Combined heat and power generation system for realizing zero-power networking of unit

Abstract

A combined heat and power generation system for achieving zero-power networking of a unit comprises a boiler steam turbine unit, an electric heating energy storage unit, a second heat exchanger, a third heat exchanger, a bypass adjusting unit and a heat supply outer network. The bypass adjusting unit is arranged between the main steam pipeline and the cold end of the boiler reheater; the electric heating energy storage unit is connected into a plant power system and stores energy through an electric heating heat storage medium. A steam bypass is led out to enter the second heat exchanger; the electric heating energy storage unit is connected into a third heat exchanger and a second heat exchanger which are connected with a heat supply external network; heat energy is obtained from the boiler steam turbine unit and the electric heating energy storage unit and used for heating a heating medium in a heat supply outer net; the peak regulation capability of the coal power unit is improved, and the new energy consumption capability is improved.

Description

Technical Field

[0001] The utility model belongs to the field of flexible peak regulation of thermal power plants, can meet the large-scale and long-term up and down peak regulation needs of the power grid, can be used for all reheat units, is not restricted by heating / non-heating conditions, meets the requirements of new power systems, and specifically relates to a cogeneration system that realizes zero-power access to the grid for units. Background Art

[0002] In order to encourage thermal power units to participate in regional deep peak regulation, many regions provide certain electricity price compensation to units participating in peak regulation. As the peak regulation depth increases, the subsidy policy given by the power grid is more favorable. Therefore, in order to further improve the peak regulation depth of coal-fired power units, improve the new energy consumption capacity, and increase the overall benefits of coal-fired power companies, a system and operation mode for achieving zero-power access to the grid for cogeneration units is proposed. The system has a wide range of applications, a small scope of transformation, a high return on investment, and high operational reliability, which is conducive to further promotion. Utility Model Content

[0003] The utility model aims to realize the peak load regulation depth of zero power access to the Internet to the maximum extent, and proposes a heat and power cogeneration system that realizes zero power access to the Internet for units.

[0004] A cogeneration system for realizing zero-power grid access of a unit, comprising a boiler steam turbine unit, an electric thermal energy storage unit, a second heat exchanger, a third heat exchanger, a bypass regulating unit, and a heat supply network; characterized in that:

[0005] The boiler steam turbine unit includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder; the main steam pipeline from the boiler enters the high-pressure cylinder, the high-pressure cylinder exhaust pipeline is connected to the cold end of the boiler reheater, the hot end pipeline of the boiler reheater is connected to the intermediate-pressure cylinder, and the intermediate-pressure cylinder exhaust pipeline is connected to the low-pressure cylinder;

[0006] The bypass regulating unit is set between the main steam pipeline and the cold end of the boiler reheater; the electric thermal energy storage unit is connected to the plant power system and stores energy by electrically heating the heat storage medium;

[0007] The steam from the exhaust pipe of the intermediate pressure cylinder bypasses and enters the hot water side of the second heat exchanger, and the cold water side of the second heat exchanger is connected to the external heating network;

[0008] The electric thermal energy storage unit is connected to the hot water side of the third heat exchanger, and the cold water side of the third heat exchanger is connected to the external heating network.

[0009] Furthermore, it also includes a first heat exchanger, the electric thermal energy storage unit is connected to the hot water side of the first heat exchanger, and the cold water side of the first heat exchanger is connected to the condensate water system.

[0010] Furthermore, the bypass regulation unit includes a high-pressure bypass and a desuperheater. The high-pressure bypass is arranged between the main steam pipe and the high-pressure cylinder exhaust pipe, and the desuperheater is connected to the boiler feed water. A regulating valve is also installed on the high-pressure bypass to adjust the main steam flow in the high-pressure bypass.

[0011] Furthermore, the electric thermal energy storage unit includes an electric heater and a heat storage tank; the electric heater and the heat storage tank are connected by a pipeline through a heating circuit; and the heat storage tank and the first heat exchanger and the third heat exchanger are connected by a pipeline through a heating circuit.

[0012] Furthermore, the electricity used by the electric heater comes from the power supply system in the plant; the outlet line of the high-voltage plant transformer of the thermal power unit is connected to the heat storage transformer, and the outlet line of the heat storage transformer is connected to the electric heater.

[0013] Furthermore, the second heat exchanger and the third heat exchanger are respectively connected to the same external heating network or different external heating networks.

[0014] Furthermore, the heat storage medium in the electric heater and the heat storage tank is water or other heat medium.

[0015] Furthermore, the cold water side of the first heat exchanger is connected in series between two stages of low-pressure heaters in the condensate water system.

[0016] Furthermore, the second heat exchanger is a steam-water heat exchanger, and the drain water enters the turbine condenser through a pipeline.

[0017] Furthermore, high-voltage isolating switches are provided at the inlet and outlet lines of the heat storage transformer, respectively.

[0018] The beneficial effects of the utility model are:

[0019] Compared with the existing technology, the utility model designs a system to achieve zero-power access to the grid for cogeneration units. By setting up equipment such as electrode boilers and related pipeline systems, the peak-shaving depth of coal-fired power units is further improved, the new energy consumption capacity is improved, and the overall benefits of coal-fired power companies are increased. In addition, the system has a wide range of applications and can achieve parallel use of multiple machines, which greatly reduces the scope of transformation and saves transformation costs. The utility model has a small transformation scope, low investment cost, high operating reliability, and is conducive to further promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a system connection diagram.

[0021] In the figure: boiler steam turbine unit 1, plant power supply system 2, electric heater 3, hot water storage tank 4, heat user 5. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] A heat and power cogeneration system for realizing zero-power grid access of a unit, comprising a boiler steam turbine unit, an electric heat storage unit, a second heat exchanger, a third heat exchanger, a bypass regulating unit, and a heat supply external network;

[0024] The boiler steam turbine unit includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder; the main steam pipeline from the boiler enters the high-pressure cylinder, the high-pressure cylinder exhaust pipeline is connected to the cold end of the boiler reheater, the hot end pipeline of the boiler reheater is connected to the intermediate-pressure cylinder, and the intermediate-pressure cylinder exhaust pipeline is connected to the low-pressure cylinder;

[0025] The bypass regulating unit is set between the main steam pipeline and the cold end of the boiler reheater; the electric thermal energy storage unit is connected to the plant power system and stores energy by electrically heating the heat storage medium;

[0026] The steam from the exhaust pipe of the intermediate pressure cylinder bypasses and enters the hot water side of the second heat exchanger, and the cold water side of the second heat exchanger is connected to the external heating network;

[0027] The electric thermal energy storage unit is connected to the hot water side of the third heat exchanger, and the cold water side of the third heat exchanger is connected to the external heating network.

[0028] Example:

[0029] Take a unit as an example. The system diagram is as follows Figure 1 As shown:

[0030] The system includes a boiler steam turbine unit 1, an electric thermal energy storage unit, a peak operation compensation unit, a heat output unit, and a bypass regulation unit.

[0031] The boiler steam turbine unit includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder. The main steam pipeline from the boiler is connected to the high-pressure cylinder, and the high-pressure cylinder exhaust pipeline is connected to the cold end inlet of the boiler reheater. The reheated steam at the hot end outlet of the boiler reheater is connected to the intermediate-pressure cylinder, and the exhaust steam of the intermediate-pressure cylinder is connected to the low-pressure cylinder. The exhaust steam of the low-pressure cylinder is connected to the turbine condenser.

[0032] The bypass regulating unit includes a high-pressure bypass and a desuperheater. The high-pressure bypass is arranged between the main steam pipeline and the high-pressure cylinder exhaust pipeline. The desuperheater is connected to the boiler feed water system. An electric isolation valve (101, 103) and an electric regulating valve (102) are also installed on the high-pressure bypass. The electric isolation valve (101, 103) is used to open or close the high-pressure bypass, and the electric regulating valve (102) is used to adjust the main steam flow in the high-pressure bypass. When the electric isolation valve (101, 103) is opened, the main steam flows through the desuperheater, and after the main steam is desuperheated and depressurized by the introduced boiler feed water, it is merged into the high-pressure cylinder exhaust pipeline again.

[0033] The electric thermal energy storage unit includes an electric heater and a hot water storage tank. The electric heater and the hot water storage tank are connected by a pipeline through a heating circuit, and a heating control valve (401 and 402) is provided on the heating circuit, and a cold water pump (403) is installed.

[0034] The electric heater (3) is used to heat the heat storage medium in the hot water storage tank. The heat storage medium is water, and other suitable media may also be used.

[0035] The electric heater (3) is powered by the power supply system in the plant. The outlet line of the high-voltage transformer of the thermal power unit is connected to the heat storage transformer (12), and the outlet line of the heat storage transformer (12) is connected to the electric heater.

[0036] The inlet and outlet lines of the heat storage transformer (12) are respectively provided with high-voltage isolating switches (11, 13) for switching the heat storage transformer (12) on or off.

[0037] The hot water storage tank is also provided with a heat supply circuit for external output, the heat supply circuit is provided with a heat supply control valve (405 and 406), and is installed with a cold water pump (404).

[0038] During the heating process: start the cold water pump (403), open the valves (401 and 402), close the valves (405 and 406), and stop the hot water pump (404).

[0039] During the heating process: start the hot water pump (404), open the valves (405 and 406), close the valves (401 and 402), and stop the cold water pump (403).

[0040] The outlet water of the heating circuit is arranged in two parallel paths, one of which is connected to the hot water side of the first heat exchanger (61) for heating the condensate of the steam turbine, and valves (614, 615) are arranged on the hot water side pipeline. The first heat exchanger (61) is a water-to-water heat exchanger, and the cold water side of the first heat exchanger (61) is connected to the steam turbine low-pressure heating system. Two outlet bypasses are arranged on the outlet water pipeline of the No. 2 low-pressure heating system of the steam turbine low-pressure heating system, and the bypasses are connected to the cold water side of the first heat exchanger (61). Electric gate valves (612 and 613) are arranged on the outlet bypasses for the input or removal of the first heat exchanger (61). A regulating valve (611) is arranged on the condensate pipeline between the two outlet bypasses, and the outlet water of the No. 2 low-pressure heating is divided into two paths, one of which flows into the downstream low-pressure heating, and the other returns to the steam turbine low-pressure heating system after being heated by the first heat exchanger (61). The flow distribution ratio of the two paths can be adjusted and controlled by the regulating valve (611).

[0041] The first heat exchanger (61) serves as a peak operation compensation unit.

[0042] Another outlet of the heating circuit is connected to the hot water side of the third heat exchanger (63) to heat the circulating water of the heating network, and valves (407, 408) are arranged on the hot water side pipeline. The third heat exchanger (63) is a water-to-water heat exchanger, and the cold water side of the third heat exchanger (63) is connected to the circulating water of the heating network, and valves (503, 504) are arranged on the cold water side pipeline.

[0043] The system also includes a second heat exchanger, which is a steam-water heat exchanger. A heat supply pipe is led out from the steam exhaust pipe of the intermediate pressure cylinder of the steam turbine, and the heat supply pipe is connected to the steam side of the steam-water (62) of the second heat exchanger, and the water side of the steam-water (62) of the second heat exchanger is connected to the circulating water of the heat network. A heat supply butterfly valve (621) is arranged on the heat supply pipe.

[0044] When the heating butterfly valve (621) is opened, part of the intermediate pressure cylinder exhaust steam enters the steam side of the second heat exchanger (62) to heat the circulating water of the heating network. The intermediate pressure cylinder exhaust steam after releasing heat in the steam side of the second heat exchanger (62) generates drainage water, which enters the turbine condenser through the pipeline. The drainage pipeline of the second heat exchanger (62) is provided with a drainage pump (622) and a valve (623).

[0045] The second heat exchanger (62) and the third heat exchanger (63) are both connected to the same heating network. The circulating water in the heating network is heated by the second heat exchanger (62) and the third heat exchanger (63) and then provided to the heat users.

[0046] The second heat exchanger (62) and the third heat exchanger (63) together constitute a heat output unit.

[0047] The second heat exchanger (62) serves as a main heat output unit, and the third heat exchanger (63) serves as an auxiliary heat output unit.

[0048] When the system is used, part or all of the main steam is led back to the boiler reheater through the bypass regulating unit, reducing the main steam entering the turbine and reducing the power generation. The electric thermal energy storage unit can also consume excess electricity and store heat, so that the unit can be connected to the grid at zero power under the grid dispatching command.

[0049] In addition, the heat stored in the electric thermal energy storage unit can be provided to external heat users through the third heat exchanger, or provided to the condensate water system through the second heat exchanger. It can not only meet the external heating demand, but also provide additional heat energy to the generator set according to the needs of the power grid.

[0050] The system can be used in parallel with multiple units. When used in parallel, only the relevant electrical and steam-water piping systems need to be modified. The principles are basically the same.

[0051] Finally, it should be noted that the above description is only an explanation of the utility model and is not intended to limit the utility model. Although the utility model has been described in detail, those skilled in the art can still modify the technical solutions described above or replace some of the technical features with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A cogeneration system for realizing zero-power grid access of a unit, comprising a boiler steam turbine unit, an electric thermal energy storage unit, a second heat exchanger, a third heat exchanger, a bypass regulating unit, and a heat supply network; characterized in that: The boiler steam turbine unit includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder; the main steam pipeline from the boiler enters the high-pressure cylinder, the high-pressure cylinder exhaust pipeline is connected to the cold end of the boiler reheater, the hot end pipeline of the boiler reheater is connected to the intermediate-pressure cylinder, and the intermediate-pressure cylinder exhaust pipeline is connected to the low-pressure cylinder; The bypass regulating unit is set between the main steam pipeline and the cold end of the boiler reheater; the electric thermal energy storage unit is connected to the plant power system and stores energy by electrically heating the heat storage medium; The steam from the exhaust pipe of the intermediate pressure cylinder bypasses and enters the hot water side of the second heat exchanger, and the cold water side of the second heat exchanger is connected to the external heating network; The electric thermal energy storage unit is connected to the hot water side of the third heat exchanger, and the cold water side of the third heat exchanger is connected to the external heating network.

2. According to claim 1, a cogeneration system for realizing zero-power grid connection of the unit, characterized in that: It also includes a first heat exchanger, the electric thermal energy storage unit is connected to the hot water side of the first heat exchanger, and the cold water side of the first heat exchanger is connected to the condensate water system.

3. According to claim 1, a cogeneration system for realizing zero-power grid connection of the unit, characterized in that: The bypass regulation unit includes a high-pressure bypass and a desuperheater. The high-pressure bypass is arranged between the main steam pipeline and the high-pressure cylinder exhaust pipeline, and the desuperheater is connected to the boiler feed water. A regulating valve is also installed on the high-pressure bypass to adjust the main steam flow in the high-pressure bypass.

4. A cogeneration system for realizing zero-power grid access of a unit according to claim 1 or 2, characterized in that: The electric thermal energy storage unit includes an electric heater and a heat storage tank; the electric heater and the heat storage tank are connected by a pipeline through a heating circuit; The heat storage tank is connected to the first heat exchanger and the third heat exchanger through a heating circuit.

5. A cogeneration system for realizing zero-power grid access of a unit according to claim 4, characterized in that: The electricity used by the electric heater comes from the power supply system in the plant; the outlet line of the high-voltage plant transformer of the thermal power unit is connected to the heat storage transformer, and the outlet line of the heat storage transformer is connected to the electric heater.

6. A cogeneration system for realizing zero-power grid access of a unit according to claim 1, characterized in that: The second heat exchanger and the third heat exchanger are respectively connected to the same external heating network or different external heating networks.

7. A cogeneration system for realizing zero-power grid access of a unit according to claim 4, characterized in that: The heat storage medium in the electric heater and the heat storage tank is water or other heat media.

8. A cogeneration system for realizing zero-power grid connection of a unit according to claim 2, characterized in that: The cold water side of the first heat exchanger is connected in series between the two-stage low-pressure heaters in the condensate water system.

9. A cogeneration system for realizing zero-power grid access of a unit according to claim 1, characterized in that: The second heat exchanger is a steam-water heat exchanger, and the drain water enters the turbine condenser through a pipeline.

10. A cogeneration system for realizing zero-power grid access of a unit according to claim 5, characterized in that: High-voltage isolating switches are also provided on the inlet and outlet lines of the heat storage transformer.

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