Turbine flexible energy supply system based on gradient utilization and operation method thereof

Abstract

The invention relates to a steam turbine flexible energy supply system based on gradient utilization and an operation method thereof. The system comprises an air cooling normal pressure condenser, a high back pressure condenser, a first-stage peak heater, a second-stage peak heater, a gradient utilization back pressure machine, a fused salt heat storage system, a steam compressor, a steam turbine and a drainage system. The air cooling normal pressure condenser, the high back pressure condenser, the first-stage peak heater and the second-stage peak heater are sequentially connected to form a fourth-stage heating energy supply system. An inlet of the air cooling normal pressure condenser is connected with a heat supply water return pipeline, and an outlet of the secondary peak heater is connected with a heat supply steam supply pipeline. The heat supply steam turbine unit is clearly divided into four gradient utilization energy supply systems, the gradient heat supply mode can be dynamically adjusted according to the heat user requirement and the deep peak regulation requirement of the unit, the problem that the energy is sharply increased due to deep peak regulation is solved, and meanwhile the livelihood heat supply and industrial steam supply guarantee capacity of the unit is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal-electric decoupling of thermal power units, and in particular relates to a flexible energy supply system for a steam turbine based on cascade utilization and an operation method thereof. Background Art

[0002] In recent years, China's energy has adhered to the development direction of clean, low-carbon, safe and efficient, vigorously developed wind power, solar energy and other clean energy power generation, and the energy structure adjustment has been accelerating. However, wind and solar power generation are characterized by randomness, intermittency and rapid changes. With the increase of new energy power generation and the overcapacity of traditional coal-fired power generation, the peak-shaving difficulty of the power grid has been aggravated. Some regions have seriously abandoned wind and solar power, which has put forward new requirements for improving the flexibility and deep peak-shaving capabilities of existing thermal power units.

[0003] At present, the country has proposed a new generation of coal-fired power construction plan, requiring thermal power units to have deeper peak-shaving capabilities. In order to meet the increasingly severe peak-shaving environment of thermal power units, it is urgently needed to conduct more systematic and in-depth research on deep thermal-electric decoupling and energy cascade utilization methods to help thermal power units better play a role in supporting and ensuring supply. Summary of the invention

[0004] The purpose of the present invention is to provide a flexible energy supply system for steam turbines based on cascade utilization and an operation method thereof. In an environment where the new generation of coal-fired power has increasingly stringent requirements for deep peak regulation of thermal power units, the steam turbine is divided into a four-stage heating energy supply system, including air-cooled normal pressure exhaust steam heating, high back pressure exhaust steam heating, first-stage peak heating and second-stage peak heating. The four-stage cascade utilization energy supply system is used to improve the external heat and steam supply capabilities of the unit under deep peak regulation conditions. The cascade utilization back pressure machine can generate electricity to replace part of the plant electricity, and can also drive the steam compressor to meet the steam pressure requirements for steam supply.

[0005] The present invention provides a steam turbine flexible energy supply system based on cascade utilization, comprising an air-cooled atmospheric pressure condenser, a high back pressure condenser, a primary peak heater, a secondary peak heater, a cascade utilization back pressure machine, a molten salt heat storage system, a steam compressor, a steam turbine and a drainage system;

[0006] The air-cooled atmospheric pressure condenser, high back pressure condenser, first-stage peak heater and second-stage peak heater are connected in sequence to form a four-stage heating energy supply system; the inlet of the air-cooled atmospheric pressure condenser is connected to the heating return water pipeline, and the outlet of the second-stage peak heater is connected to the heating steam supply pipeline;

[0007] The steam turbine is connected to the air-cooled atmospheric pressure condenser through an atmospheric pressure exhaust pipeline, and the air-cooled atmospheric pressure condenser is connected to the drain system;

[0008] The steam turbine is connected to the high back pressure condenser through a high back pressure exhaust pipeline, and the high back pressure condenser is connected to the drain system;

[0009] The steam turbine is connected to the step back pressure machine via a middle row steam extraction pipeline, the step back pressure machine is connected to the first level peak heater, and the first level peak heater is connected to the drain system;

[0010] The steam turbine is connected to the molten salt thermal storage system through a hot re-extraction pipeline, the molten salt thermal storage system is connected to the secondary peak heater through a first valve, and the secondary peak heater is connected to the drain system;

[0011] The steps are connected to the heat and steam supply pipeline via the steam compressor using a back pressure machine;

[0012] The molten salt thermal storage system is connected to the primary peak heater via a second valve.

[0013] The present invention also provides an operation method of the steam turbine flexible energy supply system based on cascade utilization, comprising:

[0014] The heating return water first enters the air-cooled atmospheric pressure condenser to absorb the heat of the atmospheric pressure exhaust steam of the air-cooled unit, and then enters the high back pressure condenser, the first-level peak heater, and the second-level peak heater in sequence; wherein, the heat source of the first-level peak heater comes from the steam extracted from the middle exhaust and after cascade power generation and the low-temperature steam released by the molten salt thermal storage system; the heat source of the second-level peak heater comes from the hot re-extraction steam after the heat release of the molten salt system.

[0015] Furthermore, the operation method also includes:

[0016] The steam compressor is used to increase the pressure of industrial steam supply to provide qualified steam that meets user needs.

[0017] Furthermore, the operation method also includes:

[0018] The cascade back pressure machine is used to generate electricity to replace part of the factory electricity, and at the same time drives the steam compressor to meet the steam supply steam pressure demand.

[0019] Furthermore, the pressure of the high back pressure condenser and the proportion of the hot re-extracted steam after heat storage in the molten salt heat storage system entering the first-stage peak heater and the second-stage peak heater are dynamically adjusted according to changes in the power generation load and heating load of the unit; the principle of the dynamic adjustment is to optimize the overall benefit of the unit.

[0020] Furthermore, the molten salt thermal storage system absorbs high-temperature steam in the temperature range of 450°C-600°C according to the thermal properties of molten salt; after the high-temperature steam of the turbine releases heat in the molten salt thermal storage system, it continues to enter the first-level peak heater and the second-level peak heater to release heat; when the deep adjustment stage entered by the unit exceeds its own thermoelectric decoupling capacity, the molten salt thermal storage system is used to supplement the generation of high-temperature steam to alleviate the unit's own thermoelectric decoupling pressure.

[0021] Through the above scheme, through the flexible energy supply system of steam turbine based on cascade utilization and its operation method, the heating steam turbine unit is clearly divided into four cascade utilization energy supply systems. The cascade heating mode can be dynamically adjusted according to the needs of heat users and the deep peak regulation needs of the unit, thereby alleviating the problem of sharp increase in energy caused by deep peak regulation, and at the same time improving the unit's ability to provide heating for people's livelihood and industrial steam supply.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a steam turbine flexible energy supply system based on cascade utilization according to the present invention.

[0024] Numbers in the figure:

[0025] 1-air-cooled normal pressure condenser; 2-high back pressure condenser; 3-first stage peak heater; 4-second stage peak heater; 5-cascade back pressure machine; 6-molten salt heat storage system; 7-steam compressor; 8-steam turbine; 9-drain system; 10-first valve; 11-second valve. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] Ginseng Figure 1As shown, this embodiment provides a steam turbine flexible energy supply system based on cascade utilization, including an air-cooled atmospheric pressure condenser 1, a high back pressure condenser 2, a first-level peak heater 3, a second-level peak heater 4, a cascade utilization back pressure machine 5, a molten salt heat storage system 6, a steam compressor 7, a steam turbine 8 and a drain system 9; the air-cooled atmospheric pressure condenser 1, the high back pressure condenser 2, the first-level peak heater 3, and the second-level peak heater 4 are connected in sequence to form a four-stage heating energy supply system; the inlet of the air-cooled atmospheric pressure condenser 1 is connected to the heating return water pipeline, and the outlet of the second-level peak heater 4 is connected to the heating steam supply pipeline; the steam turbine is connected to the air-cooled atmospheric pressure condenser 1 through the atmospheric pressure exhaust pipeline, and the air-cooled atmospheric pressure condenser 1 It is connected to the drain system 9; the steam turbine is connected to the high back pressure condenser 2 through the high back pressure exhaust pipeline, and the high back pressure condenser 2 is connected to the drain system 9; the steam turbine is connected to the step utilization back pressure machine 5 through the middle exhaust steam extraction pipeline, the step utilization back pressure machine 5 is connected to the first-level peak heater 3, and the first-level peak heater 3 is connected to the drain system 9; the steam turbine is connected to the molten salt heat storage system 6 through the hot re-extraction pipeline, the molten salt heat storage system 6 is connected to the second-level peak heater 4 through the first valve, and the second-level peak heater 4 is connected to the drain system 9; the step utilization back pressure machine 5 is connected to the heating and steam supply pipeline through the steam compressor 7; the molten salt heat storage system 6 is connected to the first-level peak heater 3 through the second valve.

[0028] The operation method of the steam turbine flexible energy supply system based on cascade utilization is as follows:

[0029] The process on the circulating water side of the heat network is as follows: the heat supply return water first enters the air-cooled atmospheric pressure condenser 1, absorbs the atmospheric pressure exhaust heat of the air-cooled unit, and then enters the high back pressure condenser 2, the first-level peak heater 3, and the second-level peak heater 4 in sequence; among them, the heat source of the first-level peak heater 3 comes from the steam extracted from the middle row and the steam after the cascade power generation and the low-temperature steam released by the molten salt heat storage system 6; the heat source of the second-level peak heater 4 comes from the heat after the molten salt system 6 releases heat and then extracts steam. If necessary, the steam compressor 7 is used to increase the pressure of the industrial steam supply to provide qualified steam that meets user needs. The use of the cascade back pressure machine 5 to generate electricity can replace part of the plant electricity, and at the same time can drive the steam compressor 7 to meet the steam supply steam pressure requirements. Before the middle row extraction enters the first-level peak heater, it first enters the cascade back pressure machine to generate electricity. This part of the electricity can be used as plant electricity and can also drive the steam compressor to provide a guarantee for the industrial steam supply pressure. By directly extracting steam using heat, the power generation load of the steam turbine main engine can be further reduced, and the heating / steam supply capacity of the unit can be improved. By using the molten salt heat storage system, the goal of tiered matching of parameters between heating companies and heat users can be achieved.

[0030] In this embodiment, the pressure of the high back pressure condenser 2 and the proportion of the hot re-extracted steam after heat storage in the molten salt heat storage system 6 entering the first-level peak heater 3 and the second-level peak heater 4 are dynamically adjusted according to the changes in the power generation load and heating load of the unit; the principle of dynamic adjustment is to optimize the overall benefit of the unit.

[0031] In this embodiment, the molten salt thermal storage system 6 can absorb high-temperature steam in the temperature range of 450°C-600°C according to the thermal properties of the molten salt; after the high-temperature steam of the turbine 8 releases heat in the molten salt thermal storage system 6, it can continue to enter the first-level peak heater 3 and the second-level peak heater 4 to release heat; when the deep adjustment stage entered by the unit exceeds its own thermoelectric decoupling capacity, the molten salt thermal storage system 6 can supplement the generation of high-temperature steam to alleviate the unit's own thermoelectric decoupling pressure.

[0032] Through the steam turbine flexible energy supply system based on cascade utilization and its operation method, the heating steam turbine unit is clearly divided into four cascade utilization energy supply systems. The cascade heating mode can be dynamically adjusted according to the needs of heat users and the deep peak regulation needs of the unit, alleviating the problem of rapid increase in energy caused by deep peak regulation, while improving the unit's ability to provide heating for people's livelihood and industrial steam supply.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A steam turbine flexible energy supply system based on cascade utilization, characterized in that: It includes an air-cooled atmospheric pressure condenser (1), a high back pressure condenser (2), a first-stage peak heater (3), a second-stage peak heater (4), a cascade back pressure machine (5), a molten salt heat storage system (6), a steam compressor (7), a steam turbine (8) and a drainage system (9); The air-cooled atmospheric pressure condenser (1), the high back pressure condenser (2), the first-stage peak heater (3), and the second-stage peak heater (4) are sequentially connected to form a four-stage heating energy supply system; The inlet of the air-cooled atmospheric condenser (1) is connected to a heat return water pipeline, and the outlet of the secondary peak heater (4) is connected to a heat steam supply pipeline; The steam turbine is connected to the air-cooled atmospheric pressure condenser (1) via an atmospheric pressure exhaust pipeline, and the air-cooled atmospheric pressure condenser (1) is connected to the drain system (9); The steam turbine is connected to the high back pressure condenser (2) via a high back pressure exhaust pipeline, and the high back pressure condenser (2) is connected to the drain system (9); The steam turbine is connected to the step-utilizing back pressure machine (5) through a middle row steam extraction pipeline, the step-utilizing back pressure machine (5) is connected to the first-stage peak heater (3), and the first-stage peak heater (3) is connected to the drain system (9); The steam turbine is connected to the molten salt heat storage system (6) via a hot re-extraction pipeline, the molten salt heat storage system (6) is connected to the secondary peak heater (4) via a first valve, and the secondary peak heater (4) is connected to the drain system (9); The steps are connected to the heat and steam supply pipeline via the steam compressor (7) using a back pressure machine (5); The molten salt heat storage system (6) is connected to the primary peak heater (3) via a second valve.

2. An operating method of the steam turbine flexible energy supply system based on cascade utilization according to claim 1, characterized in that: include: The heating return water first enters the air-cooled atmospheric pressure condenser (1) to absorb the heat of the atmospheric pressure exhaust steam of the air-cooled unit, and then enters the high back pressure condenser (2), the first-stage peak heater (3), and the second-stage peak heater (4) in sequence; wherein the heat source of the first-stage peak heater (3) comes from the steam extracted from the middle exhaust and after cascade power generation and the low-temperature steam released by the molten salt thermal storage system (6); the heat source of the second-stage peak heater (4) comes from the hot re-extraction steam after the heat release of the molten salt system (6).

3. The operating method according to claim 2, characterized in that: Also includes: The steam compressor (7) is used to increase the pressure of industrial steam supply to provide qualified steam that meets user needs.

4. The operating method according to claim 3, characterized in that: Also includes: The step-type back pressure machine (5) is used to generate electricity to replace part of the factory electricity, and at the same time drives the steam compressor (7) to meet the steam supply steam pressure requirement.

5. The operating method according to claim 2, characterized in that: The pressure of the high back pressure condenser (2) and the ratio of the hot re-extracted steam after heat storage in the molten salt heat storage system (6) entering the first-stage peak heater (3) and the second-stage peak heater (4) are dynamically adjusted according to the changes in the power generation load and heating load of the unit; the principle of the dynamic adjustment is to optimize the overall benefit of the unit.

6. The operating method according to claim 2, characterized in that: The molten salt thermal storage system (6) absorbs high-temperature steam in the temperature range of 450°C-600°C according to the thermal properties of the molten salt; after the high-temperature steam of the steam turbine (8) releases heat in the molten salt thermal storage system (6), it continues to enter the first-level peak heater (3) and the second-level peak heater (4) to release heat; when the deep adjustment stage entered by the unit exceeds its own thermoelectric decoupling capacity, the molten salt thermal storage system (6) is used to supplement the generation of high-temperature steam to relieve the unit's own thermoelectric decoupling pressure.

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