Heat exchange control system and method applied to thermal inertia tube bundle

Abstract

The invention provides a heat exchange control system and method applied to a thermal inertia tube bundle, and relates to the field of heat exchange. Under the condition that the target heat exchange requirement exists, the main pipeline valve is closed, the inflow control valve and the outflow control valve are opened, and the heat conduction particles output by the particle output device are mixed with the working medium to obtain particle suspension liquid; due to the fact that the heat conduction coefficient of the heat conduction particles is larger than that of the working medium flowing into the inflow bypass pipeline, the heat conduction coefficient of particle suspension liquid obtained after the heat conduction particles and the working medium are mixed is larger than that of the working medium. And heat exchange between the working medium and the inner wall surface of the thermal inertia tube bundle during rapid load change is enhanced, and the working medium heat exchange rate is increased when the working medium is under-temperature, so that the working medium can reach the required temperature, the heat exchange accuracy is improved, and safe operation of subsequent equipment is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of heat exchange, and more specifically, to a heat exchange control system and method applied to a thermal inertia tube bundle. Background Art

[0002] In recent years, the proportion of new energy represented by wind and solar energy in power generation has increased year by year. In order to fully absorb new energy, traditional thermal power units need to frequently participate in peak load regulation tasks, which requires thermal power units to have better flexibility. However, high load change rates also bring challenges to the stable operation of thermal power units. Unlike the steady state, during the rapid load change of thermal power units, due to the heat storage effect (thermal inertia) of the metal wall of the boiler heating surface tube bundle, the heat released by the hot flue gas and the heat absorbed by the working fluid, such as steam, may be different, causing the change of steam parameters to lag. For example, during the rapid load increase of the boiler, part of the heat is absorbed by the thermal inertia tube bundle and used for its own temperature increase, which may cause the steam to be underheated; when the boiler quickly reduces the load, the heat of the thermal inertia tube bundle will be transferred to the steam to cool itself, which may cause the steam to overheat.

[0003] For the boiler thermal inertia tube bundle, the steam temperature can be controlled by adjusting the coal-water ratio or spraying water to reduce the temperature. However, the former has a slow response speed. Even if the coal-water ratio is adjusted in time, due to the huge thermal inertia of the boiler thermal inertia tube bundle, the steam temperature will continue to rise (or fall) for a period of time, which is difficult to adapt to the rapid load change process. The latter cannot be applied to the steam under-temperature condition. Summary of the invention

[0004] In view of this, the present application provides a heat exchange control system and method applied to a thermal inertia tube bundle to solve the problem of under-temperature of the working fluid caused by rapid load changes.

[0005] In order to solve the above technical problems, this application adopts the following technical solutions:

[0006] A heat exchange control system applied to a thermal inertia tube bundle, comprising:

[0007] Inflow main pipeline, outflow main pipeline, inflow bypass pipeline and outflow bypass pipeline;

[0008] The inflow main pipeline and the inflow bypass pipeline are connected to the input end of the thermal inertia tube bundle after being arranged in parallel, and the inflow main pipeline and the outflow bypass pipeline are connected to the output end of the thermal inertia tube bundle after being arranged in parallel;

[0009] The main inflow pipe and the main inflow pipe are respectively provided with main pipe valves; the inflow bypass pipe is provided with an inflow control valve and a particle output device, and the outflow bypass pipe is provided with an outflow control valve and a particle recovery device; the particle output device stores heat-conductive particles; the thermal conductivity of the heat-conductive particles is greater than the thermal conductivity of the working fluid flowing into the inflow bypass pipe;

[0010] When there is a target heat exchange demand, the main line valve is closed, the inflow control valve and the outflow control valve are opened, the heat-conductive particles output by the particle output device are mixed with the working fluid to obtain a particle suspension, and the particle suspension flows through the thermal inertia tube bundle.

[0011] Optionally, the particle output device is a mixer, and the mixer is connected to the inlet bypass pipeline in the form of a variable cross-section, so that the mixer uses the pressure difference generated when the working medium flows through the variable cross-section to drive the heat-conductive particles to mix with the working medium.

[0012] Optionally, the particle output device includes a heat-conducting particle storage device and a particle flow control valve;

[0013] According to the flow sequence of the working medium in the inflow bypass pipeline, the heat-conducting particle storage device is arranged before the particle flow control valve.

[0014] Optionally, the inflow control valve includes a first bypass valve and a second bypass valve; the first bypass valve is arranged before the heat-conductive particle storage device, and the second bypass valve is arranged after the particle flow control valve.

[0015] Optionally, the outflow control valve includes a third bypass valve and a fourth bypass valve, and the particle recovery device is arranged between the third bypass valve and the fourth bypass valve.

[0016] Optionally, the particle recovery device comprises:

[0017] Separators and discharge devices are connected in sequence.

[0018] Optionally, the third bypass valve and the fourth bypass valve are respectively arranged at two ends of the separator.

[0019] Optionally, the main line valve, the inflow control valve and the outflow control valve are controlled to open and close by a controller in the heat exchange control system.

[0020] A heat exchange control method applied to a thermal inertia tube bundle is applied to the above-mentioned heat exchange control system, and the heat exchange control method comprises:

[0021] When there is a target heat exchange demand, the main line valve is controlled to be closed, and the inflow control valve and the outflow control valve are controlled to be opened, and the heat-conductive particles output by the particle output device are mixed with the working fluid to obtain a particle suspension, and the particle suspension flows through the thermal inertia tube bundle.

[0022] Optionally, after controlling the inflow control valve and the outflow control valve to open, the method further includes:

[0023] In the case where the particle output device includes a heat-conducting particle storage device and a particle flow control valve, the opening of the particle flow control valve is adjusted based on the load change rate and the working medium flow rate.

[0024] The present application provides a heat exchange control system and method applied to a thermal inertia tube bundle. In the present application, the heat exchange control system includes an inflow main line, an inflow main line, an inflow bypass line, and an outflow bypass line. The inflow main line and the inflow bypass line are connected to the input end of the thermal inertia tube bundle after being arranged in parallel, and the inflow main line and the outflow bypass line are connected to the output end of the thermal inertia tube bundle after being arranged in parallel. The inflow main line and the inflow main line are respectively provided with main line valves, the inflow bypass line is provided with an inflow control valve and a particle output device, the outflow bypass line is provided with an outflow control valve and a particle recovery device, and the particle output device stores heat-conductive particles, and the thermal conductivity of the heat-conductive particles is greater than the thermal conductivity of the working fluid flowing into the inflow bypass line. On the basis of this structure, when there is a target heat exchange demand, the main pipeline valve is closed, the inflow control valve and the outflow control valve are opened, and the heat-conductive particles output by the particle output device are mixed with the working fluid to obtain a particle suspension. Since the thermal conductivity of the heat-conductive particles is greater than the thermal conductivity of the working fluid flowing into the inflow bypass pipeline, the thermal conductivity of the particle suspension after the two are mixed is greater than the thermal conductivity of the working fluid. When the particle suspension flows through the thermal inertia tube bundle, the heat exchange between the working fluid and the inner wall of the thermal inertia tube bundle is enhanced during rapid load changes, and the heat exchange rate of the working fluid is increased when the working fluid is under-temperature, so that the working fluid can reach the required temperature, improve the accuracy of heat exchange, and ensure the safe operation of subsequent equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1A schematic structural diagram of a heat exchange control system applied to a thermal inertia tube bundle provided in an embodiment of the present invention;

[0027] Figure 2 A schematic structural diagram of another heat exchange control system applied to a thermal inertia tube bundle provided in an embodiment of the present invention;

[0028] Figure 3 A flow chart of a heat exchange control method applied to a thermal inertia tube bundle provided in an embodiment of the present invention;

[0029] Figure 4 A graph showing changes in the heat absorption power of a final superheater over time at different load changing rates during a load increase process provided by an embodiment of the present invention;

[0030] Figure 5 A schematic diagram of the growth value of the steam-tube bundle heat exchange power under different variable load rates provided by an embodiment of the present invention;

[0031] Figure 6 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] At present, the temperature regulation operation of the corresponding object can be achieved by heat exchange. Taking the power generation scenario as an example, in order to fully absorb new energy, traditional thermal power units have gradually changed from the main power source to the supporting and regulating power source, and frequently participate in the peak load regulation task, which requires thermal power units to have better flexibility. In the supporting and regulating power sources, part of the electricity is provided by clean energy, such as wind power and solar energy, and part of the electricity is provided by thermal power units. At night or when there is insufficient light, most of the load electricity needs to be provided by thermal power units. At this time, the thermal power units have a large high load change rate, which brings challenges to the stable operation of thermal power units. During the operation of the thermal power unit, the flue gas generated by the boiler can heat the steam to generate electricity using steam. Unlike the operation in a steady state, during the rapid load change of the thermal power unit, due to the heat storage effect (thermal inertia) of the metal wall of the boiler heating surface tube bundle, the heat released by the hot flue gas and the heat absorbed by the steam may be different, causing the steam parameter change to lag. When the boiler rapidly increases its load, part of the heat is absorbed by the thermal inertia tube bundle and used to heat itself, which may cause the steam to be under-temperatured. When the boiler rapidly decreases its load, the heat of the thermal inertia tube bundle will be transferred to the steam, causing it to cool itself, which may cause the steam to be over-temperatured.

[0034] For the boiler thermal inertia tube bundle, although the steam temperature can be controlled by adjusting the coal-water ratio and spraying water to reduce the temperature, the former has a slow response speed. Even if the coal-water ratio is adjusted in time, due to the huge thermal inertia of the boiler thermal inertia tube bundle, the steam temperature will continue to rise (or fall) for a period of time, which is difficult to adapt to the rapid load change process. The latter cannot be applied to the steam under-temperature condition.

[0035] In addition, both methods are measures to ensure the temperature of the unit's working fluid, and do not start from solving the thermal inertia of the boiler's heating surface tube bundle. Traditional thermal inertia control mostly uses the method of preheating (or cooling), that is, preheating (or cooling) the thermal inertia pipeline before the unit's working fluid passes through, but this method is not suitable for continuously running boiler pipelines, especially the heating surface tube bundle inside the boiler.

[0036] Therefore, when the working fluid is under-temperature due to rapid load changes, it is necessary to quickly adjust the working fluid temperature to adapt to continuous operation conditions. In an embodiment of the present invention, heat-conductive particles are used to form a particle suspension with a high thermal conductivity coefficient with the unit working fluid, so as to enhance the heat exchange between the unit working fluid and the inner wall of the heating surface tube bundle during rapid load changes, improve the heat exchange efficiency, and adapt to the continuous operation process and the under-temperature scenario during rapid load changes. During heat exchange, the amount of injected heat-conductive particles can be adjusted according to the load change rate of the boiler and the working fluid flow rate, which reduces the lag in the change of the unit working fluid parameters caused by the thermal inertia of the boiler heating surface tube bundle during rapid load changes, ensures the safe operation of subsequent equipment, and has the advantages of low cost, wide adaptability, easy implementation and convenient modification.

[0037] Based on the above content, an embodiment of the present application provides a heat exchange control system applied to a thermal inertia tube bundle, such as Figure 1 As shown, including:

[0038] The main inflow line 01 , the main inflow line 02 , the bypass inflow line 03 , and the bypass outflow line 04 .

[0039] Among them, the inflow main pipeline 01 can also be called the inlet pipeline section, the inflow main pipeline 02 can also be called the outlet pipeline section, the inflow bypass pipeline 03 can also be called the inlet pipeline section bypass, and the outflow bypass pipeline 04 can also be called the outlet pipeline section bypass.

[0040] Among them, the pipeline structure of the inflow main line 01, the inflow main line 02, the inflow bypass line 03 and the outflow bypass line 04 can be configured according to actual conditions. The inflow main line 01 and the inflow main line 02 constitute a working fluid flow path, and the inflow bypass line 03 and the outflow bypass line 04 constitute another working fluid flow path. In actual scenarios, different working fluid flow paths are used for working fluid circulation depending on whether it is a rapid load change scenario. In one embodiment, in a non-rapid load change scenario, that is, a steady-state scenario, the inflow main line 01 and the inflow main line 02 are used for working fluid circulation, and in a rapid load change scenario, the inflow bypass line 03 and the outflow bypass line 04 are used for working fluid circulation.

[0041] The main inflow line 01 and the bypass inflow line 03 are connected to the input end of the thermal inertia tube bundle after being arranged in parallel, and the main inflow line 02 and the bypass outflow line 04 are connected to the output end of the thermal inertia tube bundle after being arranged in parallel.

[0042] The thermal inertia tube bundle may be any tube bundle with thermal inertia, such as a boiler heating surface tube bundle (specifically, a tube of a final superheater), etc. In this scenario, the working medium flowing through the thermal inertia tube bundle is steam.

[0043] The main inflow pipe 01 and the main inflow pipe 02 are respectively provided with main pipe valves; the inflow bypass pipe 03 is provided with an inflow control valve and a particle output device 3, and the outflow bypass pipe 04 is provided with an outflow control valve and a particle recovery device 5.

[0044] Among them, the main line valve (such as Figure 1 21 and 22), inflow control valve (such as Figure 1 11 and 12) and outflow control valve (such as Figure 1 41 and 22) in the figure can adopt a switch such as a solenoid valve that can be turned on and off. If a solenoid valve is adopted, the solenoid valve can be turned on or off manually or by a controller according to the actual configuration.

[0045] Among them, the inflow control valve can also be called the inlet pipe section bypass valve, which is located on the inflow bypass pipeline 03 and introduces the working fluid of the inlet pipe section main line into the inlet pipe section bypass.

[0046] Among them, the outflow control valve can also be called the outlet pipe section bypass valve, which is located on the outflow bypass pipeline 04 and introduces the working fluid of the outlet pipe section main line into the outlet pipe section bypass.

[0047] The particle output device 3 stores heat-conducting particles, and the thermal conductivity of the heat-conducting particles is greater than the thermal conductivity of the working fluid flowing into the bypass pipe 03. In one implementation, the heat-conducting particles are solid particles with high thermal conductivity, which can form a relatively stable particle suspension with high thermal conductivity after mixing with the working fluid. The size and type of the heat-conducting particles are not limited, and can be SiO 2 Particles, Al 2 O 3 Particles and phase change microcapsules, etc.

[0048] The particle recovery device 5 is mainly used to recover the heat-conducting particles in the particle suspension, thereby separating the heat-conducting particles from the working medium, so that the working medium can enter the subsequent equipment.

[0049] On the basis of the above structure, in the case of a target heat exchange demand, the main line valve is manually or controlled by a controller to be closed, and the inflow control valve and the outflow control valve are subsequently controlled to be opened. The heat-conductive particles output by the particle output device 3 are mixed with the working fluid to obtain a particle suspension. When the particle suspension flows through the thermal inertia tube bundle, compared with a method in which only the working fluid flows through the thermal inertia tube bundle, since the thermal conductivity of the particle suspension is greater than the thermal conductivity of the working fluid, the use of the particle suspension can enhance the heat exchange between the working fluid of the unit and the inner wall of the heated surface tube bundle during rapid load changes, so that the working fluid quickly absorbs heat and increases its own temperature.

[0050] In one embodiment, taking a boiler as an example, Figure 1 As for the flue gas generated by the boiler, the high-temperature flue gas is used to heat the working medium in the thermal inertia tube bundle. During the heating process, the heat storage effect of the metal wall of the tube bundle will absorb part of the heat of the flue gas, so that the temperature of the working medium cannot reach the required temperature. Therefore, through the particle suspension in the present invention, it is possible to accelerate the heat obtained by the working medium from the metal wall of the tube bundle, increase its own temperature, and quickly reach the required temperature.

[0051] In this embodiment, when there is a target heat exchange demand, the main pipeline valve is closed, the inflow control valve and the outflow control valve are opened, and the heat-conductive particles output by the particle output device 3 are mixed with the working fluid to obtain a particle suspension. Since the thermal conductivity of the heat-conductive particles is greater than the thermal conductivity of the working fluid flowing into the inflow bypass pipeline 03, the thermal conductivity of the particle suspension after the two are mixed is greater than the thermal conductivity of the working fluid. When the particle suspension flows through the thermal inertia tube bundle, the heat exchange between the working fluid and the inner wall of the thermal inertia tube bundle is enhanced during rapid load changes, and the heat exchange rate of the working fluid is increased when the working fluid is under-temperature, so that the working fluid can reach the required temperature, improve the accuracy of heat exchange, and ensure the safe operation of subsequent equipment.

[0052] Based on any of the above embodiments, the particle output device 3 is a mixer, which is connected to the inlet bypass pipe 03 in the form of a variable cross-section, so that the mixer uses the pressure difference generated when the working medium flows through the variable cross-section to drive the heat-conductive particles to mix with the working medium.

[0053] Specifically, Figure 2 As shown, the mixer can be a Venturi-type fluid-solid mixer. The type and form of the Venturi-type fluid-solid mixer are not limited and can be adjusted according to engineering requirements, and only needs to meet the mixing requirements. The Venturi-type fluid-solid mixer uses the pressure difference generated when the working fluid flows through the variable cross-section to drive the heat conductive particles to mix with the working fluid.

[0054] In one implementation, the particle output device 3, i.e., the above-mentioned mixer, includes a heat-conducting particle storage device 31 and a particle flow control valve 32. According to the flow sequence of the working medium in the inflow bypass line 03, the heat-conducting particle storage device 31 is arranged before the particle flow control valve 32.

[0055] The particle flow control valve 32 controls the flow of the thermally conductive particles outputted from the thermally conductive particle storage device 31 by controlling the valve opening, thereby achieving regulation of the concentration of the particle suspension, and the type of valve is not limited.

[0056] In one implementation, Figure 2 As shown, the inflow control valve includes a first bypass valve 11 and a second bypass valve 12 ; the first bypass valve 11 is arranged before the thermal conductive particle storage device 31 , and the second bypass valve 12 is arranged after the particle flow control valve 32 .

[0057] The first bypass valve 11 and the second bypass valve 12 are turned on and off at the same time. When it is necessary to introduce the working medium into the bypass pipeline 03, the main pipeline valve is closed, and the first bypass valve 11 and the second bypass valve 12 are opened. At this time, the working medium can enter the bypass pipeline 03.

[0058] In one implementation, the outflow control valve includes a third bypass valve and a fourth bypass valve, and the particle recovery device 5 is disposed between the third bypass valve and the fourth bypass valve.

[0059] like Figure 1 and Figure 2 As shown, a particle recovery device 5 is provided between the third bypass valve 41 and the fourth bypass valve 42. The particle recovery device 5 is mainly used to separate the heat-conducting particles from the working fluid in the particle suspension. The particle suspension first passes through the third bypass valve 41 and enters the particle recovery device 5. In the particle recovery device 5, the heat-conducting particles are separated from the working fluid, and the heat-conducting particles are output downward. The working fluid passes through the fourth bypass valve 42 and returns to the main flow line 02 to enter the subsequent equipment.

[0060] In one implementation, the particle recovery device 5 comprises:

[0061] A separator 51 and a discharge device 52 are connected in sequence.

[0062] The connection structure of the separator 51 and the discharge device 52 is shown in FIG. Figure 2 As shown, Figure 2 In the embodiment, the separator 51 is arranged above the discharge device 52.

[0063] The separator 51 in this embodiment may be a fluid-solid separator 51 for separating the heat-conducting particles from the working medium. The type of the fluid-solid separator 51 is not limited, and may be a cyclone separator 51, a gravity separator 51, and the like.

[0064] In this embodiment, the fluid-solid separator 51 is on the outflow bypass pipe 04, and has a discharge trough at its lower end. The discharge trough recycles the heat-conducting particles separated by the fluid-solid separator 51 for subsequent recycling. The size and type of the discharge trough are not limited and can be adjusted according to engineering requirements.

[0065] In one implementation, the third bypass valve 41 and the fourth bypass valve 42 are respectively disposed at two ends of the separator 51 .

[0066] More specifically, the particle suspension first passes through the third bypass valve 41 and enters the particle recovery device 5. In the fluid-solid separator 51 in the particle recovery device 5, the heat-conducting particles are separated from the working medium, and the heat-conducting particles are output downward to the discharge tank. After the heat-conducting particles are collected by the discharge tank, the heat-conducting particles can be placed in the heat-conducting particle storage device 31 to facilitate subsequent mixing with the working medium for recycling. The working medium returns to the main flow line 02 through the fourth bypass valve 42 and enters the subsequent equipment.

[0067] In one implementation, the main line valve, the inflow control valve and the outflow control valve are controlled to open and close by a controller in the heat exchange control system.

[0068] Among them, the controller in the embodiment of the present invention can be a controller in a mobile phone, server, electronic device, cloud device, etc., or it can be a controller configured separately for the heat exchange control system. The type and structure of the specific controller are not limited.

[0069] The controller has control logic for controlling the above valves, and can realize the opening and closing of the valves according to requirements.

[0070] In this embodiment, the Venturi fluid-solid mixer utilizes the pressure difference generated when the working fluid flows through the variable cross-section to drive the heat-conductive particles to mix with the working fluid, thereby generating a particle suspension with a relatively high thermal conductivity coefficient. The particle flow control valve 32 controls the flow of the heat-conductive particles by controlling the valve opening, thereby realizing the regulation of the concentration of the particle suspension. The heat-conductive particles and the unit working fluid form a particle suspension with a high thermal conductivity coefficient, thereby enhancing the heat exchange between the unit working fluid and the inner wall of the heating surface bundle during rapid load changes, thereby reducing the lag in the change of the unit working fluid parameters (such as the working fluid temperature) caused by the thermal inertia of the boiler heating surface bundle during rapid load changes, thereby enabling the working fluid temperature to reach the required temperature, thereby enabling the working fluid to enter the subsequent equipment at the same temperature as the temperature set by the equipment, without a temperature difference, thereby ensuring the safe operation of the subsequent equipment, and having the advantages of low cost, wide adaptability, easy implementation and convenient modification.

[0071] Based on the above embodiment of the heat exchange control system, another embodiment of the present application discloses a heat exchange control method applied to a thermal inertia tube bundle, which is applied to the above heat exchange control system, referring to Figure 3 , the heat exchange control method comprises:

[0072] S11. Determine whether there is a target heat exchange demand; if so, execute step S12.

[0073] In one embodiment, the above control operation can be performed by a controller in a heat exchange control system.

[0074] During the operation of the controller, the operating status of the equipment can be detected. The operating status of the equipment is generally divided into two types. One is the steady-state operating status. In this state, the equipment load is stable and unchanged. The other is the variable load operating state. In this state, the equipment load will change. At this time, if the load change rate is greater than the rate threshold, it is called a fast variable load state. If the load change rate is not greater than the rate threshold, it is called a slow variable load state.

[0075] In the embodiment of the present invention, the existence of a target heat exchange demand means that the device is in a fast load change state. The controller can collect load changes to determine whether the current device is in a fast load change state, and further determine whether there is a target heat exchange demand.

[0076] S12, controlling the main line valve to close, and controlling the inflow control valve and the outflow control valve to open, the heat-conductive particles output by the particle output device are mixed with the working fluid to obtain a particle suspension, and the particle suspension flows through the thermal inertia tube bundle.

[0077] In steady-state operation, the main line valve is open, the inflow control valve and the outflow control valve are closed, and the thermal inertia control device remains silent.

[0078] When the boiler is in rapid load change operation, the inflow control valve and the outflow control valve are opened, and the main pipeline valve is closed. The working medium flows through the inflow bypass pipeline 03, and the Venturi fluid-solid mixer injects heat-conducting particles into the working medium. The heat-conducting particles are mixed with the working medium to eventually form a relatively stable particle suspension with a high thermal conductivity coefficient.

[0079] After the particle suspension completes heat exchange with the thermal inertia tube bundle, it enters the fluid-solid separator 51 for separation, and after separation, the heat-conducting particles enter the discharge tank for recovery.

[0080] After the boiler load change operation ends, the heat exchange control system continues to operate for a period of time t (the time t is related to the boiler load change rate and the thermal physical parameters of the thermal inertia pipe section) and then shuts down to recover all the heat-conducting particles as much as possible and keep the temperature of the working fluid stable.

[0081] In one implementation, after controlling the inflow control valve and the outflow control valve to open, the heat exchange control method further includes:

[0082] In the case where the particle output device includes a heat-conducting particle storage device and a particle flow control valve, the opening of the particle flow control valve is adjusted based on the load change rate and the working medium flow rate.

[0083] In actual scenarios, when the particle output device includes a thermally conductive particle storage device and a particle flow control valve, the particle flow control valve can be used to adjust the flow of the thermally conductive particles output by the thermally conductive particle storage device.

[0084] More specifically, the sticking of the particle flow control valve can be determined according to the load change rate and the working fluid flow rate, thereby adjusting the amount of injected thermal conductive particles.

[0085] In actual scenarios, the corresponding relationship among the load change rate, the working fluid flow rate and the opening of the particle flow control valve may be pre-configured, for example, the corresponding relationship may be stored in a table or the like.

[0086] In the specific configuration process of the corresponding relationship, the corresponding relationship can be established by considering load change rate, working fluid flow rate, thermal conductivity of heat-conducting particles, thermal conductivity of working fluid, temperature of working fluid, and required temperature of working fluid, etc. In one implementation, the corresponding relationship can be obtained through multiple experiments.

[0087] In the actual control process, after detecting the load change rate and the working fluid flow rate, the opening of the corresponding particle flow control valve can be obtained by looking up the table, and then the opening can be used to control the corresponding heat-conducting particle flow rate to better meet the temperature requirements of the working fluid.

[0088] In this embodiment, when there is a target heat exchange demand, the main pipeline valve is closed, the inflow control valve and the outflow control valve are opened, and the heat-conductive particles output by the particle output device are mixed with the working fluid to obtain a particle suspension. Since the thermal conductivity of the heat-conductive particles is greater than the thermal conductivity of the working fluid flowing into the inflow bypass pipeline 03, the thermal conductivity of the particle suspension after the two are mixed is greater than the thermal conductivity of the working fluid. When the particle suspension flows through the thermal inertia tube bundle, the heat exchange between the working fluid and the inner wall of the thermal inertia tube bundle is enhanced during rapid load changes, and the heat exchange rate of the working fluid is increased when the working fluid is under-temperature, so that the working fluid can reach the required temperature, improve the accuracy of heat exchange, and ensure the safe operation of subsequent equipment.

[0089] It should be noted that the bypass valve, mixer and particle recovery device in the present invention only occur during the period of rapid load change of the boiler and have no effect on the stable load operation of the boiler.

[0090] In addition, the installation, debugging, disassembly maintenance and automation transformation of the present invention have no influence on the normal operation of the boiler heating surface tube bundle. It can be installed at the beginning of equipment design or during equipment operation. It has the advantages of easy implementation, simple installation and convenient transformation.

[0091] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention will be further described in detail below by taking the final superheater tube bundle of a coal-fired unit as an example in conjunction with the accompanying drawings.

[0092] In this embodiment, the final superheater of a 350MW supercritical tower-type once-through boiler in a power plant is modified to add a heat exchange control system, which can also be called a thermal inertia control device. Figure 1 and 2As shown. The straight tube section (i.e. thermal inertia tube bundle) of a tube of the final superheater is selected for analysis. The specification of the straight tube section is Φ51×8mm and the length is 13687mm. The structural material of the tube body is S30432 with a density of 7940kg / m 3 The study considers the temperature-related changes in material properties. A typical load-increasing condition is selected for study: steady-state 75% THA (turbines heat acceptance) rises to 100% THA and then operates stably. The boundary conditions used in the simulation are shown in Table 1.

[0093] Table 1 Boundary conditions used in simulation

[0094]

[0095]

[0096] The working medium in the embodiment of the present invention is steam, and the heat release power of the flue gas to the outer wall of the tube is defined as P f , in kW; the heat release power from the inner wall of the tube to the steam is P g , the unit is kW. Define the tube heat absorption as positive, heat release as negative, then the tube heat absorption power ΔP can be expressed as ΔP = P f -P g When the boiler is in steady state operation, the heat transfer power of flue gas-tube bundle is P f Heat exchange power P with steam-tube bundle g When the boiler is operated with variable load, affected by the thermal inertia of the tube bundle of the final superheater, P f and P g The balance is broken. The heat transferred by the flue gas to the tube bundle is not only absorbed by the steam, but also used to change the temperature of the tube bundle itself. Figure 4 The figure shows the change of the heat absorption power of the final superheater with time at different load change rates during the load increase process. Figure 4 (a) It can be seen that under different variable load rates, P f It increases linearly with time during the load increase process and remains unchanged when the load is stable, all stabilizing at around 61.2kW. This shows that during the load increase process, the heat exchange between the flue gas and the tube bundle is only related to the boiler load and is not affected by the load change rate. Figure 4 (b) shows the variation of the heat transfer power of the steam-tube bundle over time. f It does not change linearly with t, P f and P g There is a certain deviation. This deviation increases with the increase of the variable load rate. The change of the heat absorption power ΔP of the straight tube section of the final superheater with time, such as Figure 4(c) As shown. Under different variable load rates, ΔP gradually increases during the load increase process, remains unchanged after reaching the peak value, and decreases to 0 when the load is stable. In this process, the growth rate and decay rate of ΔP heat absorption power are related to the variable load rate. The greater the variable load rate, the faster the growth rate and decay rate of ΔP. In addition, the peak value of ΔP also increases with the increase of the variable load rate.

[0097] The above research shows that in the process of variable load, the heat transfer power P of the flue gas-tube bundle f Heat exchange power P with steam-tube bundle g There is a deviation. f Determined by the boiler load and not affected by the load change rate. g Affected by the load change rate, the heat absorption power of the final superheater changes during the load change process. Therefore, increasing the heat exchange between the steam and the inner wall of the final superheater during the load change process helps to reduce the impact of thermal inertia on steam parameters.

[0098] use Figure 1 or the thermal inertia control device disclosed in 2, due to the addition of particles with high thermal conductivity, the thermal conductivity of the mixed working fluid increases, and the steam-tube bundle heat exchange power P g Also increased. Figure 5 It shows that when the thermal conductivity of the mixed working fluid increases from 0.1W / (m·K) to 0.5W / (m·K), the growth value of the steam-tube bundle heat transfer power at different variable load rates ΔP g It can be seen that ΔP g is always greater than 0, and ΔP g The peak value of increases with the increase of the variable load rate. This shows that the use of Figure 1 Or 2's thermal inertia control device can reduce the impact of the thermal inertia of the heating surface tube bundle of the rapid load change boiler on the steam parameters to a certain extent.

[0099] In this embodiment, the heat-conductive particles in the thermal inertia control device are used to form a particle suspension with a high thermal conductivity coefficient with the unit working fluid, so as to enhance the heat exchange between the unit working fluid and the inner wall of the heating surface tube bundle during rapid load changes. The amount of injected particles is adjusted according to the load change rate of the boiler and the working fluid flow rate, thereby reducing the lag in the change of the unit working fluid parameters caused by the thermal inertia of the boiler heating surface tube bundle itself during the rapid load change process, so that the working fluid temperature reaches the required temperature.

[0100] An embodiment of the present application also provides an electronic device for executing the above-mentioned heat exchange control method.

[0101] refer to Figure 6As shown, it shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiments of the present application. The electronic device in the embodiments of the present application may include but is not limited to fixed terminals such as mobile phones, notebook computers, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Figure 6 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0102] like Figure 6 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage device 608 into a random access memory (RAM) 603. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 603. The processing device 601, the ROM 602, and the RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0103] Typically, the following devices may be connected to the I / O interface 605: an input device 606 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 607 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 608 including, for example, a memory card, a hard disk, etc.; and a communication device 609. The communication device 609 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although Figure 6 An electronic device having various devices is shown, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead.

[0104] An embodiment of the present application also provides a computer program product including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements any heat exchange control method for a thermal inertia tube bundle provided in the embodiment of the present application.

[0105] A computer-readable storage medium is also provided in an embodiment of the present application. The storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any one of the heat exchange control methods for a thermal inertia tube bundle provided in the embodiment of the present application.

[0106] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A heat exchange control system applied to a thermal inertia tube bundle, characterized in that: include: Inflow main pipeline, outflow main pipeline, inflow bypass pipeline and outflow bypass pipeline; The inflow main pipeline and the inflow bypass pipeline are connected to the input end of the thermal inertia tube bundle after being arranged in parallel, and the inflow main pipeline and the outflow bypass pipeline are connected to the output end of the thermal inertia tube bundle after being arranged in parallel; The main inflow pipe and the main inflow pipe are respectively provided with main pipe valves; the inflow bypass pipe is provided with an inflow control valve and a particle output device, and the outflow bypass pipe is provided with an outflow control valve and a particle recovery device; the particle output device stores heat-conductive particles; the thermal conductivity of the heat-conductive particles is greater than the thermal conductivity of the working fluid flowing into the inflow bypass pipe; When there is a target heat exchange demand, the main line valve is closed, the inflow control valve and the outflow control valve are opened, the heat-conductive particles output by the particle output device are mixed with the working fluid to obtain a particle suspension, and the particle suspension flows through the thermal inertia tube bundle.

2. The heat exchange control system applied to the thermal inertia tube bundle according to claim 1, characterized in that: The particle output device is a mixer, and the mixer is connected to the inflow bypass pipeline in the form of a variable cross-section, so that the mixer drives the heat-conducting particles to mix with the working medium by using the pressure difference generated when the working medium flows through the variable cross-section.

3. The heat exchange control system applied to the thermal inertia tube bundle according to claim 2, characterized in that: The particle output device includes a heat-conducting particle storage device and a particle flow control valve; According to the flow sequence of the working medium in the inflow bypass pipeline, the heat-conducting particle storage device is arranged before the particle flow control valve.

4. The heat exchange control system applied to the thermal inertia tube bundle according to claim 3 is characterized in that: The inflow control valve includes a first bypass valve and a second bypass valve; the first bypass valve is arranged before the heat-conducting particle storage device, and the second bypass valve is arranged after the particle flow control valve.

5. The heat exchange control system applied to the thermal inertia tube bundle according to any one of claims 1 to 4, characterized in that: The outflow control valve includes a third bypass valve and a fourth bypass valve, and the particle recovery device is arranged between the third bypass valve and the fourth bypass valve.

6. The heat exchange control system applied to the thermal inertia tube bundle according to claim 5, characterized in that: The particle recovery device comprises: Separators and discharge devices are connected in sequence.

7. The heat exchange control system applied to the thermal inertia tube bundle according to claim 6, characterized in that: The third bypass valve and the fourth bypass valve are respectively arranged at two ends of the separator.

8. The heat exchange control system applied to the thermal inertia tube bundle according to claim 1, characterized in that: The main line valve, the inflow control valve and the outflow control valve are controlled to open and close by a controller in the heat exchange control system.

9. A heat exchange control method applied to a thermal inertia tube bundle, characterized in that: Applied to the heat exchange control system according to any one of claims 1 to 8, the heat exchange control method comprises: When there is a target heat exchange demand, the main line valve is controlled to be closed, and the inflow control valve and the outflow control valve are controlled to be opened, and the heat-conductive particles output by the particle output device are mixed with the working fluid to obtain a particle suspension, and the particle suspension flows through the thermal inertia tube bundle.

10. The heat exchange control method applied to the thermal inertia tube bundle according to claim 9, characterized in that: After controlling the inflow control valve and the outflow control valve to open, the method further includes: In the case where the particle output device includes a heat-conducting particle storage device and a particle flow control valve, the opening of the particle flow control valve is adjusted based on the load change rate and the working medium flow rate.

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