KR102347814B1 - Vaporizer for selective catalytic reduction denitrification system for power generation - Google Patents

Abstract

The present invention relates to a vaporization chamber, a urea water injection unit supplying urea water from an upper portion of the vaporization chamber, an exhaust gas inlet connected to the upper side of the vaporization chamber into which exhaust gas flows, and the exhaust gas flowing in connected to the exhaust gas inlet Selective catalytic reduction denitration facility for power generation comprising an exhaust gas heating unit for heating gas to a preset temperature, an exhaust gas outlet disposed below the vaporization chamber through which exhaust gas flows, and a sediment discharge unit disposed below the vaporization chamber provide a vaporizer.

Description

Vaporizer for selective catalytic reduction denitrification system for power generation

The embodiment relates to a vaporizer for a selective catalytic reduction denitrification facility for power generation. More particularly, it relates to a vaporizer for a selective catalytic reduction denitration facility for power generation for changing the structure of the vaporizer and increasing the vaporization efficiency.

The exhaust gas emitted through the process of obtaining heat and power by burning fossil fuels inevitably contains NOx components (nitrogen oxides), which have been found to be the causative substances of photo smog, acid rain, and respiratory diseases. In response to this, selective catalytic reduction in which ammonia is used as a reducing agent to decompose nitrogen and water so that NOx components do not affect the human body is being used in various ways.

The conventional exhaust gas denitration apparatus uses a selective catalytic reduction method for denitrifying NOx components in exhaust gas using ammonia water dissolved in a storage tank as a reducing agent. However, ammonia is classified as a substance harmful to the human body because it has a toxic odor and a stimulant odor, and a conventional device using such ammonia uses a high-pressure gas pressure vessel as a storage tank for the management of ammonia, To be additionally equipped with ammonia treatment safety facilities such as an ammonia detector to detect ammonia leakage, a storage tank shower to clean the leaked ammonia, and a tank to dissolve the gas generated in the storage tank in water and treat it with wastewater. Therefore, there is a problem that not only high technology is required, but also high cost and a lot of time are required to construct the facility, and above all, when leaking, there is a problem that it has a harmful effect on the human body.

In order to solve the above problems, the conventional denitrification device does not use ammonia water but uses urea water dissolved in a storage tank to inject the urea water into the exhaust gas flow through the injection nozzle, After changing the urea water into vapor phase ammonia, the NOx component is denitrified using the catalyst inside the reactor to obtain the optimum denitrification efficiency and to effectively prevent environmental pollution due to the NOx component or ammonia.

However, there is a problem in that the generator is stopped due to the accumulation of sediment in the process of changing the urea water to ammonia, and there is a problem in that the operation must be stopped to remove the accumulated sediment.

Republic of Korea Patent Registration No. 10-0788982.

The embodiment aims to minimize the generation of deposits during the reaction of urea water in a vaporizer for a selective catalytic reduction denitration facility.

In addition, it aims to improve the urea-ammonia conversion rate of the vaporizer and the homogeneity of the ammonia concentration distribution.

In addition, it aims to prevent clogging by accumulating deposits in the lower part of the carburetor.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned here will be clearly understood by those skilled in the art from the following description.

An embodiment of the present invention, the vaporization chamber; a urea water injection unit supplying urea water from the upper part of the vaporization chamber; an exhaust gas inlet connected to an upper side of the vaporization chamber into which exhaust gas is introduced; an exhaust gas heating unit connected to the exhaust gas inlet and heating the introduced exhaust gas to a preset temperature; an exhaust gas outlet disposed below the vaporization chamber through which exhaust gas flows; and a sediment discharge unit disposed under the vaporization chamber.

Preferably, the exhaust gas heating unit controls a moving pipe through which the exhaust gas moves and a heating unit is disposed, a control valve disposed in one region of the moving pipe, a bypass line connected to one side of the control valve, and the temperature of the exhaust gas. It may include a temperature sensor to detect, and a control unit for opening and closing the control valve using the sensing information of the temperature sensor.

Preferably, the control unit may move the exhaust gas to the bypass line when the temperature of the exhaust gas sensed by the temperature sensor is 300° C. or higher.

Preferably, when the temperature of the exhaust gas sensed by the temperature sensor is less than 300 ℃, the control unit may be characterized in that it moves the exhaust gas to the heating unit.

Preferably, the heating unit may be characterized in that an electric heating device is used.

Preferably, the heating unit may be characterized in that a tube heater is used.

Preferably, the cross-sectional area of the moving pipe in which the heating unit is installed may be set to be larger than the cross-sectional area of the general moving pipe.

Preferably, the urea water spray unit may be characterized in that the spray angle is 90 degrees or more when the liquid is sprayed.

Preferably, the urea water injection unit may be characterized in that the diffusion angle is 30 degrees or more when the gas is injected.

Preferably, the sediment discharge unit may be characterized in that a plurality of on-off valves are provided.

Preferably, the plurality of on-off valves may be sequentially opened and closed.

Preferably, the plurality of on-off valves may be automatically opened and closed when a preset time comes.

Preferably, the cross section of the moving pipe in which the heating unit is installed may be characterized in that it has a rectangular cross section.

The control valve includes a first control valve and a second control valve, wherein the first control valve is disposed on the inlet side of the heating unit, and the second control valve is disposed on the bypass line. Vaporizer for selective catalytic reduction denitrification facility.

According to the embodiment, the sediment at the bottom of the carburetor is solidified to prevent the generator from being stopped due to clogging, thereby enabling stable facility operation.

In addition, maintenance is facilitated through efficient reaction and discharge, and additional work such as emergency recovery does not occur.

In addition, it is possible to reduce the possibility of loss of unplanned maintenance of the generator due to the occurrence of clogging.

Various and advantageous advantages and effects of the present invention are not limited to the above, and will be more easily understood in the course of describing specific embodiments of the present invention.

1 is a view showing a schematic diagram of a selective catalytic reduction denitration facility system for power generation;
2 is a view showing the structure of a vaporizer for a selective catalytic reduction denitration facility for power generation according to an embodiment of the present invention;
3 is a view showing the structure of the exhaust gas heating unit, which is a component of FIG. 2,
4 is a view showing the degree of evaporation of urea water according to the exhaust gas temperature in FIG. 2,
5 is a view showing the ammonia conversion rate and the mixing degree according to the injection angle of the urea water injection unit in FIG. 2;
FIG. 6 is a view showing a cross section of the heating unit of FIG. 2 .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of the components may be selected between the embodiments. It can be combined and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those of ordinary skill in the art to which the present invention belongs, unless specifically defined and described explicitly. It may be interpreted as a meaning, and generally used terms such as terms defined in advance may be interpreted in consideration of the contextual meaning of the related art.

In addition, the terminology used in the embodiments of the present invention is for describing the embodiments and is not intended to limit the present invention.

In this specification, the singular form may also include the plural form unless otherwise specified in the phrase, and when it is described as “at least one (or more than one) of A and (and) B, C”, it is combined with A, B, and C It may include one or more of all possible combinations.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

These terms are only for distinguishing the component from other components, and are not limited to the essence, order, or order of the component by the term.

And, when it is described that a component is 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also with the component It may also include a case of 'connected', 'coupled' or 'connected' due to another element between the other elements.

In addition, when it is described as being formed or disposed on “above (above) or under (below)” of each component, the top (above) or bottom (below) is one as well as when two components are in direct contact with each other. Also includes a case in which another component as described above is formed or disposed between two components. In addition, when expressed as “upper (upper) or lower (lower)”, the meaning of not only the upward direction but also the downward direction based on one component may be included.

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components are given the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted.

1 to 6, in order to clearly understand the present invention conceptually, only the main characteristic parts are clearly shown, and as a result, various modifications of the illustration are expected, and the scope of the present invention is limited by the specific shape shown in the drawings it doesn't have to be

1 is a view showing a schematic diagram of a selective catalytic reduction denitration facility system for power generation.

1, in the selective catalytic reduction denitration facility system for power generation, the exhaust gas discharged from the exhaust gas discharge unit moves for denitration.

The exhaust gas discharge unit refers to a power generation facility that discharges exhaust gas. Among the air pollutants generated during the incineration of solid materials and fossil fuels such as coal-fired power plants, BC oil, and LNG used in power generation facilities, the most important materials to be removed are sulfur oxides (SOx), nitrogen oxides (NOx) and dust. This is being regulated through the Seoul Metropolitan Area Air Pollutant Emission Allowance System.

Among air pollutants, nitrogen oxides (NOx) are mainly emitted from mobile pollutants such as automobile exhaust gas and fixed pollutants such as power plants and industrial combustion facilities. are installing

The selective catalytic reduction (SCR) method used in the present invention injects ammonia or urea into the exhaust gas, mixes it with air or steam, and passes it through the catalyst bed of the reactor operated at 200 to 400 ° C to reduce NOx. It is a technology to convert nitrogen and water by reduction, and the main reactions are as follows.

4NO + 4NH3 + O2 → 4N2 + 6H2O

NO + NO2 + 3NH3 → 2N2 + 3H2O

In the case of using such a selective catalytic reduction method, ammonia is generated inside the vaporizer using urea water, and the generated ammonia is injected into the reactor to react with the exhaust gas to remove nitrogen.

In the present invention, the exhaust gas discharged from the exhaust gas discharge unit is partially supplied to the vaporization chamber 100 through an exhaust gas blower, and a part moves to the ammonia inlet and moves to the reactor with ammonia supplied from the vaporization chamber 100. nitrogen will be removed.

2 is a view showing the structure of a vaporizer for a selective catalytic reduction and denitration facility for power generation according to an embodiment of the present invention, and FIG. 3 is a view showing the structure of the exhaust gas heating unit 400 which is a component of FIG. 4 is a view showing the degree of evaporation of urea water according to the exhaust gas temperature in FIG. 2, FIG. 5 is a view showing the ammonia conversion rate and the mixing degree according to the injection angle of the urea water injection unit 200 in FIG. 2, FIG. is a view showing a cross section of the heating unit 411 of FIG. 2 .

2 to 6, the vaporizer 1 for a selective catalytic reduction denitration facility for power generation according to an embodiment of the present invention is a vaporization chamber 100, a urea water injection unit 200, an exhaust gas inlet unit 300 , may include an exhaust gas heating unit 400 , an exhaust gas outlet 500 , and a sediment discharge unit 600 .

The vaporization chamber 100 may react with the exhaust gas and urea water to generate ammonia, and discharge the generated ammonia. The urea water injection unit 200 may be connected to the upper portion of the vaporization chamber 100 , the exhaust gas inlet 300 may be connected to the upper side, and the exhaust gas outlet 500 may be connected to the lower side of the vaporization chamber 100 .

The bottom surface of the vaporization chamber 100 may have a funnel structure inclined toward the center. A sediment discharge unit 600 may be connected to the center of the bottom surface of the vaporization chamber 100 .

The shape of the vaporization chamber 100 is not limited, but it is preferable to have a cylindrical structure so that the inflowing exhaust gas and the urea water are mixed in the trajectory of the cyclone-type swirling flow.

The urea water injection unit 200 may be disposed on the vaporization chamber 100 to spray the urea water toward the bottom surface. Referring to FIGS. 2 and 5 in parallel, the urea water injection unit 200 is UC (Urea Conversion ratio) according to the injection angle when spraying at a preset temperature (in FIG. 5, 300° C. is a preset temperature) and You can check the amount of change in UI (Uniformity Index).

As shown in FIG. 5 , UC maintains a high and constant value of about 95-96% regardless of the change in the droplet spraying angle (gas nozzle diffusion angle). However, UI can maintain a high level of 83-87% or 76-79% when the liquid spray angle is maintained at 90 degrees or more and the gas nozzle diffusion angle is maintained at 30 degrees or more.

Therefore, in the present invention, it is possible to help improve the performance of the vaporizer by adjusting the angle of the urea water sprayed from the urea water injection unit 200 .

The exhaust gas inlet 300 may be connected to the upper side of the vaporization chamber 100 to introduce exhaust gas. The exhaust gas inlet 300 may be disposed so that exhaust gas flows from the upper side of the vaporization chamber 100 to the sidewall. This is to allow the incoming exhaust gas to be mixed with the urea water while rotating in the trajectory of the cyclone-type swirling flow. The shape of the exhaust gas inlet 300 is not limited and may be deformed into various shapes.

The exhaust gas heating unit 400 may be connected to the exhaust gas inlet 300 to heat the inflowing exhaust gas to a preset temperature.

The exhaust gas heating unit 400 may include a moving pipe 410 , a control valve 420 , a bypass line 430 , a temperature sensor 440 , and a control unit 450 .

In the moving pipe 410 , exhaust gas moves and a heating unit 411 may be disposed. The moving pipe 410 provides a passage through which the exhaust gas supplied through the exhaust gas blower can move to the carburetor.

The control valve 420 may be disposed in one region of the moving pipe 410 to control the movement direction of the exhaust gas. The control valve 420 may allow the exhaust gas to directly flow into the vaporization chamber 100 through the heating unit 411 or the bypass line 430 according to the temperature of the exhaust gas. In one embodiment, the control valve 420 includes a first control valve 421 and a second control valve 422, the first control valve 421 is the inlet side of the heating unit 411, the second The second control valve 422 may be disposed on the bypass line 430 . The control unit 450 may control the opening and closing of each of the first control valve 421 and the second control valve 422 to adjust the direction in which the exhaust gas flows.

The bypass line 430 is connected to branch from the control valve 420 , and exhaust gas may move according to the control of the control valve 420 .

The temperature sensor 440 may be installed in one area of the moving pipe 410 to measure the temperature of the moving exhaust gas. In an embodiment, the temperature sensor 440 may be installed on the inlet side of the bypass line 430 to measure the temperature of the exhaust gas.

The controller 450 may set the movement direction of the exhaust gas by opening and closing the control valve 420 using the detection information of the temperature sensor 440 .

Basically, the exhaust gas is discharged at a high temperature. However, the power plant is restarted after stopping, or in the case of initial operation, the temperature falls below the reference temperature.

Referring to FIG. 4 , UC, UI, and urea deposition rate according to changes in exhaust gas temperature are shown. UC maintains a high and constant value of about 95-96% when the exhaust gas temperature is 225 °C or higher, but it can be seen that UC decreases rapidly when the temperature is lowered to 225 °C or lower. However, UI maintains a value of 82-87% without significant change with the increase of exhaust gas temperature.

In addition, it can be seen that the urea deposition rate decreases rapidly as the exhaust gas temperature increases, and the deposition rate approaches almost zero when the exhaust gas temperature is 300°C.

Accordingly, the exhaust gas heating unit 400 may increase the efficiency of the vaporizer by heating the exhaust gas according to the temperature of the exhaust gas introduced thereto.

In addition, the heating unit 411 may be an electronic heating device. In the case of using a commonly used fin-tube heater, dust may accumulate in the fin area and plugging may occur. This not only reduces the heat transfer efficiency, but also poses a risk of fire. Therefore, in the present invention, the heating unit 411 may be a tube heater 411a.

In addition, the cross-sectional area of the moving pipe 410 in which the heating unit 411 is disposed may be set to be larger than the cross-sectional area of the general moving pipe 410 . The above-mentioned tube heater 411a heats the exhaust gas in a convection transfer manner. In this case, pressure loss may occur. In the present invention, the cross-sectional area of the pipe can be enlarged to prevent such pressure loss.

In one embodiment, the cross section of the moving pipe 410 in which the heating unit 411 is installed may be provided in a rectangular shape. Through this, the installation of the plurality of tube heaters 411a can be facilitated, and the heat transfer effect can be increased.

The exhaust gas outlet 500 is disposed below the vaporization chamber 100 so that the exhaust gas may flow out. At this time, the exhaust gas reacted with the urea water may move to the ammonia injection unit.

The sediment discharge unit 600 is installed on the bottom surface of the vaporization chamber 100 so that the sediment deposited thereunder can be discharged. It is isocyanic acid generated by incomplete conversion of urea water into ammonia by spraying urea water at a low temperature.

In the present invention, the sediment arranging unit may be disposed in one pipe connected to the central portion of the inclined floor, and a plurality of on/off valves 610 may be provided. The plurality of opening/closing valves 610 may be controlled to automatically open or close according to whether a timer or the exhaust gas heating unit 400 operates.

The sediment existing in the liquid phase due to the temperature inside the vaporization chamber 100 can be opened and closed sequentially even while the vaporizer is in operation to stably discharge the sediment. can

As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions are possible within the range that does not depart from the essential characteristics of the present invention by those of ordinary skill in the art to which the present invention pertains. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are for explaining, not limiting, the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments and the accompanying drawings . The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: vaporization chamber
200 ; Urea water supply part
300: exhaust gas inlet
400: exhaust gas heating unit
410: moving pipe
411a: tube heater
411: heating part
420: control valve
430: bypass line
440: temperature sensor
450: control unit
500: exhaust gas outlet
600: sediment discharge unit
610: on-off valve

Claims (14)

vaporization chamber;
a urea water injection unit supplying urea water from the upper part of the vaporization chamber;
an exhaust gas inlet connected to an upper side of the vaporization chamber into which exhaust gas is introduced;
an exhaust gas heating unit connected to the exhaust gas inlet and heating the introduced exhaust gas to a preset temperature;
an exhaust gas outlet disposed below the vaporization chamber through which exhaust gas flows; and
a sediment discharge unit disposed under the vaporization chamber;
includes,
An electric heating device is used for the heating unit, and the heating unit is provided with a plurality of tube heaters,
The cross-sectional area of the moving pipe in which the heating unit is installed is set to be larger than the cross-sectional area of the general moving pipe,
The urea water injection unit has a spray angle of 90 degrees or more when liquid is sprayed, or a diffusion angle of 30 degrees or more when gas is sprayed,
The sediment discharge unit is provided with a plurality of on-off valves in one pipe, and the carburetor for selective catalytic reduction denitration facility for power generation, characterized in that the opening and closing proceeds sequentially. According to claim 1,
The exhaust gas heating unit
A moving pipe in which the exhaust gas moves and the heating part is disposed,
A control valve disposed in one area of the moving pipe,
a bypass line connected to one side of the control valve;
a temperature sensor for sensing the temperature of the exhaust gas; and
A vaporizer for a selective catalytic reduction denitration facility for power generation including a control unit for opening and closing a control valve using the sensing information of the temperature sensor. 3. The method of claim 2,
The control unit carburetor for selective catalytic reduction denitration facility for power generation, characterized in that for moving the exhaust gas to the bypass line when the temperature of the exhaust gas sensed by the temperature sensor is 300 ℃ or more. 3. The method of claim 2,
The control unit carburetor for selective catalytic reduction denitration facility for power generation, characterized in that for moving the exhaust gas to the heating unit when the temperature of the exhaust gas sensed by the temperature sensor is less than 300 ℃ delete delete delete delete delete delete delete According to claim 1,
The plurality of on/off valves are automatically opened and closed when a preset time is reached. According to claim 1,
A vaporizer for selective catalytic reduction denitration facility for power generation, characterized in that the cross section of the moving pipe in which the heating unit is installed has a rectangular cross section. 3. The method of claim 2,
The control valve includes a first control valve and a second control valve,
The first control valve is the inlet side of the heating unit, the second control valve is a vaporizer for a selective catalytic reduction denitration facility for power generation, characterized in that disposed on the bypass line.

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