Denitration and ammonia spraying mixing device of gas turbine and operation method of denitration and ammonia spraying mixing device

Abstract

The gas turbine denitration ammonia spraying mixing device is installed at the front end in a waste heat boiler, an ammonia spraying grid, a flow equalizing mixer and an SCR catalyst layer are sequentially arranged in the flue gas flowing direction, the ammonia spraying grid comprises a plurality of ammonia supply main pipes, each ammonia supply main pipe is vertically connected with a plurality of ammonia supply branch pipes, and the ammonia supply branch pipes are connected with the flow equalizing mixer. The ammonia supply branch pipes located in the same vertical line direction are jointly connected with the same ammonia spraying main pipe, ammonia spraying branch pipes are evenly and vertically arranged on the two sides of each ammonia spraying main pipe, and a nozzle is arranged at the end of each ammonia spraying branch pipe. According to the invention, the mounting space of the denitration device is saved, and meanwhile, the uniformity of ammonia in the flue gas is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of gas turbine flue gas denitration, and in particular relates to a gas turbine denitration ammonia spraying mixing device and an operating method thereof. Background Art

[0002] In the context of low-carbon energy transformation, gas-fired power generation units have become rapidly popular due to their lower pollutant emissions than traditional coal-fired units. Although the NOx concentration generated per unit of power generation by gas turbines is about 50-70% lower than that of coal-fired boilers, the total NOx emissions still present a significant environmental load because their flue gas flow rate can reach 2-3 times that of coal-fired units of the same level.

[0003] To meet this environmental challenge, various regions have promulgated stricter NOx emission standards for gas turbines. In order to meet emission standards, SCR denitrification systems have been promoted to become standard equipment in gas power plants. However, the gas turbine tail flue is compactly arranged, which puts higher requirements on the design and installation of the SCR denitrification ammonia injection system. How to achieve dynamic and precise ammonia injection control in a limited space has become a key technical breakthrough direction for improving the performance of the SCR system of gas units. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a gas turbine denitrification ammonia injection mixing device and an operating method thereof.

[0005] The specific technical solutions are as follows: A gas turbine denitrification ammonia injection mixing device is installed at the front end of the waste heat boiler, and is arranged in the direction of flue gas flow in sequence: an ammonia injection grid, a flow equalizer and an SCR catalyst layer; the ammonia injection grid comprises a plurality of ammonia supply main pipes, each of which is vertically connected to a plurality of ammonia supply branch pipes; a plurality of ammonia supply branch pipes located in the same vertical line are connected to the same ammonia injection main pipe; ammonia injection branch pipes are evenly and vertically arranged on both sides of each ammonia injection main pipe, and a nozzle is arranged at the end of each ammonia injection branch pipe.

[0006] Furthermore, rectangular flow-balancing holes are evenly arranged on the flow-balancing mixer, and spoilers are evenly arranged around each flow-balancing hole and are arranged along the flow direction of the smoke.

[0007] Furthermore, the spoiler is rectangular, and one side of the spoiler is connected to the edge of the flow balancing hole.

[0008] Furthermore, the ammonia injection branch pipes are evenly distributed in the cross section of the flue, each ammonia injection branch pipe corresponds to 4 equal flow holes, and 4 nozzles are arranged at the end of each ammonia injection branch pipe, each nozzle facing one equal flow hole.

[0009] Furthermore, the inner diameter of the ammonia injection branch pipe is 4-8 times the inner diameter of the nozzle, the inner diameter of the ammonia injection main pipe is 2-4 times the inner diameter of the ammonia injection branch pipe, and both ends of the ammonia injection main pipe are sealed.

[0010] Furthermore, the side length of the spoiler is half of the side length of the flow balancing hole.

[0011] The invention discloses an operating method of a denitration ammonia injection mixing device for a gas engine, comprising the following steps: a denitration reducing agent is introduced into an ammonia supply main pipe, is distributed through an ammonia supply branch pipe, enters an ammonia injection main pipe, then enters an ammonia injection branch pipe, and finally enters a flue through a nozzle; the denitration reducing agent is mixed with flue gas and flows through a uniform flow hole, and is affected by a spoiler to form a vortex to make the mixture uniform, and then passes through an SCR catalyst layer to react.

[0012] The beneficial effects of the present invention are: The present invention evenly distributes ammonia through an ammonia spraying grid, adopts a flow-equalizing mixer to form a swirl of smoke passing through flow-equalizing holes, and improves the uniformity of ammonia in the smoke. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a layout diagram of the device of the present invention; Figure 2 This is a schematic diagram of the structure of the ammonia injection grid after installation of the present invention; Figure 3 It is a partial structural schematic diagram of the ammonia injection grid; Figure 4 Schematic diagram of the structure of the flow mixer.

[0014] In the figure: 1. Waste heat boiler; 2. Ammonia injection grid; 21. Ammonia supply main pipe; 22. Ammonia supply branch pipe; 23. Ammonia injection main pipe; 24. Ammonia injection branch pipe; 25. Nozzle; 3. Flow equalizing mixer; 31. Flow equalizing hole; 32. Spoiler; 4. SCR catalyst layer. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited thereto.

[0016] like Figure 1 As shown, a denitration ammonia spraying and mixing device for a gas turbine is installed at the front end of a waste heat boiler 1, and is provided with an ammonia spraying grid 2, a flow mixer 3 and an SCR catalyst layer 4 in the direction of flue gas flow. Figure 2 and Figure 3 As shown, Figure 3(a) is a front view of a partial structure of the ammonia injection grid 2, and (b) is a side view of a partial structure. The ammonia injection grid 2 includes a plurality of ammonia supply main pipes 21 arranged in parallel transversely, and a plurality of ammonia supply branch pipes 22 are evenly and vertically connected to each ammonia supply main pipe 21. The ammonia supply branch pipes 22 are parallel to each other, and a plurality of ammonia supply branch pipes 22 located on the same vertical line are connected to the same ammonia injection main pipe 23. The ammonia injection main pipes 23 are arranged vertically parallel to each other, and ammonia injection branch pipes 24 are evenly and vertically arranged on both sides of each ammonia injection main pipe 23. Four nozzles 25 are arranged at the end of each ammonia injection branch pipe 24. The inner diameter of the ammonia injection branch pipe 24 is 4-8 times the inner diameter of the nozzle 25, and the inner diameter of the ammonia injection main pipe 23 is 2-4 times the inner diameter of the ammonia injection branch pipe 24. Both ends of the ammonia injection main pipe 23 are sealed.

[0017] like Figure 4 As shown, Figure 4 (a) is the front view of the flow-equalizing mixer 3, and (b) is the side view. Rectangular flow-equalizing holes 31 are evenly arranged on the flow-equalizing mixer 3. Each flow-equalizing hole 31 is evenly arranged with spoilers 32 opened along the flow direction of the flue gas around it. The spoiler 32 is rectangular, and one side of the spoiler 32 is connected to the edge of the flow-equalizing hole 31. The side length of the spoiler 32 is half of the side length of the flow-equalizing hole 31.

[0018] The ammonia injection branch pipes 24 are evenly distributed in the cross section of the flue. Each ammonia injection branch pipe 24 corresponds to four equal flow holes 31 , and each nozzle 25 faces one equal flow hole 31 .

[0019] An operating method of a gas engine denitration ammonia injection mixing device comprises the following steps: a denitration reducing agent is introduced into an ammonia supply main pipe 21, is distributed through an ammonia supply branch pipe 22, enters an ammonia injection main pipe 23, then enters an ammonia injection branch pipe 24, and finally enters a flue through a nozzle 25; the denitration reducing agent is mixed with the flue gas and flows through a uniform flow hole 31, is affected by a spoiler 32 to form a vortex to make it evenly mixed, and then passes through an SCR catalyst layer 4 to react.

Claims

1. A gas turbine denitrification ammonia spray mixing device, installed at the front end of a waste heat boiler (1), characterized in that: The ammonia injection grid (2), the flow-averaging mixer (3) and the SCR catalyst layer (4) are arranged in order along the flue gas flow direction. The ammonia injection grid (2) comprises a plurality of ammonia supply main pipes (21). Each ammonia supply main pipe (21) is vertically connected to a plurality of ammonia supply branch pipes (22). The plurality of ammonia supply branch pipes (22) located in the same vertical line orientation are connected to the same ammonia injection main pipe (23). Ammonia injection branch pipes (24) are evenly and vertically arranged on both sides of each ammonia injection main pipe (23). A nozzle (25) is arranged at the end of each ammonia injection branch pipe (24).

2. A gas engine denitrification and ammonia injection mixing device as claimed in claim 1, characterized in that: The flow-balancing mixer (3) is evenly provided with rectangular flow-balancing holes (31), and each flow-balancing hole (31) is evenly provided with spoilers (32) arranged along the flow direction of the smoke around it.

3. A gas engine denitrification and ammonia injection mixing device as claimed in claim 2, characterized in that: The spoiler (32) is rectangular, and one side of the spoiler (32) is connected to the edge of the flow balancing hole (31).

4. A gas engine denitrification and ammonia injection mixing device as claimed in claim 2, characterized in that: The ammonia injection branch pipes (24) are evenly distributed in the cross section of the flue, each ammonia injection branch pipe (24) corresponds to four equal flow holes (31), and four nozzles (25) are provided at the end of each ammonia injection branch pipe (24), each nozzle (25) facing one equal flow hole (31).

5. A gas engine denitrification and ammonia injection mixing device as claimed in claim 1, characterized in that: The inner diameter of the ammonia injection branch pipe (24) is 4-8 times the inner diameter of the nozzle (25), the inner diameter of the ammonia injection main pipe (23) is 2-4 times the inner diameter of the ammonia injection branch pipe (24), and both ends of the ammonia injection main pipe (23) are sealed.

6. A gas engine denitrification and ammonia injection mixing device as claimed in claim 1, characterized in that: The side length of the spoiler (32) is half the side length of the flow balancing hole (31).

7. An operating method for a gas engine denitration ammonia injection mixing device as claimed in any one of claims 1 to 6, comprising the following steps: a denitration reducing agent is introduced into the ammonia supply main pipe (21), is distributed through the ammonia supply branch pipe (22), enters the ammonia injection main pipe (23), then enters the ammonia injection branch pipe (24), and finally enters the flue through the nozzle (25); the denitration reducing agent is mixed with the flue gas and flows through the flow-averaging hole (31), is affected by the spoiler (32) to form a vortex to make it evenly mixed, and then passes through the SCR catalyst layer (4) to react.

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