Electrode steam boiler and heat decoupling system with heat storage steam supply

Abstract

The application discloses an electrode steam boiler and a heat-electricity decoupling system of heat storage steam supply, which comprises a heat and power cogeneration unit system, an electrode steam boiler and a heat storage steam supply system and an electric network connected with the two systems, wherein the electrode steam boiler and the heat storage steam supply system comprises an electrode steam boiler and a spherical heat storage tank; when the unit is deeply peak-regulated, steam can be provided by the electrode steam boiler, instant steam can be provided to the outside and steam can be supplied to the spherical heat storage tank at the same time, heat can be stored in the form of high-parameter saturated medium, the on-grid power of the unit can be reduced or even zero, when the unit is peak-regulated, the spherical heat storage tank is put into operation to release heat and supply steam, the steam extraction of the heat and power unit can be reduced or even no steam extraction, and the on-grid power of the unit can be increased. The heat-electricity decoupling system can provide steam and power supply demand, improve the operation flexibility, deep peak-regulation capacity and peak-regulation capacity of the unit under the premise of guaranteeing the provision of steam heat load.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of flexible transformation of thermal power generating units, and particularly relates to a system for improving the thermal-electric decoupling capacity of a combined heat and power unit. BACKGROUND

[0002] Under the background of the "double carbon" target, increasing the installed capacity and power generation proportion of renewable energy power generation is the main development trend of the energy industry. In 2023, the proportion of wind power and solar power generation in China reached 15.0%, while the proportion of thermal power generation has decreased to nearly 66.6%. With the continuous reduction of wind and solar power generation costs, renewable energy power generation will continue to develop rapidly in the future. However, due to weather and climate conditions, wind power, solar power and other power generation methods generally have intermittency and volatility. In order to make up for the reduction of power grid stability due to the incorporation of renewable energy, thermal power generating units need to bear heavier peak shaving, peak shaving and rapid load change tasks. The existing thermal power generating unit operation flexibility is limited by the minimum technical output of the unit, and the low load rate of the unit cannot be further reduced, which limits the deep peak shaving capacity of the unit.

[0003] Therefore, it has become an urgent problem to provide a system that can improve the thermal-electric decoupling capacity of a combined heat and power unit to improve the operation flexibility, deep peak shaving capacity and peak shaving capacity of the unit, and respond to the peak shaving and peak shaving demand of the power grid. SUMMARY

[0004] In order to solve the problems existing in the prior art, the purpose of the present application is to provide an electrode steam boiler and a thermal-electric decoupling system for heat storage and steam supply to improve the thermal-electric decoupling capacity of a combined heat and power unit. The system uses an electrode steam boiler to generate steam and a spherical heat storage tank to store heat, which can realize thermal-electric decoupling of a thermal power generating unit and is suitable for deep peak shaving and peak shaving of a thermal power generating unit.

[0005] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0006] An electrode steam boiler and a thermal-electric decoupling system for heat storage and steam supply, comprising: a combined heat and power unit system, an electrode steam boiler and a heat storage and steam supply system, and a power grid;

[0007] The combined heat and power unit system comprises a steam turbine, a generator and a step-up transformer, the steam turbine is connected with the generator for driving the generator to generate electricity, the generator is connected with the step-up transformer, and the combined heat and power unit system supplies steam to the outside through a first external steam supply pipeline;

[0008] The electrode steam boiler and heat storage steam supply system comprises an electrode steam boiler, a high-pressure steam cylinder, a spherical heat storage tank, a medium-pressure steam cylinder, a steam heater, a desalted water supply tank, an oxygen remover supply pump, a heat storage tank supply pump, an electrode boiler oxygen remover, an electrode boiler water supply pump and a step-down transformer, a steam outlet of the electrode steam boiler is connected with a first steam inlet of the high-pressure steam cylinder, a second steam outlet of the high-pressure steam cylinder is connected with a second steam inlet of the medium-pressure steam cylinder, a third steam outlet of the high-pressure steam cylinder is connected with a first steam inlet of the spherical heat storage tank, a second steam outlet of the spherical heat storage tank is connected with a first steam inlet of the medium-pressure steam cylinder, a third steam outlet of the medium-pressure steam cylinder is connected with a steam inlet of the steam heater, a steam outlet of the steam heater is connected with an external steam supply through a second external steam supply pipeline, a fourth steam outlet of the medium-pressure steam cylinder is connected with a second steam inlet of the electrode boiler oxygen remover, a third water supply outlet of the electrode boiler oxygen remover is connected with a water supply inlet of the electrode boiler water supply pump, a water supply outlet of the electrode boiler water supply pump is connected with a water supply inlet of the electrode steam boiler, a first water supply inlet of the electrode boiler oxygen remover is connected with a water supply outlet of the oxygen remover supply pump, a water supply inlet of the oxygen remover supply pump is connected with a second water supply outlet of the desalted water supply tank, a first water supply inlet of the desalted water supply tank is connected with a chemical desalted water system, a third water supply outlet of the desalted water supply tank is connected with a water supply inlet of the heat storage tank supply pump, and a water supply outlet of the heat storage tank supply pump is connected with a third water supply inlet of the spherical heat storage tank.

[0009] The power grid is connected with the step-up transformer, and the power grid is further connected with the electrode steam boiler through the step-down transformer.

[0010] Preferably, the steam turbine comprises a steam turbine high-pressure cylinder, a steam turbine medium-pressure cylinder and a steam turbine low-pressure cylinder, and the steam turbine high-pressure cylinder, the steam turbine medium-pressure cylinder, the steam turbine low-pressure cylinder and the generator are sequentially connected in the steam flow direction.

[0011] The cogeneration unit system further comprises a boiler, a condenser, a condensate pump, a low-pressure heater, an oxygen remover, a water supply pump and a high-pressure heater, a main steam outlet of the boiler is connected with a steam inlet of the steam turbine high-pressure cylinder, an exhaust port of the steam turbine high-pressure cylinder is connected with a reheat steam inlet of the boiler, a reheat steam outlet of the boiler is connected with a steam inlet of the steam turbine medium-pressure cylinder, an exhaust port of the steam turbine medium-pressure cylinder is connected with a steam inlet of the steam turbine low-pressure cylinder, and an exhaust port of the steam turbine low-pressure cylinder is sequentially connected with a water inlet of the boiler through the condenser, the condensate pump, the low-pressure heater, the oxygen remover, the water supply pump and the high-pressure heater.

[0012] Further preferably, the low-pressure heaters are composed of a plurality of low-pressure heaters with different heating steam pressures connected in series, in the flow direction of the water vapor, the heating steam pressures of the low-pressure heaters are arranged from high to low, in the flow direction of the condensed water, the heating steam pressures of the low-pressure heaters are arranged from low to high, the water vapor of each low-pressure heater flows to the condenser by gravity in turn from high to low in the heating steam pressure, the heating steam of each low-pressure heater corresponds to the extraction port in the steam turbine matching the heating steam pressure of the low-pressure heater;

[0013] the heating steam of the deaerator corresponds to the extraction port in the steam turbine matching the heating steam pressure of the deaerator;

[0014] the high-pressure heaters are composed of a plurality of high-pressure heaters with different heating steam pressures connected in series, in the flow direction of the water vapor, the heating steam pressures of the high-pressure heaters are arranged from high to low, in the flow direction of the feed water, the heating steam pressures of the high-pressure heaters are arranged from low to high, the water vapor of each high-pressure heater flows to the deaerator by gravity in turn from high to low in the heating steam pressure, the heating steam of each high-pressure heater corresponds to the extraction port in the steam turbine matching the heating steam pressure of the high-pressure heater.

[0015] Further preferably, the first pressure adjusting valve is arranged on the connecting pipeline between the second steam outlet of the high-pressure cylinder and the second steam inlet of the medium-pressure cylinder;

[0016] the expansion flash valve is arranged on the connecting pipeline between the second steam outlet of the spherical regenerative tank and the first steam inlet of the medium-pressure cylinder;

[0017] the second pressure adjusting valve is arranged on the connecting pipeline between the fourth steam outlet of the medium-pressure cylinder and the second steam inlet of the electrode boiler deaerator.

[0018] Further preferably, the electrode steam boiler comprises a plurality of parallel electrode steam boilers, and the feed water inlet pipeline and the steam outlet pipeline connected with the feed water inlet and the steam outlet of each electrode steam boiler are respectively arranged in parallel according to the pipeline medium properties.

[0019] Further preferably, the spherical regenerative tank comprises a plurality of parallel spherical regenerative tanks, and the steam inlet pipeline, the steam outlet pipeline and the make-up water inlet pipeline connected with the first steam inlet, the second steam outlet and the third make-up water inlet of each spherical regenerative tank are respectively arranged in parallel according to the pipeline medium properties.

[0020] Further preferably, the electrode steam boiler comprises a high-voltage electrode, a boiler outer cylinder, a boiler inner cylinder, a first steam-water separation device and an inner circulation pipeline, wherein the high-voltage electrode is connected with the step-down transformer and is inserted into the boiler inner cylinder through the boiler outer cylinder, the boiler inner cylinder is arranged in the boiler outer cylinder, the boiler outer cylinder is connected to the boiler inner cylinder through the inner circulation pipeline, the inner circulation pipeline is provided with a boiler inner circulation pump, the boiler outer cylinder is respectively provided with a water inlet and a steam outlet, and the steam outlet is arranged at the top of the boiler outer cylinder and is internally provided with the first steam-water separation device.

[0021] Further preferably, the spherical heat storage tank internally comprises a steam ejector and a second steam-water separation device, the steam ejector is connected with the first steam inlet of the spherical heat storage tank, and the second steam-water separation device is arranged at the input end of the second steam outlet of the spherical heat storage tank.

[0022] Further preferably, the steam heater adopts an electric heating, molten salt heating or solid heating mode.

[0023] Further preferably, the first pair of external steam supply pipelines are provided with first steam supply regulating valves, and the second pair of external steam supply pipelines are provided with second steam supply regulating valves.

[0024] The beneficial effects of the present application are as follows:

[0025] 1. The spherical heat storage tank technology is adopted, stress is uniformly distributed, the surface area is smallest, the material consumption is least, and the heat loss is smallest compared with a non-spherical container with the same capacity; the electrode steam boiler and the spherical heat storage tank are jointly arranged, the steam produced by the electrode steam boiler can be directly delivered to a steam user or can be delivered to the spherical heat storage tank to be stored in the form of high-parameter saturated water or saturated steam; the electrode steam boiler and the heat storage steam supply system can guarantee the stability of the steam parameters on the user side through the buffering and balancing effect of the spherical heat storage tank.

[0026] 2. Whether in the heating period or in the non-heating period, the electrode steam boiler and the heat storage steam supply thermoelectric decoupling system provided by the present application can be put into operation to provide steam for heating steam, industrial steam or other process steam.

[0027] 3. The electrode steam boiler has a rapid response speed and can realize deep peak shaving of a combined heat and power unit in a short time, and can provide instant steam heat energy while storing heat; the spherical heat storage tank has a rapid response speed in releasing heat to provide steam heat energy, can realize peak demand of the unit in a short time, has a rapid response speed, high reliability and low cost.

[0028] 4. The heat and electricity decoupling system can meet the demand of providing steam heat energy and electric energy, improve the operation flexibility of the cogeneration unit and the accommodation capacity of the power grid to new energy, and the electrode steam boiler has high flexibility in peak regulation, can accurately regulate the power according to the demand, realize flexible load balance and adapt to the change of actual demand.

[0029] 5. When the power grid requires deep peak regulation of the cogeneration unit, the unit itself operates at not less than the minimum technical output, the electrode steam boiler is put into operation to generate steam, the unit output is reduced or even zero; when the power grid requires peak shaving of the cogeneration unit, the spherical heat storage tank is put into operation to release heat and supply steam, the steam extraction of the cogeneration unit is reduced or even stopped, and the unit output is increased; the heat and electricity decoupling system can meet the demand of providing steam and power supply in heating period and non-heating period, and can improve the operation flexibility, deep peak regulation capacity and peak shaving capacity of the cogeneration unit under the premise of providing steam heat load. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings needed in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art according to these drawings.

[0031] Figure 1 is a structural schematic diagram of the electrode steam boiler and the heat and electricity decoupling system provided by the present application;

[0032] Figure 2 is a characteristic diagram of the cogeneration unit before and after the electrode steam boiler is configured in the embodiment, wherein the curve ABCD is the characteristic curve of the cogeneration unit before the electrode steam boiler is configured, the curve ABB'C'D'D is the characteristic curve of the cogeneration unit after the electrode steam boiler is configured, Pe,min and Pe,max are the minimum and maximum power generation of the cogeneration unit in the pure condensing condition, Ph,max and Ph',max are the maximum heat supply power of the cogeneration unit before and after the electrode steam boiler is configured, and Pe,h and Pe',h are the power generation corresponding to the maximum heat supply power of the cogeneration unit before and after the electrode steam boiler is configured.

[0033] Reference signs:

[0034] 1-Combined heat and power unit system; 1.1-Boiler; 1.2-High pressure cylinder of steam turbine; 1.3-Middle pressure cylinder of steam turbine; 1.4-Low pressure cylinder of steam turbine; 1.5-Generator; 1.6-Condenser; 1.7-Condensate pump; 1.8-Low pressure heater; 1.9-Deaerator; 1.10-Feed water pump; 1.11-High pressure heater; 1.12-Boost transformer; 1.13-First steam supply regulating valve; 2-Electrode steam boiler and heat storage steam supply system; 2.1-Electrode steam boiler; 2.2-High pressure cylinder; 2.3-Spherical heat storage tank; 2.4-Middle pressure cylinder; 2.5-Steam heater; 2.6-Desalted water supply tank; 2.7-Deaerator water supply pump; 2.8-Heat storage tank water supply pump; 2.9-Electrode boiler deaerator; 2.10-Electrode boiler feed water pump; 2.11-Step-down transformer; 2.12-First pressure regulating valve; 2.13-Expansion flash valve; 2.14-Second pressure regulating valve; 2.15-Second steam supply regulating valve; 3-Power grid. DETAILED DESCRIPTION

[0035] In order to make the technical personnel in the art better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings.

[0036] Unless otherwise explicitly specified and limited, the terms "first", "second", "third" or "fourth" in the present application are only used for description purposes, and cannot be understood as indicating or implying relative importance; the term "connected" should be understood in a broad sense, for example: it can be fixed connection, detachable connection or integral connection, it can be mechanical connection, electrical connection or direct connection, it can also be indirectly connected through intermediate medium, or it can be the communication inside two elements.

[0037] As shown in Figure 1 The present application is an electrode steam boiler and heat storage steam supply heat and electricity decoupling system, which comprises a combined heat and power unit system 1, an electrode steam boiler and heat storage steam supply system 2 and a power grid 3.

[0038] The combined heat and power unit system 1 comprises a steam turbine, a generator 1.5 and a boost transformer 1.12, the steam turbine is connected with the generator 1.5, used for driving the generator 1.5 to generate electricity, the generator 1.5 is connected with the boost transformer 1.12, and the combined heat and power unit system 1 supplies steam to the outside through a first external steam supply pipeline;

[0039] The electrode steam boiler and heat storage steam supply system 2 comprises an electrode steam boiler 2.1, a high-pressure steam cylinder 2.2, a spherical heat storage tank 2.3, a medium-pressure steam cylinder 2.4, a steam heater 2.5, a desalted water supply tank 2.6, an oxygen remover water supply pump 2.7, a heat storage tank water supply pump 2.8, an electrode boiler oxygen remover 2.9, an electrode boiler water supply pump 2.10, and a step-down transformer 2.11, wherein a steam outlet of the electrode steam boiler 2.1 is connected to a first steam inlet of the high-pressure steam cylinder 2.2 through a pipeline; a second steam outlet of the high-pressure steam cylinder 2.2 is connected to a second steam inlet of the medium-pressure steam cylinder 2.4 through a pipeline; a third steam outlet of the high-pressure steam cylinder 2.2 is connected to a first steam inlet of the spherical heat storage tank 2.3 through a pipeline; a second steam outlet of the spherical heat storage tank 2.3 is connected to a first steam inlet of the medium-pressure steam cylinder 2.4 through a pipeline; a third steam outlet of the medium-pressure steam cylinder 2.4 is connected to a steam inlet of the steam heater 2.5 through a pipeline; a steam outlet of the steam heater 2.5 is connected to an external steam supply through a second pair of external steam supply pipelines; a fourth steam outlet of the medium-pressure steam cylinder 2.4 is connected to a second steam inlet of the electrode boiler oxygen remover 2.9 through a pipeline; a third water supply outlet of the electrode boiler oxygen remover 2.9 is connected to a water supply inlet of the electrode boiler water supply pump 2.10 through a pipeline; a water supply outlet of the electrode boiler water supply pump 2.10 is connected to a water supply inlet of the electrode steam boiler 2.1 through a pipeline; a first water supply inlet of the electrode boiler oxygen remover 2.9 is connected to a water supply outlet of the oxygen remover water supply pump 2.7 through a pipeline; a water supply inlet of the oxygen remover water supply pump 2.7 is connected to a second water supply outlet of the desalted water supply tank 2.6 through a pipeline; a first water supply inlet of the desalted water supply tank 2.6 is connected to a chemical desalted water system through a pipeline; a third water supply outlet of the desalted water supply tank 2.6 is connected to a water supply inlet of the heat storage tank water supply pump 2.8 through a pipeline; and a water supply outlet of the heat storage tank water supply pump 2.8 is connected to a third water supply inlet of the spherical heat storage tank 2.3 through a pipeline.

[0040] The power grid 3 is connected to the step-up transformer 1.12, and is further connected to the electrode steam boiler 2.1 through the step-down transformer 2.11.

[0041] As an improvement of the technical solution, the steam turbine comprises a steam turbine high-pressure cylinder 1.2, a steam turbine medium-pressure cylinder 1.3, and a steam turbine low-pressure cylinder 1.4, which are sequentially connected in the steam flow direction.

[0042] The cogeneration unit system 1 further comprises a boiler 1.1, a condenser 1.6, a condensate pump 1.7, a low-pressure heater 1.8, a deaerator 1.9, a feedwater pump 1.10, and a high-pressure heater 1.11, wherein a main steam outlet of the boiler 1.1 is connected to a steam inlet of the high-pressure cylinder 1.2 of the steam turbine through a pipeline; a steam exhaust outlet of the high-pressure cylinder 1.2 of the steam turbine is connected to a reheat steam inlet of the boiler 1.1 through a pipeline; a reheat steam outlet of the boiler 1.1 is connected to a steam inlet of the intermediate-pressure cylinder 1.3 of the steam turbine through a pipeline; a steam exhaust outlet of the intermediate-pressure cylinder 1.3 of the steam turbine is connected to a steam inlet of the low-pressure cylinder 1.4 of the steam turbine through a pipeline; a steam exhaust outlet of the low-pressure cylinder 1.4 of the steam turbine is connected to a steam inlet of the condenser 1.6 through a pipeline; a condensate outlet of the condenser 1.6 is connected to a condensate inlet of the condensate pump 1.7 through a pipeline; a condensate outlet of the condensate pump 1.7 is connected to a condensate inlet of the low-pressure heater 1.8 through a pipeline; a condensate outlet of the low-pressure heater 1.8 is connected to a condensate inlet of the deaerator 1.9 through a pipeline; a feedwater outlet of the deaerator 1.9 is connected to a feedwater inlet of the feedwater pump 1.10 through a pipeline; a feedwater outlet of the feedwater pump 1.10 is connected to a feedwater inlet of the high-pressure heater 1.11 through a pipeline; and a feedwater outlet of the high-pressure heater 1.11 is connected to a feedwater inlet of the boiler 1.1 through a pipeline.

[0043] According to the steam parameter requirements, the steam extraction port for external steam supply of the cogeneration unit system is arranged on the high-pressure cylinder 1.2 or the intermediate-pressure cylinder 1.3 of the steam turbine.

[0044] As an improvement of the technical solution, the low-pressure heater 1.8 is composed of a plurality of low-pressure heaters with different heating steam pressures connected in series, wherein the heating steam pressure of each low-pressure heater is arranged from high to low in the flow direction of the drain, and the heating steam pressure of each low-pressure heater is arranged from low to high in the flow direction of the condensate, the drain of each low-pressure heater is caused to flow to the condenser 1.6 by gravity in a step-by-step manner from high to low in the heating steam pressure, and the heating steam of each low-pressure heater corresponds to the steam extraction port from the steam turbine matched with the heating steam pressure of the low-pressure heater.

[0045] The heating steam of the deaerator 1.9 corresponds to the steam extraction port from the steam turbine matched with the heating steam pressure of the deaerator 1.9.

[0046] The high-pressure heater 1.11 is composed of a plurality of high-pressure heaters with different heating steam pressures in series, in the flow direction of the water vapor, the heating steam pressure of each high-pressure heater is from high to low, in the flow direction of the feed water, the heating steam pressure of each high-pressure heater is from low to high, the water vapor of each high-pressure heater is self-flowing to the deaerator 1.9 in the order of the heating steam pressure from high to low, and the heating steam of each high-pressure heater corresponds to the extraction steam from the steam turbine at the extraction port matched with the heating steam pressure of each high-pressure heater.

[0047] As an improvement of the technical solution, a first pressure adjusting valve 2.12 is arranged on the connecting pipeline from the second steam outlet of the high-pressure cylinder 2.2 to the second steam inlet of the medium-pressure cylinder 2.4.

[0048] The second steam outlet of the spherical heat storage tank 2.3 is connected to the first steam inlet of the medium-pressure cylinder 2.4 through a connecting pipeline, and an expansion flash valve 2.13 is arranged on the connecting pipeline.

[0049] The fourth steam outlet of the medium-pressure cylinder 2.4 is connected to the second steam inlet of the electrode boiler deaerator 2.9 through a connecting pipeline, and a second pressure adjusting valve 2.14 is arranged on the connecting pipeline.

[0050] The first pressure adjusting valve 2.12 and the expansion flash valve 2.13 cooperate with each other to adjust the ratio of the external steam supply and the heat storage steam of the electrode steam boiler and the heat storage steam supply system.

[0051] As an improvement of the technical solution, the electrode steam boiler 2.1 includes a plurality of parallel electrode steam boilers, and the feed water inlet pipeline and the steam outlet pipeline connected to the feed water inlet and the steam outlet of each electrode steam boiler are respectively arranged in parallel according to the pipeline medium properties.

[0052] As an improvement of the technical solution, the spherical heat storage tank 2.3 includes a plurality of parallel spherical heat storage tanks, and the steam inlet pipeline, the steam outlet pipeline, and the water inlet pipeline connected to the first steam inlet, the second steam outlet, and the third water inlet of each spherical heat storage tank are respectively arranged in parallel according to the pipeline medium properties. Preferably, the expansion flash valve 2.13 is arranged on the total pipeline after the convergence of each steam outlet pipeline. By using the spherical heat storage tank technology, the stress distribution is uniform, the surface area is smallest, the material consumption is least, and the heat loss is smallest compared with the same capacity non-spherical container. The electrode steam boiler 2.1 and the spherical heat storage tank 2.3 are jointly arranged, the steam produced by the electrode steam boiler 2.1 can be directly delivered to the steam user or stored in the spherical heat storage tank 2.3 in the form of high-parameter saturated water or saturated steam. The electrode steam boiler and the heat storage steam supply system 2 can ensure the stability of the steam parameters on the user side through the buffering and balancing effect of the spherical heat storage tank.

[0053] As the improvement of the technical scheme, the electrode steam boiler 2.1 mainly comprises a high-voltage electrode, a boiler outer cylinder, a boiler inner cylinder, a first steam-water separation device, an internal circulation pipeline, a dosing system and a blowdown system, wherein the step-down transformer 2.11 is connected with the high-voltage electrode, the high-voltage electrode is inserted into the boiler inner cylinder through the boiler outer cylinder, the boiler inner cylinder is arranged in the boiler outer cylinder, and the boiler outer cylinder is connected to the boiler inner cylinder through the internal circulation pipeline, the internal circulation pipeline is provided with a boiler internal circulation pump, the boiler outer cylinder is respectively provided with a feed water inlet and a steam outlet, the steam outlet is arranged at the top of the boiler outer cylinder and internally arranged with the first steam-water separation device, the first steam-water separation device can improve the dryness, quality of the steam at the outlet of the boiler and maintain the stable operation of the boiler, the dosing system arranged in the boiler can adjust the electrical conductivity of the boiler water within a certain reasonable range, the blowdown system arranged in the boiler can reduce the salt content and alkalinity of the boiler water, maintain appropriate water quality indicators, reduce the corrosion and scaling on the metal surface of the boiler, thereby ensuring the heat transfer efficiency and normal operation of the boiler.

[0054] As the improvement of the technical scheme, the spherical heat storage tank 2.3 mainly comprises a steam ejector and a second steam-water separation device, the steam ejector is connected with the first steam inlet of the spherical heat storage tank 2.3, steam with high pressure and energy is introduced, through the jetting action, the energy can be transmitted to the working medium in the spherical heat storage tank 2.3 more quickly and uniformly, so as to realize the transfer and storage of steam energy; the second steam-water separation device is arranged at the second steam outlet input end of the spherical heat storage tank 2.3, can effectively separate the water droplets carried in the steam, ensure that the steam output from the second steam outlet of the spherical heat storage tank 2.3 has high dryness and purity, meet the requirements of the subsequent use equipment on the quality of the steam.

[0055] As the improvement of the technical scheme, the steam heater 2.5 can adopt electric heating, molten salt heating or solid heating and the like, the heat of the molten salt heating or the solid heating can also come from the peak shaving electricity of the combined heat and power unit during the deep peak shaving period, when the steam is supplied to the outside for heating the heat network heater to provide heating heat load, the steam heater 2.5 can not be put into operation.

[0056] As the improvement of the technical scheme, the first external steam supply pipeline is provided with a first steam supply regulating valve 1.13, the second external steam supply pipeline is provided with a second steam supply regulating valve 2.15, the first steam supply regulating valve 1.13 and the second steam supply regulating valve 2.15 can cooperate with each other to adjust the proportion of the external steam supply amount of the combined heat and power unit system and the external steam supply amount of the electrode steam boiler and the heat storage steam supply system, preferably, the first external steam supply pipeline and the second external steam supply pipeline are merged into a total pipeline and then supply steam to the outside.

[0057] The operation mode of the electrode steam boiler and the heat storage steam supply combined heat and power decoupling system provided by the application is as follows:

[0058] When the power grid requires the combined heat and power unit to operate in deep peak shaving, the electrode steam boiler 2.1 and its supporting system are put into operation to generate steam, and the steam generated by the electrode steam boiler 2.1 is sent to two places through the high-pressure steam distribution cylinder 2.2, one of which is sent to the medium-pressure steam distribution cylinder 2.4 through the first pressure adjusting valve 2.12 to supply steam to the outside, and the other of which is sent to the spherical heat storage tank 2.3 to store steam and heat in the heat storage tank; when the power grid requires the combined heat and power unit to operate in non-peak shaving, the electrode steam boiler 2.1 and its supporting system are stopped; when the power grid requires the combined heat and power unit to operate in peak shaving (especially in top peak shaving), the spherical heat storage tank 2.3 and its supporting system are put into operation, and the high-parameter saturated liquid in the spherical heat storage tank 2.3 is released through the expansion flash valve 2.13 to supply steam to the medium-pressure steam distribution cylinder 2.4 and then to the outside; when the power grid requires the combined heat and power unit to operate in non-peak shaving and non-peak shaving, whether the spherical heat storage tank 2.3 and its supporting system are put into operation needs to be determined according to the deep peak shaving time of the unit each time, the capacity of the electrode steam boiler, the heat storage capacity of the spherical heat storage tank, the real-time on-grid electricity price, the steam heat price and other factors.

[0059] The combined heat and power unit system 1 and the electrode steam boiler and heat storage steam supply system 2 can realize various steam supply operation modes: the combined heat and power unit system 1 alone supplies steam, the electrode steam boiler and heat storage steam supply system 2 alone supplies steam, and the combined heat and power unit system 1 and the electrode steam boiler and heat storage steam supply system 2 jointly supply steam.

[0060] The electrode steam boiler and heat storage steam supply system 2 can realize various steam supply operation modes: the electrode steam boiler 2.1 alone supplies steam, the spherical heat storage tank 2.3 alone supplies steam, and the electrode steam boiler 2.1 and the spherical heat storage tank 2.3 jointly supply steam.

[0061] The deep peak shaving capacity of the electrode steam boiler and heat storage steam supply system 2 is:

[0062] The power generated by the generator 1.5 of the combined heat and power unit system 1 is input into the power grid 3 through the step-up transformer 1.12, and the electric energy of the power grid 3 is input into the electrode steam boiler 2.1 through the step-down transformer 2.11 to convert the electric energy into steam heat energy, and the combined heat and power unit has a maximum deep peak shaving capacity C P :

[0063] C P =C EB +k BC η EB C EB ;

[0064] wherein, C EB is the capacity of the electrode steam boiler 2.1, η EB is the electric-to-heat efficiency of the electrode steam boiler 2.1, and k BCThe slope of the maximum extraction point connecting curve corresponding to each steam admission condition of the combined heat and power unit on the characteristic diagram of the combined heat and power unit is shown in the following formula. Figure 2

[0065] The peak capacity of the present application is:

[0066] During the peak period of the unit, the spherical heat storage tank 2.3 releases heat to supply steam, the combined heat and power unit reduces extraction or even does not extract steam, and the unit increases the power output to the grid. When the grid requires the maximum output of the combined heat and power unit, the additional peak capacity of the combined heat and power unit is C T :

[0067] C T =k AB P HB ;

[0068] Wherein, P HB is the heat supply load of the spherical heat storage tank 2.3 releasing heat to supply steam, the corresponding heat supply load of the combined heat and power unit reducing extraction is also P HB , k AB is the slope of the heat and power curve at the maximum steam admission condition of the combined heat and power unit (taking a positive value), as shown in the following formula. Figure 2

[0069] Taking a 300MW subcritical once-through intermediate reheated wet extraction condensing steam turbine generator unit as an example, when the unit is at the maximum steam admission condition, the heating extraction amount of the unit is adjusted in the range of 0-560t / h, the heat supply load of the unit is adjusted in the range of 0-367MW, the power output of the unit is adjusted in the range of 242-335MW, the slope of the maximum extraction point connecting curve corresponding to each steam admission condition of the unit k BC =0.66, the slope of the heat and power curve at the maximum steam admission condition of the unit (taking a positive value) k AB =0.25, the capacity of the electrode steam boiler 2.1 C EB =80MW, and the electric-to-thermal efficiency of the electrode steam boiler 2.1 η EB =99%.

[0070] When the unit is deeply peak-regulating, compared with not operating the electrode steam boiler 2.1, operating the electrode steam boiler 2.1 at the load rate of 100% increases the maximum deep peak-regulating capacity of the combined heat and power unit C P :

[0071] C P =C EB +k BC η EB C EB =80+0.66×0.99×80=132.3MW;

[0072] That is, 44% Pe (Pe represents the rated power generation of the unit).

[0073] ​​At the peak of the unit, the spherical heat storage tank 2.3 releases heat to supply steam load P HQ Assume 160MW, the maximum output period of the combined heat and power unit adds the peak capacity C T :

[0074] C T = k AB P HB = 0.25*160=40MW;

[0075] That is 13.3% Pe (Pe represents the rated power of the unit).

[0076] This example shows that the electrode steam boiler and heat storage steam supply heat and electricity decoupling system with electrode steam boiler and spherical heat storage tank can realize heat and electricity decoupling; can improve the deep peak shaving capacity of the combined heat and power unit to promote new energy consumption; can improve the peak capacity of the combined heat and power unit to avoid power shortage of the power grid and ensure stable operation of the power grid.

[0077] The existing heat and electricity decoupling technology of the combined heat and power unit using electrode boiler and hot water heat storage tank can only be put into operation to provide heating heat load during the heating period, and cannot be put into operation during the non-heating period. The electrode steam boiler and heat storage steam supply heat and electricity decoupling system of the present application is different, and can be put into operation to provide steam for heating steam, industrial steam or other process steam whether during the heating period or the non-heating period.

[0078] The existing heat and electricity decoupling technology of the combined heat and power unit using molten salt heat storage can not be limited by the nature, use and heating season of steam, but the response speed is general, the reliability is general, and the cost is high. The electrode steam boiler and heat storage steam supply heat and electricity decoupling system of the present application has rapid response speed of the electrode steam boiler, can realize deep peak shaving of the combined heat and power unit in a short time, and can provide instant steam heat energy while storing heat; the spherical heat storage tank has rapid response speed of releasing heat to provide steam heat energy, and can meet the peak demand of the unit in a short time; the electrode steam boiler and heat storage steam supply heat and electricity decoupling system of the present application has fast response speed, high reliability and low cost.

[0079] The electrode steam boiler and heat storage steam supply heat and electricity decoupling system of the present application can realize heat and electricity decoupling of the combined heat and power unit, meet the demand of providing steam heat energy and electric energy to the outside, improve the operation flexibility of the combined heat and power unit and the consumption capacity of the power grid to new energy. In addition, the system has high flexibility in peak shaving with the electrode steam boiler, can accurately adjust the power according to the demand, realizes flexible load balance, and adapts to the change of actual demand.

[0080] The electrode steam boiler and the heat-electricity decoupling system of heat storage steam supply of the application can realize heat-electricity decoupling and provide steam and power supply demand simultaneously, and can improve the operation flexibility, deep peak regulation capacity and peak capacity of the heat and power unit under the premise of guaranteeing steam heat load.

[0081] The above has described certain exemplary embodiments of the application by way of illustration only, and it is needless to say that the described embodiments can be modified in various ways without departing from the spirit and scope of the application for those skilled in the art. Therefore, the above drawings and description are illustrative in nature and should not be understood as limiting the scope of protection of the claims of the application.

Claims

1. An electrode steam boiler and a thermal-electric decoupling system for heat storage and steam supply, characterized in that: include: Combined heat and power generation system (1), electrode steam boiler and thermal storage steam supply system (2) and power grid (3); The cogeneration unit system (1) comprises a steam turbine, a generator (1.5) and a step-up transformer (1.12); the steam turbine is connected to the generator (1.5) and is used to drive the generator (1.5) to generate electricity; the generator (1.5) is connected to the step-up transformer (1.12); the cogeneration unit system (1) supplies steam to the outside through a first external steam supply pipeline; The electrode steam boiler and heat storage steam supply system (2) comprises an electrode steam boiler (2.1), a high-pressure steam cylinder (2.2), a spherical heat storage tank (2.3), a medium-pressure steam cylinder (2.4), a steam heater (2.5), a desalted water supply tank (2.6), a deaerator water supply pump (2.7), a heat storage tank water supply pump (2.8), an electrode boiler deaerator (2.9), an electrode boiler feed water pump (2.10) and a step-down transformer (2.11). The steam outlet of the electrode steam boiler (2.1) is connected to the high-pressure steam cylinder (2.2). The first steam inlet of the steam cylinder (2.2), the second steam outlet of the high-pressure sub-cylinder (2.2) is connected to the second steam inlet of the medium-pressure sub-cylinder (2.4), the third steam outlet of the high-pressure sub-cylinder (2.2) is connected to the first steam inlet of the spherical heat storage tank (2.3), the second steam outlet of the spherical heat storage tank (2.3) is connected to the first steam inlet of the medium-pressure sub-cylinder (2.4), and the third steam outlet of the medium-pressure sub-cylinder (2.4) is connected to the steam inlet of the steam heater (2.5). The steam outlet of the steam heater (2.5) supplies steam to the outside through the second external steam supply pipe. The fourth steam outlet of the medium-pressure steam cylinder (2.4) is connected to the second steam inlet of the electrode boiler deaerator (2.9). The third feed water outlet of the electrode boiler deaerator (2.9) is connected to the feed water inlet of the electrode boiler feed water pump (2.10). The feed water outlet of the electrode boiler feed water pump (2.10) is connected to the feed water inlet of the electrode steam boiler (2.1). The first feed water outlet of the electrode boiler deaerator (2.9) is connected to the feed water inlet of the electrode boiler deaerator (2.9). The water supply inlet is connected to the water supply outlet of the deaerator water supply pump (2.7), the water supply inlet of the deaerator water supply pump (2.7) is connected to the second water supply outlet of the desalted water supply tank (2.6), the first water supply inlet of the desalted water supply tank (2.6) is connected to the chemical desalted water system, the third water supply outlet of the desalted water supply tank (2.6) is connected to the water supply inlet of the heat storage tank water supply pump (2.8), and the water supply outlet of the heat storage tank water supply pump (2.8) is connected to the third water supply inlet of the spherical heat storage tank (2.3); The power grid (3) is connected to the step-up transformer (1.12), and the power grid (3) is also connected to the electrode steam boiler (2.1) via the step-down transformer (2.11).

2. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1 are characterized in that: The steam turbine comprises a steam turbine high-pressure cylinder (1.2), a steam turbine intermediate-pressure cylinder (1.3) and a steam turbine low-pressure cylinder (1.4); the steam turbine high-pressure cylinder (1.2), the steam turbine intermediate-pressure cylinder (1.3), the steam turbine low-pressure cylinder (1.4) and the generator (1.5) are connected in sequence according to the direction of steam flow; The cogeneration unit system (1) further comprises a boiler (1.1), a condenser (1.6), a condensate pump (1.7), a low-pressure heater (1.8), a deaerator (1.9), a feedwater pump (1.10) and a high-pressure heater (1.11); the main steam outlet of the boiler (1.1) is connected to the steam inlet of the high-pressure cylinder (1.2) of the steam turbine; the exhaust port of the high-pressure cylinder (1.2) of the steam turbine is connected to the reheat steam inlet of the boiler (1.1); the reheat steam of the boiler (1.1) is connected to the reheat steam inlet of the steam turbine (1.2); The outlet is connected to the steam inlet of the intermediate-pressure cylinder (1.3) of the steam turbine, the exhaust port of the intermediate-pressure cylinder (1.3) of the steam turbine is connected to the steam inlet of the low-pressure cylinder (1.4) of the steam turbine, and the exhaust port of the low-pressure cylinder (1.4) of the steam turbine is connected to the feed water inlet of the boiler (1.1) through the condenser (1.6), the condensate pump (1.7), the low-pressure heater (1.8), the deaerator (1.9), the feed water pump (1.10) and the high-pressure heater (1.11) in sequence.

3. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 2 are characterized in that: The low-pressure heater (1.8) is composed of a plurality of low-pressure heaters with different heating steam pressures connected in series. In the direction of drain flow, the heating steam pressure of each low-pressure heater is from high to low, and in the direction of condensate flow, the heating steam pressure of each low-pressure heater is from low to high. The drain of each low-pressure heater flows step by step from high to low according to its heating steam pressure to the condenser (1.6). The heating steam of each low-pressure heater corresponds to the extraction port in the steam turbine that matches the heating steam pressure of each low-pressure heater. The heating steam of the deaerator (1.9) corresponds to a steam extraction port in the steam turbine whose pressure matches the heating steam of the deaerator (1.9); The high-pressure heater (1.11) is composed of a plurality of high-pressure heaters with different heating steam pressures connected in series. In the direction of drain flow, the heating steam pressure of each high-pressure heater is from high to low, and in the direction of feed water flow, the heating steam pressure of each high-pressure heater is from low to high. The drain of each high-pressure heater flows step by step from high to low according to its heating steam pressure to the deaerator (1.9). The heating steam of each high-pressure heater corresponds to the extraction port in the steam turbine that matches the heating steam pressure of each high-pressure heater.

4. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1 are characterized in that: A first pressure regulating valve (2.12) is provided on the connecting pipe from the second steam outlet of the high-pressure sub-cylinder (2.2) to the second steam inlet of the medium-pressure sub-cylinder (2.4); A capacity expansion flash valve (2.13) is provided on the connecting pipe from the second steam outlet of the spherical heat storage tank (2.3) to the first steam inlet of the medium-pressure steam cylinder (2.4); A second pressure regulating valve (2.14) is provided on the connecting pipe from the fourth steam outlet of the medium-pressure steam cylinder (2.4) to the second steam inlet of the electrode boiler deaerator (2.9).

5. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1 are characterized in that: The electrode steam boiler (2.1) comprises a plurality of electrode steam boilers connected in parallel, and the water inlet pipes and steam outlet pipes respectively connected to the water inlet and steam outlet of each electrode steam boiler are arranged in parallel according to the properties of the pipe medium.

6. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1 are characterized in that: The spherical heat storage tank (2.3) comprises a plurality of spherical heat storage tanks connected in parallel, and the steam inlet pipe, steam outlet pipe and water supply inlet pipe respectively connected to the first steam inlet, second steam outlet and third water supply inlet of each spherical heat storage tank are arranged in parallel according to the properties of the pipe medium.

7. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1 are characterized in that: The electrode steam boiler (2.1) includes a high-voltage electrode, a boiler outer tube, a boiler inner tube, a first steam-water separation device and an internal circulation pipeline, wherein the high-voltage electrode is connected to the step-down transformer (2.11) and inserted into the boiler inner tube through the boiler outer tube, the boiler inner tube is arranged inside the boiler outer tube, the boiler outer tube is connected to the boiler inner tube through an internal circulation pipeline, the internal circulation pipeline is equipped with a boiler internal circulation pump, and a water inlet and a steam outlet are respectively provided on the boiler outer tube, the steam outlet is arranged at the top of the boiler outer tube and has the first steam-water separation device built in.

8. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1 are characterized in that: The spherical heat storage tank (2.3) comprises a steam ejector and a second steam-water separation device, the steam ejector is connected to a first steam inlet of the spherical heat storage tank (2.3), and the second steam-water separation device is arranged at a second steam outlet input end of the spherical heat storage tank (2.3).

9. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1, characterized in that: The steam heater (2.5) adopts electric heating, molten salt heating or solid heating.

10. The electrode steam boiler and the thermal-electric decoupling system for heat storage and steam supply according to claim 1, characterized in that: The first external steam supply pipeline is equipped with a first steam supply regulating valve (1.13), and the second external steam supply pipeline is equipped with a second steam supply regulating valve (2.15).

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