High-efficiency operation coal power unit thermodynamic system and control method

Abstract

The invention relates to an efficient operation coal power unit thermodynamic system and an efficient operation coal power unit thermodynamic system control method. The coal power unit thermodynamic system capable of operating efficiently comprises a first low-pressure cylinder group and a second low-pressure cylinder group which are connected in parallel; the first cylinder group steam admission amount of the first low-pressure cylinder group and the second cylinder group steam admission amount of the second low-pressure cylinder group are set according to a preset proportion, and the sum of the first cylinder group steam admission amount and the second cylinder group steam admission amount meets the rated working condition use requirement of the thermodynamic system; a first cylinder group steam inlet of the first low-pressure cylinder group is connected with a medium-pressure steam transmission pipeline of the thermodynamic system of the coal power unit in efficient operation through a first medium-pressure steam transmission branch; a second cylinder group steam inlet of the second low-pressure cylinder group is connected with the medium-pressure steam transmission pipeline through a second medium-pressure steam transmission branch; a first valve is arranged on the first medium-pressure steam transmission branch and used for adjusting a first steam inlet parameter of the first low-pressure cylinder set. By the adoption of the thermodynamic system, the wide-load efficiency of the whole unit can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of power generation units, and in particular to a thermal system of a coal-fired power generation unit with high efficiency and a control method for the thermal system of a coal-fired power generation unit with high efficiency. Background Art

[0002] Power generation from coal-fired power plants is a complex energy conversion process involving the interconversion of multiple energy forms. The steam turbine in a coal-fired power plant's thermal system, operating efficiently, is a crucial component of this energy conversion process. Its operating efficiency and performance directly impact the overall efficiency and performance of the unit. The steam turbine's cylinders are divided into high-pressure, intermediate-pressure, and low-pressure cylinders based on the steam inlet parameters. In actual operation, the high-pressure cylinder generates work through the main steam, and the exhaust steam enters the boiler reheater for heating before entering the intermediate-pressure cylinder to generate work. The exhaust steam from the intermediate-pressure cylinder then enters the low-pressure cylinder to generate work.

[0003] Traditional turbine units are typically built with maximum power generation as the goal, so the turbine's low-pressure cylinder is typically designed based on rated operating conditions. However, with the development of renewable energy and the construction of new power systems, coal-fired power is gradually shifting towards regulating and supporting power sources. Ultra-supercritical units with large steam inlets generally operate at low to medium loads, failing to fully utilize their high efficiency at rated load. Therefore, improving the operating efficiency of the turbine's low-pressure cylinder under various load conditions, thereby enhancing the wide-load efficiency of the entire unit, is a pressing issue for current generators. Summary of the Invention

[0004] Based on this, it is necessary to provide a high-efficiency coal-fired power unit thermal system and a high-efficiency coal-fired power unit thermal system control method that can improve the wide-load efficiency of the entire unit in response to the above technical problems.

[0005] In a first aspect, the present application provides a highly efficient thermal system for a coal-fired power plant, the highly efficient thermal system comprising: a first low-pressure cylinder group and a second low-pressure cylinder group connected in parallel;

[0006] The steam intake amount of the first cylinder group of the first low-pressure cylinder group and the steam intake amount of the second cylinder group of the second low-pressure cylinder group are set according to a preset ratio, and the steam intake amount of the first cylinder group and the steam intake amount of the second cylinder group meet the rated operating condition usage requirement of the thermal system of the coal-fired power unit with high efficiency operation;

[0007] The first cylinder group steam inlet of the first low-pressure cylinder group is connected to the medium-pressure steam transmission pipeline of the thermal system of the efficiently operating coal-fired power unit through a first medium-pressure steam transmission branch; the second cylinder group steam inlet of the second low-pressure cylinder group is connected to the medium-pressure steam transmission pipeline through a second medium-pressure steam transmission branch;

[0008] The first intermediate-pressure steam transmission branch is provided with a first valve for adjusting a first steam inlet parameter of the first low-pressure cylinder group.

[0009] In one embodiment, the thermal system of the highly efficient coal-fired power unit further comprises: a heat recovery component for extracting low-pressure exhaust steam from the first low-pressure cylinder group and the second low-pressure cylinder group to heat boiler feed water;

[0010] The first low-pressure exhaust port of the first low-pressure cylinder group is connected to the heat recovery component through a first low-pressure exhaust channel; the second low-pressure exhaust port of the second low-pressure cylinder group is connected to the heat recovery component through a second low-pressure exhaust channel.

[0011] In one embodiment, a second valve is provided on the first low-pressure steam exhaust passage for controlling the opening and closing of the first low-pressure steam exhaust passage.

[0012] In one embodiment, the steam intake amount of the second cylinder group is greater than the steam intake amount of the first cylinder group;

[0013] A third valve is provided on the second intermediate-pressure steam transmission branch for adjusting the second steam inlet parameters of the second intermediate- and low-pressure cylinder groups.

[0014] In one embodiment, a fourth valve is provided on the second low-pressure steam exhaust passage for controlling the opening and closing of the second low-pressure steam exhaust passage.

[0015] In one embodiment, the heat recovery assembly includes a first low-pressure heater, a second low-pressure heater, a third low-pressure heater, and a fourth low-pressure heater;

[0016] The first low-pressure heater, the second low-pressure heater, the third low-pressure heater and the fourth low-pressure heater are sequentially connected through a water supply channel, and steam extraction temperatures of the first low-pressure heater, the second low-pressure heater, the third low-pressure heater and the fourth low-pressure heater are sequentially decreased;

[0017] The first low-pressure exhaust port is connected to the second low-pressure heater and the fourth low-pressure heater through the first low-pressure exhaust passage; the second low-pressure exhaust port is connected to the first low-pressure heater and the third low-pressure heater through the second low-pressure exhaust passage.

[0018] In a second aspect, the present application provides a method for controlling a thermal system of a coal-fired power plant with high efficiency, which is applied to the thermal system of the coal-fired power plant with high efficiency as described above. The method comprises:

[0019] Obtaining operating condition information of the thermal system of the efficiently operating coal-fired power unit;

[0020] When it is determined based on the operating condition information that the thermal system of the efficiently operating coal-fired power generation unit is in a rated operating condition, controlling a first valve of the thermal system of the efficiently operating coal-fired power generation unit to be at a maximum opening;

[0021] If the thermal system of the efficiently operating coal-fired power unit is not in the rated operating condition, determining, based on the operating condition information, an operating condition range within which the operating condition of the thermal system of the efficiently operating coal-fired power unit falls; the operating condition range is determined based on a first matching load condition corresponding to the steam intake of the first cylinder group and a second matching load condition corresponding to the steam intake of the second cylinder group;

[0022] Based on the operating condition range, the valve opening of the first valve in the thermal system of the efficiently operating coal-fired power unit is adjusted.

[0023] In one embodiment, the steam intake amount of the second cylinder group is greater than the steam intake amount of the first cylinder group;

[0024] Determining the valve opening of the first valve in the thermal system of the efficiently operating coal-fired power unit based on the operating condition range includes:

[0025] When the operating condition range is a first low-load operating condition range, a target valve opening of the first valve is determined based on a load difference between an operating condition of the thermal system of the efficiently operating coal-fired power unit and a second matched load condition; an upper limit of the first low-load operating condition range is the rated operating condition, and a lower limit is the second matched load condition;

[0026] The opening of the first valve is adjusted according to the target valve opening.

[0027] In one embodiment, the method further comprises:

[0028] When the operating range is a second low-load operating range, reducing the opening of the first valve to a safe opening; the upper limit of the second low-load operating range is the second matching load condition, and the lower limit is the first matching load condition;

[0029] Close the second valve provided on the first low-pressure exhaust passage in the thermal system of the efficiently operating coal-fired power unit.

[0030] In one embodiment, the method further comprises:

[0031] When the operating condition range is the third low load condition, adjusting the valve opening of the first valve to the maximum opening; the upper limit value of the third low load condition is the first matching load condition;

[0032] Opening a second valve provided on a first low-pressure exhaust steam passage in the thermal system of the efficiently operating coal-fired power unit;

[0033] Close the fourth valve on the second low-pressure exhaust passage in the thermal system of the efficiently operating coal-fired power unit and the third valve on the second medium-pressure steam transmission branch in the thermal system of the efficiently operating coal-fired power unit.

[0034] The above-mentioned highly efficient thermal system of a coal-fired power unit and the method for controlling the highly efficient thermal system of a coal-fired power unit are as follows: the highly efficient thermal system of the coal-fired power unit includes a first low-pressure cylinder group and a second low-pressure cylinder group connected in parallel, the first low-pressure cylinder group being connected to a medium-pressure steam transmission pipeline via a first medium-pressure steam transmission branch, and the second low-pressure cylinder group being connected to the medium-pressure steam transmission pipeline via a second medium-pressure steam transmission branch, wherein a first valve is provided on the first medium-pressure steam transmission branch, and a first steam inlet parameter of the first low-pressure cylinder group can be adjusted by adjusting the valve opening of the first valve. Since the steam inlet volume of the first cylinder group and the steam inlet volume of the second cylinder group meet the rated operating requirements of the highly efficient thermal system of the coal-fired power unit, when the highly efficient thermal system of the coal-fired power unit is operating at the rated operating conditions, the valve opening of the first valve can be adjusted to a fully open position, so that both the first low-pressure cylinder group and the second low-pressure cylinder group can achieve optimal energy conversion efficiency. When the operating conditions of the thermal system of a highly efficient coal-fired power unit begin to decline, the valve opening of the first valve can be adjusted to maintain the high energy conversion efficiency of the second low-pressure cylinder group by reducing the steam intake of the first low-pressure cylinder group, thereby improving the energy conversion efficiency of the overall low-pressure cylinder group and achieving high efficiency in wide-load operation of the thermal system of the highly efficient coal-fired power unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the structure of a thermal system of a coal-fired power unit operating efficiently in one embodiment;

[0036] Figure 2 Schematic diagram of the structure of a thermal system of a coal-fired power unit operating efficiently in another embodiment;

[0037] Figure 3 Schematic diagram of the structure of a thermal system of a coal-fired power unit operating efficiently in another embodiment;

[0038] Figure 4 Schematic diagram of the structure of a thermal system of a coal-fired power unit operating efficiently in another embodiment;

[0039] Figure 5 Schematic diagram of the structure of a thermal system of a coal-fired power unit operating efficiently in another embodiment;

[0040] Figure 6Schematic diagram of the structure of a thermal system of a coal-fired power unit operating efficiently in another embodiment;

[0041] Figure 7 1 is a flow chart of a method for controlling a thermal system of a coal-fired power plant with high efficiency in one embodiment;

[0042] Figure 8 1 is a flow chart of a method for controlling a thermal system of a coal-fired power plant with high efficiency in another embodiment;

[0043] Figure 9 This is a structural block diagram of a thermal system control device for a coal-fired power plant operating efficiently in one embodiment;

[0044] Figure 10 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment.

[0045] Description of Figure Numbers:

[0046] First low-pressure cylinder group 101; second low-pressure cylinder group 102; medium-pressure steam transmission pipeline 103; heat recovery component 104; first cylinder group steam inlet 1011; first medium-pressure steam transmission branch 1012; first valve 1013; first low-pressure exhaust port 1014; first low-pressure exhaust channel 1015; first valve 1016; second cylinder group steam inlet 1021; second medium-pressure steam transmission branch 1022; second low-pressure exhaust port 1023; second low-pressure exhaust channel 1024; third valve 1025; fourth valve 1026; first low-pressure heater 1041; second low-pressure heater 1042; third low-pressure heater 1043; fourth low-pressure heater 1044. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0048] Since the thermal system of traditional high-efficiency coal-fired power units is usually built with the goal of increasing power generation, the low-pressure cylinder of the turbine is usually designed based on the rated operating conditions. That is, the low-pressure cylinder in a traditional steam turbine can only maintain high-efficiency energy conversion under rated operating conditions. Under medium and low load conditions, the reheated steam parameters generated by the thermal system of the high-efficiency coal-fired power unit do not match the design values corresponding to the rated operating conditions, such as reduced steam inlet flow and lower steam inlet pressure. This will lead to a decrease in the energy conversion efficiency of the low-pressure cylinder, which is one of the reasons for the increase in coal consumption of coal-fired power units under medium and low load conditions.

[0049] In order to improve the operating efficiency of the low-pressure cylinder of the steam turbine under various load conditions, and thus improve the wide-load efficiency of the entire unit, such as Figure 1 As shown, the present application provides a highly efficient thermal system for a coal-fired power plant. The highly efficient thermal system for a coal-fired power plant comprises: a first low-pressure cylinder group 101 and a second low-pressure cylinder group 102 connected in parallel.

[0050] The steam intake of the first cylinder group of the first low-pressure cylinder group 101 and the steam intake of the second cylinder group of the second low-pressure cylinder group 102 are set according to a preset ratio, and the steam intake of the first cylinder group and the steam intake of the second cylinder group meet the rated operating conditions of the thermal system of the coal-fired power unit with efficient operation.

[0051] A first cylinder group steam inlet 1011 of the first low-pressure cylinder group 101 is connected to a medium-pressure steam transmission pipeline 103 of the efficiently operating coal-fired power unit thermal system via a first medium-pressure steam transmission branch 1012. A second cylinder group steam inlet 1021 of the second low-pressure cylinder group 102 is connected to the medium-pressure steam transmission pipeline 103 via a second medium-pressure steam transmission branch 1022. A first valve 1013 is provided on the first medium-pressure steam transmission branch 1012 for adjusting a first steam inlet parameter of the first low-pressure cylinder group 101.

[0052] The low-pressure cylinder group is an energy conversion device that uses the exhaust steam from the intermediate-pressure cylinders of the thermal system of a highly efficient coal-fired power unit to perform work, achieving energy conversion. A low-pressure cylinder group can be formed by combining two identical low-pressure cylinders in parallel.

[0053] The first cylinder group steam intake rate of the first low-pressure cylinder group 101 refers to the designed steam intake rate of the first low-pressure cylinder group 101, that is, the corresponding steam intake rate that needs to pass through the first low-pressure cylinder group 101 when the first low-pressure cylinder group 101 achieves the optimal energy conversion efficiency. The second cylinder group steam intake rate of the second low-pressure cylinder group 102 refers to the designed steam intake rate of the second low-pressure cylinder group 102, that is, the corresponding steam intake rate that needs to pass through the second low-pressure cylinder group 102 when the second low-pressure cylinder group 102 achieves the optimal energy conversion efficiency.

[0054] Among them, the sum of the steam intake of the first cylinder group and the steam intake of the second cylinder group meets the rated operating condition usage requirements of the thermal system of the efficiently operating coal-fired power unit, which means that when the thermal system of the efficiently operating coal-fired power unit is operating at the rated operating condition, the first low-pressure cylinder group 101 and the second low-pressure cylinder group 102 can receive all the steam discharged by the high-pressure cylinders in the thermal system of the efficiently operating coal-fired power unit. When designing the thermal system, by ensuring that the sum of the steam intake of the first cylinder group and the steam intake of the second cylinder group meets the rated operating condition usage requirements of the thermal system of the efficiently operating coal-fired power unit, the energy conversion efficiency of the thermal system of the efficiently operating coal-fired power unit under the rated operating condition can be guaranteed. It is understandable that the specific design scheme of the steam intake of the first cylinder group and the second cylinder group can be determined based on the actual usage of the thermal system of the efficiently operating coal-fired power unit.

[0055] In one embodiment, the relationship between the steam inlet volume of the first and second cylinder groups is expressed as a ratio. The steam inlet ratio of the first and second low-pressure cylinder groups 101, 102 can be designed based on the length of time the coal-fired power unit operates at medium and low loads in the location where the unit is located. For example, if the unit actually operates at 40% load for a significant period of time, the steam inlet ratio of the first and second low-pressure cylinder groups 101, 102 can be set to 4:6, meaning the steam inlet volume of the first cylinder group is 40% of the total amount of reheat steam generated by the unit under rated conditions, and the steam inlet volume of the second cylinder group is 60% of the total amount of intermediate-pressure exhaust steam generated by the intermediate-pressure cylinders under rated conditions. For another example, if the unit actually operates at 30% load for a significant period of time, the steam inlet ratio of the first and second low-pressure cylinder groups 101, 102 can be set to 3:7, meaning the steam inlet volume of the first cylinder group is 30% of the total amount of intermediate-pressure exhaust steam generated by the intermediate-pressure cylinders under rated conditions, and the steam inlet volume of the second cylinder group is 70% of the total amount of intermediate-pressure exhaust steam generated by the intermediate-pressure cylinders under rated conditions. The ratio of the steam intake of the first cylinder group to the steam intake of the second cylinder group can be 1:9, 2:8, 3:7, 4:6, 5:5, etc.

[0056] The intermediate-pressure steam transmission pipeline 103 is a main gas transmission pipeline for transmitting intermediate-pressure cylinder exhaust steam. The steam inlet end of the intermediate-pressure steam transmission pipeline 103 can be connected to the intermediate-pressure cylinder exhaust end of the thermal system of an efficiently operating coal-fired power unit to receive steam discharged from the intermediate-pressure cylinder. The first intermediate-pressure steam transmission branch 1012 is a steam transmission pipeline for transmitting the intermediate-pressure cylinder exhaust steam to the first low-pressure cylinder group 101. The first cylinder group steam inlet 1011 of the first low-pressure cylinder group 101 can be connected to the intermediate-pressure steam transmission pipeline 103 via the first intermediate-pressure steam transmission branch 1012, allowing the intermediate-pressure cylinder exhaust steam to be transmitted to the first low-pressure cylinder group 101 for energy conversion. The second intermediate-pressure steam transmission branch 1022 is a steam transmission pipeline for transmitting the intermediate-pressure cylinder exhaust steam to the second low-pressure cylinder group 102. The second cylinder group steam inlet 1021 of the second low-pressure cylinder group 102 can be connected to the intermediate-pressure steam transmission pipeline 103 through the second intermediate-pressure steam transmission branch 1022, so that the intermediate-pressure cylinder exhaust steam can be transmitted to the second low-pressure cylinder group 102 for energy conversion.

[0057] Among them, a first valve 1013 is provided on the first intermediate-pressure steam transmission branch 1012 for adjusting the first steam inlet parameter of the first low-pressure cylinder group 101. The first steam inlet parameter is parameter information used to characterize the transmission status of the intermediate-pressure cylinder exhaust steam entering the first low-pressure cylinder group 101. The first steam inlet parameter may include the steam inlet volume and / or steam inlet pressure of the intermediate-pressure cylinder exhaust steam. By providing the first valve 1013 on the first intermediate-pressure steam transmission branch 1012, when the operating load of the thermal system of the efficiently operating coal-fired power unit changes, the intermediate-pressure cylinder exhaust steam inlet parameter of the first low-pressure cylinder group 101 can be adjusted according to the change in the operating load.

[0058] Specifically, when the operating condition of the thermal system of the efficiently operating coal-fired power unit is the rated operating condition, the opening of the first valve can be adjusted to fully open, and the exhaust steam of the intermediate pressure cylinder enters the first low-pressure cylinder group 101 and the second low-pressure cylinder group 102 respectively, and both cylinder groups can achieve the best energy conversion efficiency.

[0059] When the operating conditions of the thermal system of a highly efficient coal-fired power unit start to reduce the load from the rated operating conditions, the opening of the first valve 1013 can be reduced according to the decrease in the operating load, thereby reducing the steam intake of the first low-pressure cylinder group 101 and ensuring the steam intake of the second low-pressure cylinder group 102. Compared with the traditional single medium and low-pressure cylinder group, the energy conversion efficiency of the entire medium and low-pressure cylinder group can be effectively improved, thereby achieving high efficiency in wide-load operation of the thermal system of the highly efficient coal-fired power unit.

[0060] Taking the steam intake ratio of the first cylinder group to the second cylinder group as 4:6 as an example, the operation of the first low-pressure cylinder group 101 and the second low-pressure cylinder group 102 under different load conditions is explained.

[0061] When the operating condition of the thermal system of the efficiently operating coal-fired power unit is the rated operating condition, the opening of the first valve is adjusted to fully open, and the exhaust steam of the intermediate pressure cylinder enters the first low-pressure cylinder group 101 and the second low-pressure cylinder group 102 respectively. At this time, the steam intake amount of the first cylinder group of the first intermediate and low-pressure cylinder 101 is 40%, and the steam intake amount of the second cylinder group of the second low-pressure cylinder group 102 is 60%. Both cylinder groups can achieve the best energy conversion efficiency.

[0062] When the operating conditions of the thermal system of a highly efficient coal-fired power unit begin to reduce the load from the rated operating conditions, the opening of the first valve 1013 can be reduced according to the decrease in the operating load, thereby reducing the steam intake of the first low-pressure cylinder group 101 and ensuring the steam intake of the second low-pressure cylinder group 102. When the coal-fired power unit operates in the load range of 100%-60%, the second low-pressure cylinder group 102 can always maintain the rated operating steam intake and operate with the best energy conversion efficiency. When the coal-fired power unit operates to a load below 60%, the energy conversion efficiency of the second low-pressure cylinder group 102 will also be higher than that of traditional medium and low-pressure cylinder groups.

[0063] The above-mentioned highly efficient coal-fired power unit thermal system includes a first low-pressure cylinder group and a second low-pressure cylinder group connected in parallel. The first low-pressure cylinder group is connected to a medium-pressure steam transmission pipeline via a first medium-pressure steam transmission branch, and the second low-pressure cylinder group is connected to the medium-pressure steam transmission pipeline via a second medium-pressure steam transmission branch. A first valve is provided on the first medium-pressure steam transmission branch, and a first steam inlet parameter of the first low-pressure cylinder group can be adjusted by adjusting the valve opening of the first valve. Because the steam inlet volume of the first cylinder group and the steam inlet volume of the second cylinder group meet the rated operating requirements of the highly efficient coal-fired power unit thermal system, when the highly efficient coal-fired power unit thermal system is operating at rated operating conditions, the valve opening of the first valve can be adjusted to a fully open position, so that both the first low-pressure cylinder group and the second low-pressure cylinder group can achieve optimal energy conversion efficiency. When the operating conditions of the thermal system of a highly efficient coal-fired power unit begin to decline, the valve opening of the first valve can be adjusted to maintain the high energy conversion efficiency of the second low-pressure cylinder group by reducing the steam intake of the first low-pressure cylinder group, thereby improving the energy conversion efficiency of the overall medium and low-pressure cylinder groups, and further achieving high efficiency in wide-load operation of the thermal system of the highly efficient coal-fired power unit.

[0064] In one embodiment, the first low-pressure cylinder group and the second low-pressure cylinder group are arranged on the same axis.

[0065] Specifically, the first low-pressure cylinder group and the second low-pressure cylinder group are arranged on the same axis, and the entire efficiently operated coal-fired power unit thermal system can be operated by only using a single generator, effectively reducing the complexity of the unit layout.

[0066] In one embodiment, Figure 2As shown, the thermal system of the coal-fired power unit with high efficiency operation further includes: a heat recovery component 104 for extracting low-pressure exhaust steam from the first low-pressure cylinder group 101 and the second low-pressure cylinder group 102 to feed water to the boiler;

[0067] The first low-pressure exhaust port 1014 of the first low-pressure cylinder group 101 is connected to the heat recovery component 104 through a first low-pressure exhaust passage 1015 ; the second low-pressure exhaust port 1023 of the second low-pressure cylinder group 102 is connected to the heat recovery component 104 through a second low-pressure exhaust passage 1024 .

[0068] Among them, the heat recovery component 104 can extract part of the steam that has done work from the first low-pressure cylinder group 101 and the second low-pressure cylinder group 102 to heat the condensate. This process is called feedwater heat recovery heating, and the corresponding steam cycle is called feedwater heat recovery cycle.

[0069] Specifically, during the operation of the thermal system of a highly efficient coal-fired power unit, the heat recovery component 104 can extract part of the steam that has already done work from the first low-pressure cylinder group 101 through the first low-pressure exhaust passage 1015, and at the same time extract part of the steam that has already done work from the second low-pressure cylinder group 102 through the second low-pressure exhaust passage 1024. The extracted steam is used to heat the feed water in the heat recovery component 104 to increase the temperature of the feed water entering the boiler.

[0070] In the above embodiment, by providing a heat recovery assembly connected to each of the first and second low-pressure cylinder groups, thermal energy can be more fully utilized, cooling losses can be reduced, and the efficiency of the entire thermal cycle can be improved. Furthermore, by extracting a portion of steam from the first and second low-pressure cylinder groups for heat recovery, the amount of steam entering the condenser of the thermal system of a highly efficient coal-fired power plant can be reduced, lowering the condenser's heat load and thereby minimizing steam erosion and damage to the condenser equipment, thereby extending the service life of the equipment associated with the thermal system of the highly efficient coal-fired power plant.

[0071] Further, such as Figure 3 As shown, a second valve 1016 is provided on the first low-pressure exhaust passage 1015 for controlling the opening and closing of the first low-pressure exhaust passage 1015 .

[0072] Specifically, in actual use, if the operating conditions of the thermal system of a highly efficient coal-fired power unit have been reduced to the point where the first low-pressure cylinder group 101 needs to be cut off to maintain the steam intake of the second low-pressure cylinder group 102, the first low-pressure cylinder group 101 can be cut off. At this time, in order to reduce the probability of damage to the heat recovery component, a second valve 1016 needs to be set on the first low-pressure exhaust passage 1015. When the first low-pressure cylinder group 101 needs to be cut off, it is only necessary to adjust the valve opening of the first valve 1013 to the valve opening corresponding to the zero output or micro-output state, and close the second valve 1016 to achieve the cylinder cutting process and continue to maintain the energy conversion efficiency of the second low-pressure cylinder group 102.

[0073] Taking the steam intake ratio of the first cylinder group to the second cylinder group as 4:6 as an example, when the operating condition of the thermal system of a highly efficient coal-fired power unit is 60% load condition, in order to enable the second low-pressure cylinder group to maintain the optimal energy conversion efficiency, it is necessary to adjust the valve opening of the first valve 1013 to the valve opening corresponding to the zero output or micro-output state, and at the same time close the second valve 1016 to realize the cylinder cutting processing of the first low-pressure cylinder group 101, so that all the reheated steam enters the second low-pressure cylinder group 102 to perform work.

[0074] In the above embodiment, by providing a second valve on the first low-pressure exhaust passage, the on-off of the first low-pressure exhaust passage can be accurately controlled, and the first low-pressure cylinder group can be cut off when necessary, so as to stably maintain the energy conversion efficiency of the second low-pressure cylinder group, thereby realizing the high efficiency of wide-load operation of the thermal system of the efficient coal-fired power unit.

[0075] In one embodiment, Figure 4 As shown, the steam intake of the second cylinder group is greater than that of the first cylinder group. A third valve 1025 is provided on the second intermediate pressure steam transmission branch 1022 for adjusting the second steam intake parameter of the second low pressure cylinder group 102 .

[0076] Specifically, when the steam intake amount of the second cylinder group is greater than that of the first cylinder group, in order to further improve the overall energy conversion efficiency of the unit, a third valve 1025 can be set on the second medium-pressure steam transmission branch 1022 to adjust the second steam intake parameters of the second low-pressure cylinder group 102.

[0077] When the operating conditions of the thermal system of a highly efficient coal-fired power unit are reduced to the point where all the exhaust steam from the intermediate-pressure cylinder is input into the second low-pressure cylinder group 102, but it is still unable to meet the requirement for the second low-pressure cylinder group 102 to operate at optimal conversion efficiency, the second steam inlet parameter of the second low-pressure cylinder group 102 can be reduced by adjusting the opening of the third valve 1025 to ensure that the first low-pressure cylinder group 101 can operate at optimal conversion efficiency.

[0078] Taking the steam intake ratio of the first cylinder group to the second cylinder group as 4:6 as an example, when the operating condition of the thermal system of a highly efficient coal-fired power unit is 60% load, the valve opening of the first valve 1013 can be adjusted to the valve opening corresponding to the zero output or micro-output state, and the second valve 1016 can be closed to realize the cylinder cutting processing of the first low-pressure cylinder group 101, so that all the exhaust steam of the medium-pressure cylinder enters the second low-pressure cylinder group 102 to perform work.

[0079] When the operating conditions of the thermal system of a highly efficient coal-fired power unit decrease from a 60% load condition to a 40% load condition, it can be assumed that even if all the reheated steam is input into the second low-pressure cylinder group 102 to perform work, it is still impossible to achieve the second low-pressure cylinder group 102 operating at optimal energy conversion efficiency. Therefore, the first valve 1013 can be readjusted to a fully open state, while the second valve 1016 is opened and the valve opening of the third valve 1025 is reduced to reduce the steam intake of the second low-pressure cylinder group 102, prioritizing the operation of the first low-pressure cylinder group 101 at optimal energy conversion efficiency, thereby achieving high efficiency in wide-load operation of the thermal system of a highly efficient coal-fired power unit.

[0080] In one embodiment, Figure 5 As shown, a fourth valve 1026 is provided on the second low-pressure exhaust passage 1024 for controlling the opening and closing of the second low-pressure exhaust passage 1024 .

[0081] Specifically, when the operating conditions of the thermal system of a highly efficient coal-fired power unit are reduced to the point where the total amount of reheated steam can only meet the requirements for the first low-pressure cylinder group 101 to operate at the optimal energy conversion efficiency, or cannot meet the requirements for the first low-pressure cylinder group 101 to operate at the optimal energy conversion efficiency, the second low-pressure cylinder group 102 can be cut off, and all the exhaust steam from the intermediate-pressure cylinders can be input into the first low-pressure cylinder group 101 to perform work. By maintaining the energy conversion efficiency of the first low-pressure cylinder group to the greatest extent, the overall operating efficiency of the thermal system of the highly efficient coal-fired power unit can be improved.

[0082] For example, if the steam intake ratio of the first cylinder group to the second cylinder group is 4:6, when the operating conditions of the thermal system of a highly efficient coal-fired power unit begin to decline from a 40% load condition, it can be assumed that even if all the exhaust steam from the intermediate-pressure cylinders were transferred to the second low-pressure cylinder group 102 to perform work, the second low-pressure cylinder group 102 would not be able to operate at optimal energy conversion efficiency. Therefore, the first valve 1013 can be readjusted to a fully open state, while the second valve 1016 is opened, the valve opening of the third valve 1025 is adjusted to a valve opening corresponding to zero output or low output, and the fourth valve 1026 is closed. This can achieve cylinder deactivation of the second low-pressure cylinder 102, allowing all the exhaust steam from the intermediate-pressure cylinders to enter the first low-pressure cylinder group 101 to perform work.

[0083] In the above embodiment, by providing a fourth valve on the second low-pressure exhaust passage, the second low-pressure cylinder group can be cut off when necessary, thereby stably maintaining the energy conversion efficiency of the first low-pressure cylinder group, thereby achieving high efficiency of wide-load operation of the thermal system of the efficiently operated coal-fired power unit.

[0084] In one embodiment, the heat recovery assembly includes a first low-pressure heater, a second low-pressure heater, a third low-pressure heater, and a fourth low-pressure heater. The first low-pressure heater, the second low-pressure heater, the third low-pressure heater, and the fourth low-pressure heater are sequentially connected via a feedwater channel, and the steam extraction temperatures of the first low-pressure heater, the second low-pressure heater, the third low-pressure heater, and the fourth low-pressure heater decrease in sequence.

[0085] Specifically, the first, second, third, and fourth low-pressure heaters are sequentially connected via a feedwater channel, and the steam extraction temperatures of the first, second, third, and fourth low-pressure heaters decrease in sequence. Therefore, after the fourth low-pressure heater heats the condensate, it can deliver the heated feedwater to the third low-pressure heater via the feedwater channel. The third low-pressure heater then reheats the feedwater using the extracted steam and delivers the reheated feedwater to the second low-pressure heater via the feedwater channel. The second low-pressure heater also reheats the feedwater using the extracted steam and delivers the reheated feedwater to the first low-pressure heater via the feedwater channel. After heating the feedwater using the extracted steam, the first low-pressure heater can deliver the heated feedwater to the deaerator of the thermal system of the efficiently operating coal-fired power unit for treatment.

[0086] In the above embodiment, by setting low-pressure heaters with different extraction steam temperatures, a multi-stage heat recovery system is formed, which can achieve cascade utilization of thermal energy, reduce energy loss, and improve the overall cycle thermal efficiency of the unit.

[0087] There are many ways to connect each low-pressure heater to the first low-pressure cylinder group and the second low-pressure cylinder group. The following examples illustrate possible connection methods:

[0088] In one embodiment, the first low-pressure heater, the second low-pressure heater, the third low-pressure heater and the fourth low-pressure heater can be connected to the first low-pressure cylinder group and the second low-pressure cylinder group at the same time. In actual use, steam of corresponding temperature can be extracted from the first low-pressure cylinder group and the second low-pressure cylinder group respectively for energy utilization.

[0089] In one embodiment, the first low-pressure exhaust port is connected to the first low-pressure heater and the second low-pressure heater through a first low-pressure exhaust passage, and the second low-pressure exhaust port is connected to the third low-pressure heater and the fourth low-pressure heater through a second low-pressure exhaust passage.

[0090] Alternatively, the first low-pressure exhaust port is connected to the third low-pressure heater and the fourth low-pressure heater via the first low-pressure exhaust passage, and the second low-pressure exhaust port is connected to the first low-pressure heater and the second low-pressure heater via the second low-pressure exhaust passage.

[0091] Specifically, the first low-pressure cylinder group can be connected to the first low-pressure heater and the second low-pressure heater through the first low-pressure exhaust passage, and the second low-pressure cylinder group can be connected to the third low-pressure heater and the fourth low-pressure heater through the second low-pressure exhaust passage.

[0092] Alternatively, the second low-pressure cylinder group may be connected to the first low-pressure heater and the second low-pressure heater via the first low-pressure exhaust passage, and the first low-pressure cylinder group may be connected to the third low-pressure heater and the fourth low-pressure heater via the second low-pressure exhaust passage.

[0093] The above two connection methods both connect one cylinder group to two consecutive low-pressure heaters, which can ensure the continuity of the steam temperature extracted from the low-pressure cylinder group.

[0094] In one embodiment, the first low-pressure exhaust port is connected to the first low-pressure heater and the third low-pressure heater through a first low-pressure exhaust passage; the second low-pressure exhaust port is connected to the second low-pressure heater and the fourth low-pressure heater through a second low-pressure exhaust passage.

[0095] Alternatively, the first low-pressure exhaust port is connected to the second low-pressure heater and the fourth low-pressure heater through the first low-pressure exhaust passage; the second low-pressure exhaust port is connected to the first low-pressure heater and the third low-pressure heater through the second low-pressure exhaust passage.

[0096] Specifically, the first low-pressure cylinder group can be connected to the first low-pressure heater and the third low-pressure heater via the first low-pressure exhaust passage, and the second low-pressure cylinder group can be connected to the second low-pressure heater and the fourth low-pressure heater via the second low-pressure exhaust passage. Alternatively, the second low-pressure cylinder group can be connected to the first low-pressure heater and the third low-pressure heater via the first low-pressure exhaust passage, and the first low-pressure cylinder group can be connected to the second low-pressure heater and the fourth low-pressure heater via the second low-pressure exhaust passage.

[0097] Both of the above connection methods are to connect a group of cylinder groups to two spaced low-pressure heaters by jumper connection, which can ensure the balance of steam temperature extracted from the low-pressure cylinder group.

[0098] In one embodiment, the second low-pressure exhaust port is connected to the first low-pressure heater and any one low-pressure heater except the first low-pressure heater through a second low-pressure exhaust passage.

[0099] Specifically, during actual operation, the probability of the first low-pressure cylinder group being cut off will be greater than the probability of the second low-pressure cylinder group being cut off. When the first low-pressure cylinder group is cut off, the first low-pressure exhaust passage will also be cut off. Therefore, in order to improve the utilization rate of steam exhaust, the second low-pressure cylinder group with a lower probability of being cut off is connected to the first low-pressure heater through the second low-pressure exhaust passage. This can improve the utilization rate of the first low-pressure heater during actual operation, extract higher temperature steam to heat the feed water, effectively improve energy utilization, and thereby improve the overall operating efficiency of the thermal system of the high-efficiency coal-fired power unit.

[0100] In one embodiment, Figure 6 As shown, a thermal system 600 of a coal-fired power unit with high efficiency is provided, including a first low-pressure cylinder group 101, a second low-pressure cylinder group 102, a medium-pressure steam transmission pipeline 103, a first low-pressure heater 1041, a second low-pressure heater 1042, a third low-pressure heater 1043 and a fourth low-pressure heater 1044.

[0101] Among them, the ratio of the steam intake of the first cylinder group to the steam intake of the second cylinder group is 4:6, and the steam intake of the first cylinder group and the steam intake of the second cylinder group meet the rated operating conditions of the thermal system of the coal-fired power unit with efficient operation.

[0102] The first cylinder steam inlet 1011 of the first low-pressure cylinder group 101 is connected to the medium-pressure steam transmission pipeline 103 of the efficiently operating coal-fired power unit thermal system via a first medium-pressure steam transmission branch 1012. The second cylinder steam inlet 1021 of the second low-pressure cylinder group 102 is connected to the medium-pressure steam transmission pipeline 103 via a second medium-pressure steam transmission branch 1022. A first valve 1013 is provided on the first medium-pressure steam transmission branch 1012 for adjusting the first steam inlet parameter of the first low-pressure cylinder group 101. A third valve 1025 is provided on the second medium-pressure steam transmission branch 1022 for adjusting the second steam inlet parameter of the second low-pressure cylinder group 102.

[0103] The first low-pressure steam exhaust port 1014 of the first low-pressure cylinder group 101 is connected to the second low-pressure heater 1042 and the fourth low-pressure heater 1044 via a first low-pressure steam exhaust passage 1015. The second low-pressure steam exhaust port 1023 of the second low-pressure cylinder group 102 is connected to the first low-pressure heater 1041 and the third low-pressure heater 1043 via a second low-pressure steam exhaust passage 1024. A second valve 1016 is provided on the first low-pressure steam exhaust passage 1015 for controlling the flow of the first low-pressure steam exhaust passage 1015. A fourth valve 1026 is provided on the second low-pressure steam exhaust passage 1024 for controlling the flow of the second low-pressure steam exhaust passage 1024.

[0104] Specifically, when the thermal system of the efficiently operating coal-fired power unit operates at rated conditions, the first valve 1013 and the third valve 1025 are adjusted to a fully open state. At this time, the first low-pressure cylinder group 101 and the second low-pressure cylinder group 102 are fully filled with steam, both meeting the optimal energy conversion efficiency.

[0105] When the operating condition of the thermal system of a highly efficient coal-fired power unit starts to reduce the load from the rated condition, i.e., 100% load, the valve opening of the first valve 1013 is reduced, the steam flow and pressure entering the first low-pressure cylinder group 101 are reduced, and at the same time, the steam flow and pressure entering the second low-pressure cylinder group 102 are maintained at a state consistent with the rated condition until the operating condition is reduced from 100% load to 60% load.

[0106] When the load is reduced to 60%, the valve opening of the first valve 1013 is adjusted to the valve opening corresponding to the zero output or micro output state, that is, the safety valve opening, and the second valve 1016 is closed at the same time to maintain the first low-pressure cylinder group 101 at zero output or micro output state, and all the steam enters the second low-pressure cylinder group 102 until the unit load is reduced from 60% load to 40% load.

[0107] When the operating condition of the thermal system of a highly efficient coal-fired power unit drops to 40% load, the valve opening of the first valve 1013 is adjusted to fully open, and the second valve 1016 is opened simultaneously. The valve opening of the third valve 1025 is adjusted to the valve opening corresponding to zero output or low output, i.e., the safety valve opening, and the fourth valve 1026 is closed simultaneously, so that the second low-pressure cylinder group 102 is maintained at zero output or low output, and all steam enters the first low-pressure cylinder group 101.

[0108] When the operating conditions of the thermal system of a highly efficient coal-fired power unit begin to decrease from 40% load, the second low-pressure cylinder 102 can be maintained at zero output or micro-output state, and the valve opening of the first valve 1013 can be reduced to reduce the amount and pressure of steam entering the first low-pressure cylinder group 101.

[0109] In the above embodiment, the thermal system of the coal-fired power unit with high efficiency can improve the energy conversion efficiency of the low-pressure cylinder group under medium and low load conditions, reduce the coal consumption of the unit, and achieve high efficiency of the coal-fired power unit under wide load conditions by setting up a grouped medium and low pressure steam turbine system.

[0110] Based on the same inventive concept, Figure 7 As shown in the figure, a method for controlling the thermal system of a coal-fired power plant with high efficiency is provided, which can be applied to Figures 1 to 6 The controller of the thermal system of the coal-fired power plant with high efficiency is used as an example for explanation. The controller is electrically connected to each valve in the thermal system of the coal-fired power plant with high efficiency, and is used to adjust the valve opening of each valve. The method comprises the following steps:

[0111] S702, obtaining operating condition information of a thermal system of a coal-fired power unit that operates efficiently.

[0112] Among them, the operating condition information is information data used to characterize the operating conditions of the thermal system of the efficiently operating coal-fired power unit. The operating condition information may include the operating conditions of the thermal system of the efficiently operating coal-fired power unit, load changes, electrical parameters of the coal-fired power unit, etc.

[0113] Specifically, the controller may obtain the operating condition information of the thermal system of the efficiently operating coal-fired power unit from the management server of the thermal system of the efficiently operating coal-fired power unit.

[0114] S704 , when it is determined based on the operating condition information that the thermal system of the efficiently operating coal-fired power generation unit is in the rated operating condition, control the first valve of the thermal system of the efficiently operating coal-fired power generation unit to be at the maximum opening.

[0115] Among them, the rated operating condition is the full-load operating condition of the thermal system of the efficiently operating coal-fired power unit. The thermal system of the efficiently operating coal-fired power unit can continuously output maximum power under the rated operating condition.

[0116] Specifically, the controller analyzes the operating condition information to obtain the operating condition of the thermal system of the coal-fired power unit, compares the operating condition with the rated condition, and determines whether the thermal system of the efficiently operating coal-fired power unit is within the rated condition. If it is determined that the thermal system of the efficiently operating coal-fired power unit is within the rated condition, the controller controls the first valve of the thermal system of the efficiently operating coal-fired power unit to be at its maximum opening.

[0117] S706: If the thermal system of the efficiently operating coal-fired power unit is not in the rated operating condition, determine the operating condition range of the thermal system of the efficiently operating coal-fired power unit according to the operating condition information.

[0118] The operating condition range is determined according to a first matching load operating condition corresponding to the steam intake amount of the first cylinder group and a second matching load operating condition corresponding to the steam intake amount of the second cylinder group.

[0119] Specifically, when the controller determines that the thermal system of the efficiently operating coal-fired power unit is not in the rated operating condition, it can analyze the operating condition information to determine the operating condition range of the thermal system of the efficiently operating coal-fired power unit.

[0120] In one embodiment, when the thermal system of a highly efficient coal-fired power generation unit is not at rated operating conditions, a first matching load condition corresponding to the steam inlet volume of a first cylinder group and a second matching load condition corresponding to the steam inlet volume of a second cylinder group in the thermal system of the highly efficient coal-fired power generation unit are obtained. The thermal system of the highly efficient coal-fired power generation unit is divided into operating conditions according to the first matching load condition and the second matching load condition to obtain candidate load condition ranges. The operating condition range of the thermal system of the highly efficient coal-fired power generation unit is then determined from the candidate operating condition ranges.

[0121] S708, based on the operating condition range, adjust the valve opening of the first valve in the thermal system of the coal-fired power unit operating with high efficiency.

[0122] Specifically, the controller can adjust the valve opening of the first valve in the thermal system of the coal-fired power unit operating with high efficiency based on the operating condition range of the operating condition.

[0123] In the above embodiment, by determining the operating condition range described in the operating conditions, and then adjusting the valve opening of the first valve in the thermal system of the efficiently operating coal-fired power unit based on the operating condition range, the adjustment efficiency and accuracy of the subsequent valve opening adjustment can be effectively improved, so that the adjustment process can better match the actual operating conditions of the unit.

[0124] In one embodiment, the steam intake amount of the second cylinder group is greater than the steam intake amount of the first cylinder group. S708, based on the operating condition range, adjusts the valve opening of a first valve in the thermal system of the efficiently operating coal-fired power unit. This includes: when the operating condition range is a first low-load operating condition range, determining a target valve opening of the first valve based on the load difference between the operating condition of the thermal system of the efficiently operating coal-fired power unit and a second matched load condition. Adjusting the opening of the first valve according to the target valve opening.

[0125] The upper limit of the first low-load operating range is the rated operating condition, and the lower limit is the second matched load condition. For example, if the ratio of the steam intake of the first cylinder group to the steam intake of the second cylinder group is 4:6, the second matched load condition can be 60%, and the first low-load operating range is 100%-60%.

[0126] Specifically, when the operating condition range is the first low-load operating condition range, the controller can calculate the load difference between the operating condition of the thermal system of the efficiently operating coal-fired power unit and the second matching load condition, determine the target valve opening of the first valve according to the load difference, and adjust the opening of the first valve according to the target valve opening.

[0127] For example, if the operating condition of the thermal system of a highly efficient coal-fired power unit is an 85% load condition and the second matching load condition is a 60% load condition, the controller can determine that the load difference is 15%. This 15% load difference will be borne by the first low-pressure cylinder group. Therefore, the controller can determine the theoretical opening of the first valve when the first low-pressure cylinder group bears the 15% load difference condition as the target valve opening of the first valve, and adjust the opening of the first valve according to the target valve opening. For example, if the operating condition increases from 70% to 85%, the controller will increase the valve opening of the first valve according to the target valve opening. Conversely, if the operating condition decreases from 100% to 85%, the controller will decrease the valve opening of the first valve according to the target valve opening.

[0128] In the above embodiment, when the target operating condition range is the first low-load operating condition range, the valve opening of the first valve is adjusted based on the load difference between the operating condition of the thermal system of the efficiently operating coal-fired power unit and the second matching load condition, thereby reducing the steam inflow of the first low-pressure cylinder group. This can enable the second low-pressure cylinder group to be continuously in the optimal operating state, thereby improving the operating efficiency of the entire efficiently operating thermal system of the coal-fired power unit.

[0129] In one embodiment, the method for controlling a thermal system of a highly efficient coal-fired power generation unit further includes: reducing the opening of the first valve to a safe opening when the operating range is within a second low-load operating range; and closing a second valve disposed on a first low-pressure exhaust passage in the thermal system of the highly efficient coal-fired power generation unit.

[0130] The upper limit of the second low-load operating range is the second matched load condition, and the lower limit is the first matched load condition. For example, if the ratio of the steam intake of the first cylinder group to the steam intake of the second cylinder group is 4:6, the first matched load condition can be 40% and the second matched load condition can be 60%. In this case, the second low-load operating range is 60%-40%.

[0131] Specifically, when the operating range is the second low-load operating range, the controller can reduce the opening of the first valve to a safe opening and, at the same time, close the second valve provided on the first low-pressure exhaust passage in the thermal system of the efficiently operating coal-fired power unit.

[0132] In the above embodiment, when the operating range is the second low-load operating range, the controller may perform cylinder cutting processing on the first low-pressure cylinder group to achieve high efficiency in wide-load operation of the entire unit.

[0133] In one embodiment, the method for controlling a thermal system of a highly efficient coal-fired power generation unit further includes: adjusting the valve opening of the first valve to a maximum opening when the operating range is a third low-load operating condition; opening a second valve disposed on a first low-pressure exhaust passage in the thermal system of the highly efficient coal-fired power generation unit; and closing a fourth valve disposed on a second low-pressure exhaust passage in the thermal system of the highly efficient coal-fired power generation unit and a third valve disposed on a second intermediate-pressure steam transmission branch in the thermal system of the highly efficient coal-fired power generation unit.

[0134] The upper limit of the third low load condition is the first matched load condition. For example, if the ratio of the steam intake of the first cylinder group to the steam intake of the second cylinder group is 4:6, the first matched load can be 40%, and the third low load condition range is less than 40%.

[0135] Specifically, when the operating range is the third low-load operating condition, the controller may adjust the valve opening of the first valve to the maximum opening, open the second valve provided on the first low-pressure exhaust passage of the thermal system of the efficiently operating coal-fired power unit, and simultaneously close the fourth valve provided on the second low-pressure exhaust passage of the thermal system of the efficiently operating coal-fired power unit and the third valve provided on the second medium-pressure steam transmission branch of the thermal system of the efficiently operating coal-fired power unit.

[0136] In the above embodiment, when the operating range is the third low-load operating condition, the controller may perform cylinder cutting processing on the second low-pressure cylinder to achieve high efficiency in wide-load operation of the entire unit.

[0137] In one embodiment, Figure 8 As shown, a method for controlling a thermal system of a coal-fired power plant with high efficiency is provided. In the thermal system of a coal-fired power plant with high efficiency, the ratio of the steam intake of the first cylinder group to the steam intake of the second cylinder group is 4:6, the first matching load is 40%, and the second matching load is 60%. The method specifically includes the following steps:

[0138] First, the controller can obtain the operating condition information of the thermal system of the efficiently operating coal-fired power unit, and based on the operating condition information, determine whether the thermal system of the efficiently operating coal-fired power unit is in the rated operating condition. When the thermal system of the efficiently operating coal-fired power unit is in the rated operating condition, the first valve and the second valve of the thermal system of the efficiently operating coal-fired power unit are controlled to be at the maximum opening. At this time, the first low-pressure cylinder group and the second low-pressure cylinder group are fully steam-intaked, meeting the steam intake of the low-pressure cylinder group at the rated operating condition.

[0139] If the thermal system of the efficiently operating coal-fired power unit is not operating at rated conditions, the operating condition range of the thermal system of the efficiently operating coal-fired power unit is determined based on the operating condition information. When the operating condition range is 100% load to 60% load, the target valve opening of the first valve is determined based on the load difference between the operating condition of the thermal system of the efficiently operating coal-fired power unit and the second matched load condition. The opening of the first valve is adjusted according to the target valve opening.

[0140] When the thermal system of a highly efficient coal-fired power unit operates at a rate between 60% and 40%, the opening of the first valve is reduced to a safe opening. The second valve, located on the first low-pressure exhaust passage of the thermal system of the highly efficient coal-fired power unit, is closed. At this point, the first low-pressure cylinder group remains at zero or minimal output. All exhaust steam from the intermediate-pressure cylinders enters the second low-pressure cylinder group.

[0141] When the operating condition of the thermal system of a highly efficient coal-fired power unit is 40% or less, adjust the valve opening of the first valve to its maximum opening. Open the second valve located on the first low-pressure exhaust steam channel of the thermal system of the highly efficient coal-fired power unit. Close the fourth valve located on the second low-pressure exhaust steam channel of the thermal system of the highly efficient coal-fired power unit and the third valve located on the second intermediate-pressure steam transmission branch of the thermal system of the highly efficient coal-fired power unit. Maintain the second low-pressure cylinder group at zero or low output. All exhaust steam from the intermediate-pressure cylinders enters the first low-pressure cylinder group.

[0142] In the above embodiment, the first low-pressure cylinder group maintains rated steam intake at a load of 60%-100%, and is more efficient than the low-pressure cylinders of conventional technology at a load below 40%-60%. Below 40% load, all the exhaust steam from the intermediate-pressure cylinder enters the first low-pressure cylinder group. The efficiency of the first low-pressure cylinder group is also higher than that of the low-pressure cylinders of conventional technology, and it has high efficiency over a wide load range.

[0143] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0144] Based on the same inventive concept, embodiments of the present application also provide a highly efficient coal-fired power unit thermal system control device for implementing the aforementioned method for efficiently operating a coal-fired power unit thermal system. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the highly efficient coal-fired power unit thermal system control device provided below can be found in the aforementioned limitations of the method for efficiently operating a coal-fired power unit thermal system, and will not be further elaborated here.

[0145] In one embodiment, Figure 9 As shown, a highly efficient thermal system control device 900 for a coal-fired power plant is provided, comprising: an operating condition information acquisition module 901, a rated operating condition control module 902, an operating condition range determination module 903, and a valve adjustment module 904, wherein:

[0146] The operating condition information acquisition module 901 is used to obtain the operating condition information of the thermal system of the coal-fired power unit that operates efficiently.

[0147] The rated operating condition control module 902 is used to control the first valve of the thermal system of the efficiently operating coal-fired power unit to be at the maximum opening when it is determined based on the operating condition information that the thermal system of the efficiently operating coal-fired power unit is at the rated operating condition.

[0148] The operating condition range determination module 903 is used to determine the operating condition range of the operating condition of the thermal system of the efficiently operating coal-fired power unit based on the operating condition information if the thermal system of the efficiently operating coal-fired power unit is not in the rated operating condition; the operating condition range is determined based on the first matching load condition corresponding to the steam intake of the first cylinder group and the second matching load condition corresponding to the steam intake of the second cylinder group.

[0149] The valve adjustment module 904 is used to adjust the valve opening of the first valve in the thermal system of the coal-fired power unit operating efficiently based on the operating condition range.

[0150] In one embodiment, the steam intake of the second cylinder group is greater than the steam intake of the first cylinder group; the valve adjustment module 904 is used to: when the operating range is the first low-load operating range, determine the target valve opening of the first valve based on the load difference between the operating condition of the thermal system of the efficiently operated coal-fired power unit and the second matching load condition; the upper limit value of the first low-load operating range is the rated operating condition, and the lower limit value is the second matching load condition; and adjust the opening of the first valve according to the target valve opening.

[0151] In one embodiment, the valve adjustment module 904 is also used to: reduce the opening of the first valve to a safe opening when the operating range is the second low load operating range; the upper limit value of the second low load operating range is the second matching load condition, and the lower limit value is the first matching load condition; close the second valve provided on the first low-pressure exhaust passage in the thermal system of the efficiently operating coal-fired power unit.

[0152] In one embodiment, the valve adjustment module 904 is also used to: when the operating range is the third low load condition, adjust the valve opening of the first valve to the maximum opening; the upper limit value of the third low load condition is the first matching load condition; open the second valve set on the first low-pressure exhaust channel in the thermal system of the efficiently operating coal-fired power unit; close the fourth valve set on the second low-pressure exhaust channel in the thermal system of the efficiently operating coal-fired power unit, and close the third valve set on the second medium-pressure steam transmission branch in the thermal system of the efficiently operating coal-fired power unit.

[0153] Each module in the highly efficient coal-fired power unit thermal system control device can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a computer device's memory in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0154] In one embodiment, a computer device is provided. The computer device may be a controller, and its internal structure diagram may be as follows: Figure 10 As shown. The computer device includes a processor, a memory, and a network interface connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store data such as operating condition information and operating condition ranges. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a method for controlling the thermal system of a coal-fired power unit with high efficiency is implemented.

[0155] Those skilled in the art will understand that Figure 10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0156] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the specific steps of the embodiment of the above-mentioned efficient operation coal-fired power unit thermal system control method are implemented.

[0157] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the specific steps of the embodiment of the above-mentioned efficient operation coal-fired power unit thermal system control method are implemented.

[0158] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the specific steps of the embodiment of the above-mentioned method for controlling a thermal system of a coal-fired power plant with high efficiency.

[0159] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, storage, and display, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the acquisition, storage, processing, and transmission of this data comply with relevant laws and regulations.

[0160] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), data processing logic devices based on quantum computing, and the like.

[0161] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0162] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A thermal system for a coal-fired power plant with high efficiency, characterized in that: The thermal system of the coal-fired power unit with high efficiency comprises: a first low-pressure cylinder group and a second low-pressure cylinder group connected in parallel; The steam intake amount of the first cylinder group of the first low-pressure cylinder group and the steam intake amount of the second cylinder group of the second low-pressure cylinder group are set according to a preset ratio, and the steam intake amount of the first cylinder group and the steam intake amount of the second cylinder group meet the rated operating condition usage requirement of the thermal system of the coal-fired power unit with high efficiency operation; The first cylinder group steam inlet of the first low-pressure cylinder group is connected to the medium-pressure steam transmission pipeline of the thermal system of the efficiently operating coal-fired power unit through a first medium-pressure steam transmission branch; the second cylinder group steam inlet of the second low-pressure cylinder group is connected to the medium-pressure steam transmission pipeline through a second medium-pressure steam transmission branch; The first intermediate-pressure steam transmission branch is provided with a first valve for adjusting a first steam inlet parameter of the first low-pressure cylinder group.

2. The thermal system of a coal-fired power plant with high efficiency according to claim 1, characterized in that: The thermal system of the coal-fired power unit with high efficiency operation further includes: a heat recovery component for extracting low-pressure exhaust steam from the first low-pressure cylinder group and the second low-pressure cylinder group to heat boiler feed water; The first low-pressure exhaust port of the first low-pressure cylinder group is connected to the heat recovery component through a first low-pressure exhaust channel; the second low-pressure exhaust port of the second low-pressure cylinder group is connected to the heat recovery component through a second low-pressure exhaust channel.

3. The high-efficiency thermal system of coal-fired power generation units according to claim 2, characterized in that: A second valve is provided on the first low-pressure steam exhaust passage for controlling the opening and closing of the first low-pressure steam exhaust passage.

4. The highly efficient thermal system for coal-fired power generation units according to claim 3, characterized in that: The steam intake amount of the second cylinder group is greater than the steam intake amount of the first cylinder group; A third valve is provided on the second intermediate-pressure steam transmission branch for adjusting the second steam inlet parameters of the second intermediate- and low-pressure cylinder groups.

5. The highly efficient thermal system for coal-fired power generation units according to claim 4, characterized in that: The second low-pressure steam exhaust passage is provided with a fourth valve for controlling the opening and closing of the second low-pressure steam exhaust passage.

6. The highly efficient thermal system for coal-fired power generation units according to claim 4 or 5, characterized in that: The heat recovery component includes a first low-pressure heater, a second low-pressure heater, a third low-pressure heater, and a fourth low-pressure heater; The first low-pressure heater, the second low-pressure heater, the third low-pressure heater and the fourth low-pressure heater are sequentially connected through a water supply channel, and steam extraction temperatures of the first low-pressure heater, the second low-pressure heater, the third low-pressure heater and the fourth low-pressure heater are sequentially decreased; The first low-pressure exhaust port is connected to the second low-pressure heater and the fourth low-pressure heater through the first low-pressure exhaust passage; the second low-pressure exhaust port is connected to the first low-pressure heater and the third low-pressure heater through the second low-pressure exhaust passage.

7. A method for controlling a thermal system of a coal-fired power plant with high efficiency, applied to the thermal system of a coal-fired power plant with high efficiency as claimed in any one of claims 1 to 6, characterized in that: The method comprises: Obtaining operating condition information of the thermal system of the efficiently operating coal-fired power unit; When it is determined based on the operating condition information that the thermal system of the efficiently operating coal-fired power generation unit is in a rated operating condition, controlling a first valve of the thermal system of the efficiently operating coal-fired power generation unit to be at a maximum opening; If the thermal system of the efficiently operating coal-fired power unit is not in the rated operating condition, determining, based on the operating condition information, an operating condition range within which the operating condition of the thermal system of the efficiently operating coal-fired power unit falls; the operating condition range is determined based on a first matching load condition corresponding to the steam intake of the first cylinder group and a second matching load condition corresponding to the steam intake of the second cylinder group; Based on the operating condition range, the valve opening of the first valve in the thermal system of the efficiently operating coal-fired power unit is adjusted.

8. The method according to claim 7, characterized in that The steam intake amount of the second cylinder group is greater than the steam intake amount of the first cylinder group; Determining the valve opening of the first valve in the thermal system of the efficiently operating coal-fired power unit based on the operating condition range includes: When the operating condition range is a first low-load operating condition range, a target valve opening of the first valve is determined based on a load difference between an operating condition of the thermal system of the efficiently operating coal-fired power unit and a second matched load condition; an upper limit of the first low-load operating condition range is the rated operating condition, and a lower limit is the second matched load condition; The opening of the first valve is adjusted according to the target valve opening.

9. The method according to claim 8, characterized in that The method further comprises: When the operating range is a second low-load operating range, reducing the opening of the first valve to a safe opening; the upper limit of the second low-load operating range is the second matching load condition, and the lower limit is the first matching load condition; Close the second valve provided on the first low-pressure exhaust passage in the thermal system of the efficiently operating coal-fired power unit.

10. The method according to claim 8, characterized in that The method further comprises: When the operating condition range is the third low load condition, adjusting the valve opening of the first valve to the maximum opening; the upper limit value of the third low load condition is the first matching load condition; Opening a second valve provided on a first low-pressure exhaust steam passage in the thermal system of the efficiently operating coal-fired power unit; Close the fourth valve on the second low-pressure exhaust passage in the thermal system of the efficiently operating coal-fired power unit and the third valve on the second medium-pressure steam transmission branch in the thermal system of the efficiently operating coal-fired power unit.

Images