Reductant injection boiler for reducing nitrogen oxide (NOX) emissions

Abstract

A reductant injection boiler for reducing the nitrogen oxides (NOx) emissions, according to the present invention, comprises: a combustion furnace in which fuel is combusted; an initial supply unit which is provided at an inlet end of the combustion furnace, and which supplies the fuel to the combustion furnace; a start-up burner which is spaced from the initial supply unit along the long axis of the combustion furnace and which supplies the fuel to the combustion furnace; a sensing unit for measuring the concentration of nitrogen oxides inside the combustion furnace; and a control unit, which controls the initial supply unit and / or the start-up burner such that a reductant is supplied to the inside of the combustion furnace, if the concentration of the nitrogen oxides is greater than or equal to a supply reference value.

Description

Reducing agent injection boiler to reduce nitrogen oxide emissions

[0001] The present invention relates to a reducing agent injection boiler for reducing nitrogen oxide emissions from a thermal power generation boiler.

[0002] Thermal power generation is used as one of the methods for generating energy for various purposes. According to this, steam generated through combustion of fuel for power generation passes through a turbine, generating rotational force, and this rotational force drives a generator to generate electrical energy.

[0003] This type of thermal power generation has the advantage of higher power generation efficiency compared to hydroelectric power generation, but has the disadvantage of causing the emission of large amounts of carbon-based environmental pollutants due to the nature of fossil fuels used.

[0004] As an example of solving the problem of thermal power generation, the preceding Korean Patent Publication No. 10-2013-0105996 discloses a boiler device for thermal power generation for re-combustion of fine coal ash.

[0005] In addition, more specifically, the above-mentioned prior art discloses that by mixing high-grade coal with a non-recyclable unburned carbon content of 6% or more and re-burning it, economic loss and environmental pollution due to waste landfill can be prevented.

[0006] However, fossil fuels such as coal have limited reserves, and to solve the problem of conventional fuel supply and demand, a method of co-firing fossil fuels and ammonia-based fuels has emerged, but the above-mentioned prior literature does not disclose any specific method for this.

[0007] In addition, the ammonia mixed fuel power generation described above has the advantage of increasing economic efficiency by reducing the use of fossil fuels and reducing carbon emissions, but this also causes the problem of increasing nitrogen oxide (NOx) emissions due to oxidation of ammonia.

[0008] As part of solving the above-described problem, the present invention aims to provide a reducing agent injection boiler for reducing nitrogen oxide emissions in order to reduce nitrogen oxide (NOx) emissions generated during thermal power generation.

[0009] A reducing agent injection boiler for reducing nitrogen oxide emissions according to the present invention is characterized by including a combustion furnace in which fuel combustion is performed inside, an initial supply unit provided at an inlet end of the combustion furnace and supplying fuel to the combustion furnace, a startup burner spaced apart from the initial supply unit along the longitudinal axis of the combustion furnace and supplying fuel to the combustion furnace, a sensing unit for measuring a nitrogen oxide concentration inside the combustion furnace, and a control unit for supplying a reducing agent inside the combustion furnace by controlling at least one of the initial supply unit and the startup burner when the nitrogen oxide concentration is higher than a supply reference value.

[0010] In addition, the control unit includes an area setting unit that sets the inner side of the circumference of the combustion chamber as a plurality of sensing areas, and the sensing unit is characterized in that at least one is provided at each position corresponding to each of the sensing areas.

[0011] In addition, the control unit is characterized by including a monitoring unit that classifies the sensing area in which nitrogen oxides exceeding the supply reference value are sensed as a high concentration area.

[0012] In addition, the startup burner is characterized in that at least two or more are provided along the circumference of the combustion furnace.

[0013] In addition, the initial supply unit and the startup burner are characterized in that they spray the reducing agent toward the high concentration region.

[0014] In addition, the initial supply unit is provided in large numbers on the inner side of the circumference of the combustion furnace, the startup burner is tiltable with respect to the circumference of the combustion furnace, and the control unit is characterized by including an injection direction determining unit that causes the inlet nozzles at positions corresponding to the high concentration region to spray the reducing agent and rotates the startup burner in a direction corresponding to the high concentration region.

[0015] In addition, the supply reference value is characterized by including a first reference value that allows the reducing agent to be supplied only through the initial supply unit, a second reference value that exceeds the first reference value and allows the reducing agent to be supplied only through the startup burner, and a third reference value that exceeds the second reference value and allows the reducing agent to be supplied through the initial supply unit and the startup burner.

[0016] In addition, the control unit is characterized by including a distance calculation unit that calculates a target distance to at least one of the initial supply unit and the startup burner and the high concentration point.

[0017] In addition, the control unit is characterized by including a diffusion angle determination unit that calculates a diffusion angle at which the reducing agent is sprayed in response to the target distance.

[0018] In addition, the control unit is characterized by including a spray speed determination unit that calculates a spray speed at which the reducing agent is supplied in response to the target distance.

[0019] According to the present invention, a reducing agent injection boiler for reducing nitrogen oxide emissions supplies a reducing agent to the combustion chamber in response to the detected nitrogen oxide (NOx) concentration. Consequently, nitrogen oxides can be reduced and removed within the combustion chamber, thereby reducing the amount of environmental pollutants, such as nitrogen oxides, emitted to the environment.

[0020] Additionally, the reducing agent injection devices track high nitrogen oxide concentrations and inject reducing agent accordingly. This reduces reducing agent consumption and significantly increases reduction efficiency.

[0021] Figure 1 is a schematic diagram showing a reducing agent injection boiler for reducing nitrogen oxide emissions according to the present invention.

[0022] Figure 2 is a flow chart showing one embodiment of a reducing agent injection boiler for reducing nitrogen oxide emissions according to the present invention.

[0023] Figure 3 is a cross-sectional view showing a state viewed from the 3-3' direction shown in Figure 1.

[0024] Fig. 4 is a cross-sectional view showing a state viewed from the 4-4' direction shown in Fig. 1.

[0025] Figure 5 is a schematic diagram showing the control unit illustrated in Figure 2.

[0026] Figure 6 is a schematic diagram showing one embodiment of the control unit illustrated in Figure 5.

[0027] Fig. 7 is a cross-sectional view showing a state viewed from the 7-7' direction shown in Fig. 6.

[0028] Fig. 8 is a cross-sectional view showing a state viewed from the 8-8' direction shown in Fig. 6.

[0029] Before proceeding with a detailed description of the present invention, specific details for implementing the present invention are included in the following examples and drawings. Furthermore, like reference numerals used throughout the specification denote like elements. Furthermore, singular expressions in this specification also include plural forms, unless specifically stated otherwise.

[0030] Hereinafter, a reducing agent injection boiler for reducing nitrogen oxide emissions according to the present invention will be described with reference to the drawings.

[0031] Fig. 1 is a schematic diagram showing a reducing agent injection boiler for reducing nitrogen oxide emissions according to the present invention. Furthermore, Fig. 2 is a flowchart showing one embodiment of a reducing agent injection boiler for reducing nitrogen oxide emissions according to the present invention.

[0032] Referring to FIGS. 1 and 2, a reducing agent injection boiler (1000) for reducing nitrogen oxide emissions according to the present invention includes a combustion chamber (100), an initial supply unit (200), a startup burner (300), a sensing unit (400), and a control unit (500). In addition, the boiler (1000) according to the present invention can be operated through a sensing step (S100), an injection means determination step (S200), a target distance calculation step (S300), a diffusion angle determination step (S400), and an injection speed determination step (S500).

[0033] At this time, nitrogen oxides (NOx) may be generated inside the boiler (1000) due to the combustion of fuel. In addition, by supplying a reducing agent (R) to reduce nitrogen oxides inside the boiler (1000), the amount of nitrogen oxide emissions may be reduced. In addition, the reducing agent (R) may be ammonia or various other compounds. In addition, the fuel may include at least one of fossil fuel, air, hydrogen, and ammonia.

[0034] The above-mentioned combustion chamber (100) has an internal hollow structure and is designed so that its long axis is erected from the ground. In addition, thermal power generation is performed by combusting fuel inside the combustion chamber (100). At this time, the inlet side of the combustion chamber (100) may be defined as the main inlet (110).

[0035] Next, Fig. 3 is a cross-sectional view showing a state viewed from the 3-3' direction shown in Fig. 1. And, Fig. 4 is a cross-sectional view showing a state viewed from the 4-4' direction shown in Fig. 1.

[0036] Referring further to FIGS. 3 and 4, the initial supply unit (200) is provided on the inside of the main inlet (110). In addition, the initial supply unit (200) may have a type of nozzle structure. In addition, a plurality of initial supply units (200) may be provided along the diameter direction of the combustion chamber (100). That is, a plurality of initial supply units (200) may be provided in parallel along the injection surface on the inside of the combustion chamber (100).

[0037] Additionally, each initial supply unit (200) can independently supply fuel / reducing agent (R) to the inside of the combustion chamber (100).

[0038] In addition, the startup burner (300) is spaced apart from the initial supply unit (200) along the longitudinal axis of the combustion chamber (100). In addition, the startup burner (300) performs an ignition / heating action toward the inside of the combustion chamber (100). In addition, fuel / reducing agent (R) can be supplied toward the inside of the combustion chamber (100) through the startup burner (300).

[0039] In addition, a plurality of startup burners (300) may be provided along the circumference of the combustion chamber (100). In addition, the startup burners (300) may be tilted with respect to the circumference of the combustion chamber (100). That is, the startup burners (300) may be rotated in a tilting manner along a direction perpendicular to the longitudinal axis of the combustion chamber. By the rotation of the above-described startup burners (300), flames / fuel may be supplied in various directions inside the combustion chamber (100).

[0040] In addition, the sensing unit (400) senses the concentration of nitrogen oxides (NOx) inside the combustion chamber (100). In addition, the sensing unit (400) can detect various environmental pollutants generated during the thermal power generation process.

[0041] In addition, the sensing unit (400) is provided on the inside of the combustion chamber (100). In addition, a plurality of sensing units (400) may be provided on the inside of the combustion chamber (100) in the circumferential direction. That is, a plurality of sensing units (400) may be provided in a direction perpendicular to the long axis of the combustion chamber (100), such as the width / diameter of the combustion chamber (100).

[0042] Additionally, a plurality of sensing units (400) may be provided within the injection range of the startup burner (300).

[0043] Next, Fig. 5 is a schematic diagram showing the control unit illustrated in Fig. 2.

[0044] And, Fig. 6 is a schematic diagram showing an embodiment of the control unit shown in Fig. 5. And, Fig. 7 is a cross-sectional view showing a state viewed from the 7-7' direction shown in Fig. 6. And, Fig. 8 is a cross-sectional view showing a state viewed from the 8-8' direction shown in Fig. 6.

[0045] Referring further to FIGS. 5 to 8, the control unit (500) includes an area setting unit (510), a monitoring unit (520), an injection means determining unit (530), a distance calculating unit (540), a diffusion angle determining unit (550), and an injection speed determining unit (560).

[0046] Here, the control unit (500) may be implemented in a medium format that can be read / edited / recorded / applied by a user device (1). In addition, the user device (1) is a means for performing input / output and editing of various data, and may be a desktop, laptop, various smart devices, PDA, or various other unmentioned computational processing devices.

[0047] In addition, the sensing unit (400), initial supply unit (200), startup burner (300), etc. can communicate with the user device (1) via the network network (2). In addition, the network network (2) can be understood as a means that oversees wired Internet computer networks, long-term evolution, Wi-Fi, Bluetooth, Internet of Things means, and various other wired / wireless communication means.

[0048] Accordingly, the sensing values ​​of the sensing unit (400) are transmitted to the user device (1), and the processing of the control unit (500) can be performed via the user device (1). In addition, the control unit (500) can control the initial supply unit (200), the startup burner (300), and other various means necessary for operating the boiler (1000) via the user device (1).

[0049] In addition, the above-mentioned area setting unit (510) can set the inner side of the circumference of the combustion chamber (100) as a plurality of sensing areas (SA). In addition, at least one sensing unit (400) can be provided at each location corresponding to each sensing area (SA).

[0050] At this time, preferably, each sensing area (SA) may have the same shape, size, and spacing. In addition, although the sensing area (SA) is illustrated as having a rectangular shape, various other shapes may be selected.

[0051] In addition, the monitoring unit (520) monitors the nitrogen oxide concentration in each sensing area (SA). In addition, through the sensing step (S100), the high-concentration area (SA-H) in which the nitrogen oxide concentration is measured to be the highest among the sensing areas (SA) is identified.

[0052] Next, through the injection means determination step (S200), the injection means determination unit (530) determines an injection means for injecting a reducing agent (R) toward the high concentration area (SA-H).

[0053] Additionally, the concentration of nitrogen oxides can be divided into multiple supply standards. Furthermore, the reducing agent (R) injection means can be determined in response to the supply standards.

[0054] For example, the supply reference value can be divided into at least a first reference value, a second reference value, and a third reference value. More specifically, within the range of the first reference value or more and below the second reference value, the reducing agent (R) can be supplied only by the initial supply unit (200). And, within the range of the second reference value or more and below the third reference value, the reducing agent (R) can be supplied only by the startup burner (300). And, in the case of the third reference value or more, the reducing agent (R) can be supplied by using both the initial supply unit (200) and the startup burner (300). In other words, it can be defined that the concentration of nitrogen oxides increases as the third reference value approaches. In addition, the specific numerical range of each reference value can be set in various ways according to the user's cooking selection.

[0055] Here, referring to FIG. 6, each sensing area (SA) can be extended along the long axis of the combustion chamber (100). And, referring to FIG. 7, among the total number of initial supply units (200), the initial supply unit (200) located at a point corresponding to the high concentration area (SA-H) can be selected as the injection means. That is, among the total number of initial supply units (200), only the initial supply units (200) located inside the high concentration area (SA-H) can be selected as the reducing agent (R) injection means.

[0056] In addition, referring to FIG. 4 and FIG. 8, the nozzle of each startup burner (300) can inject the reducing agent (R) while facing the high concentration area (SA-H) by the tilting structure / function described above. That is, each startup burner (300) can inject the reducing agent (R) so as to follow the high concentration area (SA-H).

[0057] Next, referring to FIGS. 6 to 8, through the target distance calculation step (S300), the distance calculation unit (540) calculates the shortest target distance (L) from each selected reducing agent (R) injection means to the high concentration area (SA-H).

[0058] Next, through the diffusion angle determination step (S400), the diffusion angle determination unit (550) determines the diffusion angle (S) at which the reducing agent (R) is diffused in the initial supply unit (200) and the startup burner (300). In addition, the diffusion angle (S) may be inversely proportional to the target distance (L).

[0059] That is, the above diffusion angle (S) can be expressed as in the following mathematical expression 1.

[0060] [Mathematical Formula 1]

[0061] S ∝ 1 / L

[0062] (Here, S = diffusion angle, L = target distance.)

[0063] For example, referring to FIGS. 6 and 8, it is assumed that both the initial supply unit (200) and the startup burner (300) are used as injection means. At this time, based on the high concentration area (SA-H) illustrated in FIG. 6, the target distance (L) measured from the startup burner (300) on the left is designated as L1, the target distance (L) measured from the initial supply unit (200) is designated as L2, and the target distance (L) measured from the startup burner (300) on the right is designated as L3. In addition, the order of magnitude of the three target distances (L) is L3>L2>L1.

[0064] And, referring to FIG. 6, FIG. 8 and mathematical expression 1, as in the example of the relationship between the target distance (L) described above, it can be seen that the diffusion angle (S) is large in the order of the startup burner (300) on the left, the initial supply part (200) and the startup burner (300) on the right.

[0065] If, in the example of FIG. 8, the diffusion angle (S) of the right startup burner (300) is the same as that of the left startup burner (300), a significant amount of reducing agent (R) may be injected outside the area range of the target high-concentration area (SA-H), which may result in waste of the reducing agent (R). Conversely, if the diffusion angle (S) of the right startup burner (300) in the example of FIG. 8 decreases, the reducing agent (R) cannot be injected over the entire area of ​​the target high-concentration area (SA-H), which makes it difficult for the NOx reduction process to be performed smoothly. Therefore, the upper limit of the diffusion angle (S) in mathematical expression 1 should correspond to the area of ​​the high-concentration area (SA-H).

[0066] Next, through the injection speed determination step (S500), the injection speed determination unit (560) determines the injection speed (V) at which the reducing agent (R) is injected from the initial supply unit (200) and the startup burner (300). For example, as in the following mathematical expression 2, the injection speed (V) may increase in proportion to the target distance (L).

[0067] [Equation 2]

[0068] V ∝ L

[0069] (Here, V=injection speed, L=target distance.)

[0070] For example, referring to FIG. 6, as in the example of the relationship between the target distances (L) mentioned above (L3>L2>L1), it can be seen that the injection speed (V) is large in the order of the startup burner (300) on the right, the initial supply part (200), and the startup burner (300) on the left.

[0071] As described above, the present invention primarily aims to provide a reducing agent injection boiler for reducing nitrogen oxide emissions. Furthermore, the embodiments described above with reference to the drawings are merely exemplary, and the scope of the present invention should be determined based on the claims. Furthermore, the scope of the present invention extends to various derivative and equivalent embodiments.

Claims

1. A combustion chamber in which fuel combustion is performed on the inside; An initial supply section provided at the inlet of the combustion chamber and supplying fuel to the combustion chamber; A start-up burner spaced apart from the initial supply section along the longitudinal axis of the combustion chamber and supplying fuel to the combustion chamber; A sensing unit for measuring the concentration of nitrogen oxides inside the combustion chamber; and A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized in that it includes a control unit that supplies reducing agent to the inside of the combustion chamber by controlling at least one of the initial supply unit and the startup burner when the nitrogen oxide concentration is higher than the supply reference value.

2. In paragraph 1, The above control unit, Including a region setting section that sets the inner surface of the circumference of the above combustion chamber into a plurality of sensing regions, The above sensing part, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized in that at least one reducing agent is provided at each location corresponding to each of the above sensing areas.

3. In paragraph 2, The above control unit, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized by including a monitoring unit that classifies a sensing area in which nitrogen oxide exceeding the supply standard is sensed as a high concentration area.

4. In paragraph 3, The above startup burner is, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized in that at least two reducing agent injection boilers are provided along the circumferential direction of the above combustion furnace.

5. In paragraph 3, The above initial supply unit and the above startup burner, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized by injecting the reducing agent toward the high concentration area.

6. In paragraph 5, The above initial supply unit, A number of them are provided on the inner side of the circumference of the above combustion chamber, The above startup burner is, It is tiltable with respect to the circumference of the above combustion chamber, The above control unit, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized in that it includes an injection direction determining unit that causes the inlet side nozzles at positions corresponding to the high concentration area to spray the reducing agent and rotates the startup burner in a direction corresponding to the high concentration area.

7. In paragraph 5, The above supply standards are: A first criterion that ensures that the reducing agent is supplied only through the initial supply unit; A second criterion that exceeds the first criterion and ensures that the reducing agent is supplied only through the startup burner; and A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized in that it exceeds the second standard and includes a third standard that the reducing agent is supplied through the initial supply unit and the startup burner.

8. In paragraph 5, The above control unit, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized by including at least one of the initial supply section and the startup burner and a distance calculating section for calculating a target distance to the high concentration point.

9. In paragraph 8, The above control unit, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized by including a diffusion angle determining unit that calculates a diffusion angle at which the reducing agent is injected in response to the target distance.

10. In paragraph 9, The above control unit, A reducing agent injection boiler for reducing nitrogen oxide emissions, characterized by including an injection speed determining unit that calculates an injection speed at which the reducing agent is supplied in response to the target distance.

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