Auxiliary variable load industrial steam supply system and control method

Abstract

The invention provides an auxiliary variable load industrial steam supply system and a control method, and belongs to the technical field of power generation and steam supply. Comprises: a boiler for generating main steam and heating cold resteam into hot resteam; the turboset is used for generating electricity by using the main steam and the hot resteam; the pressure regulating power generation module is used for regulating the pressure of the input main steam and generating power by using the main steam to form industrial steam supply steam; the fused salt heat storage and release module is used for heating the cold fused salt into hot lava by using the hot resteam and heating the industrial steam supply steam output by the first heat exchanger or the heater by using the hot lava; the first heat exchanger is used for heating the industrial steam supply steam output by the pressure regulating power generation module by utilizing the steam output by the fused salt heat storage and release module; the heater is used for heating the industrial steam supply steam output by the voltage regulation power generation module; and the heat user is used for utilizing the industrial steam supply steam. The structure is simple, and the flexibility and the energy utilization rate of the combined heat and power generation unit can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation and steam supply, and in particular to an auxiliary variable load industrial steam supply system, a control method for the auxiliary variable load industrial steam supply system, an electronic device and a readable storage medium. Background Art

[0002] At present, the following methods are usually used to supply high-temperature and high-pressure industrial steam: the first is to directly supply it with a small boiler; the second is to extract the main steam from a large thermal power generating unit to reduce the temperature and pressure for supply, thereby realizing cogeneration of heat and power; the third is to extract the first-stage extraction steam from a large thermal power generating unit, raise the temperature through a heat exchanger, and then supply it to the outside, thereby realizing cogeneration of heat and power.

[0003] Among them, the solution of extracting the first-stage steam and supplying it to the outside after heating it through a heat exchanger can solve the problems of low technical level, poor maintenance, low thermal efficiency and environmental protection level of coal-fired boilers, and high fuel cost of gas-fired boilers in direct supply of small boilers, and can solve the problems of reduced steam quality and energy waste in the supply of main steam with reduced temperature and pressure. However, the solution of extracting the first-stage steam and supplying it to the outside after heating it through a heat exchanger only considers meeting the needs of industrial steam supply parameters, and cannot assist the rapid load change of the cogeneration unit, which limits the scope of application of the unit. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide an industrial steam supply system and control method for auxiliary load variation, so as to solve the above-mentioned solution of extracting the first-stage steam, supplying it to the outside after heating it through a heat exchanger, which only considers meeting the requirements of industrial steam supply parameters and cannot assist the cogeneration unit in rapid load variation, thus limiting the scope of application of the unit.

[0005] In order to achieve the above object, an embodiment of the present invention provides an auxiliary variable load industrial steam supply system, the system comprising: A boiler is used to generate main steam and heat the cold resteam formed after the main steam passes through the steam turbine unit into hot resteam; a steam turbine unit connected to the boiler for generating electricity using main steam and hot resteam; A pressure regulating power generation module is connected to the main steam outlet of the boiler and is used to regulate the pressure of the input main steam and generate electricity to form industrial steam supply steam; The molten salt heat storage and release module is connected to the steam supply outlet of the first heat exchanger, the steam supply outlet of the first heater and the hot re-steam outlet of the boiler, and is used to heat the cold molten salt into hot lava using the hot re-steam, and to heat the industrial steam supply steam after primary heating output by the first heat exchanger or heater using the hot lava to form the industrial steam supply steam after secondary heating; The first heat exchanger is connected to the steam outlet of the molten salt heat storage and release module and the steam supply outlet of the pressure regulating power generation module, and is used to heat the industrial steam supply steam output by the pressure regulating power generation module using the hot re-steam output by the molten salt heat storage and release module to form the industrial steam supply steam after one heating; A heater connected to the steam supply outlet of the pressure regulating power generation module, used for heating the industrial steam supply steam output by the pressure regulating power generation module to form the industrial steam supply steam after primary heating; The heat user is connected to the steam supply outlet of the molten salt heat storage and release module to utilize the industrial steam supply after secondary heating.

[0006] Optionally, the voltage regulating power generation module includes: Pressure reducing valve, used to reduce or regulate the pressure of the input main steam; The back-pressure steam turbine is connected to the pressure reducing valve and is used to generate electricity using the decompressed main steam and form industrial steam supply steam.

[0007] Optionally, the heater is an electric heater, which is electrically connected to the back-pressure steam turbine and is used to heat the industrial steam supply steam output by the pressure regulating power generation module using the electric energy generated by the back-pressure steam turbine.

[0008] Optionally, the molten salt heat storage and release module includes: A second heat exchanger, a hot tank, a third heat exchanger and a cold tank forming a circulation pipeline are sequentially connected, a first valve is provided between the second heat exchanger and the cold tank, and a second valve is provided between the hot tank and the third heat exchanger; The steam inlet of the second heat exchanger is connected to the hot resteam outlet of the boiler, and the steam outlet of the second heat exchanger is connected to the steam inlet of the first heat exchanger, so as to heat the cold molten salt with the hot resteam to form hot molten salt; The steam supply inlet of the third heat exchanger is connected to the steam supply outlet of the first heat exchanger, and the steam supply outlet of the third heat exchanger is connected to a heat user, so as to utilize hot molten salt to heat industrial steam supply to form cold molten salt.

[0009] Cold tanks for storing cold molten salt; Hot tanks, used to store hot molten salt.

[0010] Optionally, the steam inlet of the second heat exchanger is provided with a third valve, and the third valve is used to control the steam flow rate of the hot resteam entering the second heat exchanger; The hot resteam inlet of the steam turbine unit is provided with a fourth valve, and the fourth valve is used to control the steam flow rate of the hot resteam entering the steam turbine unit.

[0011] In a second aspect, an embodiment of the present invention further provides a control method for an auxiliary variable load industrial steam supply system, which is applied to the above-mentioned auxiliary variable load industrial steam supply system, and the method includes: Obtaining the actual power generation load and target power generation load of the steam turbine unit; If the actual power generation load is less than the target power generation load, the theoretical openings of the second valve, the third valve and the fourth valve are calculated based on the load difference between the actual power generation load and the target power generation load, and the openings of the second valve, the third valve and the fourth valve are adjusted to the corresponding theoretical openings so that the actual power generation load is equal to the target power generation load; If the actual power generation load is greater than the target power generation load, the theoretical openings of the first valve, the third valve and the fourth valve are calculated based on the load difference between the actual power generation load and the target power generation load, and the openings of the first valve, the third valve and the fourth valve are adjusted to the corresponding theoretical openings so that the actual power generation load is equal to the target power generation load.

[0012] Optionally, based on the load difference between the actual power generation load and the target power generation load, the theoretical openings of the second valve, the third valve, and the fourth valve are calculated, including: The theoretical openings of the second valve, the third valve, and the fourth valve are calculated using the following formula: ; in, is the theoretical opening of the second valve; is the theoretical opening of the third valve; is the theoretical opening of the fourth valve; is the current opening of the second valve; is the current opening of the third valve; is the current opening of the fourth valve; is the specific heat capacity of hot resteam; is the specific heat capacity of the lava; It is the load difference between the actual power generation load and the target power generation load; and is the correction factor; and is the fitting coefficient.

[0013] Optionally, based on the load difference between the actual power generation load and the target power generation load, the theoretical openings of the first valve, the third valve, and the fourth valve are calculated, including: The theoretical openings of the first valve, the third valve, and the fourth valve are calculated using the following formula: ; in, is the theoretical opening of the first valve; is the theoretical opening of the third valve; is the theoretical opening of the fourth valve; is the current opening of the first valve; is the current opening of the third valve; is the current opening of the fourth valve; is the specific heat capacity of hot resteam; is the specific heat capacity of the lava; It is the load difference between the actual power generation load and the target power generation load; and is the correction factor; and is the fitting coefficient.

[0014] In a third aspect, an embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned control method for the auxiliary variable load industrial steam supply system when executing the computer program.

[0015] In a fourth aspect, an embodiment of the present invention further provides a readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the above-mentioned control method for an auxiliary variable load industrial steam supply system.

[0016] This technical solution utilizes the heat storage and release capacity of the heat exchanger and the molten salt heat storage and release module to decouple the hot resteam extraction from the industrial steam supply. The hot resteam extraction volume is adjustable within a certain range, which helps to improve the system's load change rate and can respond quickly to variable load demands, thereby improving the flexibility of the cogeneration unit. It has a wide range of applications, realizes cascade utilization of steam, and improves the energy conversion level of the cogeneration system.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a structural schematic diagram of the auxiliary variable load industrial steam supply system provided by the present invention; Figure 2 It is a flow chart of a control method for an auxiliary variable load industrial steam supply system provided by the present invention.

[0019] Description of Reference Numerals 1- boiler; 2- steam turbine unit; 3- voltage regulating power generation module; 4-molten salt heat storage and release module; 5-first heat exchanger; 6-heater; 7-heat user; 21-first steam turbine; 22-second steam turbine; 31-pressure reducing valve; 32-back pressure steam turbine; 41-second heat exchanger; 42-hot tank; 43-third heat exchanger; 44-cold tank; 101-first valve; 102-second valve; 103-third valve; 104-Fourth valve. DETAILED DESCRIPTION

[0020] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0021] In the embodiments of the present invention, unless otherwise specified, directional words such as "up, down, left, right" generally refer to the directions or positional relationships shown in the accompanying drawings, or the directions or positional relationships in which the inventive product is usually placed when in use.

[0022] The terms “first”, “second”, “third”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0023] The terms "parallel", "vertical", etc. do not mean that the components must be absolutely parallel or vertical, but can be slightly tilted. For example, "parallel" only means that its direction is more parallel than "vertical", and does not mean that the structure must be completely parallel, but can be slightly tilted.

[0024] The terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal, vertical or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In addition, the terms "roughly" and "basically" are intended to explain that the relevant content does not require absolute precision, but can have certain deviations. For example, "roughly equal" does not only mean absolute equality. Since it is difficult to achieve absolute "equality" in actual production and operation, there are generally certain deviations. Therefore, in addition to absolute equality, "roughly equal" also includes the above-mentioned situation with certain deviations. Taking this as an example, in other cases, unless otherwise specified, the terms "roughly" and "basically" have similar meanings to the above.

[0026] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Figure 1 It is a structural schematic diagram of the auxiliary variable load industrial steam supply system provided by the present invention; Figure 2 It is a flow chart of a control method for an auxiliary variable load industrial steam supply system provided by the present invention.

[0028] like Figure 1 As shown, this embodiment provides an auxiliary variable load industrial steam supply system, the system comprising: Boiler 1, used for generating main steam and heating cold resteam formed after the main steam passes through steam turbine unit 2 into hot resteam; a steam turbine unit 2, connected to the boiler 1, for generating electricity using main steam and hot resteam; The pressure regulating power generation module 3 is connected to the main steam outlet of the boiler 1 and is used to regulate the pressure of the input main steam and generate electricity using the main steam to form industrial steam supply steam; The molten salt heat storage and release module 4 is connected to the steam supply outlet of the first heat exchanger 5, the steam supply outlet of the heater 6 and the hot re-steam outlet of the boiler 1, and is used to heat the cold molten salt into hot lava using the hot re-steam, and to heat the industrial steam supply steam after primary heating output by the first heat exchanger 5 or the heater 6 using the hot lava to form the industrial steam supply steam after secondary heating; The first heat exchanger 5 is connected to the steam outlet of the molten salt heat storage and release module 4 and the steam supply outlet of the pressure regulating power generation module 3, and is used to heat the industrial steam supply steam output by the pressure regulating power generation module 3 with the hot re-steam output by the molten salt heat storage and release module 4 to form the industrial steam supply steam after one heating; The heater 6 is connected to the steam supply outlet of the pressure regulating power generation module 3 and is used to heat the industrial steam supply steam output by the pressure regulating power generation module 3 to form the industrial steam supply steam after primary heating; The heat user 7 is connected to the steam supply outlet of the molten salt heat storage and release module 4 to utilize the industrial steam supply steam after secondary heating.

[0029] Specifically, in this embodiment, the steam turbine unit 2 includes a first steam turbine 21 and a second steam turbine 22. The first steam turbine 21 is connected to the main steam outlet of the boiler 1, uses the main steam to generate electricity and form cold resteam, and the steam outlet of the first steam turbine 21 is connected to the cold resteam inlet of the boiler 1. The boiler heats the cold resteam to form hot resteam, and then transports the hot resteam to the second steam turbine 22. The second steam turbine 22 uses the hot resteam to generate electricity.

[0030] Furthermore, the voltage regulating power generation module 3 comprises: The pressure reducing valve 31 is used to reduce the pressure of the input main steam; The back-pressure steam turbine 32 is connected to the pressure reducing valve 31 and is used to generate electricity using the decompressed main steam and form industrial steam supply steam.

[0031] Specifically, in this embodiment, the pressure reducing valve 31 is provided to achieve the regulation of steam pressure. At the same time, a back-pressure steam turbine 32 is provided and connected to the pressure reducing valve 31 to generate electricity using the decompressed main steam and form industrial steam supply steam. The generated electricity can be used as factory electricity to reduce heating costs.

[0032] Furthermore, the heater 6 is an electric heater, which is electrically connected to the back-pressure steam turbine 32 and is used to heat the industrial steam supply steam output by the pressure regulating power generation module 3 using the electric energy generated by the back-pressure steam turbine 32 .

[0033] Specifically, in this embodiment, the heater 6 can use the electric energy generated by the back pressure steam turbine 32 to heat the industrial steam supply steam output by the pressure regulating power generation module 3, and the heater 6 is usually not working. When the steam flow entering the second heat exchanger 41 is less than the preset threshold, the heater 6 is controlled to work and replace the second heat exchanger 41 to heat the industrial steam supply steam, that is, the heater 6 and the second heat exchanger 41 do not work at the same time, and ensure that the temperature value of the industrial steam heated by the heater 6 reaches the set temperature threshold. More specifically, the steam supply inlet of the heater 6 and the steam supply inlet of the first heat exchanger 5 are both provided with valves for realizing the on-off control of the flow entering the heater 6 and the first heat exchanger 5.

[0034] Furthermore, the molten salt heat storage and release module 4 comprises: A second heat exchanger 41, a hot tank 42, a third heat exchanger 43 and a cold tank 44 forming a circulation pipeline are sequentially connected, a first valve 101 is provided between the second heat exchanger 41 and the cold tank 44, and a second valve 102 is provided between the hot tank 42 and the third heat exchanger 43; The steam inlet of the second heat exchanger 41 is connected to the hot resteam outlet of the boiler 1, and the steam outlet of the second heat exchanger 41 is connected to the steam inlet of the first heat exchanger 5, so as to heat the cold molten salt with the hot resteam to form hot molten salt; The steam supply inlet of the third heat exchanger 43 is connected to the steam supply outlet of the first heat exchanger 5, and the steam supply outlet of the third heat exchanger 43 is connected to a heat user, so as to utilize hot molten salt to heat industrial steam to form cold molten salt.

[0035] A cold tank 44 for storing cold molten salt; The hot tank 42 is used to store hot molten salt.

[0036] Specifically, in this embodiment, the operating temperature range of the molten salt heat storage module 4 is 450-500°C, and binary molten salt is used as the heat storage medium. Therefore, the temperature of the cold molten salt stored in the cold tank 44 is 450 degrees, and the temperature of the hot molten salt stored in the hot tank 42 is 500 degrees. By controlling the opening of the first valve 101, the flow of the cold molten salt delivered to the second heat exchanger 41 can be adjusted, so that the second heat exchanger 41 is used to heat the 450-degree cold molten salt to form 500-degree hot molten salt. The opening of the second valve 102 is controlled to adjust the flow of the hot molten salt delivered to the third heat exchanger 43, so that the third heat exchanger 43 is used to heat the industrial steam below 450 degrees to form 450-degree industrial steam.

[0037] In another embodiment, a driving pump is provided between the second heat exchanger 41 and the cold tank 44, and between the hot tank 42 and the third heat exchanger 43, for driving the molten salt to flow and improving the fluidity of the molten salt.

[0038] Further, the steam inlet of the second heat exchanger 41 is provided with a third valve 103, and the third valve 103 is used to control the steam flow rate of the hot resteam entering the second heat exchanger 41; The hot resteam inlet of the steam turbine unit 2 is provided with a fourth valve 104 , and the fourth valve 104 is used to control the steam flow rate of the hot resteam entering the steam turbine unit 2 .

[0039] Specifically, in this embodiment, by cooperating with the third valve 103 and the fourth valve 104, it is possible to control the steam flow entering the second heat exchanger 41 and the steam flow of the hot resteam entering the steam turbine unit 2, thereby achieving both variable load peak regulation and a stable supply of industrial steam.

[0040] This embodiment also provides a control method for an auxiliary variable load industrial steam supply system, which is applied to the above-mentioned auxiliary variable load industrial steam supply system, such as Figure 2 As shown, the method includes: Obtaining the actual power generation load and target power generation load of the steam turbine unit; If the actual power generation load is less than the target power generation load, the theoretical openings of the second valve, the third valve and the fourth valve are calculated based on the load difference between the actual power generation load and the target power generation load, and the openings of the second valve, the third valve and the fourth valve are adjusted to the corresponding theoretical openings so that the actual power generation load is equal to the target power generation load; If the actual power generation load is greater than the target power generation load, the theoretical openings of the first valve, the third valve and the fourth valve are calculated based on the load difference between the actual power generation load and the target power generation load, and the openings of the first valve, the third valve and the fourth valve are adjusted to the corresponding theoretical openings so that the actual power generation load is equal to the target power generation load.

[0041] More specifically, for the auxiliary variable load high-temperature and high-pressure industrial steam supply system, the method for maintaining stable industrial steam pressure is to adjust the opening of the pressure reducing valve 31, and the method for maintaining stable industrial steam temperature includes adjusting the extraction hot resteam flow, starting the molten salt heating process or the molten salt heat release process, etc.

[0042] Preferably, when the electric load needs to be increased quickly, the flow rate of the extracted hot resteam is reduced, more hot resteam is sent to the steam turbine unit 2, the electric load output by the steam turbine unit 2 is increased within a certain period of time, and the heat storage capacity of the first heat exchanger 5 is used to maintain the industrial steam temperature stable. When the electric load needs to be reduced quickly, the flow rate of the extracted hot resteam is increased, the amount of hot resteam entering the steam turbine unit 2 is reduced, the electric load output by the steam turbine unit 2 is reduced within a certain period of time, and the heat storage capacity of the first heat exchanger 5 is used to maintain the industrial steam temperature stable.

[0043] Preferably, when the electric load needs to be increased quickly, if the heat storage capacity of the first heat exchanger 5 is insufficient to maintain the industrial steam temperature stable and the industrial steam temperature drops, the molten salt heat release process is started, and the heat stored in the molten salt heat storage and release module 4 is used to heat the industrial steam using the third heat exchanger 43 to maintain the industrial steam temperature stable. When the electric load needs to be reduced quickly, if the heat storage capacity of the first heat exchanger 5 is insufficient to maintain the industrial steam temperature stable and the industrial steam temperature rises, the molten salt heating process is started, and the hot steam heat energy is used to heat the cold molten salt using the second heat exchanger 41 and stored in the molten salt heat storage and release module 4, thereby reducing the amount of heating of the industrial steam by the first heat exchanger 5 and maintaining the industrial steam temperature stable.

[0044] Preferably, if after the molten salt heat release process is completed, the amount of salt stored in the cold tank 44 is greater than that in the hot tank 42, the molten salt heating process is started at an appropriate time to balance the amount of salt stored in the two tanks; if after the molten salt heating process is completed, the amount of salt stored in the hot tank 42 is greater than that in the cold tank 44, the molten salt heat release process is started at an appropriate time to balance the amount of salt stored in the two tanks.

[0045] Preferably, when the electrical and thermal loads are stable, the molten salt heat release process and the molten salt heating process are started regularly to heat the pipelines of the second heat exchanger 41 and the third heat exchanger 43, so that the molten salt heat storage and release module 4 can maintain a hot standby state for a long time and can be quickly put into use when the load needs to be changed.

[0046] Preferably, the molten salt heating process is stopped when one of the following two conditions is met: (1) The hot tank 42 is full; (2) The following conditions are met at the same time: the system electrical and thermal loads are stable, and there is no need for rapid load changes; the second heat exchanger 41 is fully heated and can maintain a hot standby state; the salt storage amounts in the hot tank 42 and the cold tank 44 are balanced.

[0047] When one of the following two conditions is met, the molten salt heat release process is stopped: (1) The cold tank 44 is full; (2) The following conditions are met at the same time: the system electrical and thermal loads are stable, and there is no need for rapid load changes; the third heat exchanger 43 is fully heated and can maintain a hot standby state; the salt storage amounts in the hot tank 42 and the cold tank 44 are balanced.

[0048] Preferably, the outlet steam temperature of the back-pressure steam turbine 32 increases as the electrical load of the system decreases; therefore, when the system operates at a low electrical load, the amount of hot resteam extraction is reduced to maintain the industrial steam temperature stable.

[0049] Preferably, the start and stop control of the molten salt heating process, the heating rate control, the start and stop control of the molten salt heat release process, the heat release rate control, the hot resteam extraction amount adjustment, etc. are all incorporated into the discrete control system DCS to achieve automatic control.

[0050] Furthermore, based on the load difference between the actual power generation load and the target power generation load, the theoretical openings of the second valve, the third valve and the fourth valve are calculated, including: The theoretical openings of the second valve, the third valve, and the fourth valve are calculated using the following formula: ; in, is the theoretical opening of the second valve; is the theoretical opening of the third valve; is the theoretical opening of the fourth valve; is the current opening of the second valve; is the current opening of the third valve; is the current opening of the fourth valve; is the specific heat capacity of hot resteam; is the specific heat capacity of the lava; It is the load difference between the actual power generation load and the target power generation load; and is the correction factor; and is the fitting coefficient.

[0051] Furthermore, based on the load difference between the actual power generation load and the target power generation load, the theoretical openings of the first valve, the third valve and the fourth valve are calculated, including: The theoretical openings of the first valve, the third valve, and the fourth valve are calculated using the following formula: ; in, is the theoretical opening of the first valve; is the theoretical opening of the third valve; is the theoretical opening of the fourth valve; is the current opening of the first valve; is the current opening of the third valve; is the current opening of the fourth valve; is the specific heat capacity of hot resteam; is the specific heat capacity of the lava; It is the load difference between the actual power generation load and the target power generation load; and is the correction factor; and is the fitting coefficient.

[0052] Specifically, the above two calculation formulas are obtained by adjusting and collecting the first valve opening, the second valve opening, the third valve opening and the fourth valve opening under different target power generation loads and different actual power generation loads in order to make the industrial steam supply meet the preset temperature, and performing data fitting analysis. When the actual power generation load is less than the target power generation load or when the actual power generation load is greater than the target power generation load, the theoretical openings of the first valve, the second valve, the third valve and the fourth valve are calculated through the corresponding calculation formulas, and the corresponding valves are controlled to adjust the openings to the corresponding theoretical openings, which can ensure precise control, ensure the timeliness of power load regulation, and at the same time ensure the stability of industrial steam supply.

[0053] In another embodiment, the PID control algorithm or the opening control model can be directly embedded in the DCS system, and the target power generation load and the actual power generation load can be used as input to determine the first valve opening, the second valve opening, the third valve opening and the fourth valve theoretical opening. The opening control model is obtained by training the neural network model based on the historical data set (the historical data set includes the first valve opening, the second valve opening, the third valve opening and the fourth valve opening corresponding to the industrial steam supply temperature under different target power generation loads and different actual power generation loads to keep the steam temperature stable).

[0054] More specifically, when it is necessary to reduce the steam flow entering the second heat exchanger 41 as much as possible, it still has a minimum steam flow, that is, the third valve 103 cannot be completely closed. When the calculated theoretical opening of the third valve 103 is less than the preset minimum opening, the third valve 103 is adjusted to the preset minimum opening to avoid solidification of the molten salt in the pipeline.

[0055] This embodiment also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned control method for the auxiliary variable load industrial steam supply system when executing the computer program.

[0056] This embodiment also provides a readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the above-mentioned control method for an auxiliary variable load industrial steam supply system.

[0057] In a specific implementation, the working method of the auxiliary variable load high temperature and high pressure industrial steam supply system mainly includes: The main steam for industrial steam supply generated by boiler 1 has a temperature of 538°C and a pressure of 24.5MPa under rated electrical load conditions. It is reduced in pressure to an industrial steam supply pressure of 4.5MPa through a pressure reducing valve 31 and a back-pressure steam turbine 32 in sequence. At the same time, the steam temperature drops to 366°C accordingly, and then is heated to an industrial steam supply temperature of 450°C through the first heat exchanger 5 and the third heat exchanger 43, and is transported to the industrial steam outlet.

[0058] The main steam for power generation generated by the boiler 1 has a temperature of 538°C and a pressure of 24.5MPa under rated electrical load conditions. It is expanded and does work in the first steam turbine 21 and then reduced to a pressure of 4.5MPa before returning to the boiler 1. After being reheated to become hot resteam, it has a temperature of 566°C and a pressure of 4.1MPa under rated electrical load conditions. A portion is extracted and respectively heated to molten salt and industrial steam through the second heat exchanger 41 and the first heat exchanger 5, and then recovered to the deaerator and finally returned to the boiler 1; the rest of the hot resteam continues to expand and does work through the second steam turbine 22, is transported to the condenser, and finally returns to the boiler 1.

[0059] Under rated electrical load conditions, the inlet and outlet parameters of the first heat exchanger 5 are as follows: The tube side (exhaust steam from back pressure turbine 32) has an inlet temperature of 366°C, an outlet temperature of 450°C, a pressure of 4.5 MPa, and a flow rate of 108 t / h; The shell side (hot resteam extraction) inlet temperature is 566℃, outlet temperature is 435℃, pressure is 4.1MPa, and flow rate is 72.6t / h.

[0060] Under rated electrical load conditions, the system can supply 600MW of external electricity and 108t / h of 4.5MPa, 450℃ industrial steam to the outside, realizing high-temperature and high-pressure industrial steam cogeneration.

[0061] During the molten salt heating process, the cold molten salt in the cold tank 44 enters the second heat exchanger 41 and is heated by the hot resteam to become hot molten salt, and enters the hot tank 42, where part of the heat of the hot resteam is stored in the molten salt heat storage and release module 4; during the molten salt heat release process, the hot molten salt in the hot tank 42 enters the third heat exchanger 43, where the heat stored in the molten salt heat storage and release module 4 is used to heat the industrial steam, and the temperature of the molten salt is reduced to become cold molten salt, and enters the cold tank 44.

[0062] The molten salt heat storage and release module 4 has an operating temperature of 450-500°C and uses binary molten salt (60% sodium nitrate, 40% potassium nitrate) as the heat storage medium. During the molten salt heating process, the extracted hot resteam superheat is used to heat the molten salt from 450°C to 500°C for storage, while the hot resteam temperature drops from 566°C to 500°C and is sent to the first heat exchanger 5; during the molten salt heat release process, the stored 500°C molten salt is used to heat the industrial steam temperature to 450°C, while the molten salt temperature drops to 450°C. It should be noted that the above temperature is the designed operating temperature of the molten salt heat storage and release system. Due to operation regulation and other reasons, the actual temperature varies.

[0063] The control method of the auxiliary variable load high-temperature and high-pressure industrial steam supply system mainly aims to utilize the heat storage and release capacity of the first heat exchanger 5 and the molten salt heat storage and release module 4 to decouple the hot resteam extraction from the industrial steam supply. The hot resteam extraction amount is adjustable within a certain range to achieve auxiliary variable load.

[0064] When the system electrical and thermal loads are stable, the methods for overcoming external disturbances and maintaining the stability of the parameters of the industrial steam supplied by the system mainly include: the method for maintaining the stability of the industrial steam pressure is to adjust the opening of the pressure reducing valve 31, and the method for maintaining the stability of the industrial steam temperature includes adjusting the flow rate of the extracted hot re-steam, starting the molten salt heating process or the molten salt heat release process, etc. The above methods are mainly used for.

[0065] When the electric load needs to be increased quickly, the flow rate of the extracted hot resteam is reduced, and more hot resteam is sent to the steam turbine unit 2, so as to increase the electric load output by the steam turbine unit 2 within a certain period of time, and at the same time, the heat storage capacity of the first heat exchanger 5 is used to maintain the industrial steam temperature stable. When the electric load needs to be reduced quickly, the flow rate of the extracted hot resteam is increased, and the amount of hot resteam entering the steam turbine unit 2 is reduced, so as to reduce the electric load output by the steam turbine unit 2 within a certain period of time, and at the same time, the heat storage capacity of the first heat exchanger 5 is used to maintain the industrial steam temperature stable.

[0066] If the heat storage capacity of the first heat exchanger 5 is insufficient to maintain the industrial steam temperature stable, the heat storage capacity of the molten salt heat storage and release module 4 is used to continue to maintain the industrial steam temperature stable. Specifically, when the electric load needs to be increased quickly, if the heat storage capacity of the first heat exchanger 5 is insufficient to maintain the industrial steam temperature stable and the industrial steam temperature drops, the molten salt heat release process is started, and the heat stored in the molten salt heat storage and release module 4 is used to heat the industrial steam to maintain the industrial steam temperature stable. When the electric load needs to be reduced quickly, if the heat storage capacity of the first heat exchanger 5 is insufficient to maintain the industrial steam temperature stable and the industrial steam temperature rises, the molten salt heating process is started, and the hot re-steam heat energy is stored in the molten salt heat storage and release system, thereby reducing the amount of heating of the industrial steam by the first heat exchanger 5 and maintaining the industrial steam temperature stable.

[0067] At the same time, in order to keep the molten salt heat storage and release module 4 in a hot standby state for a long time and to be quickly put into use when the load changes, the following control methods are adopted: First, if the amount of salt stored in the cold tank 44 is more than that in the hot tank 42 after the molten salt heat release process is completed, the molten salt heating process is started at an appropriate time to balance the amount of salt stored in the two tanks; if the amount of salt stored in the hot tank 42 is more than that in the cold tank 44 after the molten salt heating process is completed, the molten salt heat release process is started at an appropriate time to balance the amount of salt stored in the two tanks. Second, when the electrical and thermal loads are stable, the molten salt heat release process and the molten salt heating process are started regularly to heat the second heat exchanger 41 and the third heat exchanger 43 pipelines to maintain the molten salt heat storage and release module 4 in a hot standby state for a long time.

[0068] The molten salt heating process must stop running if the following conditions are met at the same time: (1) The system's electrical and thermal loads are stable, with no need for rapid load changes; (2) The second heat exchanger 41 is heated sufficiently and can maintain a hot standby state; (3) The salt storage amounts in the hot tank 42 and the cold tank 44 are balanced.

[0069] In particular, in order to ensure the safety of the molten salt heat storage and release module 4, the molten salt heating process is stopped when the heat tank 42 is full.

[0070] The molten salt exothermic process stops running when the following conditions are met at the same time: (1) The system's electrical and thermal loads are stable, with no need for rapid load changes; (2) The third heat exchanger 43 is heated sufficiently and can maintain a hot standby state; (3) The salt storage amounts in the hot tank 42 and the cold tank 44 are balanced.

[0071] In particular, in order to ensure the safety of the molten salt heat storage and release module 4, the molten salt heat release process is stopped when the cold tank 44 is full.

[0072] According to calculation, the outlet steam temperature of the back pressure steam turbine 32 increases as the electrical load of the auxiliary variable load high temperature and high pressure industrial steam supply system decreases. Therefore, when the system is stably operating under low electrical load conditions, the hot re-steam extraction volume needs to be reduced compared to the rated electrical load conditions to maintain the industrial steam temperature stable.

[0073] Specifically, under rated electrical load conditions, the inlet steam pressure of the pressure reducing valve 31 is 24.5 MPa, the temperature is 538°C, and the outlet steam pressure is 12 MPa, the temperature is 486°C; the outlet steam pressure of the back-pressure turbine 32 is 4.5 MPa, the temperature is 366°C, and after heating by the first heat exchanger 5, the steam pressure is 4.5 MPa, the temperature is 450°C, and the flow rate is 108 t / h; when the molten salt heating process stops running, the hot resteam pressure is 4.1 MPa, the temperature is 566°C, and the flow rate is 72.6 t / h, and after passing through the first heat exchanger 5, the hot resteam temperature is reduced to 435°C.

[0074] Under this load condition, if the molten salt heating process is started, the hot resteam pressure is 4.1MPa, the temperature is 566℃, and the flow rate is increased to 99.3t / h. After passing through the second heat exchanger 41, the temperature is 500℃, and after passing through the first heat exchanger 5, the temperature is reduced to 410℃. The industrial steam temperature at the outlet of the first heat exchanger 5 remains unchanged at 450℃.

[0075] Under this load condition, if the molten salt heat release process is started, the hot steam pressure is 4.1MPa, the temperature is 566℃, and the flow rate is reduced to 50t / h. After passing through the first heat exchanger 5, the temperature is reduced to 435℃, and the industrial steam temperature can be increased from 366℃ to 429℃. The third heat exchanger 43 uses the stored molten salt to continue heating the industrial steam and further increase its temperature to 450℃.

[0076] Under the condition of 75% electric load, the inlet steam pressure of the pressure reducing valve 31 is 18.1MPa, the temperature is 538℃, the outlet steam pressure is 12MPa, the temperature is 508℃; the outlet steam pressure of the back pressure turbine 32 is 4.5MPa, the temperature is 386.7℃, and after heating by the first heat exchanger 5, the steam pressure is 4.5MPa, the temperature is 450℃, and the flow rate is 108t / h; the extracted hot resteam pressure is 3MPa, the temperature is 566℃, and the flow rate is 55.4t / h, and after passing through the first heat exchanger 5, the hot resteam temperature is reduced to 435℃.

[0077] Under this load condition, if the molten salt heating process is started, the hot resteam pressure is 3MPa, the temperature is 566℃, and the flow rate is increased to 75.1t / h. The temperature is 500℃ after passing through the second heat exchanger 41, and the temperature is reduced to 410℃ after passing through the first heat exchanger 5. The industrial steam temperature at the outlet of the first heat exchanger 5 remains unchanged at 450℃.

[0078] Under this load condition, if the molten salt heat release process is started, the hot steam pressure is 3MPa, the temperature is 566℃, and the flow rate is reduced to 30t / h. After passing through the first heat exchanger 5, the temperature is reduced to 435℃, and the industrial steam temperature can be increased from 386.7℃ to 424℃. The third heat exchanger 43 uses the stored molten salt to continue to heat the industrial steam and further increase its temperature to 450℃.

[0079] Under the condition of 50% electric load, the inlet steam pressure of the pressure reducing valve 31 is 12MPa, the temperature is 538℃, and the outlet steam pressure is 12MPa, the temperature is 538℃; the outlet steam pressure of the back pressure turbine 32 is 4.5MPa, the temperature is 414.3℃, and after heating by the first heat exchanger 5, the steam pressure is 4.5MPa, the temperature is 450℃, and the flow rate is 108t / h; the extracted hot resteam pressure is 2MPa, the temperature is 566℃, and the flow rate is 31.5t / h, and after passing through the first heat exchanger 5, the hot resteam temperature is reduced to 435℃.

[0080] Under this load condition, if the molten salt heating process is started, the hot resteam pressure is 2MPa, the temperature is 566℃, and the flow rate is increased to 50.9t / h. After passing through the second heat exchanger 41, the temperature is 500℃, and after passing through the first heat exchanger 5, the temperature is reduced to 425℃. The industrial steam temperature at the outlet of the first heat exchanger 5 remains unchanged at 450℃.

[0081] Under this load condition, if the molten salt heat release process is started, the hot steam pressure is 2MPa, the temperature is 566℃, and the flow rate is reduced to 10t / h. After passing through the first heat exchanger 5, the temperature is reduced to 435℃, and the industrial steam temperature can be increased from 414.3℃ to 427℃. The third heat exchanger 43 uses the stored molten salt to continue to heat the industrial steam and further increase its temperature to 450℃.

[0082] The optional implementation modes of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical scheme of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0083] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage molten salt, including several instructions for making a single-chip microcomputer, a chip or a processor (processor) perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage molten salt includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other molten salts that can store program codes.

[0084] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner when there is no contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations. In addition, various implementation modes of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed by the embodiments of the present invention.

Claims

1. An auxiliary variable load industrial steam supply system, characterized in that: The system comprises: A boiler (1) is used to generate main steam and heat cold resteam formed after the main steam passes through the steam turbine unit (2) into hot resteam; A steam turbine unit (2) connected to the boiler (1) for generating electricity using main steam and hot resteam; A pressure regulating power generation module (3) is connected to the main steam outlet of the boiler (1) and is used to regulate the pressure of the input main steam and generate electricity to form industrial steam supply steam; The molten salt heat storage and release module (4) is connected to the steam supply outlet of the first heat exchanger (5), the steam supply outlet of the heater (6) and the hot re-steam outlet of the boiler (1), and is used to heat the cold molten salt into hot lava using the hot re-steam, and to heat the primary heated industrial steam supply steam output by the first heat exchanger (5) or the heater (6) using the hot lava to form secondary heated industrial steam supply steam; A first heat exchanger (5) is connected to the steam outlet of the molten salt heat storage and release module (4) and the steam supply outlet of the pressure regulating power generation module (3), and is used to heat the industrial steam supply steam output by the pressure regulating power generation module (3) using the hot re-steam output by the molten salt heat storage and release module (4), thereby forming the industrial steam supply steam after primary heating; A heater (6) is connected to the steam supply outlet of the pressure regulating power generation module (3) and is used to heat the industrial steam supply steam output by the pressure regulating power generation module (3) to form once-heated industrial steam supply steam; The heat user (7) is connected to the steam supply outlet of the molten salt heat storage and release module (4) to utilize the industrial steam supply steam after secondary heating.

2. The auxiliary variable load industrial steam supply system according to claim 1, characterized in that: The voltage regulating power generation module (3) comprises: A pressure reducing valve (31) for reducing the pressure of input main steam; The back-pressure steam turbine (32) is connected to the pressure reducing valve (31) and is used to generate electricity using the decompressed main steam and to form industrial steam supply steam.

3. The auxiliary variable load industrial steam supply system according to claim 2, characterized in that: The heater (6) is an electric heater, electrically connected to the back-pressure steam turbine (32), and is used to heat the industrial steam supply steam output by the pressure regulating power generation module (3) using the electric energy generated by the back-pressure steam turbine (32).

4. The auxiliary variable load industrial steam supply system according to claim 3, characterized in that: The molten salt heat storage and release module (4) comprises: A second heat exchanger (41), a hot tank (42), a third heat exchanger (43), and a cold tank (44) are sequentially connected to form a circulation pipeline, a first valve (101) is provided between the second heat exchanger (41) and the cold tank (44), and a second valve (102) is provided between the hot tank (42) and the third heat exchanger (43); The steam inlet of the second heat exchanger (41) is connected to the hot resteam outlet of the boiler (1), and the steam outlet of the second heat exchanger (41) is connected to the steam inlet of the first heat exchanger (5), so as to utilize the hot resteam to heat the cold molten salt to form hot molten salt; The steam supply inlet of the third heat exchanger (43) is connected to the steam supply outlet of the first heat exchanger (5), and the steam supply outlet of the third heat exchanger (43) is connected to a heat user, so as to use the hot molten salt to heat the industrial steam supply to form cold molten salt; A cold tank (44) for storing cold molten salt; The hot tank (42) is used to store hot molten salt.

5. The auxiliary variable load industrial steam supply system according to claim 4, characterized in that: The steam inlet of the second heat exchanger (41) is provided with a third valve (103), and the third valve (103) is used to control the steam flow rate of the hot resteam entering the second heat exchanger (41); The hot resteam inlet of the steam turbine unit (2) is provided with a fourth valve (104), and the fourth valve (104) is used to control the steam flow rate of the hot resteam entering the steam turbine unit (2).

6. A control method for an auxiliary variable load industrial steam supply system, applied to the auxiliary variable load industrial steam supply system of claim 5, characterized in that: The method comprises: Obtaining the actual power generation load and target power generation load of the steam turbine unit; If the actual power generation load is less than the target power generation load, the theoretical openings of the second valve, the third valve and the fourth valve are calculated based on the load difference between the actual power generation load and the target power generation load, and the openings of the second valve, the third valve and the fourth valve are adjusted to the corresponding theoretical openings so that the actual power generation load is equal to the target power generation load; If the actual power generation load is greater than the target power generation load, the theoretical openings of the first valve, the third valve and the fourth valve are calculated based on the load difference between the actual power generation load and the target power generation load, and the openings of the first valve, the third valve and the fourth valve are adjusted to the corresponding theoretical openings so that the actual power generation load is equal to the target power generation load.

7. The control method of the auxiliary variable load industrial steam supply system according to claim 6, characterized in that: Based on the load difference between the actual power generation load and the target power generation load, the theoretical openings of the second valve, the third valve and the fourth valve are calculated, including: The theoretical openings of the second valve, the third valve, and the fourth valve are calculated using the following formula: ； in, is the theoretical opening of the second valve; is the theoretical opening of the third valve; is the theoretical opening of the fourth valve; is the current opening of the second valve; is the current opening of the third valve; is the current opening of the fourth valve; is the specific heat capacity of hot resteam; is the specific heat capacity of the lava; It is the load difference between the actual power generation load and the target power generation load; and is the correction factor; and is the fitting coefficient.

8. The control method of the auxiliary variable load industrial steam supply system according to claim 6, characterized in that: Based on the load difference between the actual power generation load and the target power generation load, the theoretical openings of the first valve, the third valve and the fourth valve are calculated, including: The theoretical openings of the first valve, the third valve, and the fourth valve are calculated using the following formula: ； in, is the theoretical opening of the first valve; is the theoretical opening of the third valve; is the theoretical opening of the fourth valve; is the current opening of the first valve; is the current opening of the third valve; is the current opening of the fourth valve; is the specific heat capacity of hot resteam; is the specific heat capacity of the lava; It is the load difference between the actual power generation load and the target power generation load; and is the correction factor; and is the fitting coefficient.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the control method for the auxiliary variable load industrial steam supply system according to any one of claims 6 to 8 is implemented.

10. A readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the control method for an auxiliary variable load industrial steam supply system according to any one of claims 6 to 8.

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