Linkage control method for fluidization fan of circulating fluidized bed boiler
By linking the online calculation module and the PI controller, the linkage between the fluidizing fan outlet baffle and the frequency converter was realized, which solved the problem of high energy consumption of the fluidizing fan in the circulating fluidized bed boiler and improved the regulation efficiency and economy.
Patent Information
- Application Number
- CN202511200328.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-26
- Publication Date
- 2025-11-14
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The fluidizing blower of the circulating fluidized bed boiler has high energy consumption, and the existing adjustment method is inefficient and uneconomical, and cannot guarantee the fluidization of the bed material through speed regulation.
An online calculation module for the opening degree and speed of the fluidizing fan outlet damper is adopted, combined with a PI controller, to realize the linkage control of the fluidizing fan frequency converter and the outlet damper. Based on the operating characteristics of bed pressure drop and primary air volume, the outlet damper and frequency converter are adjusted in real time.
It reduces the regulating energy consumption of fluidizing blowers, improves their regulating efficiency, and meets the operating requirements under different boiler loads.
Smart Images
Figure CN120946602A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of circulating fluidized bed boiler control technology, and more specifically, to a method for linkage control of fluidizing blowers in a circulating fluidized bed boiler. Background Technology
[0002] Circulating fluidized bed combustion technology is a clean coal combustion technology. It involves adding coal and desulfurizing agents to the bed in the combustion chamber, and then using forced air from the bottom of the furnace to suspend the bed for fluidized combustion. It is particularly suitable for burning low-quality fuels with high ash, high sulfur, and low volatile matter (such as coal gangue), which are difficult for conventional pulverized coal boilers to handle. It features low-cost, high-efficiency in-furnace desulfurization and low NOx emissions. X Advantages include emissions reduction. Circulating fluidized bed boilers have developed rapidly, with increasingly larger capacities, playing a crucial role in changing the power supply structure and realizing the cascade utilization of energy.
[0003] One of the main problems in the operation of circulating fluidized bed boilers is the high energy consumption of fluidizing blowers (i.e., primary air fans). This is mainly due to two reasons: First, the primary air in a circulating fluidized bed boiler plays the role of fluidizing the bed material. Bed materials weighing tens to hundreds of tons need to be fluidized by primary air with a high energy head, so the power consumption of the primary air fan is relatively large. Second, the adjustment method of primary air is uneconomical.
[0004] In existing technologies, the fluidizing blowers of circulating fluidized bed boilers almost all use inlet baffle regulation. Figure 1 As shown, the air volume and pressure are adjusted by changing the opening of the inlet baffle, which is an inefficient and energy-intensive adjustment method. Furthermore, fluidizing blowers are not suitable for using only variable speed regulation because as the rotational speed decreases, the primary air volume decreases by the first power of the rotational speed, while the total pressure decreases by the square of the rotational speed. This results in a drastic drop in the total pressure of the fluidizing blower, which cannot guarantee the fluidization of the bed material. Therefore, using only variable speed regulation for fluidizing blowers in circulating fluidized bed boilers is not feasible, while using only inlet baffle regulation is uneconomical. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a method for linkage control of fluidizing blowers in circulating fluidized bed boilers.
[0006] To address the above technical problems, this invention provides a method for the coordinated control of fluidizing fans in a circulating fluidized bed boiler. Based on the operating characteristics of the circulating fluidized bed boiler's bed pressure drop and primary air volume, an online calculation module for the fluidizing fan outlet damper opening and speed is set up. This module provides real-time setpoints for the fluidizing fan outlet damper opening and fan speed under different boiler loads. A PI controller is used to adjust the outlet damper and frequency converter respectively, thereby achieving coordinated control of the fluidizing fan frequency converter and outlet damper.
[0007] Furthermore, the online calculation module for the fluidizing blower outlet damper opening and speed determines the bed pressure drop and primary air volume based on the operating characteristics of the bed pressure drop and primary air volume; calculates the resistance of the primary air and flue gas system to determine the fluidizing blower outlet damper opening and the total pressure of the fluidizing blower; and, based on the blower performance under total pressure, flow rate, and rated speed, combined with the principle of similar operating conditions, provides real-time setpoints for the fluidizing blower outlet damper opening and blower speed under different boiler loads.
[0008] Furthermore, the bed pressure drop in the online calculation module for the fluidizing blower outlet damper opening and rotational speed... and primary air volume The following is determined: (1) (2) Where R is the boiler load rate.
[0009] Furthermore, the fan outlet damper opening and speed online calculation module includes the fan outlet damper opening. The calculation is as follows: (3) In equation (3), It is the bed pressure drop resistance characteristic coefficient, which is determined by the design flow operating point; It is a resistance coefficient related to the opening degree of the fluidizing blower outlet damper, and is a correlation determined by damper opening resistance characteristic tests. When the bed pressure drop... Primary air volume Sum of coefficients Given that, the corresponding baffle opening can be determined by equation (3). .
[0010] Furthermore, the fan speed in the online calculation module for the fan outlet damper opening and rotational speed is calculated based on the fluidizing fan performance under total pressure, flow rate, and rated speed, combined with the principle of similar operating conditions.
[0011] Furthermore, the linkage control system of the frequency converter and the outlet damper is based on the given values of the opening of the fluidizing fan outlet damper and the fan speed under different boiler loads calculated in real time. The system uses a PI controller to adjust the outlet damper and the frequency converter respectively, thereby realizing the linkage control of the fluidizing fan frequency converter and the outlet damper.
[0012] This invention incorporates the operating characteristics of the bed pressure drop and primary air volume of a circulating fluidized bed boiler into the automatic control system of the primary air fan. An online calculation module is set up to calculate in real time the set value of the fluidized bed fan outlet damper opening and the set value of the frequency converter speed under different boiler loads, thereby realizing the linkage control between the fluidized bed fan outlet damper and the frequency converter. Attached Figure Description
[0013] Figure 1 This refers to the existing technology of the circulating fluidized bed boiler primary air fan inlet damper control system; Figure 2 Operating characteristics of bed pressure drop in circulating fluidized bed boilers; Figure 3 Operating characteristics of primary air volume in circulating fluidized bed boilers; Figure 4 This invention relates to a primary air fan control system for a circulating fluidized bed boiler. Figure 5 A schematic diagram for determining the opening degree and rotational speed of the primary air fan outlet damper in a circulating fluidized bed boiler. Detailed Implementation
[0014] This invention provides a typical embodiment of a circulating fluidized bed boiler fluidizing fan linkage control method. The method involves acquiring load commands, determining the bed pressure drop and primary air volume based on the operating characteristics of the bed pressure drop and primary air volume, calculating the resistance of the primary air system, determining the primary air fan outlet damper opening and the primary air fan total pressure, calculating the fluidizing fan speed based on the primary air fan performance under total pressure, flow rate, and rated speed, combined with the principle of similar operating conditions, and using the calculated fluidizing fan outlet damper opening and speed as setpoints. A PI controller is then used to adjust the outlet damper and frequency converter respectively, achieving linkage control of the fluidizing fan frequency converter and outlet damper. This meets the operating requirements of the circulating fluidized bed boiler while reducing adjustment energy consumption.
[0015] according to Figure 2 , Figure 3 The bed pressure drop Δp shown l The operating characteristics of the primary air volume Q1 are used to determine the bed pressure drop based on the boiler load rate R. and primary air volume .
[0016] Bed pressure drop and primary air fan outlet damper opening and primary air volume Related, can be described as: (1) In equation (1), It is the bed pressure drop resistance characteristic coefficient, which is determined by the design flow operating point; This is a resistance coefficient related to the opening degree of the primary air fan outlet damper, and it is a correlation determined by damper opening resistance characteristic tests. When the bed pressure drop... Primary air volume Sum of coefficients Given that, the corresponding baffle opening can be determined by equation (1). .
[0017] Primary air fan full pressure It can be obtained through calculation of the resistance of the flue gas system: (2) In equation (2), The resistance loss between the primary air fan outlet and the air preheater outlet is calculated as follows: calculate, The drag coefficient is determined through drag characteristic tests; The resistance loss of the hot air duct between the air preheater outlet and the air distribution panel chamber is calculated as follows: calculate, The drag coefficient is determined through drag characteristic tests.
[0018] Total pressure from the blower and traffic The operating point of the fan can be determined, such as Figure 5 1 point shown.
[0019] Figure 5 In the diagram, point 0 represents the operating point of the primary air fan at its rated flow rate, where the rotational speed is... The fan performance curve and the fan outlet damper opening are as follows: The intersection of the resistance curves. Draw the resistance curve through point 1. Its performance curve intersects with the wind turbine's performance curve at two points, which are similar operating points to point one. The flow rate at point two is... The result can be obtained by combining the resistance curve and the fan performance curve:
[0020] have to: (3) Based on the principle of similar operating conditions, determine the fan speed at point 1: (4) (6) Opening degree of the outlet damper of the output fan And fan speed This enables automatic linkage control of the fan outlet baffle and frequency converter for each actuator.
[0021] Based on the above-mentioned control method for the primary air fan of a circulating fluidized bed boiler, those skilled in the art can implement a linkage control method for the primary air fan frequency converter and the outlet damper based on the operating characteristics of the bed pressure drop. Other technical contents and technical terms involved in this specification should be understood and implemented in accordance with common knowledge and conventional technical means in this field, or they can be implemented through reasonable analysis and reasoning methods.
Claims
1. A method for linkage control of fluidizing blowers in a circulating fluidized bed boiler, characterized in that: Based on the operating characteristics of the circulating fluidized bed boiler bed pressure drop and primary air volume, an online calculation module for the fluidizing fan outlet damper opening and speed is set up to provide real-time setpoints for the fluidizing fan outlet damper opening and fan speed under different boiler loads. A PI controller is used to adjust the outlet damper and frequency converter respectively to achieve linkage control between the fluidizing fan frequency converter and the outlet damper.
2. The method for linkage control of fluidizing blowers in a circulating fluidized bed boiler according to claim 1, characterized in that: The online calculation module for fluidizing fan outlet damper opening and speed determines the bed pressure drop and primary air volume based on the operating characteristics of the bed pressure drop and primary air volume; calculates the resistance of the primary air and flue gas system to determine the fluidizing fan outlet damper opening and the total pressure of the fluidizing fan; and, based on the fan performance under total pressure, flow rate, and rated speed, combined with the principle of similar operating conditions, provides real-time setpoints for the fluidizing fan outlet damper opening and fan speed under different boiler loads.
3. The method for linkage control of fluidizing blowers in a circulating fluidized bed boiler according to claim 2, characterized in that: Bed pressure drop in the online calculation module for fluidized bed blower outlet damper opening and rotational speed and primary air volume The following is determined: （1） （2） Where R is the boiler load rate.
4. The method for linkage control of fluidizing blowers in a circulating fluidized bed boiler according to claim 2, characterized in that: The fan outlet damper opening and speed online calculation module includes the fan outlet damper opening. The calculation is as follows: （3） In equation (3), It is the bed pressure drop resistance characteristic coefficient, which is determined by the design flow operating point; It is a resistance coefficient related to the opening degree of the fluidizing blower outlet damper, and is a correlation determined by the damper opening resistance characteristic test; when the bed pressure drop Primary air volume Sum of coefficients Given that, the corresponding baffle opening can be determined by equation (3). .
5. The method for linkage control of fluidizing blowers in a circulating fluidized bed boiler according to claim 2, characterized in that: The fan speed in the online calculation module for the fan outlet damper opening and rotational speed is calculated based on the fluidized fan performance under total pressure, flow rate, and rated speed, combined with the principle of similar operating conditions.
6. The method for linkage control of fluidizing blowers in a circulating fluidized bed boiler according to claim 1, characterized in that: The linkage control system of the frequency converter and the outlet damper is based on the real-time calculation of the opening degree of the fluidizing fan outlet damper and the fan speed under different boiler loads. The system uses a PI controller to adjust the outlet damper and the frequency converter respectively, so as to realize the linkage control of the fluidizing fan frequency converter and the outlet damper.