An improved flexible frequency modulation operation system and method for cylinder cutting heating unit
Through the cooperation of flexible frequency modulation controller and heat grid heater, the problem of poor frequency modulation quality of large cogeneration units during back pressure heating is solved, efficient frequency modulation control and energy saving effects are achieved, and coal consumption and assessment losses are reduced. .
Patent Information
- Application Number
- CN202010444478.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-05-23
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2040-05-23
AI Technical Summary
After the large cogeneration unit cuts off the low-pressure cylinder and runs, the back pressure heating results in the frequency regulation quality that cannot meet the scheduling requirements, and the operational economy is poor, making it difficult to achieve deep peak shaving and new energy consumption.
Using flexible frequency regulation controller and appropriate control algorithms, the steam inlet control valve of the fully opened unit and the steam inlet control valve of the heat grid heater are adjusted, and the heat storage capacity of the heating pump pipe and the water pipe of the heat grid can be achieved instantaneously. Power regulation reduces the loss of inlet steam throttling, improves the quality of frequency modulation response and energy-saving efficiency.
More efficient frequency regulation control is achieved, the coal consumption rate of power supply is reduced by about 0.5g/kwh, the average operating efficiency of high-pressure cylinders is improved by 1%, and the loss of 5 million yuan for dispatched assessment is reduced.
Smart Images
Figure CN111677566B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of thermal power generation, and in particular relates to an improved flexible frequency modulation operation system and method for a cylinder cutting heating unit. Background Art
[0002] The centralized heating of large-scale cogeneration units is currently facing a new situation of new energy consumption and deep peak regulation. Removing the low-pressure cylinder for heating transformation can increase the heating capacity and increase the deep peak regulation capacity of the unit. This has been widely promoted in the industry this year.
[0003] For large cogeneration units, especially after the low-pressure cylinder is cut off, the unit's extraction and condensing operation mode is changed to back-pressure heating and combined power generation operation mode. The operation mode changes greatly, and the back-pressure heating operation leads to electricity being determined by heat, which has a certain impact on the unit's peak load regulation.
[0004] Especially with the current outstanding problem of new energy consumption, the requirements for deep peak regulation and frequency regulation of heating units are still high. Using the traditional steam inlet regulation method to perform frequency regulation control once can easily lead to the frequency regulation quality failing to meet the dispatching requirements, and being frequently assessed, and the operation economy itself is not optimal.
[0005] For units that cut off the low-pressure cylinder for heating, it is necessary to study better frequency regulation control operation methods from the perspective of energy-saving regulation and frequency regulation quality. Summary of the invention
[0006] The object of the present invention is to provide an improved flexible frequency modulation operation system and method for a cylinder cutting heating unit. By setting a flexible frequency modulation controller and adopting a suitable control algorithm, when the cylinder cutting heating operation is realized, the fully open unit steam inlet control valve is preferentially adopted and the heat network heater steam inlet regulating valve is used for response regulation. By making full use of the heat storage capacity of the heating steam extraction pipeline and the large-capacity heat network water pipeline, the unit is subjected to instantaneous power regulation, thereby achieving the purpose of primary frequency regulation, reducing the unit steam inlet throttling loss, improving the frequency regulation response quality and realizing energy-saving frequency regulation.
[0007] The present invention provides an improved cylinder-cutting heating unit flexible frequency modulation operation system, comprising a steam turbine high- and medium-pressure cylinder, a low-pressure cylinder, a heating network heater, a frequency modulation controller, an isolation valve, a regulating valve, a steam inlet control valve, and a heating network water pipeline;
[0008] The middle cylinder steam exhaust port of the high and medium pressure cylinders is connected to the low pressure cylinder inlet through a connecting pipeline and an isolation valve on the pipeline; the middle cylinder steam exhaust port of the high and medium pressure cylinders is connected to the steam side inlet of the heat network heater through a connecting pipeline and a regulating valve on the pipeline; the water side inlet and outlet of the heat network heater are connected to the heat network water pipeline; the steam inlet control valve is connected to the steam inlet of the high and medium pressure cylinders through a steam pipeline; the frequency modulation controller input port is connected through a cable to receive frequency modulation demand instructions and calculate a given signal as a controller; the frequency modulation controller output port is connected to the steam inlet control valve signal input port and the regulating valve signal input port through a cable.
[0009] The present invention also provides a frequency modulation operation method of the system, comprising:
[0010] When the unit cuts off the low-pressure cylinder by closing the isolation valve to operate with back pressure heating of the high and medium pressure cylinders, the frequency modulation controller is used to simultaneously control the steam inlet control valve and the regulating valve to achieve synchronous regulation of the unit's steam inlet volume and the heating steam extraction volume;
[0011] Under normal frequency regulation operation mode, the frequency regulation controller sends a command to fully open the steam inlet control valve 100%, and at the same time sends a command to flexibly control the frequency regulation of the regulating valve; when the normal frequency regulation range is exceeded, the frequency regulation controller sends a command to allow the steam inlet control valve to participate in the regulation as a supplementary frequency regulation method; in the non-heating season, the regulating valve is closed, and the frequency regulation controller only sends a command to the steam inlet control valve for frequency regulation control, thereby realizing flexible frequency regulation operation of the unit under different conditions.
[0012] Through the above scheme, through the improved flexible frequency modulation operation system and method of the cylinder cutting heating unit, firstly, the cylinder cutting operation unit can be realized in the normal heating frequency modulation, the frequency modulation controller calculates and issues the frequency modulation demand instruction, and only the instantaneous control of the regulating valve opening is adopted while the steam inlet control valve is kept fully open, so that the control operation of the unit's primary frequency modulation can be realized, so that the unit's steam inlet throttling loss is minimized and the high and medium pressure 1 efficiency is guaranteed; the control valve and the regulating valve can be synchronously operated by the frequency modulation controller to achieve a larger primary frequency modulation action operation demand, always ensure the control quality of the unit's primary frequency modulation, and reduce the loss of scheduling assessment during the heating season. For a typical 300WM cylinder cutting heating unit, compared with the conventional single steam inlet throttling primary frequency modulation control method, the power supply coal consumption rate can be reduced by about 0.5g / kwh, and the average operation efficiency of the high-pressure cylinder can be increased by 1%, and the loss of assessment can be reduced by 5 million yuan in one heating season.
[0013] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1It is a structural schematic diagram of the flexible frequency modulation operation system of the improved cylinder cutting heating unit of the present invention.
[0015] Numbers in the figure:
[0016] 1- high and medium pressure cylinders of steam turbine; 2- low pressure cylinder; 3- heating network heater; 4- frequency modulation controller; 5- isolation valve; 6- regulating valve; 7- steam inlet control valve; 8- heating network water pipeline; 9- frequency modulation demand instruction. DETAILED DESCRIPTION
[0017] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0018] Ginseng Figure 1 As shown, this embodiment provides an improved flexible frequency modulation operation system for a cylinder cutting heating unit, comprising a high and medium pressure cylinder 1 of a steam turbine, a low pressure cylinder 2, a heating network heater 3, a frequency modulation controller 4, an isolation valve 5, a regulating valve 6, a steam inlet control valve 7, a heating network water pipeline 8, a frequency modulation demand instruction 9 and a connection system thereof, wherein the middle cylinder exhaust port of the high and medium pressure cylinder 1 enters the inlet part of the low pressure cylinder 2 through a connecting pipeline and the isolation valve 5 on the pipeline; the middle cylinder exhaust port of the high and medium pressure cylinder 1 is connected to the steam side inlet of the heating network heater 3 through a connecting pipeline and the regulating valve 6 on the pipeline; the water side inlet and outlet of the heating network heater 3 are connected to the heating network water pipeline 8; the steam inlet control valve 7 is connected to the steam inlet of the high and medium pressure cylinder 1 through a steam pipeline; the input port of the frequency modulation controller 4 is connected through a cable to receive the frequency modulation demand instruction 9 and calculate a given signal as a controller; the output port of the frequency modulation controller 4 is connected to the signal input port of the steam inlet control valve 7 through a cable; the output port of the frequency modulation controller 4 is connected to the signal input port of the regulating valve 6 through a cable.
[0019] The improved cylinder cutting heating unit flexible frequency modulation operation method includes:
[0020] When the unit cuts off the low-pressure cylinder 2 by closing the isolation valve 5 to operate with back pressure heating of the high- and medium-pressure cylinders 1, in order to ensure continuous and stable heating and the quality of the unit's primary frequency regulation response, a flexible frequency regulation controller 4 is used to simultaneously control the steam inlet control valve 7 and the regulating valve 6 to achieve synchronous regulation of the unit's steam inlet volume and heating steam extraction volume.
[0021] Under normal frequency regulation operation mode, the frequency regulation controller 4 sends a command to fully open the steam inlet control valve 7 100%, and at the same time sends a command to flexibly control the frequency regulation of the regulating valve 6; when it exceeds the normal frequency regulation range, the frequency regulation controller 4 sends a command to make the steam inlet control valve 7 participate in the regulation as a supplementary frequency regulation method; in the non-heating season, the regulating valve 6 is closed, and the frequency regulation controller 4 only sends a command to the steam inlet control valve 7 for frequency regulation control, thereby realizing flexible frequency regulation operation of the unit under different conditions.
[0022] When the unit is in normal heating and frequency modulation, the frequency modulation controller 4 calculates and issues a frequency modulation demand instruction 9. Only by instantaneously controlling the opening of the regulating valve 6 and keeping the steam inlet control valve 7 fully open, the unit's primary frequency modulation can be controlled and operated, minimizing the unit's steam inlet throttling loss and ensuring the efficiency of the high and medium pressure cylinders 1.
[0023] When the frequency modulation demand is large, the control valve 7 and the regulating valve 6 can be synchronously operated by the frequency modulation controller 4 to achieve a larger primary frequency modulation operation demand, always ensure the control quality of the unit's primary frequency modulation, and reduce the loss of scheduling assessment during the heating season. For a typical 300WM cylinder cutting heating unit, compared with the conventional single steam inlet throttling primary frequency modulation control method, the power supply coal consumption rate can be reduced by about 0.5g / kwh, and the average operating efficiency of the high-pressure cylinder can be increased by 1%, which can reduce the loss of assessment by 5 million yuan in one heating season.
[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A frequency modulation operation method, characterized in that: Based on the improved cylinder cutting heating unit flexible frequency modulation operation system, the system includes steam turbine high and medium pressure cylinders, low pressure cylinders, heating network heaters, frequency modulation controllers, isolation valves, regulating valves, steam inlet control valves, and heating network water pipelines; The middle cylinder exhaust port of the high and medium pressure cylinder is connected to the low pressure cylinder inlet through the connecting pipeline and the isolation valve on the pipeline; the middle cylinder exhaust port of the high and medium pressure cylinder is connected to the steam side inlet of the heating network heater through the connecting pipeline and the regulating valve on the pipeline; the water side inlet and outlet of the heating network heater are connected to the heating network water pipeline; the steam inlet control valve is connected to the steam inlet of the high and medium pressure cylinder through the steam pipeline; the input port of the frequency modulation controller is connected through a cable to receive the frequency modulation demand instruction and calculate the given signal as a controller; the output port of the frequency modulation controller is connected to the steam inlet control valve signal input port and the regulating valve signal input port through a cable; The method comprises: When the unit cuts off the low-pressure cylinder by closing the isolation valve to operate with back pressure heating of the high and medium pressure cylinders, the frequency modulation controller is used to simultaneously control the steam inlet control valve and the regulating valve to achieve synchronous regulation of the unit's steam inlet volume and the heating steam extraction volume; Under normal frequency regulation operation mode, the frequency regulation controller sends a command to fully open the steam inlet control valve 100%, and at the same time sends a command to flexibly control the frequency regulation of the regulating valve; when it exceeds the normal frequency regulation range, the frequency regulation controller sends a command to allow the steam inlet control valve to participate in the regulation as a supplementary frequency regulation method; in the non-heating season, the regulating valve is closed, and the frequency regulation controller only sends a command to the steam inlet control valve for frequency regulation control, thereby realizing flexible frequency regulation operation of the unit under different conditions.