Double-machine parallel thermal power generation system based on pre-position machine balance high deviation parameter

Abstract

This application relates to a dual-unit parallel thermal power generation system, comprising: a first steam turbine generator set connected to a coal-fired boiler via a first branch of a superheated steam header and also connected to the coal-fired boiler via a first branch of a reheated steam header; the steam inlet of a back-pressure turbine connected to the coal-fired boiler via a second branch of the superheated steam header; the steam inlet of a second steam turbine generator set connected to the back-pressure turbine and also connected to the coal-fired boiler via a second branch of the reheated steam header; the input end of a first feedwater regeneration assembly connected to the first steam turbine generator set, and the feedwater outlet of the first feedwater regeneration assembly connected to the coal-fired boiler; and the feedwater outlet of a second feedwater regeneration assembly connected to the feedwater inlet of the first feedwater regeneration assembly. This solves the matching problem of high-parameter boilers and two in-service steam turbines with significantly different rated parameters being unable to operate efficiently and safely in parallel, improving boiler operating safety and significantly enhancing the overall thermal economy of the system.

Description

Technical Field

[0001] This application relates to the field of thermal power generation technology, and in particular to a dual-unit parallel thermal power generation system based on the high deviation parameter of the front-end unit. Background Technology

[0002] Among the coal-fired power generating units in operation, there are a large number of subcritical, supercritical and ultra-supercritical units with different parameter levels. Due to the different construction years and different technical routes, these units have significant differences in their main steam parameters, reheat steam parameters and regenerative system parameters.

[0003] With changes in the power grid load structure, large-capacity, high-parameter generating units often need to operate in conjunction with relatively low-parameter units. However, the mismatch in their rated operating parameters makes direct parallel operation technically challenging. In existing technologies, if steam generated by a high-parameter boiler is directly fed into turbines of different parameter levels, the high-parameter steam cannot meet the inlet parameter requirements of the low-parameter turbine, necessitating significant throttling, pressure reduction, and temperature reduction, resulting in substantial energy loss and a significant decrease in system thermal economy. Conversely, simply reducing the load or shutting down the low-parameter unit fails to fully leverage the safe operation advantages of the high-parameter boiler and the overall power generation capacity of the unit. This issue urgently needs to be addressed. Summary of the Invention

[0004] This application provides a dual-unit parallel thermal power generation system based on balancing high deviation parameters of the front-end unit, in order to solve the matching problem that high-parameter boilers and two in-service steam turbines with huge differences in rated parameters cannot be operated in parallel efficiently and safely. It achieves improved boiler operation safety, reduced plant power consumption, and significantly improved overall thermal economy of the system under medium and low load conditions without the need for large-scale modification of the original unit.

[0005] This application provides a dual-unit parallel thermal power generation system based on balancing high deviation parameters of the front-end unit, including: A coal-fired boiler used to generate steam; The first steam turbine generator set is connected to the superheated steam outlet of the coal-fired boiler via a first branch of the superheated steam header. The first steam turbine generator set is also connected to the reheated steam outlet of the coal-fired boiler via a first branch of the reheated steam header. A back-pressure steam turbine, wherein the steam inlet of the back-pressure steam turbine is connected to the superheated steam outlet of the coal-fired boiler via a second branch of the superheated steam header; The second steam turbine generator set has its steam inlet connected to the steam outlet of the back-pressure steam turbine, and the second steam turbine generator set is connected to the reheat steam outlet of the coal-fired boiler through the second branch of the reheat steam header. The first feedwater regeneration component has its input end connected to the output end of the first steam turbine generator set, and its feedwater outlet connected to the feedwater inlet of the coal-fired boiler. The second water supply regeneration component has its water supply outlet connected to the water supply inlet of the first water supply regeneration component.

[0006] Optionally, in some embodiments, the first steam turbine generator set includes: The first cylinder of the first steam turbine, the steam inlet of the first cylinder is connected to the superheated steam outlet of the coal-fired boiler, and the steam outlet of the first cylinder is connected to the cold reheat steam inlet of the coal-fired boiler. The second cylinder of the first steam turbine has its steam inlet connected to the reheat steam outlet of the coal-fired boiler, and its steam outlet is connected to the input end of the first feedwater regeneration assembly via the third cylinder of the first steam turbine.

[0007] Optionally, in some embodiments, the second steam turbine generator set includes: The fourth cylinder of the second steam turbine, wherein the steam inlet of the fourth cylinder is connected to the steam outlet of the back-pressure steam turbine, and the steam outlet of the fourth cylinder is connected to the cold resteam inlet of the coal-fired boiler; The fifth cylinder of the second steam turbine has its steam inlet connected to the reheat steam outlet of the coal-fired boiler, and its steam outlet is connected to the input end of the second feedwater regeneration assembly via the sixth cylinder of the second steam turbine.

[0008] Optionally, in some embodiments, the first feedwater regeneration component includes: The first deaerator is connected to the output of the first steam turbine generator set. The first water supply pump has its input end connected to the output end of the first deaerator. The first heating component has its input end connected to the output end of the first water pump, and its output end connected to the water inlet of the coal-fired boiler.

[0009] Optionally, in some embodiments, the first heating component includes: The first heater has its inlet end connected to the output end of the first water pump; A second heater, wherein the inlet end of the second heater is connected to the outlet end of the first heater; The third heater has its inlet end connected to the outlet end of the second heater, and its outlet end connected to the feedwater inlet of the coal-fired boiler.

[0010] Optionally, in some embodiments, the second feedwater regeneration component includes: The second deaerator is connected to the output of the second steam turbine generator set. The second water supply pump has its input end connected to the output end of the second deaerator. The second heating component has its input end connected to the output end of the second water pump, and its water outlet connected to the water inlet of the first heating component.

[0011] Optionally, in some embodiments, the second heating component includes: The fourth heater, the inlet of which is connected to the output of the second water pump; The fifth heater, the inlet of which is connected to the outlet of the fourth heater; The sixth heater has its inlet end connected to the outlet end of the fifth heater, and its outlet end connected to the input end of the first heating component.

[0012] Optionally, in some embodiments, the dual-unit parallel thermal power generation system further includes: a reheat steam temperature regulating station, wherein the hot end of the reheat steam temperature regulating station is located on the pipeline between the reheat steam outlet of the coal-fired boiler and the second turbine generator set, for regulating the reheat steam temperature entering the second turbine generator set, and the coal-fired cold end of the reheat steam temperature regulating station is located on the boiler inlet feedwater pipeline, for heating the inlet feedwater of the coal-fired boiler.

[0013] Optionally, in some embodiments, the dual-unit parallel thermal power generation system further includes: a pressure regulating station, which is located between the steam outlet of the first cylinder of the first turbine generator set and the cold resteam inlet of the coal-fired boiler, for regulating the cold resteam pressure.

[0014] Optionally, in some embodiments, the dual-unit parallel thermal power generation system further includes: a feedwater booster pump, disposed between the liquid outlet of the first heating component and the feedwater inlet of the coal-fired boiler, for pressurizing and delivering feedwater to the coal-fired boiler.

[0015] According to the dual-unit parallel thermal power generation system provided in this application embodiment, the first steam turbine generator set is connected to the coal-fired boiler via a first branch of the superheated steam header and also via a first branch of the reheat steam header; the steam inlet of the back-pressure turbine is connected to the coal-fired boiler via a second branch of the superheated steam header; the steam inlet of the second steam turbine generator set is connected to the back-pressure turbine, and the second steam turbine generator set is connected to the coal-fired boiler via a second branch of the reheat steam header; the input end of the first feedwater regeneration component is connected to the first steam turbine generator set, and the feedwater outlet of the first feedwater regeneration component is connected to the coal-fired boiler; the feedwater outlet of the second feedwater regeneration component is connected to the feedwater inlet of the first feedwater regeneration component. This solves the matching problem of high-parameter boilers and two in-service steam turbines with significantly different rated parameters being unable to operate efficiently and safely in parallel, achieving improved boiler operating safety, reduced plant power consumption, and significantly improved overall system thermal economy under medium and low load conditions without requiring large-scale modifications to the original unit.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a dual-unit parallel thermal power generation system based on balancing high deviation parameters of the front-end unit, according to an embodiment of this application.

[0018] Reference numerals: 1-Coal-fired boiler; 2-First cylinder block of the first steam turbine; 3-Second cylinder block of the first steam turbine; 4-First deaerator; 5-First feedwater pump; 6-First heater; 7-Second heater; 8-Third heater; 9-Feedwater booster pump; 10-Fourth heater; 11-Fifth heater; 12-Sixth heater; 13-Second feedwater pump; 14-Second deaerator; 15-Fourth cylinder block of the second steam turbine; 16-Third cylinder block of the second steam turbine; 17-Back pressure steam turbine; 18-Reheat steam temperature regulating station; 19-Pressure regulating station; 100-First steam turbine generator set; 200-Second steam turbine generator set; 300-First feedwater regeneration assembly; 400-Second feedwater regeneration assembly. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0020] Those skilled in the art will understand that advanced pure condensing subcritical units operate at a minimum load of 20% of rated load, and pure condensing supercritical units operate at a minimum load of 30% of rated load. As the primary source of carbon emissions in my country's energy and power sector, coal-fired power plants need to take multiple measures to reduce their own carbon emissions. In the process of profound changes in the structure and form of the power system, coal-fired power, as an important system peak-shaving and inertia-supporting power source, still needs to further explore its flexible regulation capabilities, improve its deep peak-shaving, rapid ramp-up, primary frequency regulation, and start-stop peak-shaving capabilities, and continuously provide high-quality services for the construction of the new power system. Efficient regulation is the core objective of the next-generation coal-fired power upgrade.

[0021] The following description, with reference to the accompanying drawings, describes a dual-unit parallel thermal power generation system according to an embodiment of this application. Addressing the matching challenge mentioned in the background art—the inability to efficiently and safely operate in parallel with a high-parameter boiler and two in-service steam turbines with significantly different rated parameters—this application provides a dual-unit parallel thermal power generation system based on balancing high-deviation parameters of the front-end turbine. High-temperature, high-pressure steam generated by a high-parameter boiler drives two steam turbine generator units (after optimization and modification to balance the parameter deviation of the in-service unit) through a front-end back-pressure turbine. This system enables the upgrading and modification of existing units' equipment and thermal systems based on in-service ultra-supercritical high-parameter units and subcritical low-parameter units. By setting up a one-boiler-two-turbine thermal system with a back-pressure turbine to balance the parameter differences of the units, and by providing corresponding operating schemes for different peak-shaving scenarios, the system achieves safe and economical operation of the unit under peak-shaving conditions. On the one hand, this system ensures that the boiler operates at a relatively high load under the premise of equal power generation output, guaranteeing boiler safety; on the other hand, it does not require significant changes to the original in-service unit equipment, resulting in lower retrofitting investment.

[0022] Specifically, Figure 1 This is a schematic diagram of a dual-unit parallel thermal power generation system based on balancing high deviation parameters of the front-end unit, provided as an embodiment of this application.

[0023] like Figure 1 As shown, the dual-unit parallel thermal power generation system includes: a coal-fired boiler 1, a first steam turbine generator set 100, a back-pressure steam turbine 17, a second steam turbine generator set 200, a first feedwater regeneration assembly 300, and a second feedwater regeneration assembly 400.

[0024] Among them, the coal-fired boiler 1 is used to generate steam; the first steam turbine generator set 100 is connected to the superheated steam outlet of the coal-fired boiler 1 through the first branch of the superheated steam header, and the first steam turbine generator set 100 is also connected to the reheated steam outlet of the coal-fired boiler 1 through the first branch of the reheated steam header; the steam inlet of the back-pressure turbine 17 is connected to the superheated steam outlet of the coal-fired boiler 1 through the second branch of the superheated steam header; the steam inlet of the second steam turbine generator set 200 is connected to the steam outlet of the back-pressure turbine 17, and the second steam turbine generator set 200 is connected to the reheated steam outlet of the coal-fired boiler 1 through the second branch of the reheated steam header; the input end of the first feedwater regeneration assembly 300 is connected to the output end of the first steam turbine generator set 100, and the feedwater outlet of the first feedwater regeneration assembly 300 is connected to the feedwater inlet of the coal-fired boiler 1; the feedwater outlet of the second feedwater regeneration assembly 400 is connected to the feedwater inlet of the first feedwater regeneration assembly 300.

[0025] In this embodiment, the coal-fired boiler 1 is a high-parameter coal-fired boiler 1. This embodiment is based on an in-service ultra-supercritical high-parameter unit and a subcritical low-parameter unit. A front-end back pressure unit is added before the low-parameter unit to match the parameter difference of the high-parameter boiler. The rated parameters of the main steam at the inlet of the front-end back pressure unit are supercritical steam parameters, and the rated parameters of the exhaust steam at the outlet of the front-end back pressure unit are subcritical steam parameters. The specifications and materials of the back pressure unit inlet and the high-pressure steam bypass related pipelines are upgraded to cope with the increase in steam parameters.

[0026] In addition, this application throttles the steam in order to reasonably match the main steam parameters of high-parameter units and low-parameter units.

[0027] Optionally, in some embodiments, the first steam turbine generator set 100 includes: a first cylinder 2 of the first steam turbine, the steam inlet of the first cylinder 2 being connected to the superheated steam outlet of the coal-fired boiler 1, and the steam outlet of the first cylinder 2 being connected to the cold reheat steam inlet of the coal-fired boiler 1; a second cylinder 3 of the first steam turbine, the steam inlet of the second cylinder 3 being connected to the reheat steam outlet of the coal-fired boiler 1, and the steam outlet of the second cylinder 3 being connected to the input end of the first feedwater regeneration assembly 300 via the third cylinder of the first steam turbine.

[0028] Among them, the first cylinder block 2 of the first steam turbine is the high-pressure cylinder of the high-parameter steam turbine, the second cylinder block 3 of the first steam turbine is the intermediate-pressure cylinder of the high-parameter steam turbine, and the third cylinder block of the first steam turbine is the low-pressure cylinder of the high-parameter steam turbine.

[0029] Optionally, in some embodiments, the second steam turbine generator set 200 includes: a fourth cylinder 16 of the second steam turbine, the steam inlet of the fourth cylinder 16 being connected to the steam outlet of the back-pressure steam turbine 17, and the steam outlet of the fourth cylinder 16 being connected to the cold reheat steam inlet of the coal-fired boiler 1; a fifth cylinder 15 of the second steam turbine, the steam inlet of the fifth cylinder 15 being connected to the reheat steam outlet of the coal-fired boiler 1, and the steam outlet of the fifth cylinder 15 being connected to the input end of the second feedwater regeneration assembly 400 via a sixth cylinder of the second steam turbine.

[0030] Among them, the fourth cylinder block 16 of the second steam turbine is the high-pressure cylinder of the low-parameter steam turbine, the fifth cylinder block 15 of the second steam turbine is the intermediate-pressure cylinder of the low-parameter steam turbine, and the sixth cylinder block of the second steam turbine is the low-pressure cylinder of the low-parameter steam turbine.

[0031] Optionally, in some embodiments, the first feedwater regeneration assembly 300 includes: a first deaerator 4, the input end of which is connected to the output end of the first steam turbine generator set 100; a first feedwater pump 5, the input end of which is connected to the output end of the first deaerator 4; and a first heating assembly, the input end of which is connected to the output end of the first feedwater pump 5, and the output end of which is connected to the feedwater inlet of the coal-fired boiler 1.

[0032] Optionally, in some embodiments, the first heating assembly includes: a first heater 6, the inlet end of which is connected to the output end of the first water pump 5; a second heater 7, the inlet end of which is connected to the outlet end of the first heater 6; and a third heater 8, the inlet end of which is connected to the outlet end of the second heater 7, and the outlet end of the third heater 8 is connected to the water inlet of the coal-fired boiler 1.

[0033] Among them, the first deaerator 4 is the deaerator of the high-parameter unit, the first feed water pump 5 is the feed water pump of the high-parameter unit, the first heater 6 is the No. 3 high-pressure heater of the high-parameter unit; the second heater 7 is the No. 2 high-pressure heater of the high-parameter unit; and the third heater 8 is the No. 1 high-pressure heater of the high-parameter unit.

[0034] Optionally, in some embodiments, the second feedwater regeneration assembly 400 includes: a second deaerator 14, the input end of which is connected to the output end of the second steam turbine generator set 200; a second feedwater pump 13, the input end of which is connected to the output end of the second deaerator 14; and a second heating assembly, the input end of which is connected to the output end of the second feedwater pump 13, and the feedwater outlet of the second heating assembly is connected to the feedwater inlet of the first heating assembly.

[0035] Optionally, in some embodiments, the second heating assembly includes: a fourth heater 12, the inlet end of which is connected to the output end of the second water pump 13; a fifth heater 11, the inlet end of which is connected to the outlet end of the fourth heater 12; and a sixth heater 10, the inlet end of which is connected to the outlet end of the fifth heater 11, and the outlet end of the sixth heater 10 is connected to the input end of the first heating assembly.

[0036] Among them, the second deaerator 14 is the deaerator for the low-parameter unit, the second feedwater pump 13 is the feedwater pump for the low-parameter unit, the fourth heater 12 is the No. 3 high-pressure heater for the low-parameter unit, the fifth heater 11 is the No. 2 high-pressure heater for the low-parameter unit, and the sixth heater 10 is the No. 1 high-pressure heater for the low-parameter unit.

[0037] Optionally, in some embodiments, the dual-unit parallel thermal power generation system further includes: a reheat steam temperature regulating station 18, the hot end of which is located on the pipeline between the reheat steam outlet of the coal-fired boiler 1 and the second turbine generator set 200, for regulating the temperature of the reheat steam entering the second turbine generator set 200; the cold end of which is located on the inlet feedwater pipeline of the coal-fired boiler, for heating the inlet feedwater of the coal-fired boiler.

[0038] Specifically, in this embodiment of the application, a reheat temperature regulating station is set up on the steam pipeline from the outlet of the high-temperature reheater of the high-parameter boiler to the intermediate-pressure cylinder of the low-parameter steam turbine to cool down the reheat steam entering the intermediate-pressure cylinder of the low-parameter steam turbine. The cooling section of the reheat temperature regulating station is connected to the outlet feedwater of the No. 1 high-pressure heater (sixth heater) of the low-parameter unit to heat the feedwater temperature.

[0039] Optionally, in some embodiments, the dual-unit parallel thermal power generation system further includes a pressure regulating station 19, which is located between the steam outlet of the first cylinder 2 of the first steam turbine generator set 100 and the cold resteam inlet of the coal-fired boiler 1, for regulating the cold resteam pressure.

[0040] Specifically, in this embodiment of the application, a pressure regulating station is designed at the cold re-outlet of the high-parameter steam turbine pressure cooker to regulate the steam pressure at the cold re-outlet.

[0041] Optionally, in some embodiments, the dual-unit parallel thermal power generation system further includes: a feedwater booster pump 9, which is disposed between the liquid outlet of the first heating component 100 and the feedwater inlet of the coal-fired boiler 1, for pressurizing and delivering feedwater to the coal-fired boiler 1.

[0042] The modification of the dual-unit parallel thermal power generation system in this application embodiment is based on two conventional coal-fired power generating units. The dual-unit parallel thermal power system is mainly equipped with a high-parameter boiler system and related pulverizing and flue gas systems, two turbine units and related extraction steam systems, a feedwater system, and a front-mounted back-pressure turbine system. The rated operating parameters of the two turbine units have a significant deviation. The front-mounted back-pressure turbine balances the parameter deviation between the two units before the high-pressure cylinder of the low-parameter turbine, meeting the system matching requirements of the two units with high parameter differences. High-temperature, high-pressure steam generated by the high-parameter boiler enters the two high-parameter differential turbine systems through a superheated steam header. One stream of steam enters the high-parameter turbine system and performs normal power generation according to the process. The other stream of steam first enters the front-mounted back-pressure turbine before the low-parameter turbine to perform power generation, adjusting the steam parameters to meet the inlet steam parameter requirements of the low-parameter turbine's high-pressure cylinder before entering the low-parameter turbine system to generate power. After the two steam streams perform work in their respective high-pressure cylinders, they merge through the reheat pipe and enter the boiler for reheating. The reheated steam then enters the intermediate and low-pressure cylinders of the two high-parameter differential steam turbines through the hot reheat header for further power generation. The exhaust steam from the low-pressure cylinders is condensed by the two streams of condensate from their respective condensers. After being reheated by their respective high and low-pressure heater systems, the condensate is collected together through the feedwater header and enters the high-parameter boiler for heating, forming a thermal cycle.

[0043] The embodiments of this application include a dual-unit parallel thermal power generation system based on a front-mounted back-pressure unit to balance the parameter deviations of the generating units, as shown in the attached figure. Figure 1 As shown, the working fluid operation process in the system is as follows: High-temperature, high-pressure steam generated by the high-parameter coal-fired boiler 1 is divided into two streams via the superheated steam header. One stream of superheated steam enters the high-parameter high-pressure cylinder 2 to generate electricity, while the other stream enters the back-pressure turbine 17 to generate electricity. After the steam parameters are reduced in temperature and pressure, it enters the low-parameter high-pressure cylinder 16 to generate electricity. The exhaust steam from the two high-pressure cylinders merges in the connecting header and enters the high-parameter coal-fired boiler 1 for reheating. The reheated steam is again divided into two streams via the reheated steam header. One stream of reheated steam enters the high-parameter intermediate-pressure cylinder 3 and the low-pressure cylinder sequentially to generate electricity. The exhaust steam from the low-pressure cylinder is then condensed into feedwater by the condenser. After being pressurized by the condensate pump and heated by the low-pressure heater system, it enters the high-parameter unit deaerator 4. Another stream of reheat steam, after being cooled by the reheat steam temperature regulating station 18, sequentially enters the low-parameter intermediate-pressure cylinder 15 and the low-pressure cylinder to generate electricity. The exhaust steam from the low-pressure cylinder is then condensed into feedwater by the condenser. After being pressurized by the condensate pump and heated by the low-pressure heater system, it enters the low-parameter unit deaerator 14. The feedwater from the outlet of the low-parameter unit deaerator 14 enters the inlet of the high-parameter unit deaerator 4 via the feedwater header, merging with the high-parameter unit feedwater. The merged feedwater then sequentially enters the high-pressure heaters (6-8) of the high-parameter units (units 3-1) for heating. After being pressurized by the feedwater booster pump, it is reheated by the reheat steam temperature regulating station 18 before entering the high-parameter coal-fired boiler 1 to form a thermal cycle.

[0044] The implementation scenario for this system is a 1000MW-class ultra-supercritical parameter boiler, a variable-pressure once-through furnace, opposed-flow combustion, solid ash discharge, single furnace, single reheat, balanced ventilation, open-air layout, all-steel frame, and fully suspended p-type structure. The designed coal type is mixed raw coal. The 1000MW-class ultra-supercritical parameter steam turbine is the N1000-26.25 / 600 / 600 (TC4F) type 1000MW ultra-supercritical, single-reheat, four-cylinder, four-exhaust, single-shaft condensing steam turbine. The 330MW-class subcritical steam turbine is the N330-16.7 / 538 / 538 type subcritical, single-reheat, two-cylinder, two-exhaust, single-shaft, reaction condensing steam turbine. The basic parameters for the subcritical steam turbine retrofit are shown in Table 1.

[0045]

[0046] Implementation scenario: The ultra-supercritical unit itself remains unchanged. To match the main steam parameters of the ultra-supercritical unit, the main steam of the subcritical unit is desuperheated and depressurized by the preheater to meet the main steam pressure of the ultra-supercritical unit; the exhaust steam of the preheater is temperature-regulated by the desuperheater to meet the main steam temperature of the ultra-supercritical unit.

[0047] (1) Modification of main steam and cooling regeneration main pipe.

[0048] An electrically operated shut-off valve was installed on the main steam pipeline of the original ultra-supercritical unit to isolate the main steam from the ultra-supercritical boiler. The exhaust steam from the high-pressure cylinder of the ultra-supercritical unit was fed into the subcritical unit's boiler cold reheat steam via a cold reheat connection pipe. Because the exhaust pressure of the high-pressure cylinder of the ultra-supercritical unit was lower than that of the subcritical unit, a cold reheat pressure mismatch occurred. Therefore, a main pipe pressure regulating station had to be installed on the subcritical unit's cold reheat pipeline. This resulted in lower reheat pressure in the subcritical boiler, and consequently, reduced efficiency in the intermediate-pressure and low-pressure cylinders of the subcritical unit.

[0049] (2) Modification of the hot regeneration main pipe.

[0050] Since the reheat temperature of subcritical units is 600℃ and that of ultra-supercritical units is 538℃, the steam from the outlet of the high-temperature reheater of the subcritical boiler cannot directly enter the intermediate-pressure cylinder of the ultra-supercritical unit. Therefore, the reheat temperature of the steam entering the ultra-supercritical unit needs to be adjusted. Thus, an ultra-supercritical unit reheat temperature regulator (steam cooler) is installed.

[0051] The reheat thermostat of ultra-supercritical units makes full use of the superheat of reheat steam to heat the high-pressure feedwater of subcritical units, thereby increasing the feedwater temperature of subcritical units, especially the feedwater temperature under low load conditions.

[0052] (3) Water supply system renovation.

[0053] The modification plan is determined based on whether the high-pressure regenerative system of the ultra-supercritical unit is in operation.

[0054] If the high-pressure regenerative system of the ultra-supercritical unit is put into use, a high-pressure feedwater booster pump needs to be installed. The feedwater from the outlet of the No. 1 high-pressure heater of the ultra-supercritical unit is boosted by the high-pressure feedwater booster pump and then merged with the feedwater from the No. 1 high-pressure outlet of the subcritical unit.

[0055] If the high-pressure regenerative system of the ultra-supercritical unit is not put into use, a low-pressure feedwater booster pump needs to be installed. The low-pressure feedwater from the deaerator of the ultra-supercritical unit is boosted by the low-pressure feedwater booster pump and then merges with the condensate from the subcritical low-pressure outlet of the subcritical unit, and enters the deaerator of the subcritical unit.

[0056] The main economic indicators of the modified one-furnace-two-machine system are shown in Table 2.

[0057]

[0058] After the renovation, the main economic indicators of the one-boiler-two-unit system are shown in Table 3 below.

[0059] Table 3

[0060] After the modification, this scheme can significantly improve the system's economy, especially at low and medium loads, and the lower the operating load, the higher the unit's efficiency.

[0061] According to the dual-unit parallel thermal power generation system proposed in this application, the first steam turbine generator set is connected to the coal-fired boiler via a first branch of the superheated steam header and also via a first branch of the reheat steam header; the steam inlet of the back-pressure turbine is connected to the coal-fired boiler via a second branch of the superheated steam header; the steam inlet of the second steam turbine generator set is connected to the back-pressure turbine, and the second steam turbine generator set is connected to the coal-fired boiler via a second branch of the reheat steam header; the input end of the first feedwater regeneration component is connected to the first steam turbine generator set, and the feedwater outlet of the first feedwater regeneration component is connected to the coal-fired boiler; the feedwater outlet of the second feedwater regeneration component is connected to the feedwater inlet of the first feedwater regeneration component. This solves the matching problem of high-parameter boilers and two in-service steam turbines with significantly different rated parameters being unable to operate efficiently and safely in parallel, achieving improved boiler operating safety, reduced plant power consumption, and significantly improved overall system thermal economy under medium and low load conditions without requiring large-scale modifications to the original unit.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0065] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0066] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0067] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0068] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0069] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A double-unit parallel thermal power generation system based on a pre-positioning machine balance high-deviation parameter, characterized in that, include: Coal-fired boilers are used to generate steam. The first steam turbine generator set is connected to the superheated steam outlet of the coal-fired boiler via a first branch of the superheated steam header. The first steam turbine generator set is also connected to the reheated steam outlet of the coal-fired boiler via a first branch of the reheated steam header. A back-pressure steam turbine, wherein the steam inlet of the back-pressure steam turbine is connected to the superheated steam outlet of the coal-fired boiler through a second branch of the superheated steam header; The second steam turbine generator set has its steam inlet connected to the steam outlet of the back-pressure steam turbine, and the second steam turbine generator set is connected to the reheat steam outlet of the coal-fired boiler through the second branch of the reheat steam header. The first feedwater regeneration component has its input end connected to the output end of the first steam turbine generator set, and its feedwater outlet connected to the feedwater inlet of the coal-fired boiler. The second water supply regeneration component has its water supply outlet connected to the water supply inlet of the first water supply regeneration component.

2. The system according to claim 1, characterized in that, The first steam turbine generator set includes: The first cylinder of the first steam turbine, the steam inlet of the first cylinder is connected to the superheated steam outlet of the coal-fired boiler, and the steam outlet of the first cylinder is connected to the cold reheat steam inlet of the coal-fired boiler. The second cylinder of the first steam turbine has its steam inlet connected to the reheat steam outlet of the coal-fired boiler, and its steam outlet is connected to the input end of the first feedwater regeneration assembly via the third cylinder of the first steam turbine.

3. The system according to claim 1, characterized in that, The second steam turbine generator set includes: The fourth cylinder of the second steam turbine, wherein the steam inlet of the fourth cylinder is connected to the steam outlet of the back-pressure steam turbine, and the steam outlet of the fourth cylinder is connected to the cold resteam inlet of the coal-fired boiler; The fifth cylinder of the second steam turbine has its steam inlet connected to the reheat steam outlet of the coal-fired boiler, and its steam outlet is connected to the input end of the second feedwater regeneration assembly via the sixth cylinder of the second steam turbine.

4. The system according to claim 1, characterized in that, The first water supply regeneration component includes: The first deaerator is connected to the output of the first steam turbine generator set. The first water supply pump has its input end connected to the output end of the first deaerator. The first heating component has its input end connected to the output end of the first water pump, and its output end connected to the water inlet of the coal-fired boiler.

5. The system according to claim 4, characterized in that, The first heating component includes: The first heater has its inlet end connected to the output end of the first water pump; The second heater has its inlet end connected to the outlet end of the first heater. The third heater has its inlet end connected to the outlet end of the second heater, and its outlet end connected to the feedwater inlet of the coal-fired boiler.

6. The system according to claim 4, characterized in that, The second water supply regeneration component includes: The second deaerator is connected to the output of the second steam turbine generator set. The second water supply pump has its input end connected to the output end of the second deaerator. The second heating component has its input end connected to the output end of the second water pump, and its water outlet connected to the water inlet of the first heating component.

7. The system according to claim 6, characterized in that, The second heating component includes: The fourth heater, the inlet of which is connected to the output of the second water pump; The fifth heater, the inlet of which is connected to the outlet of the fourth heater; The sixth heater has its inlet end connected to the outlet end of the fifth heater, and its outlet end connected to the input end of the first heating component.

8. The system according to claim 1, characterized in that, Also includes: The reheat steam temperature regulating station has its hot end located on the pipeline between the reheat steam outlet of the coal-fired boiler and the second steam turbine generator set, for regulating the temperature of the reheat steam entering the second steam turbine generator set. The cold end of the reheat steam temperature regulating station is located on the inlet feedwater pipeline of the coal-fired boiler, for heating the inlet feedwater of the coal-fired boiler.

9. The system according to claim 1, characterized in that, Also includes: A pressure regulating station is located between the steam outlet of the first cylinder of the first steam turbine generator set and the cold resteam inlet of the coal-fired boiler, and is used to regulate the cold resteam pressure.

10. The system according to claim 4, characterized in that, Also includes: A feedwater booster pump is installed between the liquid outlet of the first heating component and the feedwater inlet of the coal-fired boiler, and is used to boost the pressure of feedwater and deliver it to the coal-fired boiler.

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