Heat supply system based on steam-electricity double drive

Abstract

The utility model discloses a heat supply system based on steam and electricity double drive, and belongs to the field of thermal power generation equipment. The system is composed of a steam-electricity double-drive induced draft fan system and a thermochemical heat storage system, and a steam exhaust port of the steam-electricity double-drive induced draft fan system is connected into a heat supply network and the thermochemical heat storage system; the thermochemical heat storage system comprises a heat exchanger, a steam-water separator and a reactor, an inlet of the heat exchanger and an inlet of the steam-water separator are connected with a steam exhaust port of the steam-electricity double-drive induced draft fan system, and an outlet of the heat exchanger and an outlet of the steam-water separator are connected with a first inlet and a second inlet of the reactor respectively. A second outlet of the reactor leads to an external atmospheric environment or subsequent treatment equipment; and a thermochemical heat storage material is arranged in the reactor. The steam-electricity double-drive induced draft fan system and the thermochemical heat storage system are coupled, steam exhausted by the steam turbine of the steam-electricity double-drive induced draft fan system can enter the thermochemical heat storage system for energy storage in the non-heat-supply season, and can also be directly connected into a heat supply network in the heat supply season and release the stored energy in the non-heat-supply season so as to jointly achieve heat supply.

Description

Technical Field

[0001] The utility model belongs to the field of thermal power generation equipment, and in particular relates to a heating system based on steam-electric dual drive. Background Art

[0002] With the proposal of my country's "dual carbon" strategic goals, the requirements for energy conservation and emission reduction are increasing. Traditional energy companies such as thermal power plants are facing huge challenges. How to reduce production energy consumption, reduce pollution emissions, and then transform into environmentally friendly enterprises is an important issue concerning the future development of traditional thermal power plants.

[0003] As one of the important auxiliary equipment of thermal power plants, the induced draft fan plays a role in exhausting the flue gas generated in the furnace, overcoming the pressure loss in the tail flue of the dust collector and other post-furnace equipment, adjusting the negative pressure of the furnace, and stabilizing combustion during the operation of the thermal power unit. The traditional induced draft fan of the thermal power plant is generally an electric drive type, but the induced draft fan, as the main auxiliary equipment of the boiler, has a large power consumption demand. The thermal power unit using a pure electric induced draft fan has a high power consumption rate, which reduces the economic benefits of the unit. The use of a small steam turbine and an electric motor to drive the induced draft fan can effectively reduce the power consumption rate of the thermal power plant, improve the economy of the unit, and thus improve the economic benefits of the thermal power plant. In addition, the exhaust steam of the small steam turbine can also be used for heating, reducing the waste of steam quality. Using steam-electric dual-drive technology instead of a simple electric-driven induced draft fan has become the development trend of the current thermal power plant transformation.

[0004] CN213684252U discloses a steam-electric dual-drive system, which includes a screw expander, a reduction gearbox, a clutch, a double-axle asynchronous motor and a rotary auxiliary machine connected in sequence. The system is suitable for small-scale traction projects in the range of 100kW-3000kW; a specific screw expander cooperates with a double-axle asynchronous motor to jointly drive the rotary auxiliary machine to achieve a steam-electric dual-drive function; the equipment investment cost is low, and the stable operation of the rotary auxiliary machine can be guaranteed, and a large amount of low-grade waste heat generated in large-scale industrial production can be utilized, which is green and environmentally friendly.

[0005] CN111828101A discloses a novel steam-electric dual-drive combined induced draft system for thermal power units. The induced draft system comprises a small back-pressure steam turbine, a constant speed ratio gearbox, an electric motor and an axial flow induced draft fan with adjustable blades. A circular flue is used to connect the electrostatic precipitator to the induced draft fan and the induced draft fan to the desulfurization absorption tower, thereby reducing the smoke resistance and improving the economic benefits of the thermal power plant.

[0006] CN116480599A discloses a steam-electric dual-drive system for an induced draft fan and a control method thereof. The system's operating stage is determined by control instructions, and the opening of a small steam turbine steam inlet regulating valve is adjusted according to a pre-obtained target opening model, thereby achieving stable switching of drive modes and being able to respond quickly when a system failure occurs, thereby improving the stability and reliability of the steam-electric dual-drive system for the induced draft fan.

[0007] CN113279992A discloses a boiler fan dual drive system and method based on a 3S coupling. When the back-pressure steam turbine cannot provide sufficient driving force to drive the induced draft fan, the system starts the drive motor and locks and engages with the back-pressure steam turbine through the 3S coupling to achieve steam-electric co-driving of the fan, thereby reducing the power consumption rate of the plant and ensuring the normal operation of the thermal power unit. Moreover, the system can convert high-temperature and high-pressure steam into steam that meets the pressure and temperature required by the heat network side to achieve heating.

[0008] Most of the existing thermal power plants still use the traditional method of electric motors to drive induced draft fans. The proportion of units using steam-electric dual-drive technology in China is relatively low, and there is little relevant application experience. There is still much room for improvement in the design and operation of the projects.

[0009] A comprehensive comparison of existing steam-electric dual-drive induced draft fan systems shows that most of the focus is on system control methods and system component improvements, but there is a lack of research on the use of steam turbine exhaust steam, which is directly introduced into the heat network for heating. In the non-heating season, this part of the heat will still be wasted and cannot be used to the maximum extent, and the advantages of the steam-electric dual-drive induced draft fan system are not fully utilized. If this part of the heat can be stored, the energy utilization rate of the unit can be further improved, and the overall economic benefits of operation can be improved. Utility Model Content

[0010] In order to solve the problem of exhaust steam utilization of the steam-electric dual-drive system in the prior art, the utility model discloses a heating system based on steam-electric dual-drive, which couples the steam-electric dual-drive induced draft fan system and the thermochemical heat storage system. The exhaust steam of the steam turbine in the steam-electric dual-drive induced draft fan system can enter the thermochemical heat storage system for energy storage in the non-heating season, and can also be directly connected to the heating network in the heating season and release the stored energy in the non-heating season to jointly achieve heating.

[0011] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0012] A heating system based on steam-electric dual drive, consisting of a steam-electric dual drive induced draft fan system and a thermochemical heat storage system, wherein the exhaust port of the steam-electric dual drive induced draft fan system is connected to a heating network and a thermochemical heat storage system;

[0013] The thermochemical heat storage system comprises a heat exchanger, a steam-water separator and a reactor. The inlet of the heat exchanger and the inlet of the steam-water separator are connected to the exhaust port of the steam-electric dual-drive induced draft fan system. The outlet of the heat exchanger and the outlet of the steam-water separator are respectively connected to the first inlet of the reactor and the second inlet of the reactor. The first outlet of the reactor is connected to the heat network, and the second outlet of the reactor leads to the external atmospheric environment or subsequent processing equipment. The first inlet and the first outlet of the reactor are connected inside the reactor, and the second inlet and the second outlet of the reactor are connected inside the reactor, and different inlets and outlets of the reactor are not connected. The reactor is built with thermochemical heat storage material.

[0014] Preferably, the steam-electric dual-drive induced draft fan system includes a back-pressure steam turbine, a clutch gear transmission, an asynchronous motor and an induced draft fan; the asynchronous motor is connected to the induced draft fan, and the back-pressure steam turbine is coaxially connected to the asynchronous motor through the clutch gear transmission, and the back-pressure steam turbine and the asynchronous motor can jointly drive the induced draft fan.

[0015] Preferably, the back-pressure steam turbine is provided with a steam exhaust port and a steam inlet, the steam inlet is connected to a steam source, and the steam exhaust port is connected to a heat network.

[0016] Preferably, the heating network inlet is provided with a heating network valve.

[0017] Preferably, the heat exchanger inlet in the thermochemical heat storage system is connected to the exhaust port of the back-pressure steam turbine, and a heat exchanger valve is provided between the heat exchanger inlet and the exhaust port of the back-pressure steam turbine, and the heat exchanger outlet is connected to the first inlet of the reactor.

[0018] Preferably, the exhaust steam entering the heat exchanger exchanges heat with the refrigerant.

[0019] Preferably, the steam-water separator inlet in the thermochemical heat storage system is connected to the exhaust port of the back-pressure steam turbine, and a steam-water separator valve is provided between the steam-water separator inlet and the exhaust port of the back-pressure steam turbine, and the steam-water separator outlet is connected to the second inlet of the reactor.

[0020] Preferably, the asynchronous motor is also connected to the power grid to realize the power supply function for the equipment in the factory.

[0021] Preferably, the thermochemical heat storage material built into the reactor is hydrated salt.

[0022] Preferably, the steam-water separator is provided with a heat-insulating jacket.

[0023] The beneficial effects of the utility model are:

[0024] The heating system based on steam-electric dual drive proposed by the utility model is equipped with a dual-drive induced draft fan system, and by coupling the thermochemical heat storage system, it can realize the step-by-step utilization of the exhaust steam of the steam turbine in the induced draft fan system, improve the utilization efficiency of the steam waste heat, reduce the waste of exhaust steam waste heat in the non-heating season, and improve the heating efficiency of the heating network in the heating season; in addition, the heating system does not require a large area of ​​land, thus avoiding the waste of land resources within the factory. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a heating system based on steam-electric dual drive shown in an embodiment of the utility model;

[0026] Among them: 1-1 back pressure steam turbine, 1-2 clutchable gear transmission, 1-3 asynchronous motor, 1-4 induced draft fan, 2-1 heat exchanger, 2-2 steam-water separator, 2-3 reactor, 2-4 heat exchanger valve, 2-5 steam-water separator valve, 3 heat network valve. DETAILED DESCRIPTION

[0027] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings.

[0028] See also Figure 1 In this embodiment, a heating system based on steam-electric dual drive is shown, which mainly includes two parts: a steam-electric dual drive induced draft fan system and a thermochemical heat storage system.

[0029] The above-mentioned steam-electric dual-drive induced draft fan system mainly includes: a back-pressure steam turbine 1-1, a clutch gearbox 1-2, an asynchronous motor 1-3, and an induced draft fan 1-4. The back-pressure steam turbine 1-1 is coaxially connected to the asynchronous motor 1-3 through the clutch gearbox 1-2, and jointly drives the induced draft fan 1-4, and the induced draft fan can be used for subsequent work. The steam outlet of the back-pressure steam turbine 1-1 is connected to the existing heating network of the power plant, and the exhaust steam enters the heating network for heating. A heating network valve 3 is provided at the entrance of the heating network. The high-temperature gas discharged from the exhaust port of the back-pressure steam turbine 1-1 needs to pass through the heating network valve 3 to enter the heating network for heating. The asynchronous motor has the functions of both a generator and an electric motor, and is connected to the power grid of the power plant to supply power to other electrical equipment in the plant.

[0030] The above-mentioned thermochemical heat storage system mainly includes: a heat exchanger 2-1, a steam-water separator 2-2, a reactor 2-3, a heat exchanger valve 2-4, and a steam-water separator valve 2-5. The inlet of the heat exchanger 2-1 is connected to the exhaust port of the back-pressure steam turbine 1-1, and a heat exchanger valve 2-4 is provided between the inlet of the heat exchanger 2-1 and the exhaust port of the back-pressure steam turbine 1-1. The outlet of the heat exchanger is connected to the first inlet of the reactor 2-3. The first outlet of the reactor 2-3 is connected to the heat network. The high-temperature gas released from the first outlet of the reactor needs to pass through the heat network valve 3 to enter the heat network for heating. The inlet of the steam-water separator 2-2 is connected to the exhaust port of the back-pressure steam turbine 1-1, and a steam-water separator valve is provided between the inlet of the steam-water separator 2-2 and the exhaust port of the back-pressure steam turbine 1-1. The outlet of the steam-water separator 2-2 is connected to the second inlet of the reactor 2-3, and the second outlet of the reactor 2-3 leads to the external atmospheric environment. It should be noted that the first inlet and the first outlet of the reactor 2-3 are connected inside the reactor 2-3, the second inlet and the second outlet of the reactor 2-3 are connected inside the reactor 2-3, and different inlets and different outlets are not connected.

[0031] In this embodiment, the reactor is a fixed bed reactor with a built-in hydrated salt thermochemical heat storage material, and the reactor outlet is connected to the power plant heat network for supplementary heat supply. The steam-water separator is a steam-water separator equipped with a thermal insulation jacket.

[0032] The working process of the above heating system is as follows:

[0033] The system starts to be used, and the asynchronous motor 1-3 directly drives the induced draft fan to operate. When the steam source parameters meet the requirements, the back-pressure steam turbine 1-1 speeds up to the synchronous speed, and the clutch makes the back-pressure steam turbine 1-1 mesh with the asynchronous motor 1-3 to jointly drive the induced draft fan 1-4. At this time, the steam turbine 1-1, the asynchronous motor 1-3 and the induced draft fan 1-4 run coaxially. The exhaust steam of the back-pressure steam turbine 1-1 enters the heating system. The specific operation mode is different in the heating season and the non-heating season, as follows:

[0034] Non-heating season: the heating network valve 3 and the heat exchanger valve 2-4 are closed, the steam separator valve 2-5 is opened, and the system is in the heat storage stage. The exhaust steam enters the steam separator 2-2, and the dry high-temperature gas at the outlet is passed into the reactor 2-3 from the second inlet to dry the hydrated salt to form anhydrous salt, realizing the conversion of thermal energy into chemical energy for storage, and the gas after the reaction is directly discharged from the second outlet of the reactor 2-3 to the atmosphere.

[0035] Heating season: the heating network valve 3 and the heat exchanger valve 2-4 are open, the steam-water separator valve 2-5 is closed, and the system is in the heat release stage. Part of the exhaust steam directly enters the heating network for heating, and part of the exhaust steam exchanges heat with the refrigerant through the heat exchanger 2-1. The low-temperature wet gas at the outlet enters the reactor 2-3 from the first inlet to react with the anhydrous salt. The anhydrous salt reacts with water vapor to form hydrated salt and releases heat. The high-temperature gas discharged from the first outlet enters the heating network through the pipe network for heating.

[0036] By implementing different operating modes in the heating season and the non-heating season, the exhaust heat of the steam turbine can be utilized to the maximum extent, thereby reducing heat loss and improving heating efficiency.

[0037] The above examples are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art from the present invention should be considered as the protection scope of the present invention.

Claims

1. A heating system based on steam-electric dual drive, characterized in that: It is composed of a steam-electric dual-drive induced draft fan system and a thermochemical heat storage system, wherein the exhaust port of the steam-electric dual-drive induced draft fan system is connected to the heat network and the thermochemical heat storage system; The thermochemical heat storage system comprises a heat exchanger (2-1), a steam-water separator (2-2) and a reactor (2-3); the inlet of the heat exchanger (2-1) and the inlet of the steam-water separator (2-2) are connected to the exhaust port of the steam-electric dual-drive induced draft fan system; the outlet of the heat exchanger (2-1) and the outlet of the steam-water separator (2-2) are respectively connected to the first inlet of the reactor (2-3) and the second inlet of the reactor (2-3); the first outlet of the reactor (2-3) is connected to the heat network; the second outlet of the reactor (2-3) is connected to the external atmospheric environment or subsequent processing equipment; the first inlet and the first outlet of the reactor (2-3) are connected inside the reactor; the second inlet and the second outlet of the reactor (2-3) are connected inside the reactor; and different inlets and outlets of the reactor (2-3) are not connected; and the reactor (2-3) has built-in thermochemical heat storage material.

2. The heating system based on steam-electric dual drive according to claim 1 is characterized in that: The steam-electric dual-drive induced draft fan system comprises a back-pressure steam turbine (1-1), a clutch gear transmission (1-2), an asynchronous motor (1-3) and an induced draft fan (1-4); the asynchronous motor (1-3) is connected to the induced draft fan (1-4), the back-pressure steam turbine (1-1) is coaxially connected to the asynchronous motor (1-3) via the clutch gear transmission (1-2), and the back-pressure steam turbine (1-1) and the asynchronous motor (1-3) can jointly drive the induced draft fan (1-4).

3. The heating system based on steam-electric dual drive according to claim 2 is characterized in that: The back-pressure steam turbine (1-1) is provided with a steam exhaust port and a steam inlet, the steam inlet is connected to a steam source, and the steam exhaust port is connected to a heat network.

4. The heating system based on steam-electric dual drive according to claim 3 is characterized in that: The heating network inlet is provided with a heating network valve (3).

5. The heating system based on steam-electric dual drive according to claim 3 is characterized in that: The inlet of the heat exchanger (2-1) in the thermochemical heat storage system is connected to the exhaust port of the back-pressure steam turbine (1-1), and a heat exchanger valve (2-4) is provided between the inlet of the heat exchanger (2-1) and the exhaust port of the back-pressure steam turbine (1-1), and the outlet of the heat exchanger is connected to the first inlet of the reactor (2-3).

6. The heating system based on steam-electric dual drive according to claim 1 or 5, characterized in that: The exhaust steam entering the heat exchanger exchanges heat with the refrigerant.

7. The heating system based on steam-electric dual drive according to claim 3 is characterized in that: The inlet of the steam-water separator (2-2) in the thermochemical heat storage system is connected to the exhaust port of the back-pressure steam turbine (1-1), and a steam-water separator valve (2-5) is provided between the inlet of the steam-water separator (2-2) and the exhaust port of the back-pressure steam turbine (1-1), and the outlet of the steam-water separator (2-2) is connected to the second inlet of the reactor (2-3).

8. The heating system based on steam-electric dual drive according to claim 2 is characterized in that: The asynchronous motor (1-3) is also connected to a power grid to realize power supply.

9. The heating system based on steam-electric dual drive according to claim 1 is characterized in that: The thermochemical heat storage material built into the reactor (2-3) is hydrated salt.

10. The heating system based on steam-electric dual drive according to claim 1 is characterized in that: The steam-water separator (2-2) is provided with a heat-insulating sleeve.

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