Multi-mass regenerative system

Abstract

The application relates to a multi-heat recovery system. The system comprises a boiler, a steam turbine, a first heat exchanger, a second heat exchanger, a first heater, an air preheater and a condenser. Flue gas generated by combustion of the boiler enters the first heat exchanger through a flue gas outlet, steam generated by combustion of the boiler enters the steam turbine through an exhaust outlet to drive the steam turbine to work and exhaust steam flows into the first heater, the second heat exchanger and the condenser through exhaust outlets respectively, the condenser converts the steam into feed water which is output to the first heater through a water outlet; the first heater heats the feed water by using steam, and the heated feed water flows into the first heat exchanger; the first heat exchanger heats the feed water by using the flue gas, and the heated feed water is sent into the boiler; the second heat exchanger preheats air by using steam, and the preheated air is sent into the air preheater; the air preheater heats the preheated air, and the heated air is sent into the boiler to participate in the combustion process. The system is beneficial to improving energy utilization.

Description

Technical Field

[0001] This application relates to the field of coal-fired power generation technology, and in particular to a multi-material regenerative system. Background Technology

[0002] The operation of a power plant is a complex and highly integrated system that encompasses multiple stages, including fuel combustion, energy conversion, steam-water circulation, and flue gas treatment.

[0003] In related technologies, a scheme using a low-temperature economizer to heat condensate involves further recovering low-temperature waste heat from the flue gas to heat boiler feedwater or other working fluids (such as heating water or industrial water), thereby further improving system efficiency. The low-temperature economizer is typically installed after the air preheater, allowing for further utilization of flue gas waste heat, reduction of flue gas temperature, and simultaneous heating of feedwater.

[0004] However, because the flue gas temperature entering the low-temperature economizer is too low, it can only heat the condensate at a relatively low temperature. The original heating source for this condensate was low-pressure cylinder extraction steam with lower parameters. Therefore, this scheme is equivalent to using flue gas of the same quality to replace steam of the same quality for heating feedwater, which has a certain energy-saving effect, but the energy utilization rate is low. Summary of the Invention

[0005] Therefore, it is necessary to provide a multi-mass regenerative system that can improve energy utilization efficiency to address the aforementioned technical problems.

[0006] This application provides a multi-mass regenerative system, which includes a boiler, a steam turbine, a first heat exchanger, a second heat exchanger, a first heater, an air preheater, and a condenser.

[0007] During the combustion process, the boiler generates flue gas which enters the first heat exchanger through the flue gas outlet. During the combustion process, the boiler generates steam which enters the steam turbine through the exhaust outlet to drive the steam turbine.

[0008] During operation, the steam discharged from the turbine flows into the first heater, the second heat exchanger and the condenser through the exhaust port. The condenser converts the steam into feedwater and outputs it to the first heater through the drain port.

[0009] The first heater uses the incoming steam to heat the incoming feedwater, and sends the heated feedwater into the first heat exchanger through the drain outlet;

[0010] The first heat exchanger uses flue gas to heat the incoming feedwater and then sends the heated feedwater into the boiler through the drain outlet.

[0011] The second heat exchanger uses the incoming steam to preheat the incoming air, and then sends the preheated air into the air preheater through the exhaust port.

[0012] The air preheater heats the preheated air and sends the heated air into the boiler through the exhaust port to participate in the combustion process in the boiler.

[0013] In one embodiment, the steam discharged from the turbine includes first steam; the system also includes a first steam regulating valve disposed between the turbine exhaust port and the first heater inlet;

[0014] The first steam regulating valve regulates the flow rate of the first steam and sends the first steam into the first heater;

[0015] The first heater uses the first steam to heat the incoming feedwater, and then sends the heated feedwater through the outlet into the first heat exchanger.

[0016] In one embodiment, the system further includes a first water supply regulating valve disposed between the drain outlet of the first heater and the inlet of the first heat exchanger, and a second water supply regulating valve disposed between the inlet of the boiler and the outlet of the first heater.

[0017] The first feedwater regulating valve regulates the flow rate of the heated feedwater output from the first heater and sends the incoming feedwater into the first heat exchanger.

[0018] The second feedwater regulating valve adjusts the flow rate of the heated feedwater output from the first heater and sends the adjusted feedwater into the boiler.

[0019] In one embodiment, the steam discharged from the turbine also includes second steam; the system also includes a second steam regulating valve disposed between the exhaust port of the turbine and the inlet of the second heat exchanger;

[0020] The second steam regulating valve regulates the flow rate of the second steam and sends the second steam into the second heat exchanger. The pressure of the first steam is greater than the pressure of the second steam.

[0021] The second heat exchanger uses the second steam to preheat the incoming air, and then sends the preheated air into the air preheater through the exhaust port.

[0022] The second heater uses the supplied second steam to heat the condensate output from the condenser, and then sends the heated condensate into the first heater through the drain outlet.

[0023] In one embodiment, the system further includes a condensate regulating valve disposed between the drain outlet of the second heat exchanger and the inlet of the second heater, and a flue gas regulating valve disposed between the exhaust outlet of the boiler and the inlet of the first heat exchanger.

[0024] The condensate regulating valve regulates the flow rate of the condensate output from the second heat exchanger after heat exchange, and sends the inflowing condensate into the second heater.

[0025] The flue gas regulating valve regulates the flow rate of the flue gas output from the boiler and sends the incoming flue gas into the first heat exchanger.

[0026] In one embodiment, the second steam regulating valve, condensate regulating valve, flue gas regulating valve and the first feedwater regulating valve are all open, and the second feedwater regulating valve is closed, so that the heat exchange capacity of the first heat exchanger and the heat exchange capacity of the second heat exchanger are matched.

[0027] In one embodiment, the second steam regulating valve, condensate regulating valve, flue gas regulating valve and the first feedwater regulating valve are all open, and the second feedwater regulating valve is closed, so that the heat exchange capacity of the first heat exchanger is greater than that of the second heat exchanger.

[0028] In one embodiment, the second steam regulating valve, the condensate regulating valve, and the second feedwater regulating valve are all closed, while the flue gas regulating valve and the first feedwater regulating valve are all open, so as to increase the feedwater temperature and reduce the flue gas heat.

[0029] In one embodiment, the second steam regulating valve, the condensate regulating valve, the flue gas regulating valve, and the first feedwater regulating valve are all open; the second feedwater regulating valve is closed.

[0030] The first steam regulating valve reduces the flow rate of the first steam so that the heat of the reduced first steam matches the heat exchange of the first heat exchanger, and the heat exchange of the first heat exchanger matches the heat exchange of the second heat exchanger.

[0031] In one embodiment, the second steam regulating valve, the condensate regulating valve, the flue gas regulating valve and the first feedwater regulating valve are all open, and the second feedwater regulating valve is closed.

[0032] The first steam regulating valve reduces the flow rate of the first steam so that the heat of the reduced first steam matches the heat exchange capacity of the first heat exchanger, and the heat exchange capacity of the first heat exchanger is greater than that of the second heat exchanger.

[0033] The aforementioned multi-material regenerative system differs from related technologies that utilize flue gas preheating to reduce flue gas temperature and heat feedwater via an economizer installed after the air preheater. Instead, it adds a second heat exchanger before the air preheater, connecting it to the turbine's steam pipeline. A first heat exchanger is added after the boiler's flue gas pipeline, using the flue gas to heat feedwater and increase the feedwater temperature on the boiler feedwater side. This effectively changes the flue gas originally intended for air preheating to one used for feedwater heating. Since some of the flue gas used for air heating is now used for feedwater heating, to improve the stability of the exhaust gas temperature and avoid affecting the air preheater outlet air temperature, steam is used to heat the air entering the air preheater, bringing the air outlet air to its previous temperature while maintaining the unit's exhaust gas temperature. This creates a multi-material regenerative system for coal-fired power units, utilizing flue gas, steam, and feedwater in a cascade manner. This increases the boiler feedwater temperature while reducing the amount of exhaust steam entering the condenser, thereby reducing cold-end losses, improving the overall energy utilization rate of the coal-fired power unit, and reducing coal consumption. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a structural block diagram of a multi-mass regenerative system in one embodiment;

[0036] Figure 2 This is a structural block diagram of a multi-mass regenerative system in another embodiment. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0038] The operation of a power plant is a complex and highly integrated system, encompassing multiple stages such as fuel combustion, energy conversion, steam-water circulation, and flue gas treatment. Specifically, firstly, fuel (such as coal) is burned in the boiler's combustion chamber, producing high-temperature flue gas with temperatures reaching over 1000°C. This high-temperature flue gas flows within the boiler, transferring heat to the boiler's water-cooled walls, superheaters, reheaters, and other heating surfaces through radiation and convection. This process causes the water in the boiler to undergo three stages: preheating, evaporation, and superheating, generating high-temperature, high-pressure steam.

[0039] Steam first enters the high-pressure cylinder of the turbine to expand and do work. The steam discharged from the high-pressure cylinder returns to the boiler for reheating, forming high-temperature reheated steam. The reheated steam then enters the intermediate-pressure cylinder of the turbine to continue expanding and doing work, and finally enters the low-pressure cylinder to complete the work process. The steam expands stage by stage in the turbine, driving the turbine rotor to rotate and converting thermal energy into mechanical energy. The turbine rotor is connected to a generator, which further converts the mechanical energy into electrical energy. The electrical energy generated by the generator is stepped up by a transformer and sent to the power grid. The steam, after doing work, exits the turbine and enters the condenser, where it is cooled by cooling water and condenses into liquid water (condensate), releasing a large amount of latent heat in the process. Condensate is pumped into the low-pressure heater by a condensate pump. The steam source for the low-pressure heater is a portion of the steam extracted from the low-pressure cylinder of the turbine. This steam heats the condensate in the low-pressure heater, raising its temperature. Subsequently, the condensate is pressurized by a feedwater pump and enters the high-pressure heater. The steam source for the high-pressure heater is a portion of the steam extracted from the high- and intermediate-pressure cylinders of the turbine. This steam further heats the feedwater in the high-pressure heater. Finally, the feedwater returns to the boiler, completing the steam-water cycle.

[0040] Meanwhile, the high-temperature flue gas generated by combustion releases heat in the boiler, reducing its temperature before entering the flue gas treatment system. It undergoes multi-stage treatment, including denitrification devices (such as SCR (Selective Catalytic Reduction) or SNCR (Selective Non-Catalytic Reduction)), dust collectors (such as electrostatic precipitators or bag filters), and desulfurization devices (such as wet desulfurization), reducing emissions of pollutants such as nitrogen oxides (NOx), particulate matter (PM), and sulfur dioxide (SO2). The treated flue gas is then discharged into the atmosphere through a chimney. To improve overall efficiency, power plants typically utilize the waste heat from the flue gas to heat the combustion air. For example, an air preheater is added between the denitrification and dust removal systems. The temperature of the flue gas entering the air preheater is 300-400℃, while the exhaust temperature is 100-200℃. The preheated air temperature is generally above 300℃.

[0041] The current method of heating condensate using a low-temperature economizer only heats the relatively low-temperature condensate because the flue gas temperature entering the economizer is too low. This condensate was originally heated by low-pressure cylinder steam with lower parameters. Therefore, this method is equivalent to using flue gas of the same quality to replace steam of the same quality for heating feedwater, which has some energy-saving effect, but the energy utilization rate is low.

[0042] In one exemplary embodiment, such as Figure 1As shown, a multi-mass regenerative system is provided, including a first heat exchanger 110, a second heat exchanger 120, an air preheater 200, a first heater 310, a boiler 400, a steam turbine 500, and a condenser 600. Wherein:

[0043] During the combustion process, the boiler 400 generates flue gas which enters the first heat exchanger 110 through the flue gas outlet. During the combustion process, the boiler 400 generates steam which enters the steam turbine 500 through the exhaust outlet to drive the steam turbine 500 to work.

[0044] Flue gas refers to the high-temperature flue gas formed after fuel is burned in the combustion chamber of a boiler.

[0045] In practice, the raw coal in the coal hopper is ground into pulverized coal, which is then sent into the boiler's combustion chamber by a blower. The high-temperature flue gas generated from the combustion flows along the boiler's flue gas duct and enters the denitrification system for denitrification treatment. The denitrified flue gas is then sent to the first heat exchanger through a pipeline. During the pulverized coal combustion process, water in the steam drum (not shown in the figure), which is connected to the water-cooled wall (not shown in the figure), circulates continuously through the water-cooled wall, absorbing the heat released during the pulverized coal combustion. Some of the water is heated and boiled in the water-cooled wall and vaporized into steam. This steam passes through the superheater (not shown in the figure) to become superheated steam. Superheated steam has very high pressure and temperature, and therefore has a large thermal potential energy. This superheated steam with thermal potential energy is introduced into the steam turbine through a pipeline. The steam turbine converts the thermal potential energy into kinetic energy, driving the turbine rotor to rotate and generating mechanical energy. The turbine rotor is connected to the generator rotor through a coupling, thereby driving the generator rotor to rotate and converting the mechanical energy of the steam turbine into electrical energy.

[0046] The steam turbine comprises core components such as a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder, which together form a three-stage system for steam energy conversion, achieving efficient power generation through multi-stage expansion. Each of the high-pressure, intermediate-pressure, and low-pressure cylinders includes multiple pressure stages.

[0047] During operation, the steam discharged from the turbine 500 flows into the first heater 310, the second heat exchanger 120 and the condenser 600 through the exhaust port. The condenser 600 converts the steam into feedwater and outputs it to the first heater 310 through the drain port.

[0048] In practice, during the process of the steam turbine converting thermal potential energy into kinetic energy, a portion of the steam that has performed work is discharged from the turbine's exhaust port. This portion of steam flows into the first heater, the second heat exchanger, and the condenser through the exhaust port. The condenser cools and condenses the incoming steam, which is then used as part of the feedwater and discharged to the first heater through the drain port.

[0049] The first heater 310 uses the incoming steam to heat the incoming feedwater, and sends the heated feedwater into the first heat exchanger 110 through the drain outlet.

[0050] In specific implementation, following the above steps, the first heater uses the working steam flowing in to exchange heat with the feedwater in the shell and tube bundle of the first heater. The steam releases heat to raise the feedwater temperature. Subsequently, the feedwater output from the first heater is sent to the first heat exchanger through the drain port of the first heater. In one embodiment, working steam can be drawn from the high-pressure cylinder and the low-pressure cylinder for heat exchange.

[0051] The first heat exchanger 110 uses flue gas to heat the incoming feedwater and sends the heated feedwater into the boiler 400 through the drain outlet.

[0052] In specific implementation, following the above implementation steps, the first heat exchanger uses the high-temperature flue gas after denitrification to exchange heat with the feedwater output from the first heater, thereby increasing the feedwater temperature. The heated feedwater is then transported to the boiler feedwater side through the drain outlet and pipeline, and the flue gas after heat exchange is output to the dust removal system for dust removal treatment through the flue gas outlet.

[0053] The second heat exchanger 120 uses the incoming steam to preheat the incoming air, and sends the preheated air into the air preheater 200 through the exhaust port.

[0054] In specific implementation, following the above steps, during boiler combustion, a blower supplies air into the boiler to provide combustion air. Before being supplied to the boiler, the air needs to be preheated by an air preheater. In this embodiment, steam that has already performed work can be drawn from the low-pressure cylinder of the turbine. This steam is then sent to the second heat exchanger through the exhaust port and pipes of the low-pressure cylinder. The second heat exchanger uses the heat of this incoming steam to preheat the air supplied by the blower. Subsequently, the preheated air is sent to the air preheater through the exhaust port, while the steam, after heat exchange, is converted into condensate and returned to the condenser. In other embodiments, the condenser can also be other condensate systems.

[0055] The air preheater 200 heats the preheated air and sends the heated air into the boiler 400 through the exhaust port to participate in the combustion process in the boiler 400.

[0056] In practice, following the steps above, a portion of the flue gas discharged from the boiler's exhaust outlet is sent to the denitrification system. This denitrified flue gas is then piped into an air preheater. The air preheater uses the heat from this flue gas to heat the preheated air output from the second heat exchanger, which is then sent into the boiler for combustion. The flue gas after heat exchange mixes with the flue gas after heat exchange in the first heat exchanger and enters the dust removal system for dust removal. After desulfurization treatment in the desulfurization system, it is discharged from the system through the chimney. Figure 2 As shown.

[0057] The aforementioned multi-material regenerative system differs from related technologies that utilize flue gas preheating to reduce flue gas temperature and heat feedwater via an economizer installed after the air preheater. Instead, it adds a second heat exchanger before the air preheater, connecting it to the turbine's steam pipeline. A first heat exchanger is added after the boiler's flue gas pipeline, using the flue gas to heat feedwater and increase the feedwater temperature on the boiler feedwater side. This effectively changes the flue gas originally intended for air preheating to one used for feedwater heating. Since some of the flue gas used for air heating is now used for feedwater heating, to improve the stability of the exhaust gas temperature and avoid affecting the air preheater outlet air temperature, steam is used to heat the air entering the air preheater, bringing the air outlet air to its previous temperature while maintaining the unit's exhaust gas temperature. This creates a multi-material regenerative system for coal-fired power units, utilizing flue gas, steam, and feedwater in a cascade manner. This increases the boiler feedwater temperature while reducing the amount of exhaust steam entering the condenser, thereby reducing cold-end losses, improving the overall energy utilization rate of the coal-fired power unit, and reducing coal consumption.

[0058] In one exemplary embodiment, the steam discharged from the turbine 500 includes first steam, such as... Figure 2 As shown, the system also includes a first steam regulating valve 710 disposed between the exhaust port of the steam turbine 500 and the inlet of the first heater 310. Wherein:

[0059] The first steam regulating valve 710 regulates the flow rate of the first steam and sends the first steam into the first heater 310.

[0060] The first heater 310 uses first steam to heat the incoming feedwater, and sends the heated feedwater through the outlet into the first heat exchanger 110.

[0061] The number of first steam regulating valves can be multiple. For example, the first steam regulating valves can be located on pipes between different pressure levels in the high-pressure cylinder and the first heater, or they can be located on pipes between the intermediate-pressure cylinder and the first heater. In this embodiment, as... Figure 2As shown, the number of first heaters matches the number of first steam regulating valves. Specifically, first steam regulating valve 12 and first steam regulating valve 13 are installed on the pipelines between the two different pressure stages of the high-pressure cylinder and the first heaters. First steam regulating valve 14 is installed on the pipeline between the intermediate-pressure cylinder and the first heaters.

[0062] In specific implementation, following the steps of the above embodiments, the high-pressure cylinder and intermediate-pressure cylinder in the steam turbine each include multiple pressure stages. Steam output from the boiler enters the high-pressure cylinder of the steam turbine to perform work. The first steam regulating valve 12 and the first steam regulating valve 13 transport the first steam that has performed work in the high-pressure cylinder to the first heater. The first steam regulating valve 14 transports the first steam that has performed work in the intermediate-pressure cylinder to the first heater. The first steam regulating valve can be an electric regulating valve, a self-operated regulating valve, or an intelligent regulating valve, etc. The first steam regulating valve can control the flow rate of the first steam according to a preset opening degree, or it can adjust the opening degree in real time according to operational requirements to adjust the flow rate of the first steam.

[0063] Following the steps above, such as Figure 2 As shown, there are multiple first heaters, exemplarily matching the number of first steam regulating valves. Assume the first steam flowing through the first extraction valve 12 is sent to the first sub-heater 312, the first steam flowing through the first extraction valve 13 is sent to the second sub-heater 314, and the first steam flowing through the first extraction valve 14 is sent to the third sub-heater 316. The feedwater output from the condenser, after deaeration by the deaerator, sequentially enters the third sub-heater 316, the second sub-heater 314, and the first sub-heater 312. The third sub-heater 316, the second sub-heater 314, and the first sub-heater 312 respectively use the first steam to heat the feedwater, increasing its temperature. Subsequently, the heated feedwater is sent to the first heat exchanger through the drain outlet of the first heater.

[0064] Understandably, as an example, such as Figure 2 The illustrated regenerative system consists of three first heaters (high-pressure heaters), one deaerator, and four second heaters (low-pressure heaters), forming an eight-stage regenerative system. The number of first steam regulating valves matches the number of first heaters, and the number of second steam regulating valves matches the number of second heaters. In other embodiments, the configuration of the regenerative system is not limited to this. For example, the regenerative system can also be a ten-stage regenerative system consisting of four first heaters, a first deaerator, and five second heaters. Correspondingly, the number and connection relationship of the first and second steam regulating valves vary adaptively according to the configuration of the regenerative system.

[0065] In this embodiment, the steam that has already done work is used to heat the feedwater, thereby improving energy efficiency.

[0066] In one exemplary embodiment, such as Figure 2 As shown, the system also includes a first water supply regulating valve 10 disposed between the drain outlet of the first heater 310 and the inlet of the first heat exchanger 110, and a second water supply regulating valve 11 disposed between the inlet of the boiler 400 and the outlet of the first heater 310.

[0067] The first water supply regulating valve 10 regulates the flow rate of the heated water output from the first heater 310, and sends the incoming water into the first heat exchanger 110.

[0068] In specific implementation, such as Figure 2 As shown, the first feedwater regulating valve 10 is installed on the pipeline between the first sub-heater 312 and the first heat exchanger. Following the above steps, the feedwater is heated stage by stage through the third sub-heater 316, the second sub-heater 314, and the first sub-heater 312, and then output from the third sub-heater 316. The output flow rate of the heated feedwater can be controlled according to the preset opening degree of the first feedwater regulating valve. The first feedwater regulating valve can be an electric regulating valve, a self-operated regulating valve, or an intelligent regulating valve, etc.

[0069] The second feedwater regulating valve 11 regulates the flow rate of the heated feedwater output from the first heater 310 and sends the feedwater into the boiler 400.

[0070] In specific implementation, such as Figure 2 As shown, the second feedwater regulating valve 11 is installed on the pipeline between the first sub-heater 312 and the boiler. The second feedwater regulating valve can be opened and closed according to actual operational needs to control the direction and flow rate of the feedwater.

[0071] In this embodiment, a water supply regulating valve is set to adapt to the power generation needs under different operating conditions.

[0072] In one exemplary embodiment, the steam discharged from the turbine 500 also includes a second type of steam, such as... Figure 2 As shown, the system also includes a second steam regulating valve 720 disposed between the steam turbine 500 and the second heat exchanger 120.

[0073] The second steam regulating valve 720 regulates the flow rate of the second steam and sends the regulated second steam into the second heat exchanger 120. The pressure of the first steam is greater than the pressure of the second steam.

[0074] Following the steps of the above embodiments, such as Figure 2 As shown, there are multiple second steam regulating valves, and correspondingly, there are multiple second heaters. The number of second steam regulating valves matches the number of second heaters. Figure 2As shown, the second steam regulating valve includes a second steam regulating valve 1, a second steam regulating valve 2, a second steam regulating valve 3, and a second steam regulating valve 4. These regulating valves are respectively connected to the steam output ports of different pressure levels in the low-pressure cylinder of the steam turbine.

[0075] In practice, the second steam regulating valve can adjust the flow rate of the second steam that has done work, which is partially drawn from the low-pressure cylinder of the steam turbine, according to a preset opening degree, so that the second steam is transported to the second heat exchanger through the pipeline.

[0076] The second heat exchanger 120 uses the second steam to preheat the incoming air, and then sends the preheated air into the air preheater 200 through the exhaust port.

[0077] In practice, following the steps described above, the second steam is fed into the second heat exchanger. The second heat exchanger uses the heat of the second steam to exchange heat with the incoming air, thereby preheating the incoming air. Subsequently, the preheated air is sent into the air preheater through a pipeline. After heat exchange, the second steam is converted into condensate and returns to the condenser through a drain outlet.

[0078] The second heater 320 uses the supplied second steam to heat the condensate output from the condenser 600, and then sends the heated condensate to the first heater 310.

[0079] In specific implementation, such as Figure 2 As shown, the second heater includes a fourth sub-heater 322, a fifth sub-heater 324, a sixth sub-heater 326, and a seventh sub-heater 328. Following the above steps, the second steam, after heat exchange in the second heat exchanger, is converted into condensate and transported to the second heater through a pipeline. A portion of the second steam drawn from the low-pressure cylinder is also transported to the second heater, where it heats the condensate. The heated condensate is then sent to the deaerator, where it undergoes deoxygenation before being fed into the first heater.

[0080] In this embodiment, the air is preheated using low-quality steam, which improves energy efficiency.

[0081] In one exemplary embodiment, such as Figure 2 As shown, the system also includes a condensate regulating valve 800 located between the drain outlet of the second heat exchanger 120 and the inlet of the second heater 320, and a flue gas regulating valve 9 located between the exhaust outlet of the boiler 400 and the inlet of the first heat exchanger 110.

[0082] The condensate regulating valve 800 regulates the flow rate of the condensate output from the second heat exchanger 120 after heat exchange, and sends the condensate into the second heater 320.

[0083] In specific implementation, such as Figure 2 As shown, there are multiple condensate regulating valves, including condensate regulating valve 1 (5), condensate regulating valve 2 (6), condensate regulating valve 3 (7), and condensate regulating valve 4 (8). These valves sequentially adjust the flow rate of the condensate after heat exchange from the second heat exchanger, and then sequentially send it into multiple second heat exchangers. Finally, the condensate flows back to the condenser via pipelines, achieving working fluid recovery.

[0084] The flue gas regulating valve 9 regulates the flow rate of the flue gas output from the boiler 400 and sends the regulated flue gas into the first heat exchanger 110.

[0085] In specific implementation, such as Figure 2 As shown, the flue gas regulating valve 9 can adjust the flow rate of the high-temperature flue gas output from the boiler according to the preset opening degree, and then send it into the first heat exchanger to achieve feedwater heating.

[0086] In this embodiment, the working fluid is recovered through the condensate regulating valve, and the operation of the first heat exchanger is controlled through the flue gas regulating valve, which helps to improve the flexibility of system operation.

[0087] In one exemplary embodiment, such as Figure 2 As shown, the second steam regulating valve 720, condensate regulating valve, flue gas regulating valve 9 and the first feedwater regulating valve 10 are all open, and the second feedwater regulating valve 11 is closed, so that the heat exchange capacity of the first heat exchanger and the heat exchange capacity of the second heat exchanger are matched.

[0088] In this embodiment, the regeneration mode of the multi-material regeneration system can be adjusted by regulating the opening and closing of different valves, thereby achieving coal consumption reduction in various dimensions. It is understood that the adjustment methods for valve opening and closing will differ depending on the type of valve. In this embodiment, electrically operated regulating valves are used as examples; the valve types described here are merely illustrative and not intended to be the only limitation.

[0089] In this embodiment, the unit's coal consumption can be reduced by increasing the feedwater temperature without changing the flue gas temperature. Specifically, a first operating control command can be sent from the terminal to the valve controller. In response to the first operating control command, the valve controller controls the second steam regulating valve (valve 1-4) and the condensate regulating valve (valve 6-8) to be in the open state, so that steam from the low-pressure cylinder is sent into the second heat exchanger to preheat the air supplied by the blower. The controller controls the flue gas regulating valve 9 and the first feedwater regulating valve 10 to be in the open state, controls the second feedwater regulating valve 11 to be in the closed state, and controls the first steam regulating valve (12-14) to be in the open state, but does not adjust the opening degree of the first steam regulating valve, so that some flue gas enters the first heat exchanger to heat the feedwater, thereby increasing the feedwater temperature entering the boiler. Subsequently, the opening degree of the second steam regulating valve can be adjusted to ensure that the heat exchange capacity of the first and second heat exchangers is the same, i.e., matched, so that the flue gas temperature remains constant. In this way, by increasing the feedwater temperature, the boiler needs to supplement fuel heat, reducing the unit's coal consumption. The opening and closing state of the second steam regulating valve can also be adjusted based on the heat exchange capacity of the first and second heat exchangers to match them. Preferably, valves 4 and 8 can be opened first. If the condition of matching the heat exchange capacity of the first and second heat exchangers is met, then the other valves in the second steam regulating valve and condensate regulating valve need not be opened.

[0090] In one exemplary embodiment, such as Figure 2 As shown, the second steam regulating valve 720, condensate regulating valve, flue gas regulating valve 9 and the first feedwater regulating valve 10 are all open, and the second feedwater regulating valve 11 is closed, so that the heat exchange capacity of the first heat exchanger is greater than that of the second heat exchanger.

[0091] In this embodiment, the unit's coal consumption can be reduced by increasing the feedwater temperature and decreasing the flue gas temperature. Specifically, in response to the second operating control command, the valve controller controls the second steam regulating valve (valve 1-4) and the condensate regulating valve (valve 6-8) to be in the open state, so that the steam from the low-pressure cylinder is sent into the second heat exchanger to preheat the air supplied by the blower. The controller controls the flue gas regulating valve 9 and the first feedwater regulating valve 10 to be in the open state, controls the second feedwater regulating valve 11 to be in the closed state, and controls the first steam regulating valve (12-14) to be in the open state, but does not adjust the opening degree of the first steam regulating valve, so that some flue gas enters the first heat exchanger to heat the feedwater, thereby increasing the feedwater temperature entering the boiler. Subsequently, the opening degree of the second steam regulating valve can be adjusted to control the heat exchange of the first heat exchanger to be greater than that of the second heat exchanger, thereby reducing the flue gas temperature. Thus, due to the increased feedwater temperature, the amount of fuel heat that the boiler needs to replenish is reduced, thus reducing the unit's coal consumption. The on / off state of the second steam regulating valve can be adjusted based on the heat exchange capacity of the first and second heat exchangers, so that the heat exchange capacity of the first heat exchanger is greater than that of the second heat exchanger. Preferably, valves 4 and 8 can be opened first. If the condition that the heat exchange capacity of the first heat exchanger is greater than that of the second heat exchanger is already met, then the other valves in the second steam regulating valve and the condensate regulating valve do not need to be opened.

[0092] In one exemplary embodiment, such as Figure 2 As shown, the second steam regulating valve 720, the condensate regulating valve, and the second feedwater regulating valve 11 are all closed, while the flue gas regulating valve 9 and the first feedwater regulating valve 10 are all open, so as to increase the feedwater temperature and reduce the flue gas heat.

[0093] In this embodiment, the unit's coal consumption can be reduced by increasing the feedwater temperature and further decreasing the flue gas temperature. Specifically, in response to the third operating control command, the valve controller controls the second steam regulating valve (valve 1~4) and the condensate regulating valve (valve 6~8) to be in the closed state, so as not to preheat the air. The controller controls the flue gas regulating valve 9 and the first feedwater regulating valve 10 to be in the open state, controls the second feedwater regulating valve 11 to be in the closed state, and controls the first steam regulating valve (12~14) to be in the open state, but does not adjust the opening degree of the first steam regulating valve, so that some flue gas enters the first heat exchanger to heat the feedwater, thereby increasing the feedwater temperature entering the boiler. Since the flue gas heats up after passing through the first heat exchanger to heat the feedwater, the flue gas temperature decreases, thereby reducing the flue gas temperature. Thus, by increasing the feedwater temperature, the unit's coal consumption is reduced.

[0094] In one exemplary embodiment, such as Figure 2As shown, the second steam regulating valve 720, condensate regulating valve, flue gas regulating valve 9, and first feedwater regulating valve 10 are all open. The second feedwater regulating valve 11 is closed.

[0095] The first steam regulating valve 710 reduces the flow rate of the first steam so that the heat of the reduced first steam matches the heat exchange of the first heat exchanger, and the heat exchange of the first heat exchanger matches the heat exchange of the second heat exchanger.

[0096] In this embodiment, the unit's coal consumption can be reduced without increasing the feedwater temperature or changing the flue gas temperature. Specifically, in response to the fourth operating control command, the controller controls the second steam regulating valve (valve 1-4) and the condensate regulating valve (valve 6-8) to be in the open state, so that the steam from the low-pressure cylinder is sent into the second heat exchanger to preheat the air supplied by the blower. The controller controls the flue gas regulating valve 9 and the first feedwater regulating valve 10 to be in the open state, and controls the second feedwater regulating valve 11 to be in the closed state, reducing the opening of the first steam regulating valve (12-14). This reduces the heat of the first steam. The reduction in opening must be such that the reduced heat of the first steam is equal to the heat exchange of the first heat exchanger, i.e., matched, so that the feedwater temperature remains unchanged, and the heat exchange of the first heat exchanger is matched with the heat exchange of the second heat exchanger, so that the flue gas temperature remains unchanged. The reduced heat from the initial steam is replenished by the first heat exchanger, ensuring that the temperature of the feedwater exiting the first heat exchanger is consistent with the feedwater temperature under the conventional method without reducing the initial steam flow. Thus, by reducing the initial steam flow, the cycle efficiency is improved, and the unit's coal consumption is reduced.

[0097] In one exemplary embodiment, such as Figure 2 As shown, the second steam regulating valve 720, condensate regulating valve, flue gas regulating valve 9 and the first feedwater regulating valve 10 are all open, while the second feedwater regulating valve 11 is closed.

[0098] The first steam regulating valve reduces the flow rate of the first steam so that the heat of the reduced first steam matches the heat exchange capacity of the first heat exchanger, and the heat exchange capacity of the first heat exchanger is greater than that of the second heat exchanger.

[0099] In this embodiment, the unit's coal consumption can be reduced by lowering the flue gas temperature without increasing the feedwater temperature. Specifically, in response to the fifth operating control command, the controller controls the second steam regulating valve (valve 1-4) and the condensate regulating valve (valve 6-8) to be in the open state, so that the steam from the low-pressure cylinder is sent into the second heat exchanger to preheat the air supplied by the blower. The controller controls the flue gas regulating valve 9 and the first feedwater regulating valve 10 to be in the open state, and controls the second feedwater regulating valve 11 to be in the closed state, so that some flue gas enters the first heat exchanger to heat the feedwater. Subsequently, the opening degree of the first steam regulating valve (12-14) is reduced to reduce the heat of the first steam. The reduction in opening degree must be controlled so that the reduced heat of the first steam is the same as the heat exchanger's heat exchange capacity, i.e., matched, so that the feedwater temperature remains unchanged and the heat exchanger's heat exchange capacity is greater than that of the second heat exchanger, thus reducing the flue gas temperature. In this way, by reducing the first steam, the circulation efficiency is improved and the unit's coal consumption is reduced.

[0100] In one example, the multi-mass regenerative system can be shut down. Specifically, the on / off state of valves 1-10 is closed, the on / off state of control valve 11 is open, and the on / off state of control valves 12-14 is open, but the opening degree is not adjusted.

[0101] The multi-material regenerative system in this embodiment can be put into operation under full load conditions of coal-fired power units, and operation control commands can be sent according to actual needs to achieve coal consumption reduction in different dimensions.

[0102] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0103] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0104] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A multi-mass regenerative system, characterized in that, The system includes a boiler, a steam turbine, a first heat exchanger, a second heat exchanger, a first heater, an air preheater, and a condenser. During combustion, the boiler generates flue gas which enters the first heat exchanger through the flue gas outlet. During combustion, the boiler generates steam which enters the steam turbine through the exhaust outlet to drive the steam turbine to work. During operation, the steam discharged from the turbine flows into the first heater, the second heat exchanger and the condenser through the exhaust port. The condenser converts the steam into feedwater and outputs it to the first heater through the drain port. The first heater uses the incoming steam to heat the incoming feedwater, and sends the heated feedwater into the first heat exchanger through the drain outlet; The first heat exchanger uses the flue gas to heat the incoming feedwater and sends the heated feedwater into the boiler through the drain outlet; The second heat exchanger uses the incoming steam to preheat the incoming air, and sends the preheated air into the air preheater through the exhaust port. The air preheater heats the preheated air and sends the heated air into the boiler through the exhaust port to participate in the combustion process in the boiler.

2. The system according to claim 1, characterized in that, The steam discharged from the steam turbine includes first steam; the system also includes a first steam regulating valve disposed between the exhaust port of the steam turbine and the inlet of the first heater; The first steam regulating valve regulates the flow rate of the first steam and sends the first steam into the first heater; The first heater uses the first steam to heat the incoming feedwater, and then sends the heated feedwater into the first heat exchanger through the outlet.

3. The system according to claim 2, characterized in that, The system further includes a first water supply regulating valve disposed between the drain outlet of the first heater and the inlet of the first heat exchanger, and a second water supply regulating valve disposed between the inlet of the boiler and the outlet of the first heater. The first feedwater regulating valve regulates the flow rate of the heated feedwater output from the first heater and sends the incoming feedwater into the first heat exchanger. The second feedwater regulating valve regulates the flow rate of the heated feedwater output from the first heater and sends the regulated feedwater into the boiler.

4. The system according to claim 2, characterized in that, The steam discharged from the steam turbine also includes a second steam; the system also includes a second steam regulating valve disposed between the exhaust port of the steam turbine and the inlet of the second heat exchanger; The second steam regulating valve regulates the flow rate of the second steam and sends the second steam into the second heat exchanger. The pressure of the first steam is greater than the pressure of the second steam. The second heat exchanger uses the second steam to preheat the incoming air, and sends the preheated air into the air preheater through the exhaust port; The second heater uses the second steam to heat the condensate output from the condenser, and then sends the heated condensate into the first heater through the drain outlet.

5. The system according to claim 4, characterized in that, The system also includes a condensate regulating valve disposed between the drain outlet of the second heat exchanger and the inlet of the second heater, and a flue gas regulating valve disposed between the exhaust outlet of the boiler and the inlet of the first heat exchanger. The condensate regulating valve regulates the flow rate of the condensate output from the second heat exchanger after heat exchange, and sends the inflowing condensate into the second heater. The flue gas regulating valve regulates the flow rate of the flue gas output from the boiler and sends the incoming flue gas into the first heat exchanger.

6. The system according to claim 5, characterized in that, The second steam regulating valve, the condensate regulating valve, the flue gas regulating valve, and the first feedwater regulating valve are all open, while the second feedwater regulating valve is closed, so that the heat exchange capacity of the first heat exchanger and the heat exchange capacity of the second heat exchanger are matched.

7. The system according to claim 5, characterized in that, The second steam regulating valve, the condensate regulating valve, the flue gas regulating valve, and the first feedwater regulating valve are all open, while the second feedwater regulating valve is closed, so that the heat exchange capacity of the first heat exchanger is greater than that of the second heat exchanger.

8. The system according to claim 5, characterized in that, The second steam regulating valve, the condensate regulating valve, and the second feedwater regulating valve are all closed, while the flue gas regulating valve and the first feedwater regulating valve are all open, so as to increase the feedwater temperature and reduce the flue gas heat.

9. The system according to claim 5, characterized in that, The second steam regulating valve, the condensate regulating valve, the flue gas regulating valve, and the first feedwater regulating valve are all open; the second feedwater regulating valve is closed. The first steam regulating valve reduces the flow rate of the first steam so that the reduced heat of the first steam matches the heat exchange of the first heat exchanger, and the heat exchange of the first heat exchanger matches the heat exchange of the second heat exchanger.

10. The system according to claim 5, characterized in that, The second steam regulating valve, the condensate regulating valve, the flue gas regulating valve, and the first feedwater regulating valve are all open, while the second feedwater regulating valve is closed. The first steam regulating valve reduces the flow rate of the first steam so that the heat of the reduced first steam matches the heat exchange of the first heat exchanger, and the heat exchange of the first heat exchanger is greater than the heat exchange of the second heat exchanger.

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