Denitration inlet and outlet double-measurement ammonia injection leveling system

Abstract

The utility model discloses a denitration inlet and outlet double measurement ammonia spraying leveling system which comprises a flue gas analyzer, a flue gas flow measurement module and an ammonia spraying flow control module, the output end of the flue gas flow measurement module is connected with the input end of the flue gas analyzer, and the output end of the flue gas analyzer is connected with the input end of the ammonia spraying flow control module; the collection end of the flue gas analyzer is respectively connected to an inlet flue and an outlet flue of the SCR denitration reactor, the flue gas flow measurement modules are respectively connected to the inlet flue and the outlet flue of the SCR denitration reactor, and the ammonia spraying flow measurement module is connected to an ammonia spraying branch of the SCR denitration reactor. The flue gas flow field and the ammonia spraying flow of the denitration system can be accurately mastered, and the ammonia spraying flow can be accurately adjusted according to the inlet flue gas flow field and the outlet NOx concentration field, so that the ammonia escape of the denitration system is reduced, the urea consumption is reduced, and accidents which influence the safe and stable operation of a unit due to the blockage problem of an air pre-heater caused by the ammonia escape are prevented.

Description

TECHNICAL FIELD

[0001] The utility model relates to flue gas treatment technical field more particularly to a kind of ammonia injection leveling system of denitration import and export double measurement. BACKGROUND

[0002] The current research and system in flow field optimization and ammonia injection optimization have good effect on stable load of unit (mainly stable high load), or small amplitude of load variation, low load variation rate and relatively stable coal quality condition. However, under the background of carbon peak and carbon neutral, new energy installation develops vigorously, and in order to consume rapidly growing and unstable new energy, deep load variation of coal-fired unit, large fluctuation of AGC instruction and fast load variation rate have become a future trend. At the same time, the current coal market is increasingly severe and complex, and the coal quality of power plant fluctuates greatly. For this future normal condition of large amplitude of load variation and variable coal quality, the existing research and system cannot achieve good control effect.

[0003] Firstly, under the condition of deep load variation of unit, large fluctuation of AGC instruction and large fluctuation of coal quality, the non-uniformity of denitration flue gas flow field is larger, and the change is more complex. The existing flow field optimization method (such as simple guide plate optimization or vertical flue ammonia injection mixing optimization) cannot improve the uniformity of overall flow field well.

[0004] Secondly, large fluctuation of load and coal quality will have a significant impact on the concentration and distribution of NO x x at the inlet of denitration system. For example, large fluctuation of load will cause large fluctuation of flue gas volume, and large fluctuation of volatile matter of coal quality will cause large fluctuation of NO x x concentration at the inlet of denitration (volatile matter increases, and NO x x concentration at the inlet decreases; volatile matter decreases, and NO x x concentration at the inlet increases), so that the total content of NO x x at the inlet of denitration fluctuates greatly. The existing ammonia injection strategy cannot control the total ammonia injection amount accurately and timely according to the large fluctuation of load and coal quality, and cannot automatically and accurately adjust the local ammonia injection amount according to the change of NO x x concentration distribution in flue gas. Some ammonia injection systems with model prediction feedforward control cannot meet the generalization requirement when load and coal quality fluctuate greatly, which leads to large control deviation and high ammonia escape.

[0005] Therefore, it is necessary to develop an ammonia injection leveling system for SCR denitration system under large fluctuation of load and coal quality, to reduce the ammonia escape amount of denitration system and realize accurate ammonia injection, which is of great significance to solve the problem of sulfuric acid hydrogen ammonia blockage of air preheater of coal-fired unit, improve the safety and economy of unit operation. UTILITY MODEL CONTENT

[0006] The technical problem to be solved by the utility model is to provide a simple structure, accurate adjustment, denitration inlet and outlet double measurement ammonia injection leveling system to solve the problems in the background art.

[0007] To solve the above technical problem, the utility model adopts the following technical scheme.

[0008] A kind of denitration inlet and outlet double measurement ammonia injection leveling system, including the flue gas analyzer for measuring the NOx concentration field at the inlet and outlet of denitration, the flue gas flow measurement module for measuring the flue gas flow at the inlet and outlet of denitration and the ammonia injection flow control module for controlling the ammonia injection flow on ammonia injection branch, the output end of flue gas flow measurement module is connected with the input end of flue gas analyzer, the output end of flue gas analyzer is connected with the input end of ammonia injection flow control module;The collection end of the flue gas analyzer is connected on the inlet flue and outlet flue of SCR denitration reactor respectively, flue gas flow measurement module is connected on the inlet flue and outlet flue of SCR denitration reactor respectively, and ammonia injection flow measurement module is connected on the ammonia injection branch of SCR denitration reactor.

[0009] Further optimize technical scheme, the flue gas flow measurement module includes the first electronic micromanometer for measuring the flow velocity field at the inlet of denitration and the second electronic micromanometer for measuring the flue gas flow velocity field at the outlet of denitration, and the output end of the first electronic micromanometer and the second electronic micromanometer is connected with the input end of flue gas analyzer respectively.

[0010] Further optimize technical scheme, the flue gas flow measurement module includes the Pitot tube for measuring the flue gas flow velocity, and the output end of Pitot tube is connected with the input end of flue gas analyzer.

[0011] Further optimize technical scheme, the ammonia injection flow control module includes the U-shaped tube pressure gauge for adjusting the ammonia injection amount arranged on ammonia injection branch.

[0012] Since the above technical scheme is adopted, the utility model has the following technical progress.

[0013] The ammonia injection leveling system for the denitration inlet and outlet double measurement provided by the utility model can accurately master the flue gas flow field and ammonia injection flow of denitration system, accurately adjust ammonia injection flow according to inlet flue gas flow field and outlet NO x Concentration field, thereby reducing ammonia escape of denitration system, reducing urea consumption, preventing the problem of air preheater blockage caused by ammonia escape from affecting safe and stable operation of unit. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1The utility model discloses a structure schematic view.

[0015] Figure 2 The utility model discloses a work flow chart.

[0016] Wherein: 1. SCR denitration reactor, 2. Inlet flue, 3. Flue gas analyzer, 4. Outlet flue, 5. First electronic micromanometer, 6. Pitot tube, 7. Second electronic micromanometer, 8. Ammonia injection branch, 9. U-shaped tube pressure gauge. DETAILED DESCRIPTION

[0017] The utility model will be further explained in detail in connection with the drawings and specific embodiment.

[0018] A kind of ammonia injection leveling system of denitration import and export double measurement, in combination Figure 1 As shown in the figure, including flue gas analyzer 3, flue gas flow measurement module and ammonia injection flow control module, flue gas analyzer 3 is used to measure the NO x Concentration field at the import and export of denitration, flue gas flow measurement device is used to measure the flue gas flow at the import and export of denitration, and ammonia injection flow control module is used to control the ammonia injection flow on ammonia injection branch.The output end of flue gas flow measurement module is connected with the input end of flue gas analyzer, and the output end of flue gas analyzer is connected with the input end of ammonia injection flow control module.

[0019] The collection end of flue gas analyzer 3 is connected on the inlet flue 2 and outlet flue 4 of SCR denitration reactor 1 respectively, flue gas flow measurement module is connected on the inlet flue 2 and outlet flue 4 of SCR denitration reactor 1 respectively, and ammonia injection flow measurement module is connected on the ammonia injection branch 8 of SCR denitration reactor 1.

[0020] Flue gas flow measurement module includes first electronic micromanometer 5, pitot tube 6 and second electronic micromanometer 7, and first electronic micromanometer 5 and pitot tube 6 are all connected on the inlet flue 2 of SCR denitration reactor 1, and first electronic micromanometer 5 and pitot tube 6 are used to measure the flow velocity field at the import of denitration.Second electronic micromanometer 7 is used to measure the flue gas flow velocity field at the export of denitration, and the output end of first electronic micromanometer, pitot tube and second electronic micromanometer is connected with the input end of flue gas analyzer respectively.

[0021] Ammonia injection flow control module includes U-shaped tube pressure gauge 9, and U-shaped tube pressure gauge 9 is arranged on ammonia injection branch 8 and is used to adjust ammonia injection amount, and is injected into SCR denitration reactor through the ammonia injection branch door on ammonia injection branch.

[0022] The utility model utilizes flue gas analyzer and electronic micromanometer and pitot tube to accurately measure the NO x Concentration field and velocity field at the import of denitration, calculate the flue gas mass concentration of ammonia injection area, that is, measure NO xThe concentration field and the velocity field correspond to the position of the measured ammonia injection area, NO x The product of the concentration field and the velocity field is the mass concentration field of the ammonia injection area, and the U-shaped tube pressure gauge is used to accurately control the ammonia injection amount.

[0023] However, in actual use, there are problems such as damage of the guide vane, failure and blockage of the denitration catalyst area, etc., and it is necessary to use the denitration outlet NO x Concentration field to fine-tune the ammonia injection flow, so as to achieve the purpose of uniform ammonia injection.

[0024] The working flow chart of the utility model is shown in Figure 2 The velocity field and NO x Concentration field of the SCR denitration reactor inlet flue are determined by the flue gas analyzer, the first electronic micro-pressure gauge and the Pitot tube; and the NO x Concentration field of each ammonia injection area is determined according to the velocity field and NO x Concentration field of the inlet flue; the resistance of each ammonia injection branch is adjusted according to the deviation of the concentration field of each area by using the U-shaped tube pressure gauge, so as to ensure that the ammonia injection amount of each area meets the distribution requirement of the NO x Concentration field; the NO x Concentration field at the denitration outlet is determined by the flue gas analyzer and the second electronic micro-pressure gauge; when the relative standard deviation of the outlet NO x Concentration field is ≤20%, the adjustment is ended; when the relative standard deviation of the outlet NO x Concentration field is >20%, according to the area with larger deviation, the corresponding ammonia injection branch door is adjusted to promote the denitration outlet NO x Concentration field relative standard deviation ≤20%.

Claims

1. A de-NOx inlet and outlet dual measurement ammonia injection leveling system, characterized by: Including the measurement of NO at the denitrification inlet and outlet x The flue gas analyzer (3) for concentration field, the flue gas flow measurement module for measuring the flue gas flow at the inlet and outlet of the denitrification reactor, and the ammonia flow control module for controlling the ammonia flow on the ammonia injection branch are provided. The output end of the flue gas flow measurement module is connected to the input end of the flue gas analyzer, and the output end of the flue gas analyzer is connected to the input end of the ammonia flow control module. The acquisition end of the flue gas analyzer (3) is connected to the inlet flue (2) and outlet flue (4) of the SCR denitrification reactor (1), respectively. The flue gas flow measurement module is connected to the inlet flue (2) and outlet flue (4) of the SCR denitrification reactor (1), respectively. The ammonia flow measurement module is connected to the ammonia injection branch (8) of the SCR denitrification reactor.

2. The ammonia injection leveling system with dual measurement at the inlet and outlet of the De-NOx according to claim 1, characterized in that: The flue gas flow measuring module comprises a first electronic micromanometer (5) arranged on the inlet flue (2) of the SCR denitration reactor (1) for measuring the flow velocity field at the denitration inlet and a second electronic micromanometer (7) arranged on the outlet flue (4) of the SCR denitration reactor (1) for measuring the flue gas flow velocity field at the denitration outlet, and the output ends of the first and second electronic micromanometers are connected to the input ends of the flue gas analyzer.

3. The ammonia injection leveling system with dual measurement at the inlet and outlet of the De-NOx according to claim 1, characterized in that: The flue gas flow measuring module comprises a Pitot tube (6) arranged on the inlet flue (2) of the SCR denitration reactor (1) for measuring the flue gas flow velocity, and the output end of the Pitot tube is connected to the input end of the flue gas analyzer.

4. The ammonia injection leveling system with dual measurement at the inlet and outlet of the De-NOx according to claim 1, characterized in that: The ammonia injection flow control module comprises a U-shaped tube pressure gauge (9) arranged on the ammonia injection branch (8) for adjusting the ammonia injection amount.

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