Waste heat utilization system of generator set

Abstract

The utility model relates to the technical field of generator sets, and discloses a waste heat utilization system of a generator set, which comprises a coal-fired generator set and a gas generator set, the coal-fired generator set comprises a boiler, a steam turbine, a condenser, a first heat exchanger, a second heat exchanger and a third heat exchanger, and the steam turbine comprises a high-pressure cylinder, an intermediate-pressure cylinder and a low-pressure cylinder. The boiler is provided with a steam outlet and a water return port, the steam outlet is sequentially connected with a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a condenser, a first heat exchanger, a second heat exchanger, a third heat exchanger and the water return port, the gas generator set comprises a gas turbine and a waste heat boiler, and a gas outlet of the gas turbine is connected with a gas inlet of the waste heat boiler. A water inlet of the waste heat boiler is connected with a water inlet of the first heat exchanger, and a water outlet of the waste heat boiler is connected with a water outlet of the first heat exchanger. According to the utility model, the tail flue gas waste heat of the gas turbine of the gas generator set is used for heating the condensed water of the coal-fired generator set, so that the tail flue gas waste heat of the gas turbine is utilized.

Description

Technical Field

[0001] The utility model relates to the technical field of generator sets, in particular to a waste heat utilization system of a generator set. Background Art

[0002] According to relevant policies on energy industry, environmental protection, and local industrial development planning, some expansion projects can only build gas-fired power plants, and together with the coal-fired power plants that have been built on the original site, a number of new power bases with both coal-fired power plants and gas-fired power plants have been formed. For example, China Shenhua Huizhou Thermal Power Branch originally planned to build four 300MW coal-fired cogeneration units in two phases. The first phase of two coal-fired units were officially put into operation in 2010. When the second phase of the project was approved in 2021, it was changed from building two new coal-fired units to building two F-class gas-fired power plants. For example, China Guodian Zhaoqing Dawang Power Plant has built two 350MW coal-fired power plants in the first phase, and is currently building two F-class gas-fired power plants, which are expected to be put into operation in 2024. By then, the gas-fired generators and coal-fired generators can form a comprehensive energy base together.

[0003] In the gas generator set, after the waste heat boiler recovers the waste heat of the tail flue gas of the gas turbine, this part of the heat energy is used in the form of external hot water supply. Hot water can be provided to the hot water type lithium bromide refrigeration unit for refrigeration, and can also be used in the pressure regulating station to heat natural gas to prevent ice blockage. However, the above uses have certain limitations. For example, if the power plant does not use hot water type lithium bromide refrigeration, there is no need to use hot water for heat exchange; if the natural gas source pressure of the power plant is low, the efficiency of the booster will be reduced after the natural gas is heated; if the incoming gas pressure is high and the temperature is high, ice blockage will not occur when the pressure is reduced, and hot water heating is not required; at this time, the waste heat of the tail flue gas of the gas turbine cannot be used, resulting in energy waste. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a generator set waste heat utilization system which utilizes the tail flue gas waste heat of the gas turbine of the gas generator set to heat the condensate of the coal-fired generator set.

[0005] In order to solve the above technical problems, the utility model provides a waste heat utilization system of a generator set, including a coal-fired generator set and a gas-fired generator set, the coal-fired generator set including a boiler, a steam turbine, a condenser, a first heat exchanger, a second heat exchanger and a third heat exchanger, the steam turbine including a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder, the boiler is provided with a steam outlet and a return water port, the steam outlet is sequentially connected to the high-pressure cylinder, the medium-pressure cylinder, the low-pressure cylinder, the condenser, the first heat exchanger, the second heat exchanger, the third heat exchanger and the return water port, the The low-pressure cylinder is provided with a first air exhaust port connected to the air inlet of the first heat exchanger, the medium-pressure cylinder is provided with a second air exhaust port connected to the air inlet of the second heat exchanger, and the high-pressure cylinder is provided with a third air exhaust port connected to the air inlet of the third heat exchanger. The gas generator set includes a gas turbine and a waste heat boiler, the air outlet of the gas turbine is connected to the air inlet of the waste heat boiler, the water inlet of the waste heat boiler is connected to the water inlet of the first heat exchanger, and the water outlet of the waste heat boiler is connected to the water outlet of the first heat exchanger.

[0006] As a preferred embodiment of the present invention, the steam turbine also includes an ultra-high pressure cylinder, the steam outlet is connected to the air inlet of the ultra-high pressure cylinder, a reheating channel is provided in the boiler, the air outlet of the reheating channel is connected to the air inlet of the high pressure cylinder, and the air outlet of the ultra-high pressure cylinder is connected to the return air port of the reheating channel.

[0007] As a preferred solution of the utility model, a fourth heat exchanger is provided on the connecting pipe between the third heat exchanger and the water return port, and the air outlet of the ultra-high pressure cylinder is connected to the air inlet of the fourth heat exchanger.

[0008] As a preferred solution of the utility model, a deaerator is provided on the connecting pipe between the second heat exchanger and the third heat exchanger, and the medium-pressure cylinder is provided with an air supply port connected to the heat source input port of the deaerator.

[0009] As a preferred embodiment of the present invention, multiple first heat exchangers are provided and arranged in sequence, multiple first air exhaust ports are provided and connected to multiple first heat exchangers in a one-to-one correspondence, the water inlet of the waste heat boiler is connected to the water inlet of one of the first heat exchangers, and the water outlet of the first heat exchanger is connected to the water outlet of the waste heat boiler.

[0010] As a preferred solution of the present utility model, a booster pump is provided in the connecting pipe between the water inlet of the waste heat boiler and the water inlet of the first heat exchanger.

[0011] The utility model embodiment provides a waste heat utilization system for a generator set. Compared with the prior art, its beneficial effects are as follows: when working, the tail flue gas of the gas turbine is transported to the waste heat boiler, and the condensed water transported to the waste heat boiler is heated and then transported back to the second heat exchanger, that is, the waste heat of the tail flue gas of the gas turbine of the gas-fired generator set is used to heat the condensed water of the coal-fired generator set, thereby realizing the utilization of the waste heat of the gas turbine set, helping to reduce the exhaust temperature of the waste heat boiler, thereby reducing the thermal pollution emission to the atmosphere, and at the same time reducing the steam extraction amount of the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder, so as to achieve the cascade utilization of energy and improve the economic benefit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model;

[0013] In the figure, 1. coal-fired power generation unit; 11. boiler; 111. steam outlet; 112. return water outlet; 113. reheating channel; 12. steam turbine; 121. high-pressure cylinder; 122. medium-pressure cylinder; 123. low-pressure cylinder; 124. ultra-high-pressure cylinder; 13. condenser; 14. first heat exchanger; 15. second heat exchanger; 16. third heat exchanger; 17. fourth heat exchanger; 18. deaerator; 2. gas-fired power generation unit; 21. gas turbine; 22. waste heat boiler; 23. booster pump. DETAILED DESCRIPTION

[0014] The following is a further detailed description of the specific implementation of the present invention 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.

[0015] like Figure 1As shown, a waste heat utilization system of a generator set in a preferred embodiment of the utility model comprises a coal-fired generator set 1 and a gas-fired generator set 2. The coal-fired generator set 1 comprises a boiler 11, a steam turbine 12, a condenser 13, a first heat exchanger 14, a second heat exchanger 15 and a third heat exchanger 16. The steam turbine 12 comprises a high-pressure cylinder 121, a medium-pressure cylinder 122 and a low-pressure cylinder 123. The boiler 11 is provided with a steam outlet 111 and a return water outlet 112. The steam outlet 111 is connected to the high-pressure cylinder 121, the medium-pressure cylinder 122, the low-pressure cylinder 123, the condenser 13, the first heat exchanger 14 and the third heat exchanger 16 in sequence. 4. The second heat exchanger 15, the third heat exchanger 16 and the water return port 112 are connected. Specifically, the steam outlet 111 of the boiler 11 is connected to the air inlet of the high-pressure cylinder 121, the air outlet of the high-pressure cylinder 121 is connected to the air inlet of the medium-pressure cylinder 122, the air outlet of the medium-pressure cylinder 122 is connected to the air inlet of the low-pressure cylinder 123, the air outlet of the low-pressure cylinder 123 is connected to the air inlet of the condenser 13, the water outlet of the condenser 13 is connected to the water inlet of the first heat exchanger 14, the water outlet of the first heat exchanger 14 is connected to the water inlet of the second heat exchanger 15, and the outlet of the second heat exchanger 15 is connected to the water inlet of the second heat exchanger 15. The water inlet is connected to the water inlet of the third heat exchanger 16, and the water outlet of the third heat exchanger 16 is connected to the return water inlet 112 of the boiler 11. In this embodiment, a condensate pump is provided in the connecting pipe between the water outlet of the condenser 13 and the water inlet of the first heat exchanger 14, and the low-pressure cylinder 123 is provided with a first air extraction port connected to the air inlet of the first heat exchanger 14, that is, the water vapor in the low-pressure cylinder 123 can be transported to the first heat exchanger 14 through the first air extraction port for heat exchange, and the medium-pressure cylinder 122 is provided with a second air extraction port connected to the air inlet of the second heat exchanger 15, that is, the water vapor in the medium-pressure cylinder 122 The water vapor can be transported to the second heat exchanger 15 for heat exchange through the second air exhaust port. The high-pressure cylinder 121 is provided with a third air exhaust port connected to the air inlet of the third heat exchanger 16, that is, the water vapor in the high-pressure cylinder 121 can be transported to the third heat exchanger 16 for heat exchange through the third air exhaust port. The gas generator set 2 includes a gas turbine 21 and a waste heat boiler 22. The air outlet of the gas turbine 21 is connected to the air inlet of the waste heat boiler 22, the water inlet of the waste heat boiler 22 is connected to the water inlet of the first heat exchanger 14, and the water outlet of the waste heat boiler 22 is connected to the water outlet of the first heat exchanger 14.

[0016] The working principle of this embodiment is as follows: the water vapor generated by the boiler 11 is sequentially transported to the high-pressure cylinder 121, the medium-pressure cylinder 122 and the low-pressure cylinder 123 of the steam turbine 12, driving the steam turbine 12 to drive the engine to work, thereby realizing power generation of the coal-fired generator set 1; then the water vapor in the low-pressure cylinder 123 is transported to the condenser 13 to condense into condensed water, and the condensed water is transported to the waste heat boiler 22 and the first heat exchanger 14 respectively, the condensed water transported to the waste heat boiler 22 is heated by the tail flue gas of the gas turbine 21 and then transported to the second heat exchanger 15, and the condensed water transported to the first heat exchanger 14 is heated by the water vapor transported from the first air extraction port to the first heat exchanger 14 and then transported to the second heat exchanger 15, then heated by the water vapor transported from the second air extraction port to the second heat exchanger 15 and then transported to the third heat exchanger 16, then heated by the water vapor transported from the third air extraction port to the third heat exchanger 16 and then transported to the boiler 1 1, realizes the circulation of condensate; in the above working process, the tail flue gas of the gas turbine 21 is transported to the waste heat boiler 22 to heat the feed water of the gas unit, and at the same time, the condensate transported to the waste heat boiler 22 is heated and then transported to the second heat exchanger 15, that is, the waste heat of the tail flue gas of the gas turbine 21 of the gas generator set 2 is used to heat the condensate of the coal-fired generator set 1, so as to realize the utilization of the waste heat of the gas turbine 21 group, which is helpful to reduce the exhaust temperature of the waste heat boiler 22, thereby reducing the thermal pollution emission to the atmosphere, and at the same time reducing the steam extraction amount of the high-pressure cylinder 121, the medium-pressure cylinder 122 and the low-pressure cylinder 123, so as to achieve the cascade utilization of energy and improve the economic benefit; the condensate system of the coal-fired generator set 1 and the feed water system of the gas generator set 2 are both desalted water, and the two are combined to form a large closed steam-water cycle, without steam-water loss during the working process, saving water and energy.

[0017] Exemplarily, in some coal-fired power generation units 1, the steam turbine 12 also includes an ultra-high pressure cylinder 124, the steam outlet 111 is connected to the air inlet of the ultra-high pressure cylinder 124, a reheating channel 113 is provided in the boiler 11, the air outlet of the reheating channel 113 is connected to the air inlet of the high pressure cylinder 121, the air outlet of the ultra-high pressure cylinder 124 is connected to the return air port of the reheating channel 113, the steam in the boiler 11 is transported to the ultra-high pressure cylinder 124 through the steam outlet 111 to do work, the water vapor after doing work is transported to the heating channel 113 through the return air port, the water vapor is heated again by the boiler 11 and transported to the high pressure cylinder 121 to do work, and then transported to the medium pressure cylinder 122 and the low pressure cylinder 123 in sequence, with high energy utilization and high work efficiency.

[0018] Exemplarily, a fourth heat exchanger 17 is provided on the connecting pipe between the third heat exchanger 16 and the return water port 112, that is, the water outlet of the third heat exchanger 16 is connected to the water inlet of the fourth heat exchanger 17, the water outlet of the fourth heat exchanger 17 is connected to the return water port 112, and the air outlet of the ultra-high pressure cylinder 124 is connected to the air inlet of the fourth heat exchanger 17, that is, after the water vapor in the ultra-high pressure cylinder 124 does work, part of the water vapor is transported to the reheating channel 113, and part of the water vapor is transported to the fourth heat exchanger 17, so that the condensed water transported to the fourth heat exchanger 17 by the third transport channel is heated, and the heated condensed water is transported back to the boiler 11.

[0019] Exemplarily, a deaerator 18 is provided on the connecting pipe between the second heat exchanger 15 and the third heat exchanger 16, that is, the water outlet of the second heat exchanger is connected to the water inlet of the deaerator 18, and the water outlet of the deaerator 18 is connected to the water inlet of the third heat exchanger 16. In this embodiment, a water feed pump is provided on the connecting pipe between the water outlet of the deaerator 18 and the water inlet of the third heat exchanger 16. The deaerator 18 can remove dissolved oxygen in the condensate to prevent oxygen corrosion of the boiler 11 and its piping system. The medium-pressure cylinder 122 is provided with an air supply port connected to the heat source input port of the deaerator 18. It can be understood that the heat of the water vapor output from the air supply port can meet the use requirements of the deaerator 18 without being excessive, so as to reasonably utilize the heat and reduce energy waste.

[0020] Exemplarily, a plurality of first heat exchangers 14 are provided and are arranged in sequence, a plurality of first air suction ports are provided and are connected to the plurality of first heat exchangers 14 in a one-to-one correspondence. It can be understood that the temperatures of the steam delivered by the first air suction ports located at different parts of the low-pressure cylinder 123 are different. In the two first heat exchangers 14 arranged in sequence along the return water direction, the temperature of the steam delivered by the first air suction port connected to the previous first heat exchanger 14 is lower than the temperature of the steam delivered by the first air suction port connected to the next first heat exchanger 14, thereby realizing gradual heating of the condensed water. Similarly, a plurality of second heat exchangers 15 and a plurality of third heat exchangers 16 can be respectively provided, and the water inlet of the waste heat boiler 22 is connected to the water inlet of one of the first heat exchangers 14, and the water outlet of the first heat exchanger 14 is connected to the water outlet of the waste heat boiler 22.

[0021] Exemplarily, a booster pump 23 is provided in the connecting pipe between the water inlet of the waste heat boiler 22 and the water inlet of the first heat exchanger 14 to ensure that condensed water at the water inlet of the first heat exchanger 14 can be transported to the water inlet of the waste heat boiler 22 .

[0022] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A waste heat utilization system for a generator set, characterized in that: It includes a coal-fired generator set and a gas-fired generator set. The coal-fired generator set includes a boiler, a steam turbine, a condenser, a first heat exchanger, a second heat exchanger and a third heat exchanger. The steam turbine includes a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder. The boiler is provided with a steam outlet and a water return port. The steam outlet is connected to the high-pressure cylinder, the medium-pressure cylinder, the low-pressure cylinder, the condenser, the first heat exchanger, the second heat exchanger, the third heat exchanger and the water return port in sequence. The low-pressure cylinder is provided with a first air extraction port connected to the air inlet of the first heat exchanger, the medium-pressure cylinder is provided with a second air extraction port connected to the air inlet of the second heat exchanger, and the high-pressure cylinder is provided with a third air extraction port connected to the air inlet of the third heat exchanger. The gas-fired generator set includes a gas turbine and a waste heat boiler. The air outlet of the gas turbine is connected to the air inlet of the waste heat boiler, the water inlet of the waste heat boiler is connected to the water inlet of the first heat exchanger, and the water outlet of the waste heat boiler is connected to the water outlet of the first heat exchanger.

2. The waste heat utilization system of a generator set according to claim 1, characterized in that: The steam turbine also includes an ultra-high pressure cylinder, the steam outlet is connected to the air inlet of the ultra-high pressure cylinder, a reheating channel is provided in the boiler, the air outlet of the reheating channel is connected to the air inlet of the high pressure cylinder, and the air outlet of the ultra-high pressure cylinder is connected to the return air port of the reheating channel.

3. The waste heat utilization system of a generator set according to claim 2, characterized in that: A fourth heat exchanger is provided on the connecting pipe between the third heat exchanger and the water return port, and the air outlet of the ultra-high pressure cylinder is connected to the air inlet of the fourth heat exchanger.

4. The waste heat utilization system of a generator set according to claim 1, characterized in that: A deaerator is provided on the connecting pipeline between the second heat exchanger and the third heat exchanger, and the intermediate pressure cylinder is provided with an air supply port connected to the heat source input port of the deaerator.

5. The waste heat utilization system of a generator set according to claim 1, characterized in that: The first heat exchangers are arranged in multiple numbers and are arranged in sequence, the first air extraction ports are arranged in multiple numbers and are connected to the multiple first heat exchangers in a one-to-one correspondence, the water inlet of the waste heat boiler is connected to the water inlet of one of the first heat exchangers, and the water outlet of the first heat exchanger is connected to the water outlet of the waste heat boiler.

6. The waste heat utilization system of a generator set according to claim 1, characterized in that: A booster pump is provided in a connecting pipe between the water inlet of the waste heat boiler and the water inlet of the first heat exchanger.

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