Main reheat steam temperature adjusting system with high water adding bypass and operation method

Abstract

The invention provides a main reheating steam temperature adjusting system with a high-pressure heater water bypass and an operation method, and belongs to the technical field of steam temperature adjustment, the main reheating steam temperature adjusting system comprises a boiler, a high-pressure cylinder, a low-pressure cylinder, a deaerator, a high-pressure heater, a small steam turbine system, a high-pressure heater water supply bypass system, a main reheating temperature adjusting system and a high-low pressure gas storage tank system; the steam flow and the feed water temperature can be controlled, so that the thermoelectric unit can respond to load fluctuation more quickly, the feed water temperature of the bypass can be changed more quickly by arranging the steam ejector and the steam ejector heat exchanger, the influence of the load fluctuation on system operation is greatly reduced, and the service life of the system is prolonged. Meanwhile, the low-pressure steam storage tank and the high-pressure steam storage tank are arranged, steam can be effectively utilized, the energy utilization efficiency is improved, and the main reheating temperature adjusting system is introduced, so that the feed water temperature can be changed more quickly, the electrical load adjusting capacity is improved, and the energy consumption level of the unit is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of steam temperature regulation, and in particular to a main reheat steam temperature regulation system with a high-pressure water bypass and an operation method thereof. Background Art

[0002] With the transformation of the global energy structure, the proportion of renewable energy such as solar energy, wind energy and other clean energy in the energy supply is continuing to rise. At the same time, the rapid development of society and the diversification of electricity demand have also increased the operating pressure of the power grid. With the continuous growth of industrial, commercial and residential electricity demand, and the popularization of emerging electrical equipment such as electric vehicles and smart homes, the power grid load has become complex and changeable.

[0003] In existing thermal power units, the high-pressure heater bypass is an important means of regulation, which can alleviate the impact of load fluctuations on the power grid to a certain extent. The high-pressure heater is one of the key equipment in thermal power units. Its main function is to use steam extraction from the steam turbine to heat the feed water and improve the thermal efficiency of the unit.

[0004] However, it is worth noting that although the high-pressure heater bypass can alleviate the impact of load fluctuations on the power grid to a certain extent, its regulation effect is also restricted by many factors. The existing regulation based on the high-pressure heater bypass still has shortcomings: the temperature control is difficult. When the unit load changes suddenly, the steam extraction pressure and temperature of the turbine will change accordingly, which will make it difficult to stably control the feed water heating temperature in the high-pressure heater. During actual operation, when the load suddenly increases, the steam extraction pressure and temperature drop instantly, which reduces the heating capacity of the high-pressure heater and causes the feed water temperature to fail to reach the set value, affecting the operation of the thermal power unit and reducing the thermal efficiency of the unit. It can be seen that the current high-pressure heater system regulation is still insufficient in temperature regulation, and we need a new regulation system to overcome the problems existing in the prior art. Summary of the invention

[0005] The object of the present invention is to provide a main reheat steam temperature control system with a high-pressure water bypass and an operating method to overcome the problems existing in the prior art. The present invention can combine a small steam turbine system, a high-pressure water bypass system, a high-pressure and low-pressure gas storage tank system and a main reheat steam temperature control system. A steam ejector is set in the high-pressure water bypass system to control the steam flow and feed water temperature, so that the thermal power unit can respond to load fluctuations more quickly; by configuring a steam ejector and a steam ejector heat exchanger, the bypass feed water temperature can be changed more quickly, which greatly reduces the impact of load fluctuations on system operation. At the same time, a low-pressure steam storage tank and a high-pressure steam storage tank are also configured, which can effectively utilize steam and improve energy utilization efficiency; by introducing the main reheat temperature control system, the feed water temperature can also be changed more quickly, the electrical load regulation capability is improved, and the energy consumption level of the unit is reduced.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a main reheat steam temperature adjustment system with a high pressure feed water bypass, comprising a boiler, a high pressure cylinder, a low pressure cylinder, a deaerator, a high pressure heater, a small steam turbine system, a high pressure feed water bypass system, a main reheat temperature adjustment system and a high and low pressure gas storage tank system; The outlet of the boiler is connected to the inlet of the high-pressure cylinder, the outlet of the high-pressure cylinder is connected to the inlet of the low-pressure cylinder, the outlet of the low-pressure cylinder is connected to the inlet of the deaerator, the outlet of the deaerator is connected to the water inlet of the high-pressure heater, the steam extraction port of the high-pressure cylinder is connected to the high-pressure heater through a pipeline, the steam outlet of the high-pressure cylinder is connected to the steam inlet of the high-pressure heater through a small steam turbine system, and the outlet of the high-pressure heater is connected to the inlet of the boiler; A high pressure feed water bypass system is connected between the outlet of the high pressure heater and the outlet of the deaerator, and the outlet of the deaerator is respectively connected to the main steam inlet and the reheat steam inlet of the boiler through the main reheat temperature adjustment system; The steam extraction port of the low-pressure cylinder is connected to the high-pressure feed water bypass system through the high- and low-pressure gas storage tank system; Furthermore, the outlet of the low-pressure cylinder is connected to the inlet of the deaerator through a condenser and a water-binding pump connected in sequence; Further, the small steam turbine system includes a small steam turbine, a small steam turbine feed water pump and a small steam turbine inlet regulating valve; The steam outlet of the high-pressure cylinder is connected to the inlet of the small steam turbine through the small steam turbine inlet regulating valve, and the outlet of the small steam turbine is connected to the water inlet of the high-pressure heater through the small steam turbine feed water pump; Furthermore, the high pressure heater feed water bypass system includes a steam ejector heat exchanger, an electric feed water pump and a high pressure heater bypass regulating valve; The outlet of the deaerator is connected to the cold source inlet of the steam ejector heat exchanger through the high-pressure heater bypass regulating valve and the electric feed water pump in sequence, and the cold source outlet of the steam ejector heat exchanger is connected to the inlet of the boiler; Further, the high and low pressure gas storage tank system includes a low pressure gas storage tank extraction valve, a high pressure gas storage tank extraction valve, a low pressure gas storage tank, a high pressure gas storage tank, a steam ejector low pressure valve, a steam ejector high pressure valve and a steam ejector; The steam extraction port of the low-pressure cylinder includes a first steam extraction port and a second steam extraction port, the first steam extraction port is connected to the low-pressure gas storage tank through a low-pressure gas storage tank steam extraction valve, and the low-pressure gas storage tank is connected to the first inlet of the steam ejector through the low-pressure valve of the steam ejector; the second steam extraction port is connected to the high-pressure gas storage tank through a high-pressure gas storage tank steam extraction valve, and the high-pressure gas storage tank is connected to the second inlet of the steam ejector through the high-pressure valve of the steam ejector, and the outlet of the steam ejector is connected to the heat source inlet of the steam ejector heat exchanger; Further, the heat source outlet of the steam ejector heat exchanger is connected to a deaerator; Further, the main reheat temperature regulating system includes a main steam temperature regulating valve and a reheat steam temperature regulating valve; The outlet of the deaerator is connected to the main steam inlet of the boiler through a main steam temperature regulating valve, and is also connected to the reheat steam inlet of the boiler through a reheat steam temperature regulating valve.

[0007] In a second aspect, the present invention provides an operation method of a main reheat steam temperature control system with a high-pressure water bypass, based on the above-mentioned main reheat steam temperature control system with a high-pressure water bypass, comprising the following steps: When the unit is running, the low-pressure cylinder sends steam to the high- and low-pressure gas storage tank system. The feed water in the deaerator is pressurized through the high-pressure feed water bypass system and heat exchanged with the steam output after passing through the high- and low-pressure gas storage tank system. The feed water after heat exchange is then sent to the boiler to maintain the stability of the feed water temperature. When the unit increases load, the flow rate of the water inlet of the high-pressure heater is reduced by adjusting the small steam turbine system, so that the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder and the high-pressure heater is reduced, and the amount of steam extracted from the high-pressure cylinder by the high-pressure heater is reduced. Then, the high-pressure and low-pressure gas storage tank systems are adjusted to increase the flow rate and temperature of the high-pressure heater bypass feed water. When the unit reduces load, the flow rate of the water inlet of the high-pressure heater is increased by adjusting the small steam turbine system, so that the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder and the high-pressure heater increases, and the amount of steam extracted from the high-pressure cylinder by the high-pressure heater increases. Then, the high-pressure and low-pressure gas storage tank systems are adjusted to reduce the flow rate and temperature of the high-pressure heater bypass feed water. Furthermore, the small steam turbine system includes a small steam turbine, a small steam turbine feed water pump and a small steam turbine inlet regulating valve, the steam outlet of the high-pressure cylinder is connected to the inlet of the small steam turbine through the small steam turbine inlet regulating valve, and the outlet of the small steam turbine is connected to the water inlet of the high-pressure heater through the small steam turbine feed water pump; The high-pressure heater feed water bypass system includes a steam ejector heat exchanger, an electric feed water pump and a high-pressure heater bypass regulating valve, the outlet of the deaerator is connected to the cold source inlet of the steam ejector heat exchanger through the high-pressure heater bypass regulating valve and the electric feed water pump in sequence, and the cold source outlet of the steam ejector heat exchanger is connected to the inlet of the boiler; The high- and low-pressure gas storage tank system comprises a low-pressure gas storage tank extraction valve, a high-pressure gas storage tank extraction valve, a low-pressure gas storage tank, a high-pressure gas storage tank, a steam ejector low-pressure valve, a steam ejector high-pressure valve and a steam ejector, the extraction port of the low-pressure cylinder comprises a first extraction port and a second extraction port, the first extraction port is connected to the low-pressure gas storage tank through the low-pressure gas storage tank extraction valve, the low-pressure gas storage tank is connected to the first inlet of the steam ejector through the steam ejector low-pressure valve; the second extraction port is connected to the high-pressure gas storage tank through the high-pressure gas storage tank extraction valve, the high-pressure gas storage tank is connected to the second inlet of the steam ejector through the steam ejector high-pressure valve, and the outlet of the steam ejector is connected to the heat source inlet of the steam ejector heat exchanger; The high-pressure heater feed water bypass system includes a steam ejector heat exchanger, an electric feed water pump and a high-pressure heater bypass regulating valve, the outlet of the deaerator is connected to the cold source inlet of the steam ejector heat exchanger through the high-pressure heater bypass regulating valve and the electric feed water pump in sequence, and the cold source outlet of the steam ejector heat exchanger is connected to the inlet of the boiler; Furthermore, when the unit is running, the low-pressure cylinder sends steam into the low-pressure gas storage tank and the high-pressure gas storage tank to provide a stable steam source for the steam ejector. The feed water in the deaerator is pressurized by the electric feed water pump and heat exchanged with the steam output after passing through the low-pressure gas storage tank and the high-pressure gas storage tank. The feed water after heat exchange is then sent to the boiler to maintain the stability of the feed water temperature. When the unit increases the load, the opening of the turbine inlet regulating valve is reduced to reduce the flow rate of the water inlet of the high-pressure heater, so that the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder and the high-pressure heater is reduced, and the amount of steam extracted from the high-pressure cylinder by the high-pressure heater is reduced. The opening of the high-pressure heater bypass regulating valve is increased to increase the water supply of the electric feed water pump, and then the steam ejector low-pressure valve and steam ejector high-pressure valve are adjusted to increase the amount of steam entering the steam ejector, so that the flow rate and temperature of the high-pressure heater bypass feed water are improved; When the unit reduces the load, the opening of the turbine inlet regulating valve is adjusted to increase the flow rate at the water inlet of the high-pressure heater, so that the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder and the high-pressure heater increases, and the amount of steam extracted from the high-pressure cylinder by the high-pressure heater increases. The opening of the high-pressure heater bypass regulating valve is adjusted down to reduce the water supply of the electric feed water pump, and then the steam ejector low-pressure valve and the steam ejector high-pressure valve are adjusted down to reduce the amount of steam entering the steam ejector, so as to reduce the flow rate and temperature of the high-pressure bypass feed water.

[0008] The above technical solution has the following advantages or beneficial effects: In the first aspect, the present invention provides a main reheat steam temperature control system with a high-pressure water bypass, which combines a small steam turbine system, a high-pressure water bypass system, a main reheat temperature control system and a high- and low-pressure gas storage tank system. The high- and low-pressure gas storage tank system can change the temperature of the feed water in the high-pressure water bypass system, and the adjustment of the main reheat temperature control system can also achieve changes in the feed water temperature and flow rate, thereby achieving a faster load adjustment response. In particular, when the grid load fluctuates, the unit state can be quickly adjusted to avoid efficiency loss. At the same time, the high- and low-pressure steam storage tanks are configured to improve the unit's ability to respond to load changes; by adjusting the small steam turbine system, the purpose of reducing or increasing the unit power can be achieved, the heat of low-pressure steam is effectively utilized in stages, the energy utilization rate is improved, and the stable operation of the high-pressure bypass boiler is guaranteed; by introducing the main reheat temperature control system, the feed water temperature can be changed more quickly, the electrical load adjustment capability is improved, and the energy consumption level of the unit is reduced; at the same time, it can also effectively reduce equipment wear and fuel consumption, while improving the environmental protection of the unit operation.

[0009] Furthermore, the condenser can create a higher vacuum at the exhaust port of the turbine, causing the steam to expand to the minimum pressure in the turbine, thereby increasing the available enthalpy drop of the steam in the turbine and improving the thermal efficiency of the cycle; the condensate is powered by the condensate pump and then transported to the boiler through the deaerator, etc., ensuring the continuity of the entire thermal cycle, helping to reduce steam-water losses and improving the overall efficiency of the system.

[0010] Furthermore, part of the steam discharged from the high-pressure cylinder enters the small steam turbine through the small steam turbine inlet regulating valve to perform work, which improves the energy utilization efficiency of the entire thermal system and helps to reduce energy waste.

[0011] Furthermore, the steam ejector heat exchanger utilizes the jet effect of steam for heat exchange without the need for an additional power source, which saves energy and simplifies the system structure; at the same time, it can also provide preheating for feed water, increase the feed water temperature, help reduce the thermal load of the boiler and improve thermal efficiency.

[0012] Furthermore, the temperature of the feed water in the high-pressure feed water bypass can be changed by the steam ejector, and steam of different pressures can be extracted respectively through the first steam extraction port and the second steam extraction port of the low-pressure cylinder, and stored in the low-pressure gas storage tank and the high-pressure gas storage tank, which helps to make full use of steam resources and avoid energy waste; the steam ejector uses the injection effect of high-speed steam to change the temperature of the feed water in the high-pressure feed water bypass, and then provides a heat source for the steam ejector heat exchanger through the mixed steam, further improving the energy utilization efficiency; through the precise control of the low-pressure gas storage tank extraction valve, the high-pressure gas storage tank extraction valve, the steam ejector low-pressure valve and the steam ejector high-pressure valve, the steam flow rate can be flexibly adjusted, which helps the system to maintain a stable operating state under different load conditions.

[0013] Furthermore, the main reheat temperature control system in the system realizes the regulation of main steam temperature and reheat steam temperature by adjusting the opening of main steam temperature control valve and reheat steam temperature control valve, thereby meeting the unit's demand for increased load changes, while reducing energy consumption, improving the economy of unit operation, and improving the unit's response capability to load changes, thus ensuring efficient and stable operation of thermal power units.

[0014] In the second aspect, the present invention provides an operating method of a main reheat steam temperature control system with a high-pressure water bypass. When the unit is running, steam is stored in a high-pressure steam storage tank and a low-pressure steam storage tank to provide a stable steam source for the steam ejector when needed. The feed water in the deaerator is pressurized by an electric feed water pump and heat exchanged with the steam output after passing through the low-pressure gas storage tank and the high-pressure gas storage tank. The feed water after heat exchange is then sent to the boiler to maintain the stability of the feed water temperature. When the unit increases or decreases the load, the flow rate of the small steam turbine feed water pump is reduced or increased by adjusting the small steam turbine inlet regulating valve, the water inlet flow rate of the high-pressure heater is also reduced or increased, the heat exchange temperature on the tube side of the high-pressure heater increases or decreases, the outlet temperature on the tube side of the high-pressure heater increases or decreases, and the shell side pressure increases or decreases, so that the high-pressure cylinder The pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure heater and the high-pressure heater decreases or increases, and the amount of steam extracted from the high-pressure cylinder by the high-pressure heater decreases or increases, so that the amount of steam entering the steam turbine to do work increases or decreases, and the power output of the steam turbine increases or decreases. By increasing or decreasing the opening of the high-pressure heater bypass regulating valve, the water supply of the electric feedwater pump can be increased or decreased. By increasing or decreasing the opening of the steam ejector low-pressure valve and the steam ejector high-pressure valve, the amount of steam entering the steam ejector is increased or decreased, so that the flow rate and temperature of the high-pressure heater bypass feedwater are increased or decreased. The bypass feedwater of the high-pressure heater absorbs more or less heat after being heated by the steam ejector heat exchanger, and then mixes with the outlet water of the high-pressure heater, thereby increasing or decreasing the flow rate and temperature of the high-pressure heater bypass feedwater, which can meet the requirements for feedwater temperature and flow rate when the load is increased, and stabilize the operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a main reheat steam temperature regulating system with a high-pressure water bypass according to the present invention; In the figure, 1- boiler; 2- high-pressure cylinder; 3- low-pressure cylinder; 4- low-pressure cylinder; 5- water pump; 6- small steam turbine; 7- deaerator; 8- small steam turbine feed water pump; 9- high-pressure heater; 10- steam ejector; 11- steam ejector heat exchanger; 12- low-pressure gas storage tank; 13- high-pressure gas storage tank; 14- small steam turbine inlet regulating valve; 15- low-pressure gas storage tank extraction valve; 16- high-pressure gas storage tank extraction valve; 17- high-pressure heater bypass regulating valve; 18- main steam temperature regulating valve; 19- reheat steam temperature regulating valve; 20- steam ejector low-pressure valve; 21- steam ejector high-pressure valve; 22- electric feed water pump. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it. In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention. It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] Embodiment 1: The present invention provides a main reheat steam temperature regulation system with a high-pressure water bypass, comprising a boiler 1, a high-pressure cylinder 2, a low-pressure cylinder 3, a condenser 4, a water pump 5, a deaerator 7, a high-pressure heater 9, a small steam turbine system, a high-pressure feed water bypass system, a main reheat temperature regulation system and a high- and low-pressure gas storage tank system; the small steam turbine system comprises a small steam turbine 6, a small steam turbine feed water pump 8 and a small steam turbine inlet regulating valve 14; the high-pressure feed water bypass system comprises a steam ejector heat exchanger 11, an electric feed water pump 22 and a high-pressure heater bypass regulating valve 17; the high- and low-pressure gas storage tank system comprises a low-pressure gas storage tank extraction valve 15, a high-pressure gas storage tank extraction valve 16, a low-pressure gas storage tank 12, a high-pressure gas storage tank 13, a steam ejector low-pressure valve 20, a steam ejector high-pressure valve 21 and a steam ejector 10; the main reheat temperature regulation system comprises a main steam temperature regulating valve 18 and a reheat steam temperature regulating valve 19.

[0018] See also Figure 1 The outlet of boiler 1 is connected to the inlet of high-pressure cylinder 2, the outlet of high-pressure cylinder 2 is connected to the inlet of low-pressure cylinder 3, the outlet of low-pressure cylinder 3 is connected to the inlet of deaerator 7 through condenser 4 and condenser pump 5 connected in sequence, the outlet of deaerator 7 is connected to the water inlet of high-pressure heater 9, the steam extraction port of high-pressure cylinder 2 is connected to high-pressure heater 9 through a pipeline, the steam outlet of high-pressure cylinder 2 is connected to the inlet of small steam turbine 6 through small steam turbine inlet regulating valve 14, the outlet of small steam turbine 6 is connected to the steam inlet of high-pressure heater 9 through small steam turbine feed water pump 8, and the outlet of high-pressure heater 9 is connected to the inlet of boiler 1; the outlet of high-pressure heater 9 and the outlet of deaerator 7 are connected to the high-pressure feed water bypass system, the outlet of deaerator 7 is connected to the cold source inlet of steam ejector heat exchanger 11 through high-pressure heater bypass regulating valve 17 and electric feed water pump 22 in sequence, the feed water flow through high-pressure heater 9 is adjusted by adjusting the high-pressure heater bypass regulating valve 17, and further adjusted The steam flow entering the high-pressure heater 9 is adjusted to adjust the feed water temperature. The cold source outlet of the steam ejector heat exchanger 11 is connected to the inlet of the boiler 1. The outlet of the deaerator 7 is connected to the main steam inlet of the boiler 1 through the main steam temperature regulating valve 18, and is also connected to the reheat steam inlet of the boiler 1 through the reheat steam temperature regulating valve 19; the extraction port of the low-pressure cylinder 4 includes a first extraction port and a second extraction port. The first extraction port is connected to the low-pressure gas storage tank 12 through the low-pressure gas storage tank extraction valve 15, and the low-pressure gas storage tank 12 is connected to the first inlet of the steam ejector 10 through the steam ejector low-pressure valve 20; the second extraction port is connected to the high-pressure gas storage tank 13 through the high-pressure gas storage tank extraction valve 16, and the high-pressure gas storage tank 13 is connected to the second inlet of the steam ejector 10 through the steam ejector high-pressure valve 21, the outlet of the steam ejector 10 is connected to the heat source inlet of the steam ejector heat exchanger 11, and the heat source outlet of the steam ejector heat exchanger 11 is connected to the deaerator 7.

[0019] Embodiment 2: The present invention provides an operation method of a main reheat steam temperature control system with a high-pressure water addition bypass, based on the above-mentioned main reheat steam temperature control system with a high-pressure water addition bypass, comprising the following steps: When the unit is running, the low-pressure cylinder 3 sends steam into the low-pressure gas storage tank 12 and the high-pressure gas storage tank 13. The high-pressure gas storage tank 13 and the low-pressure gas storage tank 12 store the steam to provide a stable steam source for the steam ejector 10 when needed. The feed water in the deaerator 7 is pressurized by the electric feed water pump 22 and heat exchanged with the steam output after passing through the low-pressure gas storage tank 12 and the high-pressure gas storage tank 13. Then, the feed water after heat exchange is sent to the boiler 1 to maintain the stability of the feed water temperature. When the unit increases load, by adjusting the opening of the small turbine inlet regulating valve 14, the flow of the small turbine feed water pump 8 is reduced, the water inlet flow of the high-pressure heater 9 is also reduced, the heat exchange temperature on the tube side of the high-pressure heater 9 rises, the outlet temperature on the tube side of the high-pressure heater 9 rises, and the shell side pressure increases, so that the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder 2 and the high-pressure heater 9 is reduced, and the amount of steam extracted from the high-pressure cylinder 2 by the high-pressure heater 9 is reduced, so that the amount of steam entering the turbine to do work is increased, and therefore, the power output of the turbine is increased; since the steam extraction of the high-pressure heater 9 is reduced, the heat of the feed water outlet of the high-pressure heater 9 becomes smaller, so it is necessary to increase the opening of the high-pressure heater bypass regulating valve 17 to increase the water supply of the electric feed water pump 22; since the steam extraction of the high-pressure heater 9 is reduced, It is necessary to increase the steam ejector low-pressure valve 20 and the steam ejector high-pressure valve 21 to increase the amount of steam entering the steam ejector 10, so as to increase the flow rate and temperature of the high-pressure heater bypass feed water; the bypass feed water of the high-pressure heater 9 absorbs more heat after being heated in the steam ejector heat exchanger 11, and then mixes with the outlet water of the high-pressure heater 9, thereby increasing the flow rate and temperature of the high-pressure heater bypass feed water, meeting the requirements for feed water temperature and flow rate when the load is increased, and stabilizing the operation of the unit; at the same time, the main reheat temperature control system in the system adjusts the main steam temperature and the reheat steam temperature by adjusting the opening of the main steam temperature control valve 18 and the reheat steam temperature control valve 19, thereby meeting the unit's demand for increased load changes, while reducing energy consumption, improving the economy of the unit operation, and improving the unit's responsiveness to load changes; When the unit reduces the load, by adjusting the opening of the turbine inlet regulating valve 14, the flow rate of the small turbine feed water pump 8 is increased, and the flow rate of the water inlet of the high-pressure heater 9 is also increased, the heat exchange temperature on the tube side of the high-pressure heater 9 is reduced, the outlet temperature on the tube side of the high-pressure heater 9 is reduced, and the shell side pressure is reduced, so that the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder 2 and the high-pressure heater 9 increases, and the amount of steam extracted from the high-pressure cylinder 2 by the high-pressure heater 9 increases, so that the amount of steam entering the turbine to do work is reduced, and therefore, the output power of the turbine is reduced; due to the increase in the steam extraction amount of the high-pressure heater 9, the heat at the feed water outlet of the high-pressure heater 9 becomes larger, so by reducing the opening of the high-pressure heater bypass regulating valve 17, the supply of the electric feed water pump 22 can be reduced. water volume; then adjust the steam ejector low-pressure valve 20 and the steam ejector high-pressure valve 21 to reduce the amount of steam entering the steam ejector 10, and the heat absorbed by the high-pressure heater bypass feed water after being heated in the steam ejector heat exchanger 11 is reduced, and then mixed with the outlet water of the high-pressure heater 9, so as to reduce the flow rate and temperature of the high-pressure heater bypass feed water, so as to meet the requirements of feed water temperature and feed water flow when the load is reduced, and stabilize the operation of the unit; at the same time, the main reheat temperature control system in the system adjusts the main steam temperature and the reheat steam temperature by adjusting the opening of the main steam temperature control valve 18 and the reheat steam temperature control valve 19, so as to meet the load demand of the unit, improve the system's response capability to variable load, and ensure the efficient and stable operation of the thermal power unit.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A main reheat steam temperature control system with high temperature water bypass, characterized in that: It includes a boiler (1), a high-pressure cylinder (2), a low-pressure cylinder (3), a deaerator (7), a high-pressure heater (9), a small steam turbine system, a high-pressure feed water bypass system, a main reheat temperature adjustment system and a high-pressure and low-pressure gas storage tank system; The outlet of the boiler (1) is connected to the inlet of the high-pressure cylinder (2), the outlet of the high-pressure cylinder (2) is connected to the inlet of the low-pressure cylinder (3), the outlet of the low-pressure cylinder (3) is connected to the inlet of the deaerator (7), the outlet of the deaerator (7) is connected to the water inlet of the high-pressure heater (9), the steam extraction port of the high-pressure cylinder (2) is connected to the high-pressure heater (9) through a pipeline, the steam outlet of the high-pressure cylinder (2) is connected to the steam inlet of the high-pressure heater (9) through a small steam turbine system, and the outlet of the high-pressure heater (9) is connected to the inlet of the boiler (1); A high pressure feed water bypass system is connected between the outlet of the high pressure heater (9) and the outlet of the deaerator (7); the outlet of the deaerator (7) is respectively connected to the main steam inlet and the reheat steam inlet of the boiler (1) through a main reheat temperature adjustment system; The steam extraction port of the low-pressure cylinder (4) is connected to the high-pressure feed water bypass system via a high- and low-pressure gas storage tank system.

2. A main reheat steam temperature control system with high pressure water bypass according to claim 1, characterized in that: The outlet of the low-pressure cylinder (3) is connected to the inlet of the deaerator (7) through a condenser (4) and a water-binding pump (5) which are connected in sequence.

3. The main reheat steam temperature control system with high pressure water bypass according to claim 1, characterized in that: The small steam turbine system comprises a small steam turbine (6), a small steam turbine feed water pump (8) and a small steam turbine inlet regulating valve (14); The steam outlet of the high-pressure cylinder (2) is connected to the inlet of the small steam turbine (6) through the small steam turbine inlet regulating valve (14), and the outlet of the small steam turbine (6) is connected to the water inlet of the high-pressure heater (9) through the small steam turbine feed water pump (8).

4. The main reheat steam temperature control system with high pressure water bypass according to claim 1, characterized in that: The high-pressure heater feedwater bypass system comprises a steam ejector heat exchanger (11), an electric feedwater pump (22) and a high-pressure heater bypass regulating valve (17); The outlet of the deaerator (7) is connected to the cold source inlet of the steam ejector heat exchanger (11) through the high-pressure heater bypass regulating valve (17) and the electric feed water pump (22) in sequence, and the cold source outlet of the steam ejector heat exchanger (11) is connected to the inlet of the boiler (1).

5. A main reheat steam temperature control system with high pressure water bypass according to claim 4, characterized in that: The high- and low-pressure gas storage tank system comprises a low-pressure gas storage tank steam extraction valve (15), a high-pressure gas storage tank steam extraction valve (16), a low-pressure gas storage tank (12), a high-pressure gas storage tank (13), a steam ejector low-pressure valve (20), a steam ejector high-pressure valve (21), and a steam ejector (10); The steam extraction port of the low-pressure cylinder (4) comprises a first steam extraction port and a second steam extraction port, the first steam extraction port being connected to the low-pressure gas storage tank (12) via a low-pressure gas storage tank steam extraction valve (15), and the low-pressure gas storage tank (12) being connected to a first inlet of the steam ejector (10) via a steam ejector low-pressure valve (20); the second steam extraction port being connected to the high-pressure gas storage tank (13) via a high-pressure gas storage tank steam extraction valve (16), and the high-pressure gas storage tank (13) being connected to a second inlet of the steam ejector (10) via a steam ejector high-pressure valve (21), and the outlet of the steam ejector (10) being connected to a heat source inlet of a steam ejector heat exchanger (11).

6. A main reheat steam temperature control system with high pressure water bypass according to claim 5, characterized in that: The heat source outlet of the steam ejector heat exchanger (11) is connected to the deaerator (7).

7. The main reheat steam temperature control system with high pressure water bypass according to claim 1, characterized in that: The main reheat temperature regulating system comprises a main steam temperature regulating valve (18) and a reheat steam temperature regulating valve (19); The outlet of the deaerator (7) is connected to the main steam inlet of the boiler (1) via a main steam temperature regulating valve (18), and is also connected to the reheat steam inlet of the boiler (1) via a reheat steam temperature regulating valve (19).

8. An operating method of a main reheat steam temperature control system with a high-pressure water bypass, based on the main reheat steam temperature control system with a high-pressure water bypass according to any one of claims 1 to 7, characterized in that: The following steps are involved: When the unit is running, the low-pressure cylinder (3) sends steam to the high-pressure and low-pressure gas storage tank system, and the feed water in the deaerator (7) is pressurized through the high-pressure feed water bypass system to exchange heat with the steam output after passing through the high-pressure and low-pressure gas storage tank system. The feed water after the heat exchange is then sent to the boiler (1) to maintain the stability of the feed water temperature. When the load of the unit increases, the flow rate at the water inlet of the high-pressure heater (9) is reduced by adjusting the small steam turbine system, so that the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder (2) and the high-pressure heater (9) is reduced, and the amount of steam extracted from the high-pressure cylinder (2) by the high-pressure heater (9) is reduced. Then, the high-pressure and low-pressure gas storage tank systems are adjusted to increase the flow rate and temperature of the high-pressure heater bypass feed water. When the unit reduces its load, the flow rate at the water inlet of the high-pressure heater (9) is increased by adjusting the small steam turbine system, thereby increasing the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder (2) and the high-pressure heater (9), thereby increasing the amount of steam extracted from the high-pressure cylinder (2) by the high-pressure heater (9), and then adjusting the high- and low-pressure gas storage tank systems to reduce the flow rate and temperature of the high-pressure heater bypass feed water.

9. The operating method of the main reheat steam temperature control system with high pressure water bypass according to claim 8, characterized in that: The small steam turbine system comprises a small steam turbine (6), a small steam turbine feed water pump (8) and a small steam turbine inlet regulating valve (14); the steam outlet of the high-pressure cylinder (2) is connected to the inlet of the small steam turbine (6) through the small steam turbine inlet regulating valve (14); and the outlet of the small steam turbine (6) is connected to the water inlet of the high-pressure heater (9) through the small steam turbine feed water pump (8); The high-pressure heater feedwater bypass system comprises a steam ejector heat exchanger (11), an electric feedwater pump (22) and a high-pressure heater bypass regulating valve (17); the outlet of the deaerator (7) is connected to the cold source inlet of the steam ejector heat exchanger (11) via the high-pressure heater bypass regulating valve (17) and the electric feedwater pump (22) in sequence; and the cold source outlet of the steam ejector heat exchanger (11) is connected to the inlet of the boiler (1); The high- and low-pressure gas storage tank system comprises a low-pressure gas storage tank extraction valve (15), a high-pressure gas storage tank extraction valve (16), a low-pressure gas storage tank (12), a high-pressure gas storage tank (13), a steam ejector low-pressure valve (20), a steam ejector high-pressure valve (21) and a steam ejector (10); the extraction port of the low-pressure cylinder (4) comprises a first extraction port and a second extraction port; the first extraction port is connected to the low-pressure gas storage tank (12) via the low-pressure gas storage tank extraction valve (15); the low-pressure gas storage tank (12) is connected to a first inlet of the steam ejector (10) via the steam ejector low-pressure valve (20); the second extraction port is connected to the high-pressure gas storage tank (13) via the high-pressure gas storage tank extraction valve (16); the high-pressure gas storage tank (13) is connected to a second inlet of the steam ejector (10) via the steam ejector high-pressure valve (21); and the outlet of the steam ejector (10) is connected to a heat source inlet of a steam ejector heat exchanger (11); The high-pressure heater feed water bypass system comprises a steam ejector heat exchanger (11), an electric feed water pump (22) and a high-pressure heater bypass regulating valve (17); the outlet of the deaerator (7) is connected to the cold source inlet of the steam ejector heat exchanger (11) via the high-pressure heater bypass regulating valve (17) and the electric feed water pump (22) in sequence; and the cold source outlet of the steam ejector heat exchanger (11) is connected to the inlet of the boiler (1).

10. The operating method of the main reheat steam temperature control system with high pressure water bypass according to claim 9, characterized in that: The steps are specifically as follows: When the unit is running, the low-pressure cylinder (3) sends steam into the low-pressure gas storage tank (12) and the high-pressure gas storage tank (13) to provide a stable steam source for the steam ejector (10). The feed water in the deaerator (7) is pressurized by the electric feed water pump (22) and heat exchange is performed with the steam output after passing through the low-pressure gas storage tank (12) and the high-pressure gas storage tank (13). The feed water after the heat exchange is then sent to the boiler (1) to maintain a stable feed water temperature. When the load of the unit is increased, the opening of the turbine inlet regulating valve (14) is reduced to reduce the flow rate of the water inlet of the high-pressure heater (9), thereby reducing the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder (2) and the high-pressure heater (9), and reducing the amount of steam extracted from the high-pressure cylinder (2) by the high-pressure heater (9). The opening of the high-pressure heater bypass regulating valve (17) is increased to increase the water supply of the electric feed water pump (22), and then the steam ejector low-pressure valve (20) and the steam ejector high-pressure valve (21) are increased to increase the amount of steam entering the steam ejector (10), thereby increasing the flow rate and temperature of the high-pressure heater bypass feed water. When the unit reduces the load, the opening of the turbine inlet regulating valve (14) is adjusted to increase the flow rate at the water inlet of the high-pressure heater (9), thereby increasing the pressure difference between the upper and lower sides of the steam extraction pipe between the high-pressure cylinder (2) and the high-pressure heater (9), and increasing the amount of steam extracted from the high-pressure cylinder (2) by the high-pressure heater (9). The opening of the high-pressure heater bypass regulating valve (17) is adjusted to reduce the water supply of the electric feed water pump (22), and then the steam ejector low-pressure valve (20) and the steam ejector high-pressure valve (21) are adjusted to reduce the amount of steam entering the steam ejector (10), thereby reducing the flow rate and temperature of the high-pressure heater bypass feed water.

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