Flue gas denitration ammonia injection system

Abstract

The utility model discloses a flue gas denitration is with spraying ammonia system, including ammonia gas delivery main pipe, reactor and mixing device, a plurality of ammonia gas delivery branch pipe are connected to ammonia gas delivery main pipe, and the gas outlet of ammonia gas delivery branch pipe is connected with the upper end inside of reactor, and the top of reactor is provided with flue gas import, and the bottom of reactor is provided with flue gas export, and the inside of reactor is provided with denitration catalyst, the mixing device for carrying out the full mixing of ammonia gas and flue gas of entering the inside of reactor is set up in the inside of reactor, and the mixing device is located the above of denitration catalyst, the utility model discloses a mixing device that is driven by at least two groups of motor and is rotated by mixed fan, and the mixed fan of reactor both sides is staggered and is set up, can form multidirectional turbulence, forcibly push ammonia gas and flue gas violent blending, effectively avoid mixing blind area, significantly improve mixing uniformity, provide good condition for subsequent denitration reaction.

Description

Technical Field

[0001] This utility model relates to the field of flue gas denitrification technology, and in particular to an ammonia injection system for flue gas denitrification. Background Technology

[0002] Industrial production processes, such as burning fossil fuels, produce flue gas containing nitrogen oxides. Nitrogen oxides are a major contributor to air pollution, forming phenomena like acid rain and photochemical smog, which pose significant threats to the environment and human health. Therefore, flue gas denitrification technology has become a crucial means of controlling nitrogen oxide emissions.

[0003] In flue gas denitrification processes, selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) are widely used. Ammonia injection systems, as a core component of these processes, directly affect important indicators such as denitrification efficiency and ammonia slip rate. Existing ammonia injection systems for flue gas denitrification face numerous problems that urgently need to be addressed.

[0004] The existing ammonia injection system suffers from poor mixing of ammonia and flue gas. Traditional mixing devices are simple in structure and mostly rely on the natural diffusion of airflow to achieve mixing. This passive mixing method makes it difficult to ensure sufficient contact between ammonia and flue gas in a short time, resulting in long mixing time, low efficiency, and seriously affecting the denitrification reaction. Utility Model Content

[0005] The purpose of this invention is to provide an ammonia injection system for flue gas denitrification, in order to solve the technical problems of insufficient contact, long mixing time, and low efficiency caused by natural diffusion mixing of airflow.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Ammonia injection system for flue gas denitrification includes:

[0008] A main ammonia gas transmission pipeline, which is connected to multiple branch ammonia gas transmission pipelines.

[0009] The reactor has an outlet for ammonia gas delivery pipe connected to the upper interior of the reactor. The reactor has a flue gas inlet at the top and a flue gas outlet at the bottom. The reactor contains a denitrification catalyst.

[0010] A mixing device is installed inside the reactor to fully mix the ammonia gas and flue gas entering the reactor. The mixing device is located above the denitrification catalyst.

[0011] As a preferred embodiment of this utility model, the mixing device includes at least two sets of motors, one set of motors is fixed on one side of the outer wall of the reactor, and the other set of motors is fixed on the other side of the outer wall of the reactor. Mixing fans are rotatably installed on the inner walls of opposite sides of the reactor via rotating shafts. The rotating shafts pass through the reactor via sealed bearings and are fixedly connected to the rotating shafts of the motors.

[0012] As a further embodiment of this invention, the mixing fans on both sides of the reactor are arranged alternately.

[0013] As a preferred embodiment of this utility model, the upper part of the reactor is provided with an ammonia injection grid with the same number of ammonia gas delivery branch pipes. The air inlet of the ammonia injection grid is connected to the air outlet of the corresponding ammonia gas delivery branch pipe. The ammonia injection grid is located above the mixing device.

[0014] As a further embodiment of this invention, an economizer is fixedly installed inside the reactor, and the economizer is positioned between the denitrification catalyst and the mixing device.

[0015] As a further embodiment of this invention, a rectifier grid is provided inside the reactor, and the rectifier grid is located between the mixing device and the economizer.

[0016] As a preferred embodiment of this utility model, a first pressure indicator for monitoring its internal pressure and a temperature indicator for monitoring the internal ammonia temperature are respectively installed on the main ammonia transmission pipeline.

[0017] As a preferred embodiment of this utility model, a second pressure gauge for monitoring the internal pressure is installed on the ammonia gas transmission branch pipeline.

[0018] As a preferred embodiment of this utility model, a flow regulating valve is installed on the ammonia gas transmission branch pipeline.

[0019] As a preferred embodiment of this utility model, both the main ammonia transmission pipeline and the branch ammonia transmission pipeline are made of 304 stainless steel.

[0020] Compared with existing technologies, the ammonia injection system for flue gas denitrification provided by this utility model has the following advantages:

[0021] The mixing device has at least two sets of motors driving the mixing fans to rotate, and the mixing fans on both sides of the reactor are staggered to form multi-directional turbulence, which forces the ammonia and flue gas to mix violently, effectively avoiding mixing blind zones, significantly improving mixing uniformity, and providing good conditions for subsequent denitrification reactions.

[0022] The upper part of the reactor is equipped with ammonia spray grids, which are the same number as the branch pipes for ammonia delivery. This grids can evenly disperse ammonia into multiple fine streams before spraying out, so that the ammonia is initially evenly distributed before entering the mixing device. Combined with the stirring of the mixing fan, this further optimizes the distribution of ammonia in the reactor.

[0023] The mixing unit, located above the denitrification catalyst, ensures thorough mixing of ammonia and flue gas before they come into contact with the catalyst, resulting in a more complete reaction and improved denitrification efficiency. Simultaneously, the economizer regulates the flue gas temperature to the optimal operating temperature range of the denitrification catalyst, further guaranteeing the efficient conduct of the catalytic reduction reaction.

[0024] Uniform distribution and thorough mixing of ammonia can reduce ammonia escape caused by excessively high local concentrations, lower the ammonia escape rate, reduce waste of reducing agent, and minimize adverse effects on the environment and equipment.

[0025] The rectifier grid is installed between the mixing unit and the economizer. It can sort out the airflow output from the mixing unit, so that the turbulent airflow is evenly distributed, reduce flow resistance, ensure that the airflow enters the economizer with a stable flow field, optimize heat exchange efficiency, and also facilitate the stable progress of the subsequent denitrification reaction. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only examples of embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model.

[0028] Figure label:

[0029] 1. Main ammonia transmission pipeline; 101. Branch ammonia transmission pipeline; 102. Flow regulating valve; 103. First pressure gauge; 104. Temperature gauge; 105. Second pressure gauge; 2. Reactor; 3. Economizer; 4. Denitrification catalyst; 5. Ammonia injection grid; 6. Mixing device; 7. Rectifying grid. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0031] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0032] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present invention should be understood according to the specific circumstances.

[0033] See Figure 1 As shown, the ammonia injection system for flue gas denitrification in this embodiment of the present invention includes an ammonia gas delivery main pipeline 1, a reactor 2, and a mixing device 6. The ammonia gas delivery main pipeline 1 is connected to multiple ammonia gas delivery branch pipelines 101. The outlet of the ammonia gas delivery branch pipelines 101 is connected to the upper interior of the reactor 2. A flue gas inlet is provided at the top of the reactor 2, and a flue gas outlet is provided at the bottom of the reactor 2. A denitrification catalyst 4 is provided inside the reactor 2. The mixing device 6, which is used to fully mix the ammonia gas and flue gas entering the reactor 2, is provided inside the reactor 2 and is located above the denitrification catalyst 4.

[0034] In the above scheme, ammonia gas is diverted from the main ammonia gas delivery pipeline 1 to multiple branch ammonia gas delivery pipelines 101. The gas then enters the upper part of reactor 2 through the outlet of each branch pipeline, where it mixes with the flue gas flowing in from the flue gas inlet at mixing device 6. Subsequently, it flows through denitrification catalyst 4 to undergo a catalytic reduction reaction to remove nitrogen oxides. The purified flue gas is discharged from the bottom outlet. Mixing device 6 ensures that ammonia gas and flue gas are uniformly mixed before contacting the catalyst, thus improving denitrification efficiency.

[0035] The mixing device 6 includes at least two sets of motors, one set of motors is fixed on one side of the outer wall of the reactor 2, and the other set of motors is fixed on the other side of the outer wall of the reactor 2. Mixing fans are rotatably installed on the inner walls of opposite sides of the reactor 2 via rotating shafts. The rotating shafts pass through the reactor 2 via sealed bearings and are fixedly connected to the rotating shafts of the motors.

[0036] A motor-driven rotating shaft rotates a mixing fan, generating forced turbulence that promotes the mixing of ammonia and flue gas within reactor 2. Sealed bearings ensure the reactor's airtightness, and motors on both sides drive mixing fans, creating a bidirectional agitated flow field to enhance the mixing effect.

[0037] The mixing fans on both sides of reactor 2 are staggered. The staggered arrangement of the mixing fans creates an asymmetric flow field, avoiding the mixing blind zone caused by unidirectional agitation. When the fans on both sides rotate, they generate cross shear force in the airflow, promoting more uniform diffusion of ammonia and flue gas.

[0038] The upper part of the reactor 2 is equipped with ammonia injection grids 5, the same number as the ammonia gas delivery branch pipes 101. The inlet of the ammonia injection grid 5 is connected to the outlet of the corresponding ammonia gas delivery branch pipe 101. The ammonia injection grids 5 are located above the mixing device 6. Ammonia gas enters the ammonia injection grids 5 through the ammonia gas delivery branch pipes 101, is dispersed into multiple fine streams through the grid holes, and is then ejected from the upper part of the reactor 2. The ammonia injection grids 5 located above the mixing device 6 allow the ammonia gas to form a preliminary distribution first, and then, in conjunction with the mixing fan, achieve tiered mixing.

[0039] An economizer 3 is fixedly installed inside reactor 2, and is positioned between the denitrification catalyst 4 and the mixing device 6. The economizer 3 utilizes the waste heat of flue gas to heat the boiler feedwater, reduces the exhaust gas temperature, and recovers heat. Its placement between the mixing device 6 and the catalyst 4 allows the flue gas temperature to be adjusted to the optimal operating range of the catalyst, ensuring efficient catalytic reaction and improving energy utilization.

[0040] The reactor 2 is equipped with a rectifier grid 7, which is located between the mixing device 6 and the economizer 3. The airflow output from the mixing device 6 may have eddies or uneven flow velocity. The rectifier grid 7 uses its grid structure to organize the airflow, making it evenly distributed, reducing flow resistance, ensuring that the airflow enters the economizer 3 with a stable flow field, and optimizing heat exchange efficiency.

[0041] The main ammonia transmission pipeline 1 is equipped with a first pressure indicator 103 for monitoring its internal pressure and a temperature indicator 104 for monitoring the temperature of the ammonia gas inside. The first pressure indicator 103 displays the ammonia pressure in the main pipeline 1 in real time, and the upstream gas supply equipment can be adjusted in case of abnormality; the temperature indicator 104 monitors the ammonia temperature to prevent liquefaction due to excessively low temperature or safety hazards caused by excessively high temperature, and provides a basis for parameter adjustment.

[0042] A second pressure gauge 105 is installed on the ammonia transmission branch pipeline 101 to monitor its internal pressure. The second pressure gauge 105 reflects the pressure status of each branch pipeline 101. If the pressure of a branch pipeline is abnormal, the location of the blockage or fault can be located, which facilitates maintenance and adjustment and ensures that the ammonia flow rate of each branch pipeline is uniform.

[0043] A flow regulating valve 102 is installed on the ammonia transmission branch pipeline 101. The flow regulating valve 102 controls the ammonia flow rate of each branch pipeline 101 by adjusting the opening degree. It can dynamically adjust the ammonia supply according to parameters such as flue gas volume and NOx concentration to achieve precise ammonia injection and reduce ammonia escape rate.

[0044] Both the main ammonia transmission pipeline 1 and the branch ammonia transmission pipeline 101 are made of 304 stainless steel. 304 stainless steel is corrosion-resistant and heat-resistant, resisting corrosion from ammonia and acidic gases in flue gas, preventing rust or perforation, ensuring safe and stable ammonia transmission, and extending service life.

[0045] The foregoing has shown and described the basic principles of the present invention. The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. The above embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the present invention without departing from the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. An ammonia injection system for flue gas denitrification, characterized in that... include: Ammonia main pipeline (1), and multiple ammonia branch pipelines (101) are connected to the ammonia main pipeline (1); The reactor (2) has an outlet of the ammonia gas delivery branch pipe (101) connected to the upper interior of the reactor (2). The top of the reactor (2) is provided with a flue gas inlet, the bottom of the reactor (2) is provided with a flue gas outlet, and the interior of the reactor (2) is provided with a denitrification catalyst (4). A mixing device (6) is provided inside the reactor (2) for fully mixing ammonia gas and flue gas entering the reactor (2), and the mixing device (6) is located above the denitrification catalyst (4).

2. The ammonia injection system for flue gas denitrification according to claim 1, characterized in that: The mixing device (6) includes at least two sets of motors, one set of motors is fixed on one side of the outer wall of the reactor (2), and the other set of motors is fixed on the other side of the outer wall of the reactor (2). The inner walls of the opposite sides of the reactor (2) are equipped with mixing fans through a rotating shaft. The rotating shaft passes through the reactor (2) through a sealed bearing and is fixedly connected to the rotating shaft of the motor.

3. The ammonia injection system for flue gas denitrification according to claim 2, characterized in that: The mixing fans on both sides of the reactor (2) are arranged alternately.

4. The ammonia injection system for flue gas denitrification according to claim 1, characterized in that: The upper part of the reactor (2) is provided with the same number of ammonia injection grids (5) as the ammonia gas delivery branch pipes (101). The inlet of the ammonia injection grid (5) is connected to the outlet of the corresponding ammonia gas delivery branch pipe (101). The ammonia injection grid (5) is located above the mixing device (6).

5. The ammonia injection system for flue gas denitrification according to claim 4, characterized in that: An economizer (3) is fixedly installed inside the reactor (2), and the economizer (3) is located between the denitrification catalyst (4) and the mixing device (6).

6. The ammonia injection system for flue gas denitrification according to claim 5, characterized in that: The reactor (2) is equipped with a rectifier grid (7) inside, which is located between the mixing device (6) and the economizer (3).

7. The ammonia injection system for flue gas denitrification according to claim 1, characterized in that: The main ammonia transmission pipeline (1) is equipped with a first pressure indicator (103) for monitoring its internal pressure and a temperature indicator (104) for monitoring the internal ammonia temperature.

8. The ammonia injection system for flue gas denitrification according to claim 1, characterized in that: A second pressure gauge (105) is installed on the ammonia transmission branch pipe (101) for monitoring its internal pressure.

9. The ammonia injection system for flue gas denitrification according to claim 1, characterized in that: A flow regulating valve (102) is installed on the ammonia gas transmission branch pipeline (101).

10. The ammonia injection system for flue gas denitrification according to any one of claims 1-9, characterized in that: Both the main ammonia transport pipeline (1) and the branch ammonia transport pipeline (101) are 304 stainless steel pipelines.

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