Boiler combustion control system

Abstract

The embodiment of the utility model provides a boiler combustion control system. The boiler combustion control system comprises a boiler body, an air preheater, a frequency conversion fan and a controller. A flue gas inlet of the air preheater is communicated with a flue gas outlet of the boiler body, an air inlet is communicated with the frequency conversion fan through a first air pipeline, and an air outlet is communicated to a combustor of the boiler body through a second air pipeline; the first air pipeline is communicated with the second air pipeline through a bypass pipeline; an oxygen and nitrogen oxide detector is arranged at a flue gas outlet of the air preheater, a temperature sensor is arranged at an air inlet of the combustor, the frequency conversion fan is provided with a frequency converter, a bypass baffle is arranged in the bypass pipeline, and the oxygen and nitrogen oxide detector, the temperature sensor, the frequency converter and the bypass baffle are all in communication connection with the controller; the air temperature of the inlet of the burner can be controlled, so that the burner of the boiler is kept in a stable burning state, and meanwhile, the content of nitric oxide in smoke is prevented from exceeding the standard.

Description

Technical Field

[0001] The utility model relates to the technical field of boilers, in particular to a boiler combustion control system. Background Art

[0002] Some existing boilers will be equipped with air preheaters at the rear, using the flue gas at the rear of the boiler to preheat the combustion air before entering the boiler, so as to improve the overall efficiency of the boiler and reduce energy consumption. However, due to the ever-changing use conditions of the client, the temperature of the tail flue gas and the combustion air will also change accordingly. Under the condition of maintaining the same combustion output, as the air temperature changes, the air pressure loss on the air duct side and the burner will also change significantly, affecting the stability of combustion; at the same time, the higher the temperature of the combustion air, the higher the combustion flame temperature and the nitrogen oxide value in the tail flue gas will be. When exceeding a certain temperature, the nitrogen oxide value in the flue gas will exceed the value specified by environmental protection requirements. Utility Model Content

[0003] In view of this, an embodiment of the utility model provides a boiler combustion control system, which can control the burner inlet air temperature, so that the burner of the boiler maintains stable combustion and avoids excessive nitrogen oxide content in the flue gas.

[0004] The utility model provides a boiler combustion control system, comprising a boiler body, an air preheater, a variable frequency fan and a controller; the smoke inlet of the air preheater is connected to the smoke outlet of the boiler body, the air inlet of the air preheater is connected to the variable frequency fan through a first air pipeline, the air outlet of the air preheater is connected to the burner of the boiler body through a second air pipeline, and the first air pipeline is connected to the second air pipeline through a bypass pipeline;

[0005] The flue gas outlet of the air preheater is provided with an oxygen and nitrogen oxide detector, the air inlet of the burner is provided with a temperature sensor, the variable frequency fan is provided with a frequency converter, and a bypass baffle is provided in the bypass pipeline. The oxygen and nitrogen oxide detectors, the temperature sensor, the frequency converter and the bypass baffle are all communicatively connected with the controller.

[0006] Optionally, the controller is configured to automatically adjust the opening of the bypass damper according to the burner inlet air temperature or the nitrogen oxide content in the flue gas detected in real time.

[0007] Optionally, the controller is configured to automatically adjust the operating frequency of the variable frequency fan according to the oxygen content in the flue gas detected in real time.

[0008] Optionally, an economizer is installed between the flue gas inlet of the air preheater and the flue gas outlet of the boiler body.

[0009] The embodiment of the utility model has the following beneficial effects: the first air pipeline on the air inlet side of the air preheater is connected with the second air pipeline on its air outlet side through a bypass pipeline, so that part of the low-temperature air can be mixed with the preheated high-temperature air, thereby adjusting the burner inlet air temperature, allowing the burner to maintain stable combustion, and at the same time avoiding excessive nitrogen oxide content in the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0011] Figure 1 It is a schematic diagram of the structure of an embodiment of the utility model;

[0012] The numbers in the figure represent:

[0013] 1. Boiler body; 2. Air preheater; 3. Variable frequency fan; 4. Controller; 5. First air pipeline; 6. Second air pipeline; 7. Burner; 8. Bypass pipeline; 9. Economizer; 10. Oxygen and nitrogen oxide detectors; 11. Temperature sensor; 12. Frequency converter; 13. Bypass baffle. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the utility model, and are not used to limit the utility model.

[0015] See also Figure 1 As shown, an embodiment of the utility model provides a boiler combustion control system, comprising a boiler body 1, an air preheater 2, a variable frequency fan 3 and a controller 4. The flue gas inlet of the air preheater 2 is connected to the flue gas outlet of the boiler body 1, the air inlet of the air preheater 2 is connected to the variable frequency fan 3 through a first air pipeline 5, the air outlet of the air preheater 2 is connected to the burner 7 of the boiler body 1 through a second air pipeline 6, and the first air pipeline 5 is connected to the second air pipeline 6 through a bypass pipeline 8.

[0016] The high-temperature flue gas discharged from the boiler body 1 can be heat exchanged with the low-temperature air introduced into the first air pipeline 5 in the air preheater 2. The low-temperature flue gas after cooling is discharged from the flue gas outlet of the air preheater 2, and the high-temperature air after heating enters the second air pipeline 6, where it is mixed with the low-temperature air introduced through the bypass pipeline 8, and then enters the burner 7 of the boiler body 1 for auxiliary combustion after the temperature is reduced. Furthermore, the embodiment of the utility model is provided with an economizer 9 between the flue gas inlet of the air preheater 2 and the flue gas outlet of the boiler body 1. The high-temperature flue gas discharged from the boiler body 1 is initially cooled by the economizer 9 and then enters the air preheater 2 for further heat exchange and cooling with the low-temperature air.

[0017] The flue gas outlet of the air preheater 2 is provided with an oxygen and nitrogen oxide detector 10, which can detect the oxygen content and nitrogen oxide content in the exhaust flue gas in real time. The air inlet of the burner 7 is provided with a temperature sensor 11, which can detect the air temperature of the burner 7 in real time. The variable frequency fan 3 is provided with a frequency converter 12 for adjusting its operating frequency, and the bypass pipeline 8 is provided with a bypass baffle 13 for adjusting its air flow. The oxygen and nitrogen oxide detector 10, the temperature sensor 11, the frequency converter 12 and the bypass baffle 13 are all connected to the controller 4 for communication.

[0018] The controller 4 is configured to automatically adjust the opening of the bypass damper 13 according to the real-time detected burner 7 inlet air temperature or the nitrogen oxide content in the flue gas. When the burner 7 inlet air temperature reaches a preset value or the nitrogen oxide content in the flue gas reaches a preset value, the controller 4 can automatically adjust the opening of the bypass damper 13 to control the combustion air within the upper limit temperature to ensure that the nitrogen oxide content in the flue gas meets the standard.

[0019] The controller 4 is also configured to automatically adjust the operating frequency of the variable frequency fan 3 according to the oxygen content in the flue gas detected in real time. When the oxygen content in the flue gas deviates from a preset value by a certain range, the controller 4 can automatically adjust the operating frequency of the variable frequency fan 3 to achieve the purpose of automatically correcting the oxygen content.

[0020] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present invention. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A boiler combustion control system, characterized in that: It comprises a boiler body, an air preheater, a variable frequency fan and a controller; the smoke inlet of the air preheater is connected to the smoke outlet of the boiler body, the air inlet of the air preheater is connected to the variable frequency fan through a first air pipeline, the air outlet of the air preheater is connected to the burner of the boiler body through a second air pipeline, and the first air pipeline is connected to the second air pipeline through a bypass pipeline; The flue gas outlet of the air preheater is provided with an oxygen and nitrogen oxide detector, the air inlet of the burner is provided with a temperature sensor, the variable frequency fan is provided with a frequency converter, and a bypass baffle is provided in the bypass pipeline. The oxygen and nitrogen oxide detectors, the temperature sensor, the frequency converter and the bypass baffle are all communicatively connected with the controller.

2. A boiler combustion control system according to claim 1, characterized in that: The controller is configured to automatically adjust the opening of the bypass damper according to the burner inlet air temperature or the nitrogen oxide content in the flue gas detected in real time.

3. A boiler combustion control system according to claim 1, characterized in that: The controller is configured to automatically adjust the operating frequency of the variable frequency fan according to the oxygen content in the flue gas detected in real time.

4. A boiler combustion control system according to claim 1, characterized in that: An economizer is installed between the flue gas inlet of the air preheater and the flue gas outlet of the boiler body.

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