Thermal power generating unit feeding and distributing device
By designing the feed distribution device of the thermal power unit, controlling the coal feeder and the eddy current heating device, the deep peak regulating capability of the thermal power unit is realized, solving the problem of reduced stability and reliability in the peak regulating process of the thermal power unit, and achieving efficient and reliable peak regulating effect.
Patent Information
- Application Number
- CN202510065821.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-02-25
AI Technical Summary
During the peak shaving process, existing thermal power units are likely to lead to reduced system stability and reliability, increase failure rate, and the initial investment and later cost of cross-season peak shaving technology route is relatively high, making it difficult to promote.
A thermal power unit feed distribution device is designed to control the output of the coal feeder and the eddy current heating device by receiving the load command of DCS, so as to achieve deep peak shaving capability, ensure that the system operates in a comfortable area and reduce the failure rate.
The deep peak regulating capability of thermal power units is achieved, breaking through the limitation of conventional minimum load value. In special scenarios, negative output peak regulating can be achieved, system stability and reliability can be maintained, fault rate is reduced, and coal is saved during peak regulating.
Smart Images
Figure CN119508835A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of power generation, and in particular to a material feeding and distributing device for a thermal power unit. Background Art
[0002] As the proportion of renewable energy power output in today's power grid gradually increases, the demand for peak load regulation in the power system is becoming increasingly urgent. The current technology mainly relies on pumped storage, battery storage, molten salt heat storage, compressed air, flywheel storage and other technologies to achieve short-term peak load regulation. The cross-seasonal peak load regulation mainly relies on the technical route of producing hydrogen from electricity and then synthesizing ammonia alcohols, which are easy to store and transport. For the above short-term peak load regulation technology, it cannot be made very large and strong mainly due to the limitation of equipment capacity. The wind-solar-hydrogen-ammonia alcohol technology route used for cross-seasonal peak load regulation has high initial investment and later costs, and it is very difficult to promote.
[0004] The current thermal power peak-shaving technology mainly relies on low-load stable combustion technology. Under the premise of not causing flameout, the flame is suppressed as much as possible to reduce the output of the entire thermal power generation system. Current practice has proved that when the flame is suppressed to a certain extent, the stability and reliability of the entire power generation system will have problems one after another. The steam dryness decreases, and the turbine and generator run at the boundary of the comfort zone for a long time, resulting in a significant increase in the system failure rate. After the furnace flame is suppressed, the temperature change rate of the steam system exceeds the limit, and the expansion difference is too large, resulting in pipe bursting problems occasionally. Summary of the invention
[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first purpose of the present invention is to provide a technical solution for achieving deep peak-shaving capability of thermal power generating units without relying on external force, so as to improve the peak-shaving capability of thermal power generating units. The peak-shaving depth can easily break through the minimum load value limit of conventional thermal power generating units. In special scenarios, the peak-shaving depth can be negative output.
[0006] The second purpose of the present invention is to allow the thermal power unit system to remain in a comfortable zone during the peak load phase, while effectively maintaining the reliability and economy of the unit and not increasing the failure rate of the unit system.
[0007] To achieve the above object, the present invention is implemented through the following technical solutions.
[0008] A feeding distribution device (1) for a thermal power unit and an internal control algorithm, wherein a first end (2) of the device is connected to a DCS control signal (5) for receiving an original coal feeder speed instruction (8) and an external load instruction (11) from the DCS, a second end (3) of the device is connected to a coal feeder (6) for controlling the speed of a coal feeder belt, and a third end (4) of the device is connected to an eddy current heating device (7) for controlling the output power of the eddy current heating device (7).
[0009] When the external load instruction (11) from the DCS is lower than the minimum load value (12) of the thermal power unit, the subtractor (13) outputs a positive value, and after passing through the judgment block (14) and the first amplifier (17), an eddy current power instruction (18) is generated to supply the excess electric energy of the unit to the eddy current heating device (7) to generate heat energy; at the same time, the instruction signal output by the judgment block (14) is adjusted by a corresponding multiple through the second amplifier (15) and then acts on the original coal feeder speed instruction (8) as a subtrahend through the selector (16), and a new coal feeder speed instruction (10) is generated through the subtractor (9) and acts on the coal feeder (6), so as to reduce the belt speed of the coal feeder (6) and reduce the input of pulverized coal fuel.
[0010] Optionally, the coal feeder (6) may also be a belt conveyor for feeding the boiler of the biomass fuel power generation system, and the new coal feeder speed instruction (10) controls and adjusts the belt speed, which is used for a similar deep peak regulation automatic control system reconstruction scheme for adding an eddy current heating system to the biomass fuel boiler.
[0011] Optionally, the coal feeder (6) may also be an air intake flow control valve of a gas-fired power generation system, and the new coal feeder speed instruction (10) controls the opening of the gas inlet air control valve, which is used for a similar deep peak regulation automatic control system reconstruction scheme in which an electric eddy current heating system is added to the gas-fired power generation system. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a schematic diagram of the system composition of the present invention.
[0013] Figure 2 This is a logical schematic diagram of the internal control algorithm of the present invention.
[0014] Figure 3 It is the main logic program inside the material distribution device in the embodiment of the present invention.
[0015] Figure 4 This is the data state 1 of the main logic program inside the material distribution device in the embodiment of the present invention.
[0016] Figure 5 This is the second state of the main logic program data inside the material distribution device in the embodiment of the present invention.
[0017] Figure 6 This is the third state of the main logic program data inside the material distribution device in the embodiment of the present invention.
[0018] Figure 7 This is the fourth state of the main logic program data inside the material distribution device in the embodiment of the present invention. DETAILED DESCRIPTION
[0019] The present embodiment is described in detail below. Examples of the embodiment are shown in the accompanying drawings. The embodiment described below with reference to the accompanying drawings is exemplary and is intended to be used to explain the present invention, but should not be understood as limiting the present invention.
[0020] In this embodiment, a 300MW thermal power generating set is selected, and the power conversion efficiency is 40%, that is, the theoretical multiple K1 of the amplifier (15) is 0.4, and the minimum load value (12) is selected as 50% of the rated output. The external load instruction (11) is a 4-20mA signal corresponding to a 0-300MW load, that is, the signal corresponding to 50% of the rated output is 12mA. When the external load instruction (11) is lower than 12mA, it indicates that the peak regulation depth exceeds the conventional regulation capacity of the thermal power generating set, and at this time, the eddy current heating device (7) is put into operation.
[0021] In this embodiment, a medium-voltage medium-frequency eddy current generator with a capacity of 150MW and an eddy current coil wrapped in a metal tube with a center band of high-temperature resistant and anti-oxidation material are selected as the eddy current heating device (7). The efficiency loss of the device is negligible. The eddy current power instruction (18) is a 4~20mA signal corresponding to a 0~150MW power output. In order to match the rated load of the thermal power unit, the theoretical multiple K2 of the amplifier (17) is 2.
[0022] The present embodiment designs and selects the ACS880 inverter, which comprises two parts. The first part of the ACS880 inverter is a programmable module integrated in the ACS880 inverter. This part is selected as the feeding distribution device (1). The internal control logic reference Figure 3 The second part of the ACS880 inverter is the inverter part, which is selected as the variable frequency speed regulating device of the coal feeder (6). The speed command of the coal feeder is also designed as a 4~20mA signal, corresponding to the belt speed of the system 0~300MW output.
[0023] The AI1 of the ACS880 inverter programmable module serves as one of the first terminals (2) of the feeding distribution device (1) to receive the original coal feeder speed instruction (8) issued by the DCS; the AI2 of the programmable module serves as the second of the first terminals (2) of the feeding distribution device (1) to receive the external load instruction (11) issued by the DCS; the AO2 of the programmable module serves as the third terminal (4) of the feeding distribution device (1) to send the eddy current power instruction (18) to the eddy current heating device (7); the SR1 address of the programmable module serves as the second terminal ( 3), used to send a new coal feeder speed command (10) to the frequency conversion speed regulating device of the coal feeder (6); DI6 of the programmable module receives a fault status feedback signal from the eddy current heating device (7). When the eddy current heating device (7) fails and stops, the state of DI6 changes from 1 to 0. At the same time, the subtrahend of the subtractor (9) is also switched to 0. The new coal feeder speed command (10) is consistent with the original coal feeder speed command (8), ensuring that the total amount of furnace feed is stable and unaffected. The system still operates in a safe area above the minimum load value (12). Only the peak load regulation capacity is limited. Figure 3 .
[0024] When the unit external load command (11) is 75%, which is higher than the working condition of 50%, the eddy current heating device (7) does not need to be put into use. At this time, the actual load command is 225MW, the command signal corresponding to AI2 is 16mA, and the output signal of the eddy current power command (18) is 4mA, corresponding to 0MW output power. The new coal feeder speed command (10) is consistent with the original coal feeder speed command (8), and the system operates normally. Figure 4 .
[0025] When the unit external load instruction (11) is 25%, which is lower than the working condition of 50%, the eddy current heating device (7) needs to be put into operation. At this time, the actual load instruction is 75MW, and the AI2 actual load instruction signal is 8mA. Under this working condition, the original coal feeder speed instruction (8) is limited to the minimum load value (12) position (i.e. 50%, 150MW). The eddy current heating device (7) receives the eddy current power instruction (18) of 12mA from the feeding distribution device (1). The eddy current heating device starts to work and puts in 50% of the rated power (i.e. 75MW). At the same time, the electric energy consumed by the eddy current heating device (7) replaces part of the calorific value of the electric coal to generate 30MW of electric energy. Therefore, the calculated electric coal input can reduce the rated capacity by 10%, that is, the coal feeder belt speed signal is reduced by 1.6mA, from 12mA to 10.4mA. At this time, the total export power of the power generation system is 75MW, achieving deep peak regulation, and also achieving the purpose of saving coal during peak regulation. Figure 5 .
[0026] When the unit external load command (11) is 25% (power 75MW), the eddy current heating device (7) that should have been working suddenly fails and stops, and the eddy current power command (18) is not effectively executed. The DI6 of the programmable module receives the fault feedback signal from the eddy current heating device (7) and jumps to zero. The selector (16) switches to output the value 0 as the subtrahend. The original coal feeder speed command (8) and the new coal feeder speed command (10) remain the same. The unit operates at 50% load. Although the deep peak regulation function is not realized at this time, the entire system remains in a safe area and does not cause the system to stop operating due to failure. Refer to Figure 6 .
[0027] When the unit external load command (11) is 0%, the actual load command is 0MW. When the load is lower than 50%, the eddy current heating device (7) needs to be put into operation. The AI2 actual load command signal is 4mA. At this time, the original coal feeder speed command (8) is limited to the minimum load value (12) position (i.e. 50%, 150MW). The eddy current heating device (7) receives the eddy current power command (18) of 20mA from the feeding distribution device (1). The eddy current heating device starts to work and puts in 100% of the rated power (i.e. 150MW). At the same time, the electric energy consumed by the eddy current heating device (7) replaces part of the calorific value of the electric coal to generate 60MW of electric energy. Therefore, the calculated electric coal input can reduce the rated capacity by 20%, that is, the coal feeder belt speed signal is reduced by 3.2mA, from 12mA to 8.8mA, and the total export power is 0MW, achieving deep peak regulation and achieving the purpose of saving coal during peak regulation. Figure 7 .
[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.
[0029] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.
Claims
1. A feeding distribution device for a thermal power unit, characterized in that: It comprises a feeding distribution device (1) and an internal control algorithm.
2. The feeding and distributing device for a thermal power unit according to claim 1, characterized in that: The first end (2) is connected to a DCS control signal (5) and is used to receive an original coal feeder speed instruction (8) and an external load instruction (11) from the DCS.
3. The feeding and distributing device for a thermal power unit according to claim 1, characterized in that: The second end (3) is connected to a coal feeder (6) and is used to control the belt speed of the coal feeder.
4. The feeding and distributing device for a thermal power unit according to claim 1, characterized in that: The third end (4) is connected to the eddy current heating device (7) and is used to control the output power of the eddy current heating device (7).
5. The feeding and distributing device for a thermal power plant as claimed in claim 1, characterized in that: When the external load command (11) from the DCS is lower than the minimum load value (12) of the thermal power unit, the excess electric energy of the unit is automatically adjusted by the feed distribution device (1) to be supplied to the eddy current heating device (7) to generate heat energy. At the same time, the feed distribution device (1) automatically adjusts and reduces the belt speed of the coal feeder (6) to reduce the input of pulverized coal fuel.
6. The feeding and distributing device for a thermal power unit as claimed in claim 1, wherein the coal feeder (6) can also be a belt conveyor for feeding biomass fuel, and is used in a similar deep peak-shaving automatic control scheme for adding an electric heating system to a boiler of a biomass fuel power generation system.
7. The feeding and distributing device for a thermal power unit as claimed in claim 1, wherein the coal feeder (6) can also be a combustible gas flow regulating valve, which is used for a similar deep peak regulation automatic control scheme of adding an electric heating system to a boiler of a gas-fired power generation system.