A direct air-cooled combined heat and power generation system coupled with a back pressure machine and a thermocline thermal storage tank and a method of operation

Abstract

The application discloses a direct air-cooling combined heat and power system coupled with a back pressure machine and a thermocline heat storage tank and an operation method. The back pressure machine and the thermocline heat storage tank are coupled, heating extraction steam is first used for work through the back pressure machine and then used for heating or stored in the thermocline heat storage tank, the heating return water heating process is optimized, the low-pressure steam turbine exhaust waste heat is reasonably utilized, the principle of energy cascade utilization is met, the energy level is matched, the steam of lower quality can be utilized to meet the heating demand, the energy utilization rate of the unit is improved, and the auxiliary power consumption rate is reduced. Through the coupling of the heating, heat storage and heat release processes, the peak regulation and frequency modulation capacity of the unit is increased, the operation flexibility of the unit is improved while the heating demand is met.

Description

Technical Field

[0001] This invention belongs to the field of energy conservation and consumption reduction technology for coal-fired power units, specifically relating to a direct air-cooled cogeneration system and its operation method that couples a back pressure turbine and a thermocline thermal storage tank. Background Technology

[0002] Energy conservation and consumption reduction in coal-fired power units is an important way for the thermal power industry to develop. At the same time, with the increase in the proportion of clean energy installed capacity, thermal power units are undertaking the important task of grid peak shaving.

[0003] However, due to thermoelectric coupling, it is difficult to flexibly allocate electrical and thermal loads in cogeneration units, resulting in high power consumption, high peak-shaving energy consumption, and slow response speed for the entire cogeneration unit. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a direct air-cooled cogeneration system and operation method of coupled back pressure turbine and inclined thermoelectric storage tank, so as to solve the problems of poor peak-shaving capacity, high peak-shaving energy consumption and slow response speed of cogeneration units in the prior art.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A direct air-cooled cogeneration system that couples a back-pressure turbine and a thermoelectric storage tank includes a boiler, a first heating network heater, a second heating network heater, a thermoelectric storage tank, and a bypass condensate heater.

[0007] The boiler's steam output line is connected to the intermediate-pressure steam turbine, and the intermediate-pressure steam turbine's steam output line is connected to both the back-pressure turbine and the low-pressure steam turbine.

[0008] The steam output pipeline of the back pressure unit is divided into two branches. The first branch is connected to the hot-side working fluid inlet of the inclined thermosphere heat storage tank, and the second branch is connected to the hot-side working fluid inlet of the second heating network heater. The hot-side working fluid outlet of the inclined thermosphere heat storage tank is connected to the hot-side working fluid inlet of the bypass condensate heater. A third branch is provided on the pipeline connecting the second branch and the hot-side working fluid inlet of the bypass condensate heater, and the third branch merges into the second branch.

[0009] The steam output pipeline of the low-pressure steam turbine is divided into two branches. One branch is connected to the hot-side working fluid inlet of the first heat network heater, and the other branch is connected to the direct air-cooling system. The outlet of the direct air-cooling system is connected to the cold-side inlet of the bypass condensate heater.

[0010] The hot-side outlet of the bypass condensate heater is connected to the cold-side inlet of the inclined thermosphere storage tank; the cold-side outlet of the bypass condensate heater is connected to the boiler.

[0011] The return water of the heating network is connected to the cold-side inlet of the first heating network heater, the cold-side outlet of the first heating network heater is connected to the cold-side inlet of the second heating network heater, and the cold-side outlet of the second heating network heater is connected to the heating network.

[0012] A further improvement of the present invention is that:

[0013] Preferably, the hot-side outlet of the second heating network heater is connected to the cold-side inlet of the inclined thermosphere storage tank.

[0014] Preferably, the cold-side working fluid outlet of the inclined thermosphere thermal storage tank is fed into the condensate system.

[0015] Preferably, the hot-side working fluid outlet of the first heating network heater is fed into the condensate system.

[0016] Preferably, the hot-side working fluid outlet of the second heating network heater is connected to the condensate inlet of the first heating network heater.

[0017] Preferably, a second control valve is provided on the first branch, and a third control valve is provided on the third branch; a fourth control valve is provided on the connecting pipeline between the hot-side working fluid outlet of the inclined thermosphere thermal storage tank and the bypass condensate heater.

[0018] Preferably, a seventh control valve is provided on the connecting pipeline between the low-pressure steam turbine and the first heating network heater.

[0019] Preferably, a tenth control valve is provided on the connecting pipeline between the direct air cooling system and the bypass condensate heater.

[0020] One operating method for the above-mentioned direct air-cooled cogeneration system of coupled back-pressure turbine and thermocline storage tank is any one of the three operating methods:

[0021] Operating Method 1: Part of the exhaust steam from the low-pressure turbine enters the first heating network heater as a heat source to heat the return water of the heating network, and the other part enters the direct air-cooling system to be cooled; the exhaust steam from the back-pressure turbine enters the second heating network heater as a heat source to reheat the return water of the heating network, and the return water of the heating network flows into the heating network.

[0022] Operating Method 2: After the heating steam is extracted and works in the back compressor, the exhaust steam from the back compressor enters the upper layer of the inclined temperature layer heat storage tank to work, and the cold water in the lower layer of the inclined temperature layer heat storage tank flows into the condensate system.

[0023] Operating Method 3: The extracted steam from the heating system does work in the back compressor and enters the first heating network heater as a heat source to heat the return water of the heating network through the exhaust steam from the low-pressure turbine. Part of the exhaust steam from the back compressor enters the second heating network heater as a heat source to heat the return water of the heating network again, and the return water of the heating network flows into the heating network. The remaining exhaust steam heat from the back compressor enters the upper layer of the inclined temperature layer heat storage tank to do work.

[0024] An operating method for a direct air-cooled cogeneration system of coupled back-pressure turbine and thermocline storage tank as claimed in the claims, characterized in that it is any one of three operating methods:

[0025] Operating Method 4: The return water of the heating network is heated sequentially by the first heating network heater and the second heating network heater; the return water in the first heating network heater is heated by the exhaust steam of the low-pressure steam turbine, and the return water in the second heating network heater is heated by the hot-side working fluid of the thermocline storage tank.

[0026] Operating Method 5: Condensate flowing out of the direct air-cooled system is heated by the hot-side working fluid of the inclined thermosphere storage tank in the bypass condensate heater. After releasing heat, the hot-side working fluid of the inclined thermosphere storage tank flows back to the cold-side working fluid inlet of the inclined thermosphere storage tank.

[0027] Operating Method Six: The return water of the heating network is heated sequentially by the first heating network heater and the second heating network heater; the return water in the first heating network heater is heated by the exhaust steam from the low-pressure turbine, and the return water in the second heating network heater is heated by a portion of the hot-side working fluid of the inclined thermocentric storage tank; the condensate flowing out from the direct air-cooled system is heated by a portion of the hot-side working fluid of the inclined thermocentric storage tank in the bypass condensate heater, and the hot-side working fluid of the inclined thermocentric storage tank flows back to the cold-side working fluid inlet of the inclined thermocentric storage tank after releasing heat.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention discloses a direct air-cooled cogeneration system that couples a back-compressor and a thermotropic thermal storage tank. Addressing the issues of energy efficiency and operational flexibility in coal-fired power plants, this system couples a back-compressor and a thermotropic thermal storage tank. The extracted steam for heating first passes through the back-compressor to perform work before being used for heating or stored in the thermotropic thermal storage tank. By optimizing the return water heating process of the heating network and rationally utilizing the waste heat from the low-pressure turbine exhaust, it conforms to the principle of energy cascade utilization and energy level matching. It can use lower-quality steam to meet heating needs, improving the unit's energy efficiency and reducing plant power consumption. The coupling of multiple processes—heat supply, storage, and release—enhances the unit's peak-shaving and frequency regulation capabilities, enabling it to simultaneously meet external electricity and heat load demands, achieving energy conservation and consumption reduction, and improving the unit's operational flexibility.

[0030] Furthermore, this invention optimizes the configuration of the heat network return water heating process, rationally utilizes the waste heat from the exhaust steam of the low-pressure turbine and the waste heat from the exhaust steam of the back compressor, meets temperature matching and energy level matching, uses lower-quality heat to meet heating demand, improves the energy utilization rate of the unit, and reduces the plant power consumption rate.

[0031] Furthermore, the present invention couples the thermocline thermal storage tank, which increases the peak shaving and frequency regulation capabilities of the unit by coupling multiple processes of heating, thermal storage and thermal release, thereby improving the operational flexibility of the unit while meeting heating demand. Attached Figure Description

[0032] Figure 1 This is a system structure diagram of the present invention.

[0033] In the diagram: 1 is the boiler, 1-1 is the superheating section, 1-2 is the reheating section, 2 is the high-pressure steam turbine, 3 is the intermediate-pressure steam turbine, 4 is the low-pressure steam turbine, 5 is the direct air-cooling system, 5-1 is the air-cooled radiator, 5-2 is the air-cooled fan, 6 is the condensate pump, 7 is the low-pressure heater, 8 is the deaerator, 9 is the feedwater pump set, 10 is the high-pressure heater, 11 is the main steam turbine generator, 12 is the first heating network heater, 13 is the second heating network heater, 14 is the thermocline thermal storage tank, 15 is the bypass condensate heater, 16 is the back pressure turbine, 17 is the back pressure turbine generator, 18 is the first control valve, 19 is the second control valve, 20 is the third control valve, 21 is the fourth control valve, 22 is the fifth control valve, 23 is the sixth control valve, 24 is the seventh control valve, 25 is the eighth control valve, 26 is the ninth control valve, and 27 is the tenth control valve. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0035] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] One embodiment of the present invention discloses a direct air-cooled cogeneration system that couples a back-pressure turbine and a thermotropic thermal storage tank, including a turbine section, a thermal storage tank section and other auxiliary sections, wherein the entire system couples the two sections together.

[0037] Specifically, in the turbine section, the working fluid sequentially passes through the interconnected superheating section 1-1 of boiler 1, high-pressure turbine 2, reheating section 1-2 of boiler 1, intermediate-pressure turbine 3, low-pressure turbine 4, direct air-cooling system 5, condensate pump 6, low-pressure heater 7, deaerator 8, feedwater pump 9, and high-pressure heater 10, before entering the superheating section 1-1 of boiler 1 to form a closed loop. The direct air-cooling system 5 includes an air-cooled radiator 5-1 and an air-cooled fan 5-2.

[0038] The heat storage tank section includes a first heat network heater 12 and a second heat network heater 13 connected in sequence, as well as a back pressure machine 16, a thermocline heat storage tank 14 and a bypass condensate heater 15 connected in sequence.

[0039] Other auxiliary components include the main steam turbine generator 11, the back pressure generator 17, the first control valve 18, the second control valve 19, the third control valve 20, the fourth control valve 21, the fifth control valve 22, the sixth control valve 23, the seventh control valve 24, the eighth control valve 25, the ninth control valve 26, and the tenth control valve 27.

[0040] As one of the preferred options, the inlet of superheated section 1-1 of boiler 1 is connected to the cold-side working fluid outlet of high-pressure heater 10; the inlet of high-pressure turbine 2 is connected to the outlet of superheated section 1-1 of boiler 1, and the outlet of high-pressure turbine 2 is connected to the inlet of reheated section 1-2 of boiler 1.

[0041] The inlet of the intermediate-pressure steam turbine 3 is connected to the outlet of the reheat section 1-2 of the boiler 1, and the outlet of the intermediate-pressure steam turbine 3 is connected to the inlet of the first control valve 18 and the inlet of the low-pressure steam turbine 4; the first control valve 18 is connected to the back pressure machine 16. The steam outlet of the back pressure compressor 16 is divided into two branches, a first branch and a second branch. The first branch is connected to the hot-side inlet of the inclined thermosphere heat storage tank 14, and the second branch is connected to the hot-side inlet of the second heating network heater 13. The hot-side outlet of the inclined thermosphere heat storage tank 14 is connected to the hot-side inlet of the bypass condensate heater 15. A fourth control valve 21 and a third branch are installed on this connecting pipeline. The inlet of the third branch is connected to the inlet of the fourth control valve 21, and the outlet of the third branch merges into the second branch, which is connected to the hot-side inlet of the second heating network heater 13. A second control valve 19 is installed on the branch connecting the steam outlet of the back pressure compressor 16 and the hot-side inlet of the inclined thermosphere heat storage tank 14. A third control valve 20 is installed on the third branch. The outlet of the third control valve 20 merges with the hot-side working fluid outlet of the inclined thermosphere heat storage tank 14 and is connected to the hot-side working fluid inlet of the bypass condensate heater 15.

[0042] The outlet of the low-pressure steam turbine 4 is connected to the inlet of the direct air-cooling system 5 and the inlet of the seventh control valve 24; the outlet of the seventh control valve 24 is connected to the hot-side working fluid inlet of the first heating network heater 12. Specifically, the direct air-cooling system 5 includes an air-cooled radiator 5-1 and an air-cooled fan 5-2. The air-cooled fan 5-2 is located on one side of the air-cooled radiator 5-1, and blows air onto the air-cooled radiator 5-1, thereby dissipating heat from the fluid flowing inside the air-cooled radiator 5-1. The inlet of the air-cooled radiator 5-1 is connected to the steam outlet of the low-pressure steam turbine 4, and the outlet of the air-cooled radiator 5-1 is connected to the inlet of the condensate pump 6.

[0043] The inlet of condensate pump 6 is connected to the outlet of direct air cooling system 5, and the outlet of condensate pump 6 is connected to the cold-side working fluid inlet of low-pressure heater 7 and the inlet of tenth control valve 27; the outlet of tenth control valve 27 is connected to the cold-side working fluid inlet of bypass condensate heater 15.

[0044] The cold-side working fluid inlet of deaerator 8 is connected to the cold-side working fluid outlet of low-pressure heater 7 and the cold-side working fluid outlet of bypass condensate heater 15. The outlet of deaerator 8 is connected to the inlet of feedwater pump group 9. The cold-side working fluid inlet of high-pressure heater 10 is connected to the outlet of feedwater pump group 9.

[0045] One embodiment of the present invention discloses a thermal storage tank section. In this thermal storage tank section, the hot-side working fluid inlet of the inclined thermocentric thermal storage tank 14 is connected to the outlet of the second control valve 19; the hot-side working fluid outlet of the inclined thermocentric thermal storage tank 14 is connected to the outlet of the third control valve 20 and the inlet of the fourth control valve 21; the cold-side working fluid inlet of the inclined thermocentric thermal storage tank 14 is connected to the outlet of the fifth control valve 22; and the cold-side working fluid outlet of the inclined thermocentric thermal storage tank 14 is connected to the inlet of the sixth control valve 23. The outlet of the sixth control valve 23 flows into the condensate system. The inlet of the fifth control valve 22 is connected to the hot-side working fluid outlet of the second heating network heater 13 and the hot-side working fluid outlet of the bypass condensate heater 15.

[0046] The hot-side working fluid inlet of the bypass condensate heater 15 is connected to the outlet of the fourth control valve 21. The hot-side working fluid outlet of the bypass condensate heater 15 is connected to the inlet of the fifth control valve 22 and the outlet of the eighth control valve 25. The cold-side working fluid inlet of the bypass condensate heater 15 is connected to the outlet of the ninth control valve 27. The inlet of the ninth control valve 27 is connected to the condensate pump 6.

[0047] Specifically, the hot-side working fluid inlet of the first heating network heater 12 is connected to the outlet of the seventh control valve 24, the inlet of the seventh control valve 24 is connected to the exhaust steam of the low-pressure cylinder 4, the hot-side working fluid outlet of the first heating network heater 12 flows into the condensate system, the cold-side working fluid of the first heating network heater 12 comes from the heating network return water, the cold-side working fluid outlet of the first heating network heater 12 is connected to the cold-side working fluid inlet of the second heating network heater 13, and the drain inlet of the first heating network heater 12 is connected to the outlet of the ninth control valve 26.

[0048] The hot-side working fluid outlet of the second heating network heater 13 is connected to the inlet of the ninth control valve 26 and the inlet of the eighth control valve 25. The cold-side working fluid outlet of the second heating network heater 13 supplies water to the heating network. The hot-side working fluid inlet of the second heating network heater 13 is connected to the outlet of the third control valve 20 and also to the steam outlet of the back pressure unit 16. The outlet of the eighth control valve 25 flows into the inlet of the fifth control valve 22 and finally into the cold-side inlet of the thermocline storage tank 14.

[0049] It should be understood that, in this embodiment, the high-pressure steam turbine 2, the intermediate-pressure steam turbine 3, and the low-pressure steam turbine 4 drive the main steam turbine generator 11 to rotate and generate electrical energy;

[0050] The back pressure unit 16 drives the back pressure unit generator 17 to rotate, generating electrical energy;

[0051] The exhaust steam from the back pressure unit 16 can enter the second heating network heater 13 as a heat source to heat the return water of the heating network, or it can enter the inclined temperature layer heat storage tank 14 to be stored.

[0052] A portion of the exhaust steam from the low-pressure turbine 4 enters the first heating network heater 12 as a heat source to heat the return water of the heating network, and the other portion enters the direct air-cooling system 5 to be cooled into condensate.

[0053] The return water from the heating network is heated sequentially by the first heating network heater 12 and the second heating network heater 13 to meet the heating demand.

[0054] The inclined temperature layer heat storage tank 14 can store the heat of the back pressure turbine exhaust steam, and can also release heat to heat the return water of the heating network or the bypass condensate, so as to meet the flexible operation of the unit.

[0055] The inlet of the back pressure unit 16 is connected to the outlet of the first control valve 18, and the outlet of the back pressure unit 16 is connected to the inlet of the second control valve 19, the outlet of the third control valve 20, and the hot-side working fluid inlet of the second heater 13 of the heating network.

[0056] The exhaust steam from the low-pressure turbine 4 enters the direct air-cooling system 5 and flows inside the air-cooled radiator 5-1. Outside the air-cooled radiator 5-1 is air. The rotation of the air-cooled fan 5-2 causes the air to flow upward and pass outside the air-cooled radiator 5-1. The air-cooled radiator 5-1 completes forced convection heat transfer, causing the exhaust steam from the low-pressure turbine 4 to condense into condensate.

[0057] One embodiment of the present invention discloses an operation method for a direct air-cooled cogeneration system that couples a back-pressure turbine and a thermotropic thermal storage tank. The operation method is as follows: the unit is an extraction condensing unit. The extraction steam for heating is connected to the intermediate-low pressure cylinder in the pipeline between the intermediate-pressure turbine 3 and the low-pressure turbine 4. The extraction steam for heating first does work in the back-pressure turbine 16. The exhaust steam from the back-pressure turbine 16 can enter the second heat network heater 13 to heat the heat network return water, or the heat from the exhaust steam from the back-pressure turbine 16 can be stored in the thermotropic thermal storage tank 14.

[0058] The heating process of exhaust steam from low-pressure turbine 4 and exhaust steam from back compressor 16 is referred to as Operation Method 1: Open the first control valve 18, the seventh control valve 24, and the ninth control valve 26, and close the second control valve 19, the third control valve 20, the fourth control valve 21, the fifth control valve 22, the sixth control valve 23, the eighth control valve 25, and the tenth control valve 26. Part of the exhaust steam from low-pressure turbine 4 enters the first heating network heater 12 as a heat source to heat the heating network return water, and the other part enters the direct air-cooling system 5. The exhaust steam from back compressor 16 enters the second heating network heater 13 as a heat source to reheat the heating network return water to meet the heating demand.

[0059] The heat storage process of storing the exhaust heat of the back pressure turbine 16 into the inclined temperature layer heat storage tank 14 is referred to as Operation Method Two: Open the first control valve 18, the second control valve 19, and the sixth control valve 23, and close the third control valve 20, the fourth control valve 21, the fifth control valve 22, the seventh control valve 24, the eighth control valve 25, the ninth control valve 26, and the tenth control valve 27. The exhaust steam of the heating extraction turbine 16 after doing work enters the upper layer of the inclined temperature layer heat storage tank 14, and part of the cold water in the lower layer of the inclined temperature layer heat storage tank 14 is discharged and merged into the condensate system.

[0060] Operating methods one and two are performed simultaneously, and this is set as operating method three. The first control valve 18, the second control valve 19, the sixth control valve 23, the seventh control valve 24, and the ninth control valve 26 are opened, while the third control valve 20, the fourth control valve 21, the fifth control valve 22, the eighth control valve 25, and the tenth control valve 27 are closed. The extracted steam for heating first performs work in the back compressor 16, and then the exhaust steam from the low-pressure turbine 4 and part of the exhaust steam from the back compressor 16 are used to meet the external heating demand. At the same time, part of the heat from the exhaust steam from the back compressor 16 is stored in the inclined temperature layer heat storage tank 14. The flow rate of the extracted steam for heating can be adjusted by adjusting the opening of the first control valve 18, thereby adjusting the power generation of the main turbine generator 11, improving the deep peak shaving capability of the unit, and enhancing the operational flexibility of the unit.

[0061] The process of releasing heat from the thermocline thermal storage tank 14 for heating (hereinafter referred to as Operation Method Four) is as follows: Open the third control valve 20, the fifth control valve 22, and the eighth control valve 25, and close the first control valve 18, the second control valve 19, the fourth control valve 21, the sixth control valve 23, the seventh control valve 24, the ninth control valve 26, and the tenth control valve 27. Then, the hot-side working fluid outlet of the thermocline thermal storage tank 14 flows into the hot-side working fluid inlet of the second heating network heater 13 through the third control valve 20. After releasing heat, it passes through the eighth control valve 25 and the fifth control valve 22, and then flows into the cold-side working fluid inlet of the thermocline thermal storage tank 14, where it meets the external heating demand together with the exhaust steam from the low-pressure steam turbine. At this time, the return water of the heating network is heated by the exhaust steam from the low-pressure steam turbine in the first heating network heater 12, and then heated by the hot-side working fluid of the thermocline thermal storage tank 14 in the second heating network heater 13 to supply water to the heating network.

[0062] The process of releasing heat from the thermocline thermal storage tank 14 to heat the bypass condensate (hereinafter referred to as Operation Method Five) is as follows: Open the fourth control valve 21, the fifth control valve 22, and the tenth control valve 27, and close the first control valve 18, the second control valve 19, the third control valve 20, the sixth control valve 23, the seventh control valve 24, the eighth control valve 25, and the ninth control valve 26. Then, the hot-side working fluid of the thermocline thermal storage tank 14 flows into the hot-side working fluid inlet of the bypass condensate heater 15 through the fourth control valve 21. After heating the bypass condensate in the bypass condensate heater 15, it flows back into the cold-side working fluid inlet of the thermocline thermal storage tank 14 through the fifth control valve 22.

[0063] When operating methods four and five are performed simultaneously, it is set as operating method six. The specific process is as follows: open the third control valve 20, the fourth control valve 21, the fifth control valve 22, the eighth control valve 25, and the tenth control valve 27, and close the first control valve 18, the second control valve 19, the sixth control valve 23, the seventh control valve 24, and the ninth control valve 26. Then, the heat from the inclined thermal storage tank 14 is used to heat the bypass condensate in the bypass condensate heater 13, and also to release heat in the second heat network heater 13. Together with the exhaust steam from the low-pressure steam turbine, it meets the external heating demand, reduces the steam extraction flow for heating and the steam extraction flow required by the low-pressure heater 7, so that the unit load can be increased quickly and the frequency regulation capability of the unit is improved.

[0064] The extracted steam for heating first passes through the back-compressor 16 to perform work before being used for heating or stored in the inclined thermostatic storage tank 14, which conforms to the principle of energy cascade utilization and energy level matching. The exhaust steam from the low-pressure turbine 4 is used to heat the return water of the heating network first, and then the exhaust steam from the back-compressor 16 or the heat from the inclined thermostatic storage tank 14 is used to heat the return water of the heating network again. This can meet the heating demand using lower-quality energy, improve the energy utilization rate of the unit, and reduce the exhaust steam entering the direct air-cooling system 13, thereby reducing the power consumption of the air-cooled fan 5-2 and lowering the plant power consumption rate. When processes 1 and 2 occur simultaneously, the deep peak-shaving capability of the unit is enhanced, and the operational flexibility of the unit is improved. When processes 3 and 4 occur simultaneously, the load of the unit can be rapidly increased, which enhances the frequency regulation capability of the unit. The coupling of multiple processes such as heating, heat storage and heat release increases the peak-shaving and frequency regulation capability of the unit, improving the operational flexibility of the unit while meeting the heating demand.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A direct air-cooled cogeneration system coupling a back-pressure turbine and a thermoelectric storage tank, characterized in that, It includes a boiler (1), a first heating network heater (12), a second heating network heater (13), a thermocline storage tank (14), and a bypass condensate heater (15). The steam output pipeline of the boiler (1) is connected to the intermediate pressure turbine (3), and the steam output pipeline of the intermediate pressure turbine (3) is connected to both the back pressure turbine (16) and the low pressure turbine (4). The steam output pipeline of the back pressure unit (16) is divided into two branches. The first branch is connected to the hot-side working fluid inlet of the inclined thermosphere heat storage tank (14), and the second branch is connected to the hot-side working fluid inlet of the second heat network heater (13). The hot-side working fluid outlet of the inclined thermosphere heat storage tank (14) is connected to the hot-side working fluid inlet of the bypass condensate heater (15). A third branch is provided on the pipeline connecting the hot-side working fluid outlet of the inclined thermosphere heat storage tank (14) and the hot-side working fluid inlet of the bypass condensate heater (15). The third branch merges into the second branch. The steam output pipeline of the low-pressure steam turbine (4) is divided into two branches. One branch is connected to the hot side working fluid inlet of the first heat network heater (12), and the other branch is connected to the direct air cooling system (5). The outlet of the direct air cooling system (5) is connected to the cold side inlet of the bypass condensate heater (15). The hot-side outlet of the bypass condensate heater (15) is connected to the cold-side inlet of the inclined thermosphere storage tank (14); the cold-side outlet of the bypass condensate heater (15) is connected to the boiler (1). The return water of the heating network is connected to the cold side inlet of the first heating network heater (12), the cold side outlet of the first heating network heater (12) is connected to the cold side inlet of the second heating network heater (13), and the cold side outlet of the second heating network heater (13) is connected to the heating network. The hot-side working fluid outlet of the second heat network heater (13) is divided into two paths: one path is connected to the cold-side inlet of the inclined thermosphere storage tank (14), and the other path is connected to the condensate inlet of the first heat network heater (12). The outlet of the direct air cooling system (5) is connected to the inlet of the condensate pump (6). The outlet of the condensate pump (6) is divided into two branches, one of which is connected to the cold side inlet of the low-pressure heater (7) and the other is connected to the cold side inlet of the bypass condensate heater (15). The cold side outlet of the low-pressure heater (7) and the cold side outlet of the bypass condensate heater (15) are connected to the cold side inlet of the deaerator (8). The outlet of the deaerator (8) is connected to the boiler (1) via the feed water pump group (9).

2. The direct air-cooled cogeneration system of coupled back-pressure turbine and thermocline storage tank according to claim 1, characterized in that, The cold-side working fluid outlet of the thermocline storage tank (14) flows into the condensate system.

3. The direct air-cooled cogeneration system of coupled back-pressure turbine and thermocline storage tank according to claim 1, characterized in that, The hot-side working fluid outlet of the first heat network heater (12) flows into the condensate system.

4. A direct air-cooled cogeneration system for coupling a back-pressure turbine and a thermoelectric storage tank according to claim 1, characterized in that, A second control valve (19) is provided on the first branch, and a third control valve (20) is provided on the third branch; a fourth control valve (21) is provided on the connecting pipe between the hot side working fluid outlet of the inclined thermosphere heat storage tank (14) and the bypass condensate heater (15).

5. A direct air-cooled cogeneration system for coupling a back-pressure turbine and a thermoelectric storage tank according to claim 1, characterized in that, A seventh control valve (24) is installed on the connecting pipeline between the low-pressure steam turbine (4) and the first heating network heater (12).

6. A direct air-cooled cogeneration system for coupling a back-pressure turbine and a thermotropic thermal storage tank according to claim 1, characterized in that, A tenth control valve (27) is installed on the connecting pipeline between the direct air cooling system (5) and the bypass condensate heater (15).

7. A method for operating a direct air-cooled cogeneration system of coupled back-pressure turbine and thermocline storage tank as described in claim 1, characterized in that, It can be any one of the three running methods: In the first operating method, part of the exhaust steam from the low-pressure turbine (4) enters the first heating network heater (12) as a heat source to heat the heating network return water, and the other part enters the direct air cooling system (5) to be cooled; the exhaust steam from the back pressure turbine (16) enters the second heating network heater (13) as a heat source to heat the heating network return water again, and the heating network return water flows into the heating network. Operating method two: After the heating steam is extracted and does work in the back compressor (16), the exhaust steam of the back compressor (16) enters the upper layer of the inclined temperature layer heat storage tank (14) to do work, and the cold water in the lower layer of the inclined temperature layer heat storage tank (14) flows into the condensate system. In the third operation method, the steam extracted for heating does work in the back compressor (16), and the exhaust steam from the low-pressure turbine (4) enters the first heating network heater (12) as a heat source to heat the return water of the heating network. Part of the exhaust steam from the back compressor (16) enters the second heating network heater (13) as a heat source to heat the return water of the heating network again, and the return water of the heating network flows into the heating network. The remaining exhaust steam heat from the back compressor (16) enters the upper layer of the inclined temperature layer heat storage tank (14) to do work.

8. A method for operating a direct air-cooled cogeneration system of coupled back-pressure turbine and thermocline storage tank as described in claim 1, characterized in that, It can be any one of the three running methods: Operating method four: the return water of the heating network is heated by the first heating network heater (12) and the second heating network heater (13) in sequence; the return water of the heating network in the first heating network heater (12) is heated by the exhaust steam of the low-pressure steam turbine (4), and the return water of the heating network in the second heating network heater (13) is heated by the hot side working fluid of the inclined thermosphere storage tank (14). Operating method five: Condensate flowing out of the direct air cooling system (5) is heated by the hot-side working fluid of the inclined thermosphere heat storage tank (14) in the bypass condensate heater (15). After the hot-side working fluid of the inclined thermosphere heat storage tank (14) releases heat, it flows back to the cold-side working fluid inlet of the inclined thermosphere heat storage tank (14). In operation method six, the return water of the heating network is heated sequentially by the first heating network heater (12) and the second heating network heater (13); the return water of the heating network in the first heating network heater (12) is heated by the exhaust steam of the low-pressure turbine (4), and the return water of the heating network in the second heating network heater (13) is heated by a portion of the hot-side working fluid of the inclined thermosphere storage tank (14); the condensate flowing out from the direct air cooling system (5) is heated by a portion of the hot-side working fluid of the inclined thermosphere storage tank (14) in the bypass condensate heater (15), and the hot-side working fluid of the inclined thermosphere storage tank (14) releases heat and flows back to the cold-side working fluid inlet of the inclined thermosphere storage tank (14).

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