the combustion gas shown in FIG. 5 includes a combustion gas injection step S1, an ammonia injection step S2, a measurement step S3, a CFD analysis step S4, a variable lift operation step S5, A gas reaction step (S6) and a discharge step (S7).

The combustion gas injecting step S1 injects the combustion gas A from the outside and injects the NOx contained in the combustion gas A into the duct 100. [

The step of injecting ammonia (S2) is a step of injecting ammonia (B) necessary for denitrifying NOx in the combustion gas (A).

The measuring step S3 is a step of measuring the concentration and the flow of NOx and ammonia B in the combustion gas A and measuring at least one of the concentration measuring part 900 and the flow measuring part 900 provided in the duct 100, It is measured by a measuring part.

The CFD analysis step S4 is a step of comparing the measured value in the measurement step S3 with a previously calculated value using a CFD program (fluid flow analysis program). That is, it is possible to check whether the NOx and ammonia should be controlled to react at a predetermined reaction ratio, by comparing the pre-calculated value with the measured value at the denitration facility.

The variable lift operation step S5 is a step of adjusting the variable lift on the basis of the information compared in the CFD analysis step S4. The variable lift can be automatically operated, and a separate adjustment part (not shown) It is also possible to adjust manually.

In the mixed gas reaction step S6, the NOx and ammonia, whose flow is controlled by the variable wool 500, are regulated once again through the fixed wing 600, and then are transferred to the catalyst processing unit 800 and converted into N2 and steam , Where the denitrified gas is generated.

The discharging step S7 is a step in which the denitrification reaction is terminated and the generated N2 and water vapor C are discharged to the outside.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1000: Denitrification facility
100: duct
120: Bend
200: inlet
300: ammonia supply unit
400:
500: variable yield
600: Fixed wing
700: outlet
800: catalyst processing section
900: concentration measuring unit
A: Combustion gas containing NOx
B: ammonia
C: N2, H2O (nitrogen gas, water vapor)

Claims (5)

In the denitration facility (1000) for denitrifying NOx contained in the combustion gas,
A duct (100) in which a combustion gas (A) flows and in which a bent portion (120) is formed;
An inlet (200) formed at the front end of the duct (100) and through which the combustion gas (A) is injected from the outside;
An ammonia supply unit 300 formed in the middle of the duct 100 for supplying ammonia B to the combustion gas A injected through the injection hole 200;
The control unit 400 controls the flow of the combustion gas A and the ammonia B by rotating or changing the angle by controlling the rotation of the bending unit 120 by 360 degrees, A variable wing 500 that adjusts and operates to be equal to a calculated value;
A fixed blade (600) for once again controlling the flow adjusted by the variable wing; And
An outlet 700 formed at the lower end of the duct 100;
And a control unit for controlling the flow of the denitrification equipment.
The apparatus of claim 1, wherein the controller (400)
Wherein the angle of the variable wing (500) is controlled by comparing the analysis result with an actual flow.
The duct (100) according to claim 1, wherein the duct
And a plurality of fixed wings (600) for uniformizing the flow of the combustion gas (A) and the ammonia (B).
The apparatus of claim 1, wherein the controller (400)
A flow measuring unit for measuring the flow of the combustion gas (A) and the ammonia (B), and a concentration measuring unit for measuring the concentration.
A method for denitrification using NOx in a denitration facility for denitrating NOx contained in combustion gas,
A combustion gas injection step (S1) in which combustion gas is injected from the outside;
An ammonia injecting step (S2) of injecting ammonia to denit NOx in the combustion gas;
A measurement step (S3) of measuring the concentration of NOx and ammonia in the combustion gas;
A CFD analysis step (S4) of analyzing an internal flow at an initially set condition;
A variable widening operation step S5 of adjusting the variable wing based on the flow analysis result obtained from the CFD analysis step;
A mixed gas reaction step (S6) in which the NOx and ammonia, whose flow is controlled by the variable wing, are regulated again through the fixed wicks, and then moved to the catalytic processing part and chemically reacted; And
A discharge step (S7) in which the reacted gas is discharged to the outside;
Wherein the denitration treatment apparatus comprises:

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