Heating system for activating purified molecular sieves using low-grade steam from thermal power plants

Abstract

The present invention discloses a heating system for activating a purified molecular sieve using low-grade steam from a thermal power unit, including a coal-fired power unit and an air purification molecular sieve activation system; part of the exhaust steam from the intermediate pressure cylinder of the coal-fired power unit enters the air purification molecular sieve activation system as a heat source; the air purification molecular sieve activation system is connected to a liquid compressed air energy storage system for removing moisture, carbon dioxide and other impurities from the air; the outlet of the liquid compressed air energy storage system is connected to a liquid compressed air energy release system. The present invention uses low-quality steam from a thermal power unit to achieve the adsorption capacity of the air purification molecular sieve, and the air flows through a finned heat exchanger and is heated before entering the air purification molecular sieve to activate it. Compared with the traditional electric heating method, the method of using the extracted steam that has done work in the steam turbine generator set as a heat source can greatly reduce the operating cost, and can reduce the electrical output of the steam turbine generator set to a certain extent while keeping the boiler output unchanged, which is beneficial for the thermal power unit to participate in deep peak regulation services.

Description

[Technical field]

[0001] The invention belongs to the technical field of power transmission, and in particular relates to a heating system for activating a purified molecular sieve by utilizing low-grade steam from a thermal power unit. [Background technology]

[0002] By the end of 2019, the cumulative installed capacity of photovoltaic and wind power reached 205 million and 210 million kilowatts, respectively, accounting for 10.2% and 10.4% of the total installed capacity (2.01 billion kilowatts); the annual total power generation reached 224.3 billion and 405.7 billion kWh, respectively, accounting for 3% and 5.5% of the annual total power generation (732.53 billion kilowatts). New energy power will develop rapidly in the future, requiring thermal power units to further tap the peak-shaving potential on the current basis. The large-scale grid connection of renewable energy power with volatility and intermittent characteristics has put forward higher requirements for the peak-shaving and valley-filling of the power grid and the safe and stable operation level. The construction of large-scale energy storage devices and the improvement of the flexibility and safety of power system operation are effective ways to solve the problem of high-proportion consumption of new energy.

[0003] At present, the main energy storage technologies include pumped storage, compressed air storage, and electrochemical storage. Pumped storage technology is mature and highly efficient, but it has problems such as geographical location restrictions and is difficult to promote on a large scale; electrochemical battery storage technology has fast response, small size, and short construction period, but it has shortcomings such as short overall life and high industrial pollution. Liquid compressed air storage technology has the characteristics of long life, low environmental pollution, and low operation and maintenance costs, and has the potential for large-scale promotion and application.

[0004] The air purification molecular sieve is one of the key equipment of the liquid compressed air energy storage system coupled with the thermal power unit. Its function is to adsorb and purify the moisture, carbon dioxide and acetylene in the air. It is arranged vertically and mainly includes molecular sieve adsorption tanks (one in operation and one in reserve), heating equipment, related auxiliary pipelines and valves, etc. In the energy storage stage, high-pressure air enters the molecular sieve for adsorption; in the energy release stage, the molecular sieve is depressurized to normal pressure, and the air is heated by high-temperature air heated by an electric heater to reduce the adsorption capacity in the adsorption tank, thereby releasing the impurities such as water droplets, carbon dioxide and acetylene adsorbed thereon and following the hot blowing airflow and the subsequent cold blowing airflow to the atmosphere, and the purified molecular sieve is "activated" to be used in the next energy storage stage.

[0005] At present, the most commonly used "activation" method is electric heating, that is, a set of electric heating equipment is set up, and the air flows through the electric heating equipment to heat up and then enters the molecular sieve for hot blowing treatment. This method uses electricity as the "activation" heat source, and the system is simple, but it has disadvantages such as high energy consumption. [Summary of the invention]

[0006] The purpose of the present invention is to solve the problems in the prior art and provide a heating system for activating a purified molecular sieve by utilizing low-grade steam from a thermal power unit.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The heating system for activating purified molecular sieves using low-grade steam from thermal power plants includes:

[0009] A coal-fired generator set, wherein part of the exhaust steam from the intermediate pressure cylinder of the coal-fired generator set is used as a heat source to enter the air purification molecular sieve activation system;

[0010] An air purification molecular sieve activation system is connected to a liquid compressed air energy storage system and is used to remove moisture, carbon dioxide and other impurities from the air; the outlet of the liquid compressed air energy storage system is connected to a liquid compressed air energy release system.

[0011] The present invention is further improved in that:

[0012] The coal-fired power generation unit includes a boiler, wherein the new steam outlet of the boiler is connected to the steam inlet of the high-pressure cylinder, the exhaust port of the high-pressure cylinder is connected to the inlet of the boiler's reheater, the reheater outlet of the boiler is connected to the steam inlet of the medium-pressure cylinder, and the exhaust port of the medium-pressure cylinder is divided into two paths, one of which is connected to the hot side inlet of the steam-gas heat exchanger of the air purification molecular sieve activation system through the first valve group, and the other is connected to the steam inlet of the low-pressure cylinder. The exhaust steam of the low-pressure cylinder is connected to the condenser, the condensate pump, the low-pressure heater group, the feed water pump group and the high-pressure heater group in sequence; the outlet of the high-pressure heater group is connected to the boiler; the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder are coaxially connected to jointly drive the generator to generate electricity.

[0013] The air purification molecular sieve activation system comprises a steam-gas heat exchanger and an air purification molecular sieve; the hot side outlet of the steam-gas heat exchanger is connected to the condenser through a drain pump; the inlet of the air purification molecular sieve is connected to the air cooler of the liquid compressed air energy storage system, and the outlet is connected to the refrigeration expander; the heat source of the air purification molecular sieve comes from the steam-gas heat exchanger.

[0014] Part of the exhaust gas of the liquid compressed air energy release system is discharged into the atmosphere, and the other part enters the fan. The outlet of the fan is connected to the cold side inlet of the steam-gas heat exchanger through a cold air pipe. The cold side outlet of the steam-gas heat exchanger is connected to the air purification molecular sieve through a hot air pipe to provide heat for it.

[0015] A second valve group is also arranged on the pipeline between the drain pump and the condenser.

[0016] The liquid compressed air energy storage system includes an air compressor, the outlet of the air compressor is connected to an air cooler, the outlet of the air cooler is connected to an air purification molecular sieve activation system, the outlet of the air purification molecular sieve activation system is connected to a refrigeration expander and a gas-liquid separator in sequence, the liquid outlet of the gas-liquid separator is connected to the inlet of a liquefied air storage device, and the outlet of the liquefied air storage device is connected to the liquid compressed air energy release system.

[0017] The liquid compressed air energy release system comprises a booster pump, the inlet of the booster pump is connected to the outlet of the liquefied air storage device, and the outlet of the booster pump is connected to the air heater and the air expansion generator in sequence.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention uses low-quality steam from a thermal power unit to achieve the adsorption capacity of an air purification molecular sieve, sets up a fan and an air duct to establish a forced mechanical ventilation system, sets up a finned heat exchanger, and introduces steam from somewhere in the steam-water circulation system of the thermal power unit into the pipe. The air flows through the finned heat exchanger and heats up before entering the air purification molecular sieve to activate it. Compared with the traditional electric heating method, the method of using the steam extracted from the steam turbine generator set as a heat source can greatly reduce the operating cost, and can reduce the power output of the steam turbine generator set to a certain extent while keeping the boiler output unchanged, which is beneficial for the thermal power unit to participate in deep peak-shaving services.

Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a system schematic diagram of the present invention.

[0022] Among them, 1-boiler, 2-high-pressure cylinder, 3-medium-pressure cylinder, 4-low-pressure cylinder, 5-generator, 6-condenser, 7-condensate pump, 8-low-pressure heater group, 9-feedwater pump, 10-high-pressure heater group, 11-valve group, 12-fan, 13-steam-gas heat exchanger, 14-drain pump, 15-air compressor, 16-air cooler, 17-air purification molecular sieve, 18-refrigeration expander, 19-gas-liquid separator, 20-liquefied air storage device, 21-liquefied air booster pump, 22-air heater, 23-air expansion generator, 24-second valve group, 25 cold air pipe, 26-hot air pipe. [Specific implementation method]

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0027] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0028] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0030] See also Figure 1 The present invention discloses a heating system for activating purified molecular sieves by utilizing low-grade steam from thermal power units, including a steam-water thermal circulation system for coal-fired power units, a liquid compressed air energy storage system, a liquid compressed air energy release system, and an air purification molecular sieve activation system.

[0031] The steam-water thermal cycle system of the coal-fired generator set includes a coal-fired generator set, and part of the exhaust steam of the intermediate pressure cylinder 3 of the coal-fired generator set enters the air purification molecular sieve activation system as a heat source;

[0032] The coal-fired power generation unit includes a boiler 1, the new steam outlet of the boiler 1 is connected to the steam inlet of the high-pressure cylinder 2, the exhaust port of the high-pressure cylinder 2 is connected to the reheater inlet of the boiler 1, the reheater outlet of the boiler 1 is connected to the steam inlet of the medium-pressure cylinder 3, and the exhaust port of the medium-pressure cylinder 3 is divided into two paths, one of which is connected to the hot side inlet of the steam-gas heat exchanger 13 of the air purification molecular sieve activation system through the first valve group 11, and the other is connected to the steam inlet of the low-pressure cylinder 4. The exhaust steam of the low-pressure cylinder 4 is connected to the condenser 6, the condensate pump 7, the low-pressure heater group 8, the feed water pump group 9 and the high-pressure heater group 10 in sequence; the outlet of the high-pressure heater group 10 is connected to the boiler 1; the high-pressure cylinder 2, the medium-pressure cylinder 3 and the low-pressure cylinder 4 are coaxially connected to drive the generator 5 together to generate electricity.

[0033] The air purification molecular sieve activation system is connected to the liquid compressed air energy storage system to remove moisture, carbon dioxide and other impurities in the air; the outlet of the liquid compressed air energy storage system is connected to the liquid compressed air energy release system.

[0034] The air purification molecular sieve activation system includes a steam-gas heat exchanger 13 and an air purification molecular sieve 17; the hot side outlet of the steam-gas heat exchanger 13 is connected to the condenser 6 through a drain pump 14; the inlet of the air purification molecular sieve 17 is connected to the air cooler 16 of the liquid compressed air energy storage system, and the outlet is connected to the refrigeration expander 18; the heat source of the air purification molecular sieve 17 comes from the steam-gas heat exchanger 13.

[0035] Part of the exhaust gas of the liquid compressed air energy release system is discharged to the atmosphere, and the other part enters the fan 12. The outlet of the fan 12 is connected to the cold side inlet of the steam-gas heat exchanger 13 through the cold air pipe 25. The cold side outlet of the steam-gas heat exchanger 13 is connected to the air purification molecular sieve 17 through the hot air pipe 26 to provide heat for it. A second valve group 24 is also provided on the pipeline between the drain pump 14 and the condenser 6.

[0036] The liquid compressed air energy storage system includes an air compressor 15, the outlet of the air compressor 15 is connected to an air cooler 16, the outlet of the air cooler 16 is connected to an air purification molecular sieve activation system, the outlet of the air purification molecular sieve activation system is connected to a refrigeration expander 18 and a gas-liquid separator 19 in sequence, the liquid outlet of the gas-liquid separator 19 is connected to the inlet of a liquefied air storage device 20, and the outlet of the liquefied air storage device 20 is connected to the liquid compressed air energy release system.

[0037] The liquid compressed air energy release system comprises a booster pump 21 , the inlet of the booster pump 21 is connected to the outlet of the liquefied air storage device 20 , and the outlet of the booster pump 21 is connected to an air heater 22 and an air expansion generator 23 in sequence.

[0038] Working process of the present invention:

[0039] The new steam at the outlet of boiler 1 passes through the high-pressure cylinder 2 of the steam turbine to perform work, then returns to the reheater of boiler 1 for secondary temperature increase, and then enters the medium-pressure cylinder 3 and the low-pressure cylinder 4 to perform work to drive the generator 5 to generate electricity. The exhaust steam of the low-pressure cylinder 4 enters the condenser 6 for condensation, and then flows through the condensate pump 7, the low-pressure heater group 8, the feed water pump group 9 and the high-pressure heater group 10 in sequence, and then enters the boiler 1 to absorb heat, completing the steam-water thermal system cycle of the coal-fired generator set.

[0040] Energy storage process of the system: air is pressurized by the air compressor 15 and then enters the air cooler 16 for cooling. After cooling, the air enters the air purification molecular sieve 17 to remove impurities such as moisture and carbon dioxide, and then enters the refrigeration expander 18 for deep cooling. The air is separated into liquid and gaseous states in the gas-liquid separator 19, and the liquid enters the liquefied air storage device 20. This is the liquefied compression energy storage process of air. At this time, the first valve group 11 and the second valve group 24 are closed.

[0041] Energy release process of the system: the liquefied air at the outlet of the liquefied air storage device 20 is pressurized by the booster pump 21, and then heated by the air heater 22 to enter the air expansion generator 23 to perform work. The exhaust is divided into two paths, one is discharged into the atmosphere, and the other is entered into the air purification molecular sieve activation system as pure air.

[0042] Air purification molecular sieve activation system: A part of the exhaust gas from the air expansion generator 23 enters the fan 12 through the air duct for pressurization, then enters the steam-gas heat exchanger 13 through the cold air duct 25 to absorb heat, then enters the air purification molecular sieve 17 for hot blowing treatment and then is discharged to the atmosphere. The steam-gas heat exchanger 13 is a tubular heat exchange structure that uses fins to enhance heat exchange. High-temperature steam is passed into the tube, and the cold air passes through the heat exchange tube bundle to achieve temperature increase. The first valve group 11 and the second valve group 24 are opened, and the exhaust steam of the medium pressure cylinder 3 enters the steam-gas heat exchanger 13 as a heat source. The condensed water after cooling and condensation is pressurized by the drain pump 14 and returned to the condenser 6 to achieve steam-water quality balance.

[0043] The low-quality steam from thermal power units is used as a heat source to restore the adsorption capacity of the air purification molecular sieve, eliminating the energy conversion link of the generator using electric heating, thus significantly reducing operating costs.

[0044] Principle of the present invention:

[0045] The present invention proposes a heating system that uses low-grade steam from a thermal power unit to activate a purified molecular sieve. A fan and an air duct are provided to establish a forced mechanical ventilation system. A finned heat exchanger is provided. Steam from somewhere in the steam-water circulation system of the thermal power unit is introduced into the pipe. The air flows through the finned heat exchanger and heats up before entering the air-purifying molecular sieve to activate it. Compared with the traditional electric heating method, the method of using the extracted steam that has done work in the steam turbine generator set as a heat source can greatly reduce the operating cost. While the boiler output remains unchanged, the electric output of the steam turbine generator set can be reduced to a certain extent, which is beneficial for the thermal power unit to participate in deep peak-shaving services.

[0046] The air purification molecular sieve "activation" system requires the hot air temperature to be no less than 170°C. Taking a 10MW liquid compressed air energy storage system as an example, the air volume is 21000Nm 3 / h, the inlet air temperature is about 20℃ and the required heat load is about 1.4MW.

[0047] The low-quality heat source of the steam-water thermodynamic cycle of a thermal power unit, such as the exhaust steam from an intermediate pressure cylinder, can meet the requirements of the air purification molecular sieve "activation" system.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heating system for activating purified molecular sieves using low-grade steam from thermal power plants, characterized in that: include: A coal-fired power generation unit, wherein part of the exhaust steam of the intermediate pressure cylinder (3) of the coal-fired power generation unit enters the air purification molecular sieve activation system as a heat source; the coal-fired power generation unit comprises a boiler (1), the new steam outlet of the boiler (1) is connected to the steam inlet of the high pressure cylinder (2), the exhaust steam outlet of the high pressure cylinder (2) is connected to the reheater inlet of the boiler (1), the reheater outlet of the boiler (1) is connected to the steam inlet of the intermediate pressure cylinder (3), and the exhaust steam outlet of the intermediate pressure cylinder (3) is divided into two paths, one of which is connected to the steam inlet of the intermediate pressure cylinder (3) through a first valve group (11). The hot side inlet of the steam-gas heat exchanger (13) of the air purification molecular sieve activation system is connected to the other side of the steam inlet of the low-pressure cylinder (4); the exhaust steam of the low-pressure cylinder (4) is connected to the condenser (6), the condensate pump (7), the low-pressure heater group (8), the feed water pump group (9) and the high-pressure heater group (10) in sequence; the outlet of the high-pressure heater group (10) is connected to the boiler (1); the high-pressure cylinder (2), the medium-pressure cylinder (3) and the low-pressure cylinder (4) are coaxially connected and jointly drive the generator (5) to generate electricity; An air purification molecular sieve activation system, wherein the air purification molecular sieve activation system is connected to a liquid compressed air energy storage system and is used to remove moisture, carbon dioxide and other impurities in the air; the outlet of the liquid compressed air energy storage system is connected to the liquid compressed air energy release system; the liquid compressed air energy storage system comprises an air compressor (15), the outlet of the air compressor (15) is connected to an air cooler (16), the outlet of the air cooler (16) is connected to the air purification molecular sieve activation system, the outlet of the air purification molecular sieve activation system is connected to a refrigeration expander (18) and a gas-liquid separator (19) in sequence, the liquid outlet of the gas-liquid separator (19) is connected to the inlet of a liquefied air storage device (20), and the outlet of the liquefied air storage device (20) is connected to the liquid compressed air energy release system; The air purification molecular sieve activation system comprises a steam-gas heat exchanger (13) and an air purification molecular sieve (17); the hot side outlet of the steam-gas heat exchanger (13) is connected to the condenser (6) via a drain pump (14); the inlet of the air purification molecular sieve (17) is connected to the air cooler (16) of the liquid compressed air energy storage system, and the outlet is connected to the refrigeration expander (18); the heat source of the air purification molecular sieve (17) comes from the steam-gas heat exchanger (13).

2. The heating system for activating purified molecular sieves using low-grade steam from thermal power plants according to claim 1, characterized in that: Part of the exhaust gas of the liquid compressed air energy release system is discharged into the atmosphere, and the other part enters the fan (12). The outlet of the fan (12) is connected to the cold side inlet of the steam-gas heat exchanger (13) through a cold air pipe (25), and the cold side outlet of the steam-gas heat exchanger (13) is connected to the air purification molecular sieve (17) through a hot air pipe (26) to provide heat for it.

3. The heating system for activating purified molecular sieves using low-grade steam from thermal power plants according to claim 1, characterized in that: A second valve group (24) is also provided on the pipeline between the drain pump (14) and the condenser (6).

4. The heating system for activating purified molecular sieves using low-grade steam from thermal power plants according to claim 1, characterized in that: The liquid compressed air energy release system comprises a booster pump (21), the inlet of the booster pump (21) is connected to the outlet of the liquefied air storage device (20), and the outlet of the booster pump (21) is connected in sequence to an air heater (22) and an air expansion generator (23).

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