Unit unit mother pipe connecting system for realizing flexible combination of machine and furnace and operation method of unit unit mother pipe connecting system

Abstract

The invention provides a unit system unit mother pipe connecting system for realizing flexible combination of machines and furnaces, which comprises at least two units and mother pipe assemblies respectively connected with the units, the plurality of units are connected through the mother pipe assemblies and a plurality of branch pipes, and each branch pipe is connected with a valve group in series. By flexibly switching the valve banks, complete decoupling of the steam turbine and the boiler can be achieved, and operation can be conducted in multiple working condition modes, including normal unit operation, multi-boiler and few-machine operation and few-boiler and multi-machine operation. By freely combining the steam turbine and the boiler, the unit has flexibility and economical efficiency under complex working conditions. The invention further provides an operation method of the unit-system unit mother pipe connecting system for achieving flexible combination of the unit and the furnace.

Description

Technical Field

[0001] The present invention belongs to the technical field of unitized units, and particularly relates to a header connection system and an operation method for a unitized unit that enables flexible combination of a boiler and a turbine. Background Art

[0002] Currently, most power plants adopt unitized units mainly operating in an independent mode, that is, each boiler, steam turbine, and generator operates as an independent unit. Under traditional high-load operating conditions, this mode has certain advantages.

[0003] However, in the context of large-scale grid connection of new energy and increasing peak shaving requirements, the disadvantages of unitized units gradually emerge. Unitized units are difficult to flexibly adapt to complex load changes. The deep load regulation range of a single unit is limited, and problems such as reduced efficiency, incomplete combustion, and increased pollutant emissions are likely to occur under low-load conditions, affecting the economy and environmental protection of the unit. Moreover, the boiler and turbine must be overhauled simultaneously, restricting each other. To solve this problem, some technologies similar to the header connection of unitized units have emerged. Connecting the unitized units of a multi-unit power plant through a header can not only share the power load to a certain extent, reasonably distribute the load, and improve the unit efficiency, but also enable standby operation in case of emergency to ensure the stability of the unit. In addition, under deep peak shaving conditions, start-up and shutdown adjustments can be quickly carried out to achieve reasonable and efficient distribution of the grid load, reduce coal consumption, and further improve the economy of the unit.

[0004] Currently, technologies similar to the header connection of unitized units mainly include the technology of centralized header units, the technology of switching header units, etc. In centralized header units, the steam of all boilers is aggregated into a single steam header, and then led from the header to steam-consuming devices such as steam turbines. In switching header units, each boiler and the corresponding steam turbine form a unit, and a connecting header is provided between the units, which has both reliability and a certain degree of flexibility.

[0005] However, the existing technologies still have deficiencies. Although the centralized header system improves the operating flexibility through a common main steam header, its stability is insufficient. The long-term and multi-condition operation of the unit may accelerate the wear of the header components, increase the equipment maintenance cost, and a local failure of the main steam header will also affect the normal operation of the entire unit.

[0006] In switching header units, a switching valve is installed at the connection between each unit and the switching header. The unit can operate in unit mode or be switched to header mode. However, switching header units are generally small-capacity industrial units and do not have a reheating steam system.

[0007] Therefore, how to overcome the above technical defects is an urgent problem for those skilled in the art. Summary of the Invention

[0008] The object of the present invention is to provide a main pipe connection system and an operation method for a unitized unit that enables flexible combination of a steam turbine and a boiler, which realizes complete decoupling of the steam turbine and the boiler, is adaptable to various operating conditions, and has flexibility and economy under complex operating conditions.

[0009] To solve the above technical problems, the present invention provides a main pipe connection system for a unitized unit that enables flexible combination of a steam turbine and a boiler, including: at least two units and a main pipe assembly respectively connected to each of the units. Wherein, each of the units includes: a boiler and a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a condenser, a condensate pump, a low-pressure heater, and a high-pressure heater connected in sequence. The main pipe assembly includes: a main steam main pipe, a low-temperature reheated steam main pipe, a high-temperature reheated steam main pipe, a condensate main pipe, and a feed water main pipe. The main steam main pipe is respectively connected to the outlet of the superheater of the boiler of each unit through a main steam switching branch pipe, and the main steam main pipe is respectively connected to the steam inlet of the high-pressure cylinder of each unit through a main steam outlet branch pipe. The outlet of the superheater and the steam inlet of the high-pressure cylinder are connected through a high-pressure cylinder steam inlet branch pipe. The low-temperature reheated steam main pipe is respectively connected to the steam outlet of the high-pressure cylinder of each unit through a low-temperature reheated steam switching branch pipe, and the low-temperature reheated steam main pipe is respectively connected to the steam inlet of the reheater of the boiler of each unit through a low-temperature reheated steam outlet branch pipe. The steam inlet of the reheater and the steam outlet of the high-pressure cylinder are connected through a reheater steam inlet branch pipe. The high-temperature reheated steam main pipe is respectively connected to the steam outlet of the reheater of the boiler of each unit through a high-temperature reheated steam switching branch pipe, and the high-temperature reheated steam main pipe is respectively connected to the steam inlet of the intermediate-pressure cylinder of each unit through a high-temperature reheated steam outlet branch pipe. The steam outlet of the reheater and the steam inlet of the intermediate-pressure cylinder are connected through a reheater steam outlet branch pipe. The condensate main pipe is respectively connected to the outlet of the condensate pump of each unit through a condensate switching branch pipe, and the condensate main pipe is respectively connected to the inlet of the low-pressure heater of each unit through a condensate outlet branch pipe. The outlet of the condensate pump and the inlet of the low-pressure heater are connected through a condensate inlet branch pipe. The feed water main pipe is respectively connected to the outlet of the high-pressure heater of each unit through a feed water switching branch pipe, and the feed water main pipe is respectively connected to the inlet of the superheater of the boiler of each unit through a feed water outlet branch pipe. The outlet of the high-pressure heater and the inlet of the superheater are connected through a feed water inlet branch pipe. A valve group is connected in series on each of the main steam branch pipes, each of the main steam outlet branch pipes, each of the high-pressure cylinder steam inlet branch pipes, each of the low-temperature reheated steam switching branch pipes, each of the low-temperature reheated steam outlet branch pipes, each of the reheater steam inlet branch pipes, each of the high-temperature reheated steam switching branch pipes, each of the high-temperature reheated steam outlet branch pipes, each of the reheater steam outlet branch pipes, each of the condensate switching branch pipes, each of the condensate outlet branch pipes, each of the condensate inlet branch pipes, each of the feed water switching branch pipes, each of the feed water outlet branch pipes, and each of the feed water inlet branch pipes.

[0010] Optionally, in the above unitized unit main pipe connection system, a deaerator and a feed water pump are connected in series between the low-pressure heater and the high-pressure heater.

[0011] Optionally, in the above unitized unit main pipe connection system, each of the valve groups is an electromagnetic valve, an electric valve, a pneumatic valve, a hydraulic valve, or a manual valve.

[0012] The present invention also provides an operation method for a unitized unit main pipe connection system that realizes flexible combination of the boiler and the turbine. Based on the above unitized unit main pipe connection system that realizes flexible combination of the boiler and the turbine, the operation method includes: When each of the units is operating normally, open the valve groups on each of the high-pressure cylinder steam inlet branch pipes, each of the reheater steam inlet branch pipes, each of the reheater steam outlet branch pipes, each of the condensate inlet branch pipes, and each of the feed water inlet branch pipes, and close the other valve groups; When each of the units is in the multi-boiler and few-turbine mode, selectively shut down the steam turbines of at least one of the units, and the steam turbines of the other units operate normally. Among them, in the selectively shut-down units, close the valve groups on the main steam outlet branch pipes and the high-pressure cylinder steam inlet branch pipes, and open the valve groups on the main steam switching branch pipes; close the valve groups on the reheater steam inlet branch pipes and the low-temperature reheated steam switching branch pipes, and open the valve groups on the low-temperature reheated steam outlet branch pipes; close the valve groups on the high-temperature reheated steam outlet branch pipes and the reheater steam outlet branch pipes, and open the valve groups on the high-temperature reheated steam switching branch pipes; close the valve groups on the condensate switching branch pipes and the condensate inlet branch pipes, and open the valve groups on the condensate outlet branch pipes; open the valve groups on each of the feed water switching branch pipes, each of the feed water outlet branch pipes, and each of the feed water inlet branch pipes; in the other normally operating units, open all the valve groups; When each of the units is in the mode of fewer boilers and more turbines, at least one boiler of the units is selectively shut down, and the boilers of the other units operate normally. Among the units with selective shutdown, the valve groups on the main steam switching branch pipe and the high-pressure cylinder steam inlet branch pipe are closed, and the valve group on the main steam outlet branch pipe is opened; the valve groups on the low-temperature reheated steam outlet branch pipe and the reheater steam inlet branch pipe are closed, and the valve group on the low-temperature reheated steam switching branch pipe is opened; the valve groups on the high-temperature reheated steam switching branch pipe and the reheater steam outlet branch pipe are closed, and the valve group on the high-temperature reheated steam outlet branch pipe is opened; the valve groups on the condensate switching branch pipe, the condensate outlet branch pipe and the condensate inlet branch pipe are opened; the valve groups on the feed water outlet branch pipe and the feed water inlet branch pipe are closed, and the valve group on the feed water switching branch pipe is opened; among the other units operating normally, all valve groups are opened.

[0013] Optionally, in the above operation method, when each of the units is in the mode of more boilers and fewer turbines, among the other normally operating steam turbines, the opening degree of the valve group on the main steam outlet branch pipe is adjusted according to requirements to control the steam volume entering the current unit, so that the main steam of the boilers of each unit enters the other normally operating steam turbines through the main steam header.

[0014] Optionally, in the above operation method, the selective shutdown of at least one boiler of the units is specifically when the boiler is in a state of maintenance, failure, two-shift operation of the unit or hot standby of the unit.

[0015] Optionally, in the above operation method, the selective shutdown of at least one steam turbine of the units is specifically when the steam turbine is in a state of maintenance, failure, two-shift operation of the unit or hot standby of the unit.

[0016] Optionally, in the above operation method, each of the valve groups is an adjusting isolation valve for controlling and adjusting the flow rate of the working medium in the pipeline.

[0017] Optionally, in the above operation method, each of the valve groups is a solenoid valve, an electric valve, a pneumatic valve, a hydraulic valve or a manual valve.

[0018] Optionally, in the above operation method, the number of the units is two.

[0019] The present invention provides a header connection system for a unitized unit for realizing flexible combination of a machine and a boiler, and its beneficial effects are as follows: Multiple units are connected through a header assembly and multiple branch pipes, and valve groups are connected in series on each branch pipe. By flexibly switching each valve group, complete decoupling of the steam turbine and the boiler can be realized, and the operation can be carried out under multiple working conditions, including normal operation of the unit, more boilers and fewer turbines, and fewer boilers and more turbines. By freely combining the steam turbine and the boiler, the unit has flexibility and economy under complex working conditions.

[0020] The present invention also provides an operation method for the main pipe connection system of a unitized unit realizing flexible combination of boiler and turbine, which has the same beneficial effects and will not be elaborated herein. Brief Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings required for use in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only the embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings according to the provided drawings without creative efforts.

[0022] Figure 1 It is a schematic diagram of a main pipe connection system of a unitized unit realizing flexible combination of boiler and turbine provided by an embodiment of the present invention; Figure 2 It is a schematic structural diagram of a boiler provided by an embodiment of the present invention.

[0023] In the above figures: 1 - Boiler; 101 - Superheater; 102 - Reheater; 2 - High-pressure cylinder; 3 - Intermediate-pressure cylinder; 4 - Low-pressure cylinder; 5 - Condenser; 6 - Condensate pump; 7 - Low-pressure heater; 8 - Deaerator; 9 - Feed water pump; 10 - High-pressure heater; V1-1, Vn-1 - Main steam main pipe switching valve groups; V1-2, Vn-2 - Main steam main pipe outlet valve groups; V1-3, Vn-3 - High-pressure cylinder steam inlet valve groups; V1-4, Vn-4 - Low-temperature reheated steam main pipe switching valve groups; V1-5, Vn-5 - Low-temperature reheated steam main pipe outlet valve groups; V1-6, Vn-6 - Reheater steam inlet valve groups; V1-7, Vn-7 - High-temperature reheated steam main pipe switching valve groups; V1-8, Vn-8 - High-temperature reheated steam main pipe outlet valve groups; V1-9, Vn-9 - Reheater steam outlet valve groups; V1-10, Vn-10 - Condensate main pipe switching valve groups; V1-11, Vn-11 - Condensate main pipe outlet valve groups; V1-12, Vn-12 - Condensate inlet valve groups; V1-13, Vn-13 - Feed water main pipe switching valve groups; V1-14, Vn-14 - Feed water main pipe outlet valve groups; V1-15, Vn-15 - Feed water inlet valve groups. Detailed Embodiments

[0024] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

[0025] The core of the present invention is to provide a header connection system and an operation method for a unitized unit that enables flexible combination of the turbine and boiler, realizes complete decoupling of the steam turbine and the boiler, is adaptable to various operating conditions, and has flexibility and economy under complex operating conditions.

[0026] In order to enable those skilled in the art to better understand the technical solutions provided by the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] Specifically, please refer to Figure 1 - Figure 2 A header connection system for a unitized unit that enables flexible combination of the turbine and boiler provided by the present invention includes: at least two units and header assemblies respectively connected to each unit.

[0028] Among them, each unit includes: a boiler 1, a high-pressure cylinder 2, an intermediate-pressure cylinder 3, a low-pressure cylinder 4, a condenser 5, a condensate pump 6, a low-pressure heater 7, a deaerator 8, a feed water pump 9, and a high-pressure heater 10. The high-pressure cylinder 2, the intermediate-pressure cylinder 3, the low-pressure cylinder 4, the condenser 5, the condensate pump 6, the low-pressure heater 7, the deaerator 8, the feed water pump 9, and the high-pressure heater 10 are connected in sequence. Among them, the interior of the boiler 1 includes a superheater 101, a reheater 102, and an economizer.

[0029] The header assembly includes: a main steam header, a low-temperature reheated steam header, a high-temperature reheated steam header, a condensate water header, and a feed water header.

[0030] The connection mode of the main steam header connection subsystem is: the main steam header is respectively connected to the outlet of the superheater 101 of the boiler 1 of each unit through a main steam switching branch pipe, and the main steam header is respectively connected to the steam inlet of the high-pressure cylinder 2 of each unit through a main steam outlet branch pipe. The outlet of the superheater 101 and the steam inlet of the high-pressure cylinder 2 are connected through a high-pressure cylinder steam inlet branch pipe.

[0031] The connection mode of the low-temperature reheated steam header connection subsystem is: the low-temperature reheated steam header is respectively connected to the steam outlet of the high-pressure cylinder 2 of each unit through a low-temperature reheated steam switching branch pipe, and the low-temperature reheated steam header is respectively connected to the steam inlet of the reheater 102 of the boiler 1 of each unit through a low-temperature reheated steam outlet branch pipe. The steam inlet of the reheater 102 and the steam outlet of the high-pressure cylinder 2 are connected through a reheater steam inlet branch pipe.

[0032] The connection mode of the high-temperature reheater steam header connection subsystem is as follows: the high-temperature reheater steam header is respectively connected to the steam outlet of the reheater 102 of the boiler 1 of each unit through a high-temperature reheater steam switching branch pipe; the high-temperature reheater steam header is respectively connected to the steam inlet of the intermediate pressure cylinder 3 of each unit through a high-temperature reheater steam outlet branch pipe; the steam outlet of the reheater 102 and the steam inlet of the intermediate pressure cylinder 3 are connected through a reheater steam outlet branch pipe.

[0033] The connection mode of the condensate water header connection subsystem is as follows: the condensate water header is respectively connected to the outlet of the condensate pump 6 of each unit through a condensate water switching branch pipe; the condensate water header is respectively connected to the inlet of the low-pressure heater 7 of each unit through a condensate water outlet branch pipe; the outlet of the condensate pump 6 and the inlet of the low-pressure heater 7 are connected through a condensate water inlet branch pipe.

[0034] The connection mode of the feed water header connection subsystem is as follows: the feed water header is respectively connected to the outlet of the high-pressure heater 10 of each unit through a feed water switching branch pipe; the feed water header is respectively connected to the inlet of the superheater 101 of the boiler 1 of each unit through a feed water outlet branch pipe; the outlet of the high-pressure heater 10 and the inlet of the superheater 101 are connected through a feed water inlet branch pipe.

[0035] Valve groups are connected in series on each main steam branch pipe, each main steam outlet branch pipe, each high-pressure cylinder steam inlet branch pipe, each low-temperature reheater steam switching branch pipe, each low-temperature reheater steam outlet branch pipe, each reheater steam inlet branch pipe, each high-temperature reheater steam switching branch pipe, each high-temperature reheater steam outlet branch pipe, each reheater steam outlet branch pipe, each condensate water switching branch pipe, each condensate water outlet branch pipe, each condensate water inlet branch pipe, each feed water switching branch pipe, each feed water outlet branch pipe and each feed water inlet branch pipe.

[0036] A header connection system for a unitized unit that realizes flexible combination of a turbine and a boiler provided by the present invention includes at least two units and a header assembly respectively connected to each unit. The multiple units are connected through the header assembly and multiple branch pipes, and valve groups are connected in series on each branch pipe. By flexibly switching each valve group, the complete decoupling of the steam turbine and the boiler can be realized, and the system can operate in multiple working conditions, freely combine the steam turbine and the boiler, and the unit has flexibility and economy under complex working conditions.

[0037] In a specific embodiment, a deaerator 8 and a feed water pump 9 are connected in series between the low-pressure heater 7 and the high-pressure heater 10.

[0038] In a specific embodiment, each valve group can be a regulating isolation valve for controlling and regulating the flow rate of the working medium in the pipeline. Specifically, each valve group is an electromagnetic valve, an electric valve, a pneumatic valve, a hydraulic valve or a manual valve.

[0039] The valve group on the main steam switching branch pipe is the main steam header switching valve group Vn-1, the valve group on the main steam outlet branch pipe is the main steam header outlet valve group Vn-2, the valve group on the high-pressure cylinder steam inlet branch pipe is the high-pressure cylinder steam inlet valve group Vn-3, the valve group on the low-temperature reheated steam switching branch pipe is the low-temperature reheated steam header switching valve group Vn-4, the valve group on the low-temperature reheated steam outlet branch pipe is the low-temperature reheated steam header outlet valve group Vn-5, the valve group on the reheater steam inlet branch pipe is the reheater steam inlet valve group Vn-6, the valve group on the high-temperature reheated steam switching branch pipe is the high-temperature reheated steam header switching valve group Vn-7, the valve group on the high-temperature reheated steam outlet branch pipe is the high-temperature reheated steam header outlet valve group Vn-8, the valve group on the reheater steam outlet branch pipe is the reheater steam outlet valve group Vn-9, the valve group on the condensate switching branch pipe is the condensate header switching valve group Vn-10, the valve group on the condensate outlet branch pipe is the condensate header outlet valve group Vn-11, the valve group on the condensate inlet branch pipe is the condensate inlet valve group Vn-12, the valve group on the feed water switching branch pipe is the feed water header switching valve group Vn-13, the valve group on the feed water outlet branch pipe is the feed water header outlet valve group Vn-14, and the valve group on the feed water inlet branch pipe is the feed water inlet valve group Vn-15.

[0040] In addition, the present invention also provides an operation method for a unitized unit header connection system that realizes flexible combination of the boiler and turbine. Based on a unitized unit header connection system that realizes flexible combination of the boiler and turbine in the above specific embodiments, the operation method includes: 1. First working condition: When each unit is operating normally, open the valve groups on each high-pressure cylinder steam inlet branch pipe, each reheater steam inlet branch pipe, each reheater steam outlet branch pipe, each condensate inlet branch pipe, and each feed water inlet branch pipe, and close other valve groups.

[0041] Specifically, close the valve groups on each main steam switching branch pipe and each main steam outlet branch pipe, open the valve groups on each high-pressure cylinder steam inlet branch pipe, and make the main steam at the outlet of the superheater 101 at the end stage of the boiler 1 enter the high-pressure cylinder 2 of the corresponding steam turbine to do work; close the valve groups on each low-temperature reheated steam switching branch pipe and each low-temperature reheated steam outlet branch pipe, open the valve groups on each reheater steam inlet branch pipe, and make the steam after passing through the high-pressure cylinder 2 enter the reheater 102 of the boiler 1 for reheating again; close the valve groups on each high-temperature reheated steam switching branch pipe and the high-temperature reheated steam outlet branch pipe, open the valve groups on each reheater steam outlet branch pipe, and make the reheated steam coming out of the reheater 102 enter the intermediate-pressure cylinder 3 to do work; close the valve groups on each condensate switching branch pipe and each condensate outlet branch pipe, open the valve groups on each condensate inlet branch pipe, and make the condensate enter the low-pressure heater 7 for heating; close the valve groups on each feed water switching branch pipe and each feed water outlet branch pipe, open the valve groups on each feed water inlet branch pipe, and make the heated water enter the feed water economizer of the boiler 1.

[0042] 2. Second operating condition: When each unit is in the multi-boiler and few-units mode, at least one steam turbine of the units is selectively shut down, and the steam turbines of other units operate normally. Among the units that are selectively shut down, the valve groups on the main steam outlet branch pipe and the high-pressure cylinder inlet branch pipe are closed, and the valve group on the main steam switching branch pipe is opened, so that the main steam enters the main steam header and then enters the high-pressure cylinders of other units to do work; the valve groups on the reheater steam inlet branch pipe and the low-temperature reheater steam switching branch pipe are closed, and the valve group on the low-temperature reheater steam outlet branch pipe is opened, so that the steam of other units operating normally enters the boilers of the units that are selectively shut down and the reheater 102 of each unit through the low-temperature reheater steam header for heating; the valve groups on the high-temperature reheater steam outlet branch pipe and the reheater steam outlet branch pipe are closed, and the valve group on the high-temperature reheater steam switching branch pipe is opened, so that the reheater steam of each unit enters the intermediate-pressure cylinders 3 of other units through the high-temperature reheater steam header; the valve groups on the condensate switching branch pipe and the condensate inlet branch pipe are closed, and the valve group on the condensate outlet branch pipe is opened, so that the condensate of other units operating normally can enter the units that are selectively shut down and the low-pressure heaters 7 of each unit through the condensate header; the valve groups on each feedwater switching branch pipe, each feedwater outlet branch pipe and each feedwater inlet branch pipe are opened, so that the heated water enters the feedwater economizers of the boilers of each unit through the feedwater header; in other units operating normally, all valve groups are opened.

[0043] 3. Third operating condition: When each unit is in the few-boiler and multi-units mode, at least one boiler of the units is selectively shut down, and the boilers of other units operate normally. Among the units that are selectively shut down, the valve groups on the main steam switching branch pipe and the high-pressure cylinder inlet branch pipe are closed, and the valve group on the main steam outlet branch pipe is opened, so that the main steam of other units can enter the high-pressure cylinders 2 of the units that are selectively shut down and the steam turbines of each unit through the main steam header to do work; the valve groups on the low-temperature reheater steam outlet branch pipe and the reheater steam inlet branch pipe are closed, and the valve group on the low-temperature reheater steam switching branch pipe is opened, so that the steam of the units that are selectively shut down and other units after passing through the high-pressure cylinders 2 enters the boilers of other units through the low-temperature reheater steam header for heating; the valve groups on the high-temperature reheater steam switching branch pipe and the reheater steam outlet branch pipe are closed, and the valve group on the high-temperature reheater steam outlet branch pipe is opened, so that the reheater steam of other units enters the units that are selectively shut down and the intermediate-pressure cylinders 3 of the steam turbines of other units through the high-temperature reheater steam header; the valve groups on the condensate switching branch pipe, the condensate outlet branch pipe and the condensate inlet branch pipe are opened, so that the condensate of the units that are selectively shut down and other units enters the low-pressure heaters 7 of each unit through the condensate header for heating; the valve groups on the feedwater outlet branch pipe and the feedwater inlet branch pipe are closed, and the valve group on the feedwater switching branch pipe is opened, so that the heated water of the units that are selectively shut down and other units enters the feedwater economizers of other units except the units that are selectively shut down through the feedwater header; in other units operating normally, all valve groups are opened.

[0044] By controlling the valve groups connecting each header pipe assembly to the unit, the flexible combination of the steam turbine and the boiler is realized, the output electric power of the steam turbine generator set under the deep peak shaving operation condition is reduced, and the stable combustion performance, unit efficiency and economic benefits under low load are maximized. In addition, the operation state of the unit can be flexibly adjusted by controlling the valve group. While meeting the peak shaving requirements of the power grid, the coal consumption is reduced, and the economy of the unit is further improved.

[0045] Obviously, the operation method of the header pipe connection system of the unit system realizing the flexible combination of the boiler and the turbine has the same beneficial effects, which will not be elaborated here.

[0046] In a specific embodiment, when each unit is in the multi-boiler and few-turbine mode, among the other normally operating steam turbines, according to the demand, the opening degree of the valve group on the main steam outlet branch pipe is adjusted to control the steam amount entering the current unit, so that the main steam of the boilers of each unit can enter the other normally operating steam turbines through the main steam header pipe.

[0047] It should be noted that at least one unit boiler is selectively shut down, specifically when the boiler is in the states of overhaul, failure, two-shift operation of the unit or unit hot standby, and all other planned or accidental shutdown situations of the boiler equipment.

[0048] At least one unit steam turbine is selectively shut down, specifically when the steam turbine is in the states of overhaul, failure, two-shift operation of the unit or unit hot standby, and all other planned or accidental shutdown situations of the steam turbine equipment.

[0049] In a specific embodiment, each valve group is a regulating isolation valve for controlling the flow rate of the working medium in the pipeline. Specifically, it is an electromagnetic valve, an electric valve, a pneumatic valve, a hydraulic valve or a manual valve. Among them, the electromagnetic valve, the electric valve, the pneumatic valve and the hydraulic valve can all be controlled by a control unit, and this control method belongs to the prior art and will not be elaborated here.

[0050] Especially, as Figure 1 shown, the number of units is two. Of course, the number of units can also be three or more.

[0051] Taking the following specific embodiment 1 as an example: A method for operating a header pipe connection system of a unit system realizing flexible combination of a boiler and a turbine provided by the present invention, and the unit can operate in three modes: normal operation, "multi-boiler and few-turbine", and "few-boiler and multi-turbine".

[0052] When the unit is operating normally, close the main steam header switching valve group Vn-1 and the main steam header outlet valve group Vn-2, and keep the high-pressure cylinder inlet valve group Vn-3 open. The main steam from the outlet of the final superheater 101 of the boiler enters the corresponding high-pressure cylinder 2 of the steam turbine to do work; close the low-temperature reheated steam header switching valve group Vn-4 and the low-temperature reheated steam header outlet valve group Vn-5, and open the boiler reheater steam inlet valve group Vn-6. The steam after passing through the high-pressure cylinder 2 enters the reheater 102 of the boiler for reheating again; close the high-temperature reheated steam header switching valve group Vn-7 and the high-temperature reheated steam header outlet valve group Vn-8, and open the boiler reheater steam outlet valve group Vn-9 to make the reheated steam enter the intermediate-pressure cylinder 3 to do work; close the condensate header switching valve group Vn-10 and the condensate header outlet valve group Vn-11, and open the condensate inlet valve group Vn-12 to make the condensate enter the low-pressure heater 7 for heating; close the feedwater header switching valve group Vn-13 and the feedwater header outlet valve group Vn-14, and open the feedwater inlet valve group Vn-15 to make the heated water enter the feedwater economizer of the boiler.

[0053] In the "multiple boilers and fewer turbines" mode, selectively shut down one or more steam turbines. Taking the shutdown of the steam turbine of Unit 1 and the normal operation of other units as an example, (n in the valve group label represents the Nth unit), the following operation contents are included: Close the main steam header outlet valve group V1-2 and the high-pressure cylinder steam inlet valve group V1-3 of Unit 1, open the main steam header switching valve group V1-1, and the main steam enters the main steam header. Other units open the high-pressure cylinder steam inlet valve group Vn-3, the main steam header outlet valve group Vn-2, and the main steam header switching valve group Vn-1, and adjust the regulating valve of the main steam header outlet valve group Vn-2 according to requirements to control the steam flow into the current unit, so that the main steam of Unit 1 and other normally operating units can enter the steam turbines of other units through the main steam header; close the reheater steam inlet valve group V1-6 and the low-temperature reheater steam header switching valve group V1-4, open the low-temperature reheater steam header outlet valve group V1-5, and other units open the reheater steam inlet valve group Vn-6, the low-temperature reheater steam header outlet valve group Vn-5, and the low-temperature reheater steam header switching valve group Vn-4, so that the steam of other units can enter the boiler reheater 102 of Unit 1 and each unit through the low-temperature reheater steam header for heating; close the high-temperature reheater steam header outlet valve group V1-8 and the reheater steam outlet valve group V1-9, open the high-temperature reheater steam header switching valve group V1-7, and other units open the high-temperature reheater steam header switching valve group Vn-7, the high-temperature reheater steam header outlet valve group Vn-8, and the reheater steam outlet valve group Vn-9, so that the reheated steam of each unit can enter the intermediate-pressure cylinder 3 of other units through the high-temperature reheater steam header; close the condensate water header switching valve group V1-10 and the condensate water inlet valve group V1-12, open the condensate water header outlet valve group V1-11, and open the condensate water header switching valve group Vn-10, the condensate water header outlet valve group Vn-11, and the condensate water inlet valve group Vn-12 of other units, so that the condensate water of other units can enter the low-pressure heaters 7 of Unit 1 and each unit through the condensate water header; open the feed water header switching valve group V1-13, the feed water header outlet valve group V1-14, and the feed water inlet valve group V1-15, and at the same time open the feed water header switching valve group Vn-13, the feed water header outlet valve group Vn-14, and the feed water inlet valve group Vn-15 of other units, so that the heated water can enter the feed water economizer of the boiler of each unit through the feed water header.

[0054] During deep peak shaving, to achieve flexible peak shaving, stable and economic operation of units in the "less boilers and more units" mode, taking the shutdown of the boiler of Unit 1 and the normal operation of other units as an example, the following operation contents are included: Close the main steam header switching valve group V1-1 and the high-pressure cylinder steam inlet valve group V1-3 of Unit 1, open the main steam header outlet valve group V1-2, and open the main steam header switching valve group Vn-1, the main steam header outlet valve group Vn-2, and the high-pressure cylinder steam inlet valve group Vn-3 for other units, so that the main steam of other units can enter the high-pressure cylinder 2 of Unit 1 and the steam turbines of each unit through the main steam header to do work; close the low-temperature reheater steam header outlet valve group V1-5 and the reheater steam inlet valve group V1-6 of Unit 1, open the low-temperature reheater steam header switching valve group V1-4, and open the low-temperature reheater steam header outlet valve group Vn-5, the reheater steam inlet valve group Vn-6, and the low-temperature reheater steam header switching valve group Vn-4 for other units, so that the steam after passing through the high-pressure cylinder 2 of Unit 1 and other units enters the boiler reheater 102 of other units through the low-temperature reheater steam header for heating; close the high-temperature reheater steam header switching valve group V1-7 and the reheater steam outlet valve group V1-9 of Unit 1, open the high-temperature reheater steam header outlet valve group V1-8, and open the high-temperature reheater steam header switching valve group Vn-7, the high-temperature reheater steam header outlet valve group Vn-8, and the reheater steam outlet valve group Vn-9 for other units, so that the reheater steam of other units enters the intermediate-pressure cylinder 3 of Unit 1 and the steam turbines of other units through the high-temperature reheater steam header; open the condensate header switching valve group V1-10, the condensate header outlet valve group V1-11, and the condensate inlet valve group V1-12 of Unit 1, and at the same time open the condensate header switching valve group Vn-10, the condensate header outlet valve group Vn-11, and the condensate inlet valve group Vn-12 of other units, so that the condensate of Unit 1 and other units enters the low-pressure heaters 7 of each unit through the condensate header for heating; close the feed water header outlet valve group V1-14 and the feed water inlet valve group V1-15 of Unit 1, open the feed water header switching valve group V1-13, and open the feed water header switching valve group Vn-13, the feed water header outlet valve group Vn-14, and the feed water inlet valve group Vn-15 of other units, so that the heated water of Unit 1 and other units enters the economizer of the boilers of other units except Unit 1 through the feed water header.

[0055] Table 1 takes multiple units as an example. The unit system operation mode is that each unit operates normally. The operation mode of few boilers and multiple turbines is that the boiler of Unit 1 is shut down, and the boilers of other units supply steam to the steam turbine of Unit 1 and the steam turbines of other units at the same time. The operation mode of multiple boilers and few turbines is that the steam turbine of Unit 1 is shut down, and the boiler of Unit 1 supplies steam to the steam turbines of other units except Unit 1 at the same time.

[0056] Table 1 Valve opening and closing status table under different operation modes

[0057] The beneficial effects brought by the technical solution provided by the present invention include: 1. The complete decoupling of the steam turbine and the boiler is achieved, and it is applicable to various operating conditions, including the normal operation of the unit, the operation mode of multiple boilers and few turbines, and the operation mode of few boilers and multiple turbines.

[0058] 2. It can respond more flexibly to the peak shaving requirements of the power grid. Especially in the case of large fluctuations in power load, it can quickly adjust the output of the unit.

[0059] 3. The efficiency and economy of the unit are effectively improved. In the case of multiple boilers and few turbines, through the optimized distribution of the plant load, the unit can operate under better conditions, improving the operation economy of the whole plant; in the case of few boilers and multiple turbines, it can flexibly respond to AGC commands, meet the requirements of deep peak shaving, and effectively reduce the operation cost at the same time.

[0060] In the description of this application, unless otherwise clearly defined, terms such as "set", "installed", "connected", etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above terms in this application in combination with the specific content of the technical solution.

[0061] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0062] Specific examples are used in this article to elaborate on the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A header connection system for a unitized unit that enables flexible combination of the boiler and turbine, characterized in that Comprising: At least two units and a header assembly respectively connected to each of the units, wherein each of the units includes: a boiler (1) and a high-pressure cylinder (2), an intermediate-pressure cylinder (3), a low-pressure cylinder (4), a condenser (5), a condensate pump (6), a low-pressure heater (7), and a high-pressure heater (10) connected in sequence, the header assembly includes: a main steam header, a low-temperature reheated steam header, a high-temperature reheated steam header, a condensate water header, and a feed water header; the main steam header is respectively communicated with the outlet of the superheater (101) of the boiler (1) of each unit through a main steam switching branch pipe, the main steam header is respectively communicated with the steam inlet of the high-pressure cylinder (2) of each unit through a main steam outlet branch pipe, and the outlet of the superheater (101) and the steam inlet of the high-pressure cylinder (2) are communicated through a high-pressure cylinder steam inlet branch pipe; the low-temperature reheated steam header is respectively communicated with the steam outlet of the high-pressure cylinder (2) of each unit through a low-temperature reheated steam switching branch pipe, the low-temperature reheated steam header is respectively communicated with the steam inlet of the reheater (102) of the boiler (1) of each unit through a low-temperature reheated steam outlet branch pipe, and the steam inlet of the reheater (102) and the steam outlet of the high-pressure cylinder (2) are communicated through a reheater steam inlet branch pipe; the high-temperature reheated steam header is respectively communicated with the steam outlet of the reheater (102) of the boiler (1) of each unit through a high-temperature reheated steam switching branch pipe, the high-temperature reheated steam header is respectively communicated with the steam inlet of the intermediate-pressure cylinder (3) of each unit through a high-temperature reheated steam outlet branch pipe, and the steam outlet of the reheater (102) and the steam inlet of the intermediate-pressure cylinder (3) are communicated through a reheater steam outlet branch pipe; the condensate water header is respectively communicated with the outlet of the condensate pump (6) of each unit through a condensate water switching branch pipe, the condensate water header is respectively communicated with the inlet of the low-pressure heater (7) of each unit through a condensate water outlet branch pipe, and the outlet of the condensate pump (6) and the inlet of the low-pressure heater (7) are communicated through a condensate water inlet branch pipe; the feed water header is respectively communicated with the outlet of the high-pressure heater (10) of each unit through a feed water switching branch pipe, the feed water header is respectively communicated with the inlet of the superheater (101) of the boiler (1) of each unit through a feed water outlet branch pipe, and the outlet of the high-pressure heater (10) and the inlet of the superheater (101) are communicated through a feed water inlet branch pipe; Valve groups are connected in series on each of the main steam branch pipes, each of the main steam outlet branch pipes, each of the high-pressure cylinder steam inlet branch pipes, each of the low-temperature reheated steam switching branch pipes, each of the low-temperature reheated steam outlet branch pipes, each of the reheater steam inlet branch pipes, each of the high-temperature reheated steam switching branch pipes, each of the high-temperature reheated steam outlet branch pipes, each of the reheater steam outlet branch pipes, each of the condensate water switching branch pipes, each of the condensate water outlet branch pipes, each of the condensate water inlet branch pipes, each of the feed water switching branch pipes, each of the feed water outlet branch pipes, and each of the feed water inlet branch pipes.

2. The header connection system of the unitized unit for realizing flexible combination of boiler and turbine according to claim 1, wherein, An deaerator (8) and a feed water pump (9) are connected in series between the low-pressure heater (7) and the high-pressure heater (10).

3. The header connection system for a unitized unit that enables flexible combination of boiler and turbine according to claim 1, characterized in that Each of the valve groups is a solenoid valve, an electric valve, a pneumatic valve, a hydraulic valve or a manual valve.

4. An operating method for a header connection system of a unitized unit that enables flexible combination of the boiler and turbine, characterized in that, Based on the unit main pipe connection system for realizing flexible combination of boiler and turbine according to any one of claims 1-3, the operation method includes: When each of the units is operating normally, open the valve groups on each high-pressure cylinder steam inlet branch pipe, each reheater steam inlet branch pipe, each reheater steam outlet branch pipe, each condensate inlet branch pipe and each feed water inlet branch pipe, and close other valve groups; When each of the units is in the multi-boiler and few-turbine mode, selectively shut down the steam turbines of at least one of the units, and the steam turbines of other units operate normally. Among them, in the selectively shut-down unit, close the valve groups on the main steam outlet branch pipe and the high-pressure cylinder steam inlet branch pipe, and open the valve group on the main steam switching branch pipe; close the valve groups on the reheater steam inlet branch pipe and the low-temperature reheater steam switching branch pipe, and open the valve group on the low-temperature reheater steam outlet branch pipe; close the valve groups on the high-temperature reheater steam outlet branch pipe and the reheater steam outlet branch pipe, and open the valve group on the high-temperature reheater steam switching branch pipe; close the valve groups on the condensate switching branch pipe and the condensate inlet branch pipe, and open the valve group on the condensate outlet branch pipe; open the valve groups on each feed water switching branch pipe, each feed water outlet branch pipe and each feed water inlet branch pipe; in other normally operating units, open all valve groups; When each of the units is in the few-boiler and multi-turbine mode, selectively shut down the boilers of at least one of the units, and the boilers of other units operate normally. Among them, in the selectively shut-down unit, close the valve groups on the main steam switching branch pipe and the high-pressure cylinder steam inlet branch pipe, and open the valve group on the main steam outlet branch pipe; close the valve groups on the low-temperature reheater steam outlet branch pipe and the reheater steam inlet branch pipe, and open the valve group on the low-temperature reheater steam switching branch pipe; close the valve groups on the high-temperature reheater steam switching branch pipe and the reheater steam outlet branch pipe, and open the valve group on the high-temperature reheater steam outlet branch pipe; open the valve groups on the condensate switching branch pipe, the condensate outlet branch pipe and the condensate inlet branch pipe; close the valve groups on the feed water outlet branch pipe and the feed water inlet branch pipe, and open the valve group on the feed water switching branch pipe; in other normally operating units, open all valve groups.

5. The operating method according to claim 4, characterized in that When each of the units is in the multi-boiler and few-turbine mode, in other normally operating steam turbines, adjust the opening degree of the valve group on the main steam outlet branch pipe according to the demand, and control the steam flow rate entering the current unit, so that the main steam of the boilers of each unit enters other normally operating steam turbines through the main steam header.

6. The operating method according to claim 4, characterized in that, The selectively shutting down the boilers of at least one of the units specifically means that the boilers are in the state of maintenance, failure, two-shift operation of the unit or hot standby of the unit.

7. The operating method according to claim 4, characterized in that The selectively shutting down the steam turbines of at least one of the units specifically means that the steam turbines are in the state of maintenance, failure, two-shift operation of the unit or hot standby of the unit.

8. The operating method according to claim 4, characterized in that Each of the valve groups is a regulating isolation valve for controlling the flow rate of the working medium in the regulating pipeline.

9. The operating method according to claim 4, characterized in that Each of the valve groups is a solenoid valve, an electric valve, a pneumatic valve, a hydraulic valve or a manual valve.

10. The operating method according to claim 4, characterized in that, The number of the units is two.

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