A method for thermal decoupling of a high-pressure combined heat and power unit

Abstract

The application provides a heat and electricity decoupling method of a high-pressure combined heat and power unit, which is applied to a heat and electricity decoupling system comprising at least two same combined heat and power units connected by a mother tube assembly, the mother tube assembly comprising a main steam mother tube, a feed water mother tube, a reheated steam hot section mother tube and a reheated steam cold section mother tube; the combined heat and power unit comprising a boiler and a steam turbine unit; the heat and electricity decoupling method comprising: determining a supplied electric load and a supplied heat load of the heat and electricity decoupling system according to an obtained current power generation mode, a target electric load and a target heat load required by a user; determining a working mode and a number of operated steam turbine units of the heat and electricity decoupling system according to the supplied electric load and the supplied heat load; and realizing the operation of the number of operated steam turbine units based on the on-off adjustment of the main steam mother tube, the feed water mother tube, the reheated steam hot section mother tube and the reheated steam cold section mother tube. The heat and electricity decoupling method of the high-pressure combined heat and power unit has high feasibility and remarkable heat and electricity decoupling effect.

Description

Technical Field

[0001] The present invention relates to the technical field of cogeneration, and in particular to a thermoelectric decoupling method for a high-voltage cogeneration unit. Background Art

[0002] Cogeneration (Cogeneration) offers advantages such as high energy efficiency, energy conservation, and environmental protection. It is a primary heat source and heating method for centralized heating in cities and industrial parks. Meanwhile, my country's coal-fired power generation industry has entered a new normal. The large-scale operation of renewable energy sources has further reduced the market share of thermal power units. To alleviate the conflict between heating and power supply for thermal power units, improve the heat-to-electricity ratio of units, and achieve thermal-electric decoupling, it is essential to achieve this.

[0003] Thermoelectric decoupling aims to resolve the conflict between electrical load and thermal load during the heating period when the unit operates in a "heat-based electricity" mode, thereby improving the unit's deep peak-shaving capability and reducing carbon emissions. Existing thermoelectric decoupling technologies include electric heating, electric heat pumps, solar thermal storage and heating, and thermal storage tank technology, and have been applied to cogeneration units for residential heating. However, for centralized heating in industrial parks, due to the need for direct supply of high-parameter steam, even with the use of a new "multi-tank-multi-heat exchanger" thermal storage system integrated with industrial heating units, there are still problems with poor economic efficiency and high equipment operation requirements. Summary of the Invention

[0004] In response to the defects or shortcomings in the existing technology, the present invention provides a thermoelectric decoupling method for a high-voltage cogeneration unit, which is applicable to high-voltage cogeneration units, has high feasibility, and has significant thermoelectric decoupling effect.

[0005] The present invention provides a thermoelectric decoupling method for a high-voltage cogeneration unit, which is applied to a thermoelectric decoupling system of a high-voltage cogeneration unit. The thermoelectric decoupling system includes at least two cogeneration units of identical composition and a main pipe assembly connected to each of the cogeneration units, wherein:

[0006] The main pipe assembly includes a main steam main pipe, a feed water main pipe, a reheat steam hot section main pipe and a reheat steam cold section main pipe; the cogeneration unit includes a boiler and a steam turbine unit, and the steam turbine unit includes a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder and a condensate recovery assembly, the high-pressure cylinder is connected to the intermediate-pressure cylinder, the intermediate-pressure cylinder is connected to the low-pressure cylinder, and the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder are respectively connected to the condensate recovery assembly, and the condensate recovery assembly is used to realize steam cooling and circulating water return;

[0007] The steam outlet of the boiler is connected to the inlet of the high-pressure cylinder through the main steam main pipe, the reheat steam outlet of the boiler is connected to the intermediate-pressure cylinder and the external heat user respectively through the reheat steam hot section main pipe, the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the boiler through the reheat steam cold section main pipe, and the output end of the condensate recovery assembly is connected to the steam inlet of the boiler through the water supply main pipe;

[0008] The thermoelectric decoupling method comprises:

[0009] Determining the supplied electric load and supplied thermal load of the thermal decoupling system according to the acquired current power generation mode, the target electric load and the target thermal load required by the user;

[0010] determining an operating mode of the thermoelectric decoupling system according to the supplied electrical load and the supplied thermal load;

[0011] Determining the number of steam turbine units put into operation according to the working mode;

[0012] Based on the on-off regulation of the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe, the operation of the operating number of the steam turbine units is achieved.

[0013] Preferably, determining the operating mode of the thermoelectric decoupling system according to the supplied electrical load and the supplied thermal load includes:

[0014] determining whether the supplied electrical load is less than the target electrical load;

[0015] When the supplied electrical load is less than the target electrical load, determining the operating mode to be the first mode; wherein the first mode is used to achieve deep peak regulation of the high-voltage cogeneration unit;

[0016] Determining whether the supplied electrical load is greater than a preset electrical load threshold, and whether the supplied thermal load is greater than a preset thermal load threshold; wherein the preset electrical load threshold is less than the target electrical load, and the preset thermal load threshold is less than the target electrical load;

[0017] When the supplied electrical load is greater than a preset electrical load threshold and the supplied thermal load is not greater than a preset thermal load threshold, determining that the operating mode is the second mode of electrical compensation mode; wherein the electrical compensation mode is used to achieve compensation for the electrical load of the high-voltage cogeneration unit when performing deep peak regulation;

[0018] When the supplied heat load is greater than the preset heat load threshold and the supplied electric load is not greater than the preset electric load threshold, determining that the operating mode is the thermal compensation mode of the second mode; wherein the thermal compensation mode is used to compensate for the heat load of the high-voltage cogeneration unit when performing deep peak regulation;

[0019] When the supplied electrical load is greater than the preset electrical load threshold, and the supplied thermal load is greater than the preset thermal load threshold, determining that the operating mode is the thermoelectric compensation mode of the second mode; wherein the thermoelectric compensation mode is used to achieve compensation of the thermal load and electrical load of the high-voltage cogeneration unit when performing deep peak regulation;

[0020] When the supplied electrical load is the same as the target electrical load, the operating mode is determined to be the third mode; wherein the third mode realizes high-load operation of the high-voltage cogeneration unit.

[0021] Preferably, the boiler includes a superheater and a reheater, a first valve and a second valve are provided on the pipeline between the superheater and the high-pressure cylinder, a third valve is provided on the pipeline between the high-pressure cylinder and the reheater, a fourth valve, a fifth valve, and a sixth valve are provided on the pipeline between the reheater and the intermediate-pressure cylinder, a fifth valve and a seventh valve are provided on the pipeline between the reheater and the heat user, an eighth valve is provided on the pipeline between the condensate recovery assembly and the superheater, and a ninth valve is provided on the pipeline between the condensate recovery assembly and the heat user;

[0022] The steam outlet of the superheater is connected to the inlet of the high-pressure cylinder through the main steam main pipe via the first valve and the second valve; the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the reheater through the reheat steam cold section main pipe via the third valve; the reheat steam outlet of the reheater is connected to the intermediate-pressure cylinder through the reheat steam hot section main pipe via the fourth valve, the fifth valve, and the sixth valve; the reheat steam outlet of the reheater is connected to the heat user through the reheat steam hot section main pipe via the fourth valve, the fifth valve, and the seventh valve;

[0023] The output end of the condensate recovery assembly is connected to the steam inlet of the superheater through the water supply main pipe via the eighth valve; the input end of the condensate recovery assembly is connected to the heat user through the ninth valve;

[0024] The main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe are all provided with stop valves.

[0025] Preferably, the operation of the operating number of steam turbine units is achieved based on the on-off regulation of the main steam header, the feedwater header, the reheat steam hot section header, and the reheat steam cold section header, including:

[0026] The stop valves on the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe are all opened to maintain the connection state, and the first valve, the fourth valve and the ninth valve of the turbine unit of at least one of the cogeneration units are closed according to the operating quantity, so that the turbine unit enters the hot standby state and the thermal-electric decoupling system enters the first mode.

[0027] Preferably, the thermoelectric decoupling system further comprises a main steam bypass heating pipeline, on which a tenth valve is provided; wherein the main steam main pipe is connected to the main steam bypass heating pipeline, and the output end of the main steam bypass heating pipeline is connected to the heat user;

[0028] The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including:

[0029] The tenth valve is opened in the first mode to enable the thermoelectric decoupling system to enter the thermal compensation mode.

[0030] Preferably, an eleventh valve is further provided on the main steam bypass heating pipeline;

[0031] The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including:

[0032] In the heat compensation mode, the heat load is distributed on demand by adjusting the eleventh valve and the seventh valve.

[0033] Preferably, the operation of the operating number of steam turbine units is achieved based on the on-off regulation of the main steam header, the feedwater header, the reheat steam hot section header, and the reheat steam cold section header, including:

[0034] In the first mode, the first valve and the fourth valve of the steam turbine unit that enters the hot standby state are opened, and the seventh valve is closed, so that the thermoelectric decoupling system enters the electric compensation mode.

[0035] Preferably, the operation of the operating number of steam turbine units is achieved based on the on-off regulation of the main steam header, the feedwater header, the reheat steam hot section header, and the reheat steam cold section header, including:

[0036] In the first mode, the tenth valve is opened, and the first valve and the fourth valve of the steam turbine unit in hot standby state are opened, and the seventh valve is closed, so that the thermoelectric decoupling system enters the thermoelectric compensation mode.

[0037] Preferably, the operation of the operating number of steam turbine units is achieved based on the on-off regulation of the main steam header, the feedwater header, the reheat steam hot section header, and the reheat steam cold section header, including:

[0038] The stop valves on the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe are all closed to maintain a disconnected state, so as to realize the operation of the operating number of the steam turbine units, so that the thermal-electric decoupling system enters the third mode; wherein, the operating number in the third mode is the same as the number of the cogeneration units.

[0039] Preferably, determining the number of steam turbine units put into operation according to the working mode includes:

[0040] Obtaining a feasible electric load range and a feasible thermal load range under each of the operating modes; wherein the feasible electric load range and the feasible thermal load range under different operating modes are different;

[0041] The number of steam turbine units put into operation is determined based on the supplied electrical load, the supplied thermal load, the maximum thermal load and the maximum power supply load of the steam turbine unit, and the feasible electrical load range and the feasible thermal load range under each of the operating modes.

[0042] Preferably, the condensate recovery assembly includes a high-pressure heater, a deaerator, a feedwater pump, a feedwater pump turbine, a low-pressure heater, a condenser, and a condensate pump;

[0043] An eighth valve is provided on the pipeline between the condensate recovery assembly and the superheater, and a ninth valve is provided on the pipeline between the condensate recovery assembly and the heat user;

[0044] The outlet of the high-pressure heater is connected to the steam inlet of the superheater through the water supply main pipe via the eighth valve, and the high-pressure heater is connected to the high-pressure cylinder, the medium-pressure cylinder, the deaerator, and the water supply pump respectively;

[0045] The feedwater pump steam turbine is respectively connected to the feedwater pump, the intermediate pressure cylinder and the low pressure cylinder;

[0046] The low-pressure heater is respectively connected to the deaerator, the medium-pressure cylinder, the low-pressure cylinder, the condenser, and the condensate pump;

[0047] The condenser is connected to the condensate pump; the ninth valve is connected to the condensate pump and the low-pressure heater respectively.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] The present invention provides a thermoelectric decoupling method for a high-voltage cogeneration unit, which adopts a main pipe to transform the thermoelectric decoupling system of multiple cogeneration units of the same type, and utilizes a main steam main pipe, a feedwater main pipe, a reheat steam hot section main pipe and a reheat steam cold section main pipe to connect the boilers of each unit in the power station in parallel, so that the supply electric load and supply heat load required by the thermoelectric decoupling system can be determined according to the target electric load and target heat load required by the user, thereby determining the steam turbine units to be put into operation in different working modes, and shutting down some steam turbines in the deep peak regulation stage. At this time, the steam turbines operate at high load and do not affect the heating quality; while the boilers operate at low load, which can significantly reduce the overall minimum technical output of the power station and can absorb a large amount of new energy electricity. In this way, flexible switching is performed according to the heat and electricity loads to achieve thermoelectric decoupling of the high-voltage cogeneration unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 This is a flow chart of a thermoelectric decoupling method for a high-voltage cogeneration unit provided by one embodiment of the present invention;

[0052] Figure 2 This is a structural schematic diagram of a thermoelectric decoupling system of a high-voltage cogeneration unit provided by one embodiment of the present invention;

[0053] Figure 3 This is a structural schematic diagram of a thermoelectric decoupling system of another high-voltage cogeneration unit provided by one embodiment of the present invention;

[0054] Reference numerals:

[0055] 11- Main steam main pipe; 12- Feedwater main pipe; 13- Reheat steam hot section main pipe; 14- Reheat steam cold section main pipe; a- Stop valve;

[0056] 2- boiler; 21- superheater; 22- reheater;

[0057] 3-steam turbine unit; 30-condensate recovery assembly; 31-high-pressure cylinder; 32-medium-pressure cylinder; 33-low-pressure cylinder;

[0058] 34 - first valve; 35 - second valve; 36 - third valve; 37 - fourth valve; 38 - fifth valve; 39 - sixth valve; 40 - seventh valve; 41 - eighth valve; 42 - ninth valve; 43 - tenth valve, 44 - eleventh valve; 4 - generator;

[0059] 301-high-pressure heater; 302-deaerator; 303-feedwater pump; 304-feedwater pump turbine; 305-low-pressure heater; 306-condenser; 307-condensate pump. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0061] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" described in the embodiments of the present invention are described from the perspectives shown in the accompanying drawings and should not be understood as limiting the embodiments of the present invention. In addition, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" of another element, it can not only be directly connected "upper" or "lower" of the other element, but also indirectly connected "upper" or "lower" of the other element through an intermediate element.

[0063] like Figure 1As shown, the embodiment of the present invention provides a method for thermoelectric decoupling of a high-voltage cogeneration unit, which is applied to Figure 2 In the thermoelectric decoupling system of the high-voltage cogeneration unit shown, the thermoelectric decoupling system includes at least two cogeneration units of identical composition and a main pipe assembly respectively connected to each cogeneration unit, wherein:

[0064] The main pipe assembly includes a main steam main pipe 11, a feed water main pipe 12, a reheat steam hot section main pipe 13 and a reheat steam cold section main pipe 14. The cogeneration unit includes a boiler 2 and a steam turbine unit 3. The steam turbine unit 3 includes a high-pressure cylinder 31, an intermediate-pressure cylinder 32, a low-pressure cylinder 33 and a condensate recovery assembly 34. The high-pressure cylinder 31 is connected to the intermediate-pressure cylinder 32, and the intermediate-pressure cylinder 32 is connected to the low-pressure cylinder 33. The high-pressure cylinder 31, the intermediate-pressure cylinder 32 and the low-pressure cylinder 32 are respectively connected to the condensate recovery assembly 30. The condensate recovery assembly 30 is used to realize steam cooling and circulating water return;

[0065] The steam outlet of the boiler 2 is connected to the inlet of the high-pressure cylinder 31 through the main steam header 11. The reheated steam outlet of the boiler 2 is connected to the intermediate-pressure cylinder 32 and the external heat user respectively through the reheated steam hot section header 13. The outlet of the high-pressure cylinder 31 is connected to the reheated steam inlet of the boiler 2 through the reheated steam cold section header 13. The output end of the condensate recovery assembly 30 is connected to the steam inlet of the boiler 2 through the water supply header 12.

[0066] Thermoelectric decoupling methods include:

[0067] Step 100: Determine the supplied electric load and supplied thermal load of the thermal decoupling system according to the acquired current power generation mode, the target electric load and the target thermal load required by the user;

[0068] Step 102: Determine the operating mode of the thermoelectric decoupling system according to the supplied electrical load and the supplied thermal load;

[0069] Step 104: Determine the number of steam turbine units put into operation according to the operating mode;

[0070] Step 106: Based on the on-off regulation of the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe, the operation of the operating number of steam turbine units is achieved.

[0071] It should be noted that cogeneration units with the same composition are cogeneration units of the same type.

[0072] In the present invention, a main pipe assembly is used to transform the thermal decoupling system of multiple cogeneration units of the same type, and the boilers of each unit in the power station are connected in parallel using the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe, so that the supply electric load and supply heat load required by the thermal decoupling system can be determined according to the target electric load and target heat load required by the user, thereby determining the turbine units to be put into operation under different working modes, and shutting down some turbines during the deep peak regulation stage. At this time, the turbines operate at high load without affecting the heating quality; while the boilers operate at low load, which can significantly reduce the overall minimum technical output of the power station and can absorb a large amount of new energy electricity. In this way, flexible switching can be performed according to the heat and electricity loads to achieve thermal decoupling of high-voltage cogeneration units.

[0073] Specifically, in step 100, the current power generation mode includes traditional thermal power generation based on a thermoelectric decoupling system, and new energy power generation modes such as wind power generation, photovoltaic power generation, and hydropower generation; when the current power generation mode includes traditional thermal power generation and new energy power generation mode, the target electric load and target thermal load required by the user are provided by these two types of power generation modes. Excluding the electric load and thermal load provided by the new energy power generation mode, the supplied electric load and supplied thermal load that the thermoelectric decoupling system needs to provide under the current power generation mode can be determined.

[0074] In some embodiments of the present invention, in step 102, determining the operating mode of the thermoelectric decoupling system according to the supplied electrical load and the supplied thermal load includes:

[0075] Determine whether the supplied power load is less than the target power load;

[0076] When the supplied power load is less than the target power load, determining the operating mode to be the first mode; wherein the first mode is used to achieve deep peak regulation of the high-voltage cogeneration unit;

[0077] Determining whether the supplied electrical load is greater than a preset electrical load threshold, and whether the supplied thermal load is greater than a preset thermal load threshold; wherein the preset electrical load threshold is less than a target electrical load, and the preset thermal load threshold is less than the target electrical load;

[0078] When the supplied electrical load is greater than a preset electrical load threshold and the supplied thermal load is not greater than a preset thermal load threshold, determining the operating mode to be the second mode of electrical compensation mode; wherein the electrical compensation mode is used to compensate for the electrical load of the high-voltage cogeneration unit when performing deep peak regulation;

[0079] When the supplied heat load is greater than a preset heat load threshold and the supplied electric load is not greater than a preset electric load threshold, determining the operating mode to be the second mode of heat compensation mode; wherein the heat compensation mode is used to compensate for the heat load of the high-voltage cogeneration unit when performing deep peak regulation;

[0080] when the supply electric load is greater than the preset electric load threshold value and the supply heat load is greater than the preset heat load threshold value, the working mode is determined as a second mode of heat and electricity compensation mode; wherein the heat and electricity compensation mode is used to realize compensation of the heat load and the electric load of the high-pressure heat and electricity cogeneration unit during deep peak shaving;

[0081] when the supply electric load is equal to the target electric load, the working mode is determined as a third mode; wherein the third mode realizes high load operation of the high-pressure heat and electricity cogeneration unit.

[0082] In some embodiments of the present application, the operation modes of the heat and electricity decoupling system include a first mode and a second mode; the first mode is used to realize deep peak shaving of the high-pressure heat and electricity cogeneration unit; the second mode is used to realize compensation of the heat load and / or the electric load of the high-pressure heat and electricity cogeneration unit during deep peak shaving; wherein the second mode includes an electric compensation mode, a heat compensation mode and a heat and electricity compensation mode.

[0083] In the present application, the electric compensation mode is used to realize compensation of the electric load of the high-pressure heat and electricity cogeneration unit during deep peak shaving; the heat compensation mode is used to realize compensation of the heat load of the high-pressure heat and electricity cogeneration unit during deep peak shaving; the heat and electricity compensation mode is used to realize compensation of the heat load and the electric load of the high-pressure heat and electricity cogeneration unit during deep peak shaving.

[0084] It should be noted that the supply electric load is less than the target electric load, and the current power generation mode is determined as a non-single thermal power generation mode, i.e. there is also a new energy power generation mode, at this time the heat and electricity decoupling system needs to enter the first mode of deep peak shaving, so that the heat and electricity decoupling system of the high-pressure heat and electricity cogeneration unit operates at low output to assist new energy power on-grid. Wherein the preset heat load threshold value and the preset electric load threshold value are respectively the upper limit of the heat load and the upper limit of the electric load that can be reached by the heat and electricity decoupling system in the first mode.

[0085] In the present application, when the heat and electricity decoupling system operates in the first mode, only part of the steam turbine units are put into operation, when the supply electric load is greater than the preset electric load threshold value and / or the supply heat load is greater than the preset heat load threshold value, there will be a supply gap in the heat load and the electric load. Therefore, the present application provides a second mode, which is an emergency compensation mode based on the first mode, i.e. the deep peak shaving mode, and the electric compensation mode, the heat compensation mode and the heat and electricity compensation mode correspond to three situations of electric load gap, heat load gap and heat and electricity load gap respectively, i.e. the second mode is a compensation operation adjustment based on the operation of the first mode.

[0086] In the present application, the third mode realizes high load operation of the high-pressure heat and electricity cogeneration unit, i.e. the heat and electricity decoupling system still operates in the original unit system, the number of operating steam turbine units is the same as the number of heat and electricity cogeneration units, i.e. all steam turbine units are put into operation.

[0087] In some embodiments of the present invention, in step 104, determining the number of steam turbine units put into operation according to the operating mode includes:

[0088] Obtaining feasible electric load ranges and feasible thermal load ranges under each working mode; wherein the feasible electric load ranges and feasible thermal load ranges under different working modes are different;

[0089] The number of steam turbine units put into operation is determined based on the supplied electrical load, supplied thermal load, maximum thermal load and maximum power supply load of the steam turbine units, and the feasible electrical load range and feasible thermal load range under each operating mode.

[0090] In some embodiments of the present invention, Figure 3 , which shows a schematic structural diagram of a thermoelectric decoupling system consisting of two identical cogeneration units, wherein the boiler 2 includes a superheater 21 and a reheater 22, a first valve 34 and a second valve 35 are provided on the pipeline between the superheater 21 and the high-pressure cylinder 31, a third valve 36 is provided on the pipeline between the high-pressure cylinder 31 and the reheater 22, a fourth valve 37, a fifth valve 38, and a sixth valve 39 are provided on the pipeline between the reheater 22 and the intermediate-pressure cylinder 32, a fifth valve 38 and a seventh valve 40 are provided on the pipeline between the reheater 22 and the heat user, an eighth valve 41 is provided on the pipeline between the condensate recovery assembly 30 and the superheater 21, and a ninth valve 42 is provided on the pipeline between the condensate recovery assembly 30 and the heat user;

[0091] The steam outlet of the superheater 21 is connected to the inlet of the high-pressure cylinder 31 through the main steam main pipe 11 via the first valve 34 and the second valve 35; the outlet of the high-pressure cylinder 31 is connected to the reheat steam inlet of the reheater 22 through the reheat steam cold section main pipe 14 via the third valve 36; the reheat steam outlet of the reheater 22 is connected to the intermediate-pressure cylinder 32 through the reheat steam hot section main pipe 13 via the fourth valve 37, the fifth valve 38, and the sixth valve 39; the reheat steam outlet of the reheater 22 is connected to the heat user through the reheat steam hot section main pipe 13 via the fourth valve 37, the fifth valve 38, and the seventh valve 40; the output end of the condensate recovery assembly 30 is connected to the steam inlet of the superheater 21 through the water supply main pipe 12 via the eighth valve 41; the input end of the condensate recovery assembly 30 is connected to the heat user through the ninth valve 42;

[0092] Stop valves 101 are provided on the main steam main pipe 11 , the feed water main pipe 12 , the reheat steam hot section main pipe 13 and the reheat steam cold section main pipe 14 .

[0093] It should be noted that the low pressure cylinder 33 is connected to the generator 4. Heat users include but are not limited to industrial steam users and heating users. The preferred heat users of the present invention are industrial users using high-parameter steam.

[0094] In some embodiments of the present application, as shown in Figure 3 Step 106 comprises:

[0095] The stop valves 101 on the main steam header 11, the feed water header 12, the hot section of the reheat steam header 13 and the cold section of the reheat steam header 14 are all opened to keep the communication, and the first valve 34, the fourth valve 37 and the ninth valve 42 of the steam turbine unit 3 of at least one of the cogeneration units are closed according to the operation number, so that the steam turbine unit 3 enters the hot standby state, and the thermal and electric decoupling system enters the first mode.

[0096] It should be noted that in the first mode, only the steam turbine unit of at least one of the cogeneration units is closed, but the boiler of the at least one of the cogeneration units is still kept running, and the rest of the cogeneration units are all normally running.

[0097] In some preferred embodiments of the present application, as shown in Figure 3 In the first mode, the eighth valve 41 and the third valve 36 are controlled to make the feed water and the reheat steam flow into the two boilers in the same proportion, so that the two boilers are operated at the same load.

[0098] It should be noted that, as shown in Figure 3 The first valve 34 and the fourth valve 37 are not shown in the upper cogeneration unit. The first valve 34 and the fourth valve 37 are preferably stop valves, i.e., the first valve 34 is a main steam stop valve, and the fourth valve 37 is a reheat steam stop valve, which are used to facilitate the closing and starting of the steam turbine unit 3 in the cogeneration unit.

[0099] In the present application, by opening the stop valves 101 of the headers in the header assembly to keep the flow, the system is operated in the header mode, and by closing the first valve 34, the fourth valve 37 and the ninth valve 42 of the lower cogeneration unit in Figure 3 the steam turbine unit 3 of the lower cogeneration unit enters the hot standby state, i.e., does not participate in power generation, but is ready to restart at any time, so that one steam turbine unit is shut down, and the other steam turbine unit (i.e., the steam turbine unit 3 in the upper cogeneration unit in Figure 2 ) keeps the cogeneration. In addition, by controlling the eighth valve 41 and the third valve 36, the feed water and the reheat steam flow into the two boilers in the same proportion, so that the two boilers are operated at the same load. In this way, by the above operation, the thermal and electric decoupling system can greatly improve the deep peak shaving capacity during the low load demand period of the power plant, and realize the thermal and electric decoupling. It should be noted that in the first mode, the seventh valve 40 of the lower cogeneration unit is also kept closed. Figure 3

[0100] ​In the present application, the boilers of each unit in the power plant are connected in parallel by using the mother tube assembly, and part of the steam turbine is shut down in the deep peak shaving stage; at this time, the steam turbine assembly operates at high load, which does not affect the heating quality; and the boiler operates at low load, which can significantly reduce the minimum technical output of the overall power plant and can accommodate a large amount of new energy power. Moreover, through the mother tube assembly, the number of steam turbines operating in the power plant is controlled according to the peak shaving demand of the cogeneration unit, thereby realizing "stopping the machine without stopping the boiler". Unlike the high-low bypass technology used for thermal decoupling in the traditional way, since several steam turbine units are shut down, each boiler will operate at a lower load, further reducing the risk of reheater overtemperature.

[0101] In some embodiments of the present application, as shown in Figure 3 The thermal decoupling system further comprises a main steam bypass heating pipeline, and the tenth valve 43 is arranged on the main steam bypass heating pipeline; wherein the main steam mother tube 11 is connected with the main steam bypass heating pipeline, and an output end of the main steam bypass heating pipeline is connected with the heat user;

[0102] Step 106 comprises:

[0103] In the first mode, the tenth valve 43 is opened to make the thermal decoupling system enter the thermal compensation mode.

[0104] In some preferred embodiments of the present application, as shown in Figure 3 The eleventh valve 44 is further arranged on the main steam bypass heating pipeline;

[0105] Step 106 comprises:

[0106] In the thermal compensation mode, the on-demand distribution of the thermal load is realized by adjusting and controlling the eleventh valve 44 and the seventh valve 40.

[0107] In the present application, on the basis of the operation in the first mode, the tenth valve 43 on the main steam bypass heating pipeline is opened to realize the thermal load gap under deep peak shaving, i.e. the thermal compensation mode operation. At the same time, by synchronously controlling the seventh valve 40 and the eleventh valve 44 of the steam turbine unit 3 that is operating, the on-demand distribution of the thermal load on the steam turbine side and the main steam side is realized.

[0108] In the present application, in the first mode, the tenth valve 43 is kept closed; the main steam bypass heating pipeline is opened, and due to the impact of a small amount of bypass main steam, the speed of restarting the steam turbine unit 3 is faster.

[0109] In some embodiments of the present application, as shown in Figure 3 Step 106 comprises:

[0110] In the first mode, the first valve 34 and the fourth valve 37 of the steam turbine unit 3 in the hot standby state are opened, and the seventh valve 40 is closed, so that the thermoelectric decoupling system enters the electric compensation mode.

[0111] In the present invention, based on the operation of the first mode, the Figure 3 The first and fourth valves 34 and 37 of the cogeneration unit located at the bottom are closed, and the seventh valve 40 is closed, shutting off the heat supply. This also closes the main steam bypass heating pipeline, allowing the steam turbine unit 3, which is in hot standby mode in the first mode, to gradually come into operation and generate electricity in a purely condensing mode to compensate for the power load shortfall. It should be noted that when steam turbine unit 3 enters purely condensing mode, operating at low load, its reheat pressure can be adjusted using the sixth valve 39 at the intermediate pressure cylinder inlet to match that of other high-load units.

[0112] In some embodiments of the present invention, Figure 3 As shown, step 106 includes:

[0113] In the first mode, the tenth valve 43 is opened, and the first valve 34 and the fourth valve 37 of the steam turbine unit 3 in hot standby state are opened, and the seventh valve 40 is closed, so that the thermoelectric decoupling system enters the thermoelectric compensation mode.

[0114] In the present invention, based on the operation of the first mode, the tenth valve 43 on the main steam bypass heating pipeline is opened to realize the heat load gap under deep peak regulation, and the heat load is distributed between the turbine side and the main steam side by the operation method of the heat compensation mode; Figure 3 The first valve 34 and the fourth valve 37 of the cogeneration unit located at the bottom are closed, the seventh valve 40 is closed, and the main steam bypass heating pipeline is closed, so that the steam turbine unit 3 in the hot standby state in the first mode is gradually put into operation, and compensates for the power load gap in a purely condensing production mode.

[0115] In some embodiments of the present invention, Figure 3 As shown, step 106 includes:

[0116] The stop valves 101 on the main steam main pipe 11, the feed water main pipe 12, the reheat steam hot section main pipe 13 and the reheat steam cold section main pipe 14 are all closed to maintain a disconnected state, so as to realize the operation of the operating number of steam turbine units, so that the thermal power decoupling system enters the third mode; wherein, the operating number in the third mode is the same as the number of cogeneration units.

[0117] In the present invention, when closing all the stop valves 101 on the main steam header 11, the feedwater header 12, the reheat steam hot section header 13, and the reheat steam cold section header 14, the tenth valve 43 of the main steam bypass heating pipeline is kept closed. This allows the thermoelectric decoupling system with the added header assembly to operate in the original unit mode, i.e., the third mode, when the demand for electricity and heat is high. And only in this mode, Figure 3 In other modes, the seventh valve 40 and the ninth valve 42 of the steam turbine unit 3 at the bottom will be opened, and they are closed. That is to say, the steam turbine unit 3 does not participate in supplying heat load in the first mode or the second mode.

[0118] In the present invention, it should be noted that, Figure 3 The structural diagram of the thermoelectric decoupling system shown does not constitute a specific limitation. The thermoelectric decoupling system can also be a plurality of cogeneration units with the same composition, and at least two cogeneration units with the same composition have no essential difference. Any cogeneration unit is applicable to the above-mentioned operation method.

[0119] Since the reheat steam control of units of different types is complicated, it is difficult to control the reheat steam when multiple units are connected in parallel through the main pipe assembly. Therefore, in the present invention, multiple cogeneration units with the same composition are connected in parallel, which can avoid the reheat steam control problem caused by the parallel connection of multiple units in the first mode: when a single unit is running, there is no need for reheat steam pressure control; when multiple units are running, the reheat steam control demand can be effectively reduced by making the steam turbines in operation operate at the same load.

[0120] It should be noted that the first valve 34 , the fourth valve 37 , the ninth valve 42 , and the tenth valve 43 are preferably stop valves; and the remaining valves are preferably regulating valves.

[0121] In some embodiments of the present invention, Figure 3 As shown, the condensate recovery assembly 30 includes a high-pressure heater 301, a deaerator 302, a feedwater pump 303, a feedwater pump turbine 304, a low-pressure heater 305, a condenser 306, and a condensate pump 307;

[0122] An eighth valve 41 is provided on the pipeline between the condensate recovery assembly 30 and the superheater 21, and a ninth valve 42 is provided on the pipeline between the condensate recovery assembly 30 and the heat user;

[0123] The outlet of the high-pressure heater 301 is connected to the steam inlet of the superheater 21 through the water supply main pipe 12 via the eighth valve 41. The high-pressure heater 301 is connected to the high-pressure cylinder 31, the medium-pressure cylinder 32, the deaerator 302, and the water supply pump 303 respectively;

[0124] The feedwater pump turbine 304 is connected to the feedwater pump 303, the intermediate pressure cylinder 32 and the low pressure cylinder 33 respectively;

[0125] The low-pressure heater 305 is respectively connected to the deaerator 302, the medium-pressure cylinder 32, the low-pressure cylinder 33, the condenser 306, and the condensate pump 307;

[0126] The condenser 306 is connected to the condensate pump 307 ; the ninth valve 42 is connected to the condensate pump 307 and the low-pressure heater 305 , respectively.

[0127] The present invention's thermal-electric decoupling method for high-voltage cogeneration units enables flexible switching based on specific thermal and electrical loads, achieving thermal-electric decoupling of high-voltage cogeneration units. It also maintains a substantially continuous feasible domain, achieving thermal-electric decoupling of high-voltage cogeneration units and broadly applicable to industrial cogeneration units. Furthermore, because the thermal-electric decoupling system significantly enhances load regulation flexibility, it can reduce unnecessary power plant output, thereby reducing CO2 emissions; it can also significantly lower the minimum technical output during periods of deep peak load regulation, significantly reducing carbon emissions during these periods.

[0128] The thermoelectric decoupling method of the high-voltage cogeneration unit of the present invention achieves significant thermoelectric decoupling and high-proportion carbon emission reduction, which is in line with the policy orientation of "three reforms and linkage"; at the same time, it does not require the addition of large-scale equipment, has a low investment cost, good economy and high safety and stability.

[0129] It should be noted that, in this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising 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, the elements defined by the sentence "comprising a ..." do not exclude the presence of other identical factors in the process, method, article or device comprising the elements.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for thermoelectric decoupling of a high-voltage cogeneration unit, characterized in that: A thermoelectric decoupling system applied to a high-voltage cogeneration unit, the thermoelectric decoupling system comprising at least two cogeneration units of identical composition and a main pipe assembly respectively connected to each of the cogeneration units, wherein: The main pipe assembly includes a main steam main pipe, a feed water main pipe, a reheat steam hot section main pipe and a reheat steam cold section main pipe; the cogeneration unit includes a boiler and a steam turbine unit, and the steam turbine unit includes a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder and a condensate recovery assembly, the high-pressure cylinder is connected to the intermediate-pressure cylinder, the intermediate-pressure cylinder is connected to the low-pressure cylinder, and the high-pressure cylinder, the intermediate-pressure cylinder and the low-pressure cylinder are respectively connected to the condensate recovery assembly, and the condensate recovery assembly is used to realize steam cooling and circulating water return; The steam outlet of the boiler is connected to the inlet of the high-pressure cylinder through the main steam main pipe, the reheat steam outlet of the boiler is connected to the intermediate-pressure cylinder and the external heat user respectively through the reheat steam hot section main pipe, the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the boiler through the reheat steam cold section main pipe, and the output end of the condensate recovery assembly is connected to the steam inlet of the boiler through the water supply main pipe; The thermoelectric decoupling method comprises: Determining the supplied electric load and supplied thermal load of the thermal decoupling system according to the acquired current power generation mode, the target electric load and the target thermal load required by the user; determining an operating mode of the thermoelectric decoupling system according to the supplied electrical load and the supplied thermal load; Determining the number of steam turbine units put into operation according to the working mode; Based on the on-off regulation of the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe, the operation of the operating number of the steam turbine units is achieved.

2. The thermoelectric decoupling method of a high-voltage cogeneration unit according to claim 1, characterized in that: The determining the operating mode of the thermoelectric decoupling system according to the supplied electrical load and the supplied thermal load includes: determining whether the supplied electrical load is less than the target electrical load; When the supplied electrical load is less than the target electrical load, determining the operating mode to be the first mode; wherein the first mode is used to achieve deep peak regulation of the high-voltage cogeneration unit; Determining whether the supplied electrical load is greater than a preset electrical load threshold, and whether the supplied thermal load is greater than a preset thermal load threshold; wherein the preset electrical load threshold is less than the target electrical load, and the preset thermal load threshold is less than the target thermal load; When the supplied electrical load is greater than a preset electrical load threshold and the supplied thermal load is not greater than a preset thermal load threshold, determining that the operating mode is the second mode of electrical compensation mode; wherein the electrical compensation mode is used to achieve compensation for the electrical load of the high-voltage cogeneration unit when performing deep peak regulation; When the supplied heat load is greater than the preset heat load threshold and the supplied electric load is not greater than the preset electric load threshold, determining that the operating mode is the thermal compensation mode of the second mode; wherein the thermal compensation mode is used to compensate for the heat load of the high-voltage cogeneration unit when performing deep peak regulation; When the supplied electrical load is greater than the preset electrical load threshold, and the supplied thermal load is greater than the preset thermal load threshold, determining that the operating mode is the thermoelectric compensation mode of the second mode; wherein the thermoelectric compensation mode is used to achieve compensation of the thermal load and electrical load of the high-voltage cogeneration unit when performing deep peak regulation; When the supplied electrical load is the same as the target electrical load, the operating mode is determined to be the third mode; wherein the third mode realizes high-load operation of the high-voltage cogeneration unit.

3. The thermoelectric decoupling method of a high-voltage cogeneration unit according to claim 2, characterized in that: The boiler includes a superheater and a reheater, a first valve and a second valve are provided on the pipeline between the superheater and the high-pressure cylinder, a third valve is provided on the pipeline between the high-pressure cylinder and the reheater, a fourth valve, a fifth valve, and a sixth valve are provided on the pipeline between the reheater and the intermediate-pressure cylinder, a fifth valve and a seventh valve are provided on the pipeline between the reheater and the heat user, an eighth valve is provided on the pipeline between the condensate recovery assembly and the superheater, and a ninth valve is provided on the pipeline between the condensate recovery assembly and the heat user; The steam outlet of the superheater is connected to the inlet of the high-pressure cylinder through the main steam main pipe via the first valve and the second valve; the outlet of the high-pressure cylinder is connected to the reheat steam inlet of the reheater through the reheat steam cold section main pipe via the third valve; the reheat steam outlet of the reheater is connected to the intermediate-pressure cylinder through the reheat steam hot section main pipe via the fourth valve, the fifth valve, and the sixth valve; the reheat steam outlet of the reheater is connected to the heat user through the reheat steam hot section main pipe via the fourth valve, the fifth valve, and the seventh valve; the output end of the condensate recovery assembly is connected to the steam inlet of the superheater through the water supply main pipe via the eighth valve; the input end of the condensate recovery assembly is connected to the heat user through the ninth valve; The main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe are all provided with stop valves.

4. The thermoelectric decoupling method of a high-voltage cogeneration unit according to claim 3, characterized in that: The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including: The stop valves on the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe are all opened to maintain the connection state, and the first valve, the fourth valve and the ninth valve of the turbine unit of at least one of the cogeneration units are closed according to the operating quantity, so that the turbine unit enters the hot standby state and the thermal-electric decoupling system enters the first mode.

5. The thermoelectric decoupling method of a high-voltage cogeneration unit according to claim 3, characterized in that: The thermoelectric decoupling system further includes a main steam bypass heating pipeline, on which a tenth valve is provided; wherein the main steam main pipe is connected to the main steam bypass heating pipeline, and the output end of the main steam bypass heating pipeline is connected to the heat user; The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including: The tenth valve is opened in the first mode to enable the thermoelectric decoupling system to enter the thermal compensation mode.

6. The thermoelectric decoupling method of a high-voltage cogeneration unit according to claim 5, characterized in that: An eleventh valve is also provided on the main steam bypass heating pipeline; The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including: In the heat compensation mode, the heat load is distributed on demand by adjusting the eleventh valve and the seventh valve.

7. The method for thermoelectric decoupling of a high-voltage cogeneration unit according to claim 3, characterized in that: The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including: In the first mode, the first valve and the fourth valve of the steam turbine unit that enters the hot standby state are opened, and the seventh valve is closed, so that the thermoelectric decoupling system enters the electric compensation mode.

8. The method for thermoelectric decoupling of a high-voltage cogeneration unit according to claim 5, characterized in that: The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including: In the first mode, the tenth valve is opened, and the first valve and the fourth valve of the steam turbine unit in hot standby state are opened, and the seventh valve is closed, so that the thermoelectric decoupling system enters the thermoelectric compensation mode.

9. The method for thermoelectric decoupling of a high-voltage cogeneration unit according to claim 2, characterized in that: The operation of the steam turbine units in the operating number is achieved by adjusting the on / off control of the main steam main pipe, the feedwater main pipe, the reheat steam hot section main pipe, and the reheat steam cold section main pipe, including: The stop valves on the main steam main pipe, the feed water main pipe, the reheat steam hot section main pipe and the reheat steam cold section main pipe are all closed to maintain a disconnected state, so as to realize the operation of the operating number of the steam turbine units, so that the thermal-electric decoupling system enters the third mode; wherein, the operating number in the third mode is the same as the number of the cogeneration units.

10. The thermoelectric decoupling method of a high-voltage cogeneration unit according to any one of claims 1 to 9, characterized in that: Determining the number of steam turbine units put into operation according to the working mode includes: Obtaining a feasible electric load range and a feasible thermal load range under each of the operating modes; wherein the feasible electric load range and the feasible thermal load range under different operating modes are different; The number of steam turbine units put into operation is determined based on the supplied electrical load, the supplied thermal load, the maximum thermal load and the maximum power supply load of the steam turbine unit, and the feasible electrical load range and the feasible thermal load range under each of the operating modes.

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