Multi-separator circulating fluidized bed three-dimensional high-mixing-rate ammonia spraying system

Abstract

The utility model discloses a three-dimensional high-mixing-rate ammonia spraying system of a multi-separator circulating fluidized bed. Wherein the flushing water source is connected with the denitration agent supply main pipe through the water regulating valve, the denitration agent solution conveying source is connected with the denitration agent supply main pipe through the solution pump and the solution regulating valve group, and the denitration agent supply main pipe is connected with the first ammonia spraying flow electric regulating valve and the second ammonia spraying flow electric regulating valve through the denitration agent supply branch; the first ammonia spraying flow electric control valve is connected with a separator inlet flue ammonia supply spray gun mounted in a separator inlet flue in a separator center cylinder; a second ammonia spraying flow electric control valve is connected with a separator center cylinder ammonia supply spray gun and a separator outlet flue ammonia supply spray gun, the separator center cylinder ammonia supply spray gun is mounted in a separator center cylinder, and the separator outlet flue ammonia supply spray gun is mounted in a separator outlet flue. The spray guns are arranged at the inlet flue of the cyclone separator, the central cylinder of the separator and the outlet of the separator at the same time, so that the ammonia escape condition is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of combustion equipment, and particularly relates to a multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system. Background Technique

[0002] As one of the main pollutants emitted by coal-fired power plants, nitrogen oxides (NOx) have caused serious harm to the atmospheric environment. In recent years, China has put forward the "ultra-low emission" requirement that the NOx emission concentration of coal-fired power plants should not be higher than 50 mg / m3. The circulating fluidized bed boiler (CFB) is a clean combustion technology, which can effectively control the emission of sulfur oxides during the combustion process and can also control the generation of NOx to a certain extent.

[0003] At present, there are mainly two technologies to solve NOx: SNCR (selective non-catalytic reduction technology) and SCR (selective catalytic reduction technology). The difference between the two is that SNCR does not require the use of a catalyst and relies on a suitable temperature window (950 - 1050 °C) to achieve the reduction of NOx; while the SCR technology uses a catalyst to promote the reduction reaction of NOx, so the reaction can be carried out at a lower temperature. However, due to the relatively high dust concentration in the circulating fluidized bed and partial desulfurization in the furnace, the honeycomb catalyst is very easy to be blocked and worn. In addition, the early designed CFB units did not consider the SCR denitration technical scheme, so there is no space and temperature condition for adding a catalyst at the boiler tail.

[0004] For the above reasons, most of the current CFBs adopt the SNCR denitration method. Since the optimal reaction temperature of the SNCR reducing agent is 950 °C - 1100 °C, when the boiler load fluctuates, the temperature in the furnace changes rapidly, and SNCR often reacts untimely or insufficiently, resulting in ammonia escape. Furthermore, the generated ammonium bisulfate will cause problems such as air preheater blockage, ash wrapping on the electrode plates and wires of the electrostatic precipitator, etc., thus affecting the denitration efficiency.

[0005] The traditional layout method of the existing SNCR technology is at the outlet of the horizontal flue and the inlet of the separator. However, due to the too fast flue gas velocity at the inlet of the CFB cyclone separator, the flue gas velocity in the horizontal flue is about 30 m / s, which is relatively fast. After the reducing agent is sprayed into the inlet of the cyclone separator, it is instantly carried into the cyclone separator by the flue gas. And due to the action of centrifugal force, the sprayed reducing agent adheres tightly to the inner wall of the cyclone separator, mixes violently with the flue gas and ash in the separator, and the residence time exceeds 1.5 seconds, resulting in low utilization rate of the reducing agent and affecting the denitration efficiency.

[0006] The existing ammonia injection process system of SNCR technology is controlled by a master valve. However, most of the separators of CFB are asymmetrically arranged, and there are inherent deviations between separators, making it impossible to adjust the ratio between separators (specific data such as the NOx generation amount, flue gas volume, and oxygen content of each separator cannot be collected). Summary of the Invention

[0007] In view of the problems existing in the background technology, the present invention provides a multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system. The technical solution includes: a boiler and a spray gun pipeline system. The boiler includes: a furnace, at least one cyclone separator, a return feeder, a boiler tail flue, and an air preheater; the top of the furnace is successively connected to the bottom of the furnace through the cyclone separator and the return feeder, and the separator central cylinder in the cyclone separator is successively connected to the separator outlet flue, the boiler tail flue, and the air preheater;

[0008] The spray gun pipeline system includes: a compressed air source, a flushing water source, a denitration agent solution delivery source, an air control valve, a solution pump, a branch electric control valve, a denitration agent supply main pipe, a water control valve, a solution control valve group, a denitration agent supply branch, a first ammonia injection flow electric control valve, an ammonia supply spray gun for the separator inlet flue, a second ammonia injection flow electric control valve, an ammonia supply spray gun for the separator central cylinder, and an ammonia supply spray gun for the separator outlet flue. The compressed air source is connected to the denitration agent supply main pipe through the air control valve, the flushing water source is connected to the denitration agent supply main pipe through the water control valve, the denitration agent solution delivery source is connected to the denitration agent supply main pipe through the solution pump and the solution control valve group, and the denitration agent supply main pipe is connected to the first ammonia injection flow electric control valve and the second ammonia injection flow electric control valve through the denitration agent supply branch;

[0009] The first ammonia injection flow electric control valve is connected to the ammonia supply spray gun for the separator inlet flue installed in the separator inlet flue in the separator central cylinder; the second ammonia injection flow electric control valve is connected to the ammonia supply spray gun for the separator central cylinder and the ammonia supply spray gun for the separator outlet flue. The ammonia supply spray gun for the separator central cylinder is installed in the separator central cylinder, and the ammonia supply spray gun for the separator outlet flue is installed in the separator outlet flue.

[0010] A branch electric control valve is provided on the denitration agent supply branch.

[0011] The number of denitration agent supply branches corresponds to the number of cyclone separators.

[0012] An in-separator-inlet-flue high-temperature flue gas sampling device connected to the control system is installed in the separator inlet flue.

[0013] The ammonia supply spray gun for the separator inlet flue, the ammonia supply spray gun for the separator central cylinder, and the ammonia supply spray gun for the separator outlet flue are all composed of multiple layers.

[0014] The setting direction of each layer is along the flue gas flow direction or perpendicular to the flue duct flow direction.

[0015] The arrangement mode of the spray guns in each layer is in the form of combination of long and short guns.

[0016] The arrangement between each layer is side-by-side arrangement, staggered arrangement or annular arrangement.

[0017] An included angle of 0 - 90° is provided between each layer.

[0018] The sum of the total flow rate of the ammonia supply spray guns in the separator central cylinder and the total flow rate of the ammonia supply spray guns in the separator outlet flue duct is 1 - 8 times the total flow rate of the ammonia supply spray guns in the separator inlet flue duct.

[0019] The beneficial effects of the present utility model are as follows:

[0020] 1. Spray guns are simultaneously arranged in the separator inlet flue duct, the separator central cylinder and the separator outlet flue duct, and an independent electric regulating valve is designed, so that the spray gun loop in each separator can be independently controlled, realizing the separate control of the ammonia supply flow rate of the separator, avoiding the increase of ammonia escape caused by the inconsistency between the flow rate distribution and the actual needs brought by the total amount control in the original system, thereby greatly improving the utilization efficiency of the spray gun and reducing ammonia escape.

[0021] 2. Each spray gun includes multiple rows with different settings, thus forming a 3D three-dimensional ammonia injection structure, improving the utilization rate of the reducing agent and the denitration efficiency. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the boiler in the embodiment of the multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system of the present utility model;

[0023] Figure 2 It is a schematic structural diagram of the spray gun pipeline system in the embodiment of the present utility model;

[0024] Figure 3 It is a schematic structural diagram of the cyclone separator in the embodiment of the present utility model.

[0025] Wherein: 1 - furnace, 2 - loop seal, 3 - cyclone separator, 4 - flue duct at the separator inlet, 5 - central cylinder of the separator, 6 - flue duct at the separator outlet, 7 - flue duct at the boiler tail, 8 - air preheater, 11 - source of compressed air, 12 - source of flushing water, 13 - source for conveying denitration agent solution, 14 - air regulating valve, 15 - solution pump, 16 - branch electric regulating valve, 17 - main pipe for supplying denitration agent, 18 - water regulating valve, 19 - solution regulating valve group, 55 - first ammonia injection flow electric regulating valve, 56 - ammonia injection lance at the flue duct of the separator inlet, 57 - second ammonia injection flow electric regulating valve, 58 - ammonia injection lance at the central cylinder of the separator, 59 - ammonia injection lance at the flue duct of the separator outlet, 510 - high-temperature flue gas sampling device at the flue duct of the separator inlet. Detailed implementation mode

[0026] The following further elaborates on the present utility model in conjunction with the attached drawings.

[0027] As Figure 1 shown in the embodiment of the present utility model, it includes: a boiler and a spray gun pipeline system. The boiler includes: 1 furnace, 1 - 8 cyclone separators 3 (including the flue duct at the separator inlet 4, the central cylinder of the separator 5, and the flue duct at the separator outlet 6), 1 - 8 loop seals 2, 1 flue duct at the boiler tail 7, and 1 - 2 air preheaters 8; the top of the furnace 1 is successively connected to the bottom of the furnace 1 through the flue duct at the separator inlet 4, the cyclone separator 3 (side wall), and the loop seal 2, and the central cylinder 5 in the cyclone separator 3 is successively connected to the flue duct at the separator outlet 6, the flue duct at the boiler tail 7, and the air preheater 8.

[0028] As Figure 2 and Figure 3 shown in the spray gun pipeline system (SNCR system), it includes: the source of compressed air 11, the source of flushing water 12, the source for conveying denitration agent solution 13, the air regulating valve 14, the solution pump 15, the branch electric regulating valve 16, the main pipe for supplying denitration agent 17, the water regulating valve 18, the solution regulating valve group 19, at least one branch for supplying denitration agent, the first ammonia injection flow electric regulating valve 55, the ammonia injection lance at the flue duct of the separator inlet 56, the second ammonia injection flow electric regulating valve 57, the ammonia injection lance at the central cylinder of the separator 58, and the ammonia injection lance at the flue duct of the separator outlet 59. The source of compressed air 11 is connected to the main pipe for supplying denitration agent 17 through the air regulating valve 14, the source of flushing water 12 is connected to the main pipe for supplying denitration agent 17 through the water regulating valve 18, the source for conveying denitration agent solution 13 is connected to the main pipe for supplying denitration agent 17 through the solution pump 15 and the solution regulating valve group 19, the main pipe for supplying denitration agent 17 is respectively connected to the first ammonia injection flow electric regulating valve 55 and the second ammonia injection flow electric regulating valve 57 in one cyclone separator 3 through the branch for supplying denitration agent, and an independent branch electric regulating valve 16 is arranged on each branch for supplying denitration agent;

[0029] The denitration agent solution is sent through the denitration agent supply branch to a number of denitration agent spray guns arranged in the inlet flue and outlet flue (or the central cylinder of the separator) of the circulating fluidized bed boiler through the first ammonia injection flow electric control valve 55 and the second ammonia injection flow electric control valve 57 respectively. After being atomized by the spray guns, it is sprayed into the boiler, fully contacting with the NOx in the boiler flue gas and undergoing a chemical reaction to achieve the purpose of denitration.

[0030] When the number of cyclone separators 3 exceeds one, due to the inherent deviation between the multiple cyclone separators 3 of the circulating fluidized bed, the ammonia injection flow of each cyclone separator 3 needs to be independently adjustable. Therefore, each separator's spray gun system has a total branch electric control valve 16 to adjust the flow, so that the branches of the denitration agent supply branch correspond to the number of cyclone separators 3.

[0031] The first ammonia injection flow electric control valve 55, as the ammonia injection amount adjustment device at the inlet, is connected through a pipeline to the ammonia supply spray gun 56 for the inlet flue of the separator installed in the inlet flue 4 of the separator; in the inlet flue 4 of the separator, there is also installed a high-temperature flue gas sampling device 510 for the inlet flue of the separator connected to the control system.

[0032] The second ammonia injection flow electric control valve 57, as the ammonia injection amount adjustment device for the central cylinder and the outlet, is connected through a pipeline to the ammonia supply spray gun 58 for the central cylinder of the separator and the ammonia supply spray gun 59 for the outlet flue of the separator. The ammonia supply spray gun 58 for the central cylinder of the separator is installed in the central cylinder 5 of the separator, and the ammonia supply spray gun 59 for the outlet flue of the separator is installed in the outlet flue 6 of the separator.

[0033] A certain number of spray guns (the ammonia supply spray gun 58 for the central cylinder of the cyclone separator and the ammonia supply spray gun 59 for the outlet flue of the separator) are arranged in the central cylinder and the outlet of the cyclone separator, and a certain number of spray guns (the ammonia supply spray gun 56 for the inlet flue of the separator) are arranged at the inlet of the cyclone separator; the spray gun flow is adjusted through the first ammonia injection flow electric control valve 55 and the second ammonia injection flow electric control valve 57; the sum of the total flow of the ammonia supply spray gun (58) for the central cylinder of the separator and the total flow of the ammonia supply spray gun (59) for the outlet flue of the separator is 1 - 8 times the total flow of the ammonia supply spray gun (56) for the inlet flue of the separator.

[0034] In this embodiment, the ammonia supply spray gun 56 for the inlet flue of the separator, the ammonia supply spray gun 58 for the central cylinder of the separator, and the ammonia supply spray gun 59 for the outlet flue of the separator are all composed of multiple layers. The arrangement method of the spray guns in each layer is a combination of long and short guns. The layers are arranged side by side, staggeredly, or in a circular arrangement, and there is an included angle of 0 - 90° between the layers, forming a 3D mixed arrangement of the spray guns to achieve full coverage and circumferential arrangement. The setting direction of each layer is along the flue gas flow direction or perpendicular to the flue gas flow direction.

[0035] A high-temperature flue gas measuring instrument is installed at the inlet of the denitration reactor, which can measure the NOx data at the inlet of the separator in real time and then promptly feedback the data to the control system.

[0036] During operation, the flue gas discharged from the top of the furnace in the boiler enters the cyclone separator 3 through the separator inlet flue 4 and is separated in the separator central cylinder 5 of the cyclone separator 3. The particles meeting the particle size (such as ash) flow downward along the wall of the separator central cylinder 5 and return to the furnace 1, while other particles enter the flue with the flue gas through the separator outlet flue 6.

[0037] During the operation of the cyclone separator 3, the spray gun pipeline system is turned on. After the denitration agent is transported through the denitration agent supply main pipe 17, it is first distributed to each cyclone separator 3 by the denitration agent supply branch and the branch electric control valve 16, and then divided into two paths and enters the first ammonia injection flow electric control valve 55 and the second ammonia injection flow electric control valve 57 respectively. Finally, it flows from the first ammonia injection flow electric control valve 55 to the ammonia supply spray gun 56 at the inlet of the separator flue to spray ammonia at the ammonia injection point of the inlet of the separator flue, spraying it into the flowing boiler flue gas for denitration reaction; at the same time, the second ammonia injection flow electric control valve 57 flows through the ammonia supply spray gun 58 in the separator central cylinder and the ammonia supply spray gun 59 at the separator outlet flue and sprays them to the ammonia injection points in the separator central cylinder and at the separator outlet flue respectively, spraying them into the flowing boiler flue gas for denitration reaction.

Claims

1. A multi-separator circulating fluidized bed three-dimensional high mixing rate ammonia injection system, characterized in that, Comprising: A boiler and a spray gun pipeline system, wherein the boiler comprises: a furnace (1), at least one cyclone separator (3), a return feeder (2), a boiler tail flue (7) and an air preheater (8); the top of the furnace (1) is successively connected to the bottom of the furnace (1) through the cyclone separator (3) and the return feeder (2), and the separator central cylinder (5) in the cyclone separator (3) is successively communicated with the separator outlet flue (6), the boiler tail flue (7) and the air preheater (8); The spray gun pipeline system comprises: a compressed air source (11), a flushing water source (12), a denitration agent solution delivery source (13), an air regulating valve (14), a solution pump (15), a branch electric regulating valve (16), a denitration agent supply main pipe (17), a water regulating valve (18), a solution regulating valve group (19), a denitration agent supply branch, a first ammonia injection flow electric regulating valve (55), an ammonia supply spray gun (56) for the separator inlet flue installed in the separator inlet flue (4) in the separator central cylinder (5), a second ammonia injection flow electric regulating valve (57), an ammonia supply spray gun (58) for the separator central cylinder and an ammonia supply spray gun (59) for the separator outlet flue, wherein the compressed air source (11) is connected to the denitration agent supply main pipe (17) through the air regulating valve (14), the flushing water source (12) is connected to the denitration agent supply main pipe (17) through the water regulating valve (18), the denitration agent solution delivery source (13) is connected to the denitration agent supply main pipe (17) through the solution pump (15) and the solution regulating valve group (19), and the denitration agent supply main pipe (17) is connected to the first ammonia injection flow electric regulating valve (55) and the second ammonia injection flow electric regulating valve (57) through the denitration agent supply branch; The first ammonia injection flow electric regulating valve (55) is connected to the ammonia supply spray gun (56) for the separator inlet flue installed in the separator inlet flue (4) in the separator central cylinder (5); the second ammonia injection flow electric regulating valve (57) is connected to the ammonia supply spray gun (58) for the separator central cylinder and the ammonia supply spray gun (59) for the separator outlet flue, the ammonia supply spray gun (58) for the separator central cylinder is installed in the separator central cylinder (5), and the ammonia supply spray gun (59) for the separator outlet flue is installed in the separator outlet flue (6).

2. The multi-separator circulating fluidized bed three-dimensional high mixing rate ammonia injection system according to claim 1, characterized in that, A branch electric regulating valve (16) is provided on the denitration agent supply branch.

3. The multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system according to claim 2, wherein, The number of the denitration agent supply branches corresponds to the number of the cyclone separators (3).

4. A multi-separator circulating fluidized bed three-dimensional high mixing rate ammonia injection system according to claim 1, characterized in that, An in-separator-inlet-flue high-temperature flue gas sampling device (510) connected to a control system is installed in the separator inlet flue (4).

5. The multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system according to claim 1, characterized in that, The ammonia supply spray gun (56) for the separator inlet flue, the ammonia supply spray gun (58) for the separator central cylinder and the ammonia supply spray gun (59) for the separator outlet flue are all composed of multiple layers.

6. The multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system according to claim 5, characterized in that The setting direction of each layer is along the flue gas flow direction or perpendicular to the flue duct flow direction.

7. A multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system according to claim 5, characterized in that, The arrangement mode of the spray guns in each layer is a combination of long and short guns.

8. A multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system according to claim 6 or 7, characterized in that, The arrangement between the layers is side-by-side arrangement, staggered arrangement or annular arrangement.

9. A multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system according to claim 8, characterized in that, An included angle of 0 to 90° is provided between the layers.

10. A multi-separator circulating fluidized bed three-dimensional high mixing ratio ammonia injection system according to claim 1, characterized in that, The sum of the total flow rates of the ammonia supply spray gun (58) for the separator central cylinder and the ammonia supply spray gun (59) for the separator outlet flue is 1 to 8 times the total flow rate of the ammonia supply spray gun (56) for the separator inlet flue.

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