Water vapor-organic Rankine cascade cycle cascade power generation device

Abstract

The utility model discloses a water vapor-organic Rankine cycle cascade power generation device which comprises a water vapor Rankine cycle power generation system and an organic Rankine cycle power generation system. The high-temperature flue gas enters a waste heat boiler of the water vapor Rankine cycle power generation system to vaporize water, and water vapor is used for driving a first heat-work power conversion device to do work and driving a first power generator to generate power; the water vapor after acting is subjected to heat exchange and condensation through a low-temperature organic medium in the organic Rankine cycle power generation system and then returns to the waste heat boiler to be vaporized again; the high-temperature flue gas is changed into medium-temperature flue gas after passing through the waste heat boiler, an organic working medium entering the heat exchanger through the heat exchanger is vaporized, and organic working medium steam is used for driving a second heat-work power conversion device to do work and driving a second power generator to generate power; and the organic working medium steam after acting is condensed to continuously condense the water vapor after acting in the water vapor Rankine cycle power generation system, so that the cascade of the power generation system and the gradient utilization of the high-temperature flue gas are realized.

Description

Technical Field

[0001] The utility model relates to a water vapor-organic Rankine cascade cycle cascade power generation device, belonging to the technical field of flue gas recycling. Background Art

[0002] With the acceleration of industrialization, energy consumption and environmental pollution have become increasingly prominent and have become key factors restricting the sustainable development of enterprises. In various industrial production processes, especially in the operation of coal-fired and gas-fired boilers, gas turbines and other combustion equipment, a large amount of high-temperature flue gas will be generated. These flue gases carry a large amount of heat energy during the emission process. If they are not recycled, it will cause serious energy waste. Therefore, high-temperature flue gas waste heat recovery technology has emerged as the times require, becoming an important means to improve energy utilization efficiency and achieve energy conservation and emission reduction.

[0003] In order to solve the problem that the waste heat of high-temperature flue gas cannot be effectively utilized, the water steam Rankine cycle power generation technology has been proposed and has received widespread attention. This technology uses water as a working fluid to convert the thermal energy of high-temperature flue gas into electrical energy through the Rankine cycle. Although the water steam Rankine cycle power generation technology has improved the utilization rate of high-temperature flue gas waste heat to a certain extent, due to the high boiling point and low specific heat capacity of water, its heat exchange efficiency under high temperature conditions is still limited, resulting in the exhaust flue gas still having a high temperature, which has caused energy waste to a certain extent. Utility Model Content

[0004] The purpose of the utility model is to provide a water vapor-organic Rankine cascade cycle cascade power generation device, which cascades water vapor Rankine cycle power generation and organic Rankine cycle power generation to achieve cascade utilization of high-temperature flue gas and effectively improve the utilization rate of high-temperature flue gas thermal energy.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A water vapor-organic Rankine cascade cycle power generation device, comprising a water vapor Rankine cycle power generation system and an organic Rankine cycle power generation system; and the water vapor Rankine cycle power generation system and the organic Rankine cycle power generation system both comprise a heat exchanger for condensing water vapor using an organic working medium;

[0007] The water steam Rankine cycle power generation system also includes a waste heat boiler, which is used to heat water with high-temperature flue gas to obtain water vapor and medium-temperature flue gas; the water vapor outlet of the waste heat boiler is connected to the water phase inlet of the waste heat boiler through the first heat-to-power conversion device, the water phase channel of the heat exchanger, and the condensate tank in sequence; and the first heat-to-power conversion device is connected to the first generator, which is used to drive the first generator to generate electricity;

[0008] The organic Rankine cycle power generation system also includes a heat exchanger, which is used to heat the organic working fluid using the medium-temperature flue gas discharged after the waste heat boiler heats the water, obtains low-temperature flue gas and discharges it, and obtains organic working fluid steam; the organic working fluid steam outlet of the heat exchanger is connected to the organic working fluid inlet of the heat exchanger in sequence through the second heat-to-power conversion device, the working fluid channel of the condenser for cooling the organic working fluid, the condensing working fluid box, and the working fluid channel of the heat exchanger; and the second heat-to-power conversion device is connected to the second generator to drive the second generator to generate electricity.

[0009] Preferably, the water steam Rankine cycle power generation system further comprises a water pump for pumping water in the condensate tank into the water steam inlet of the waste heat boiler.

[0010] Preferably, the organic Rankine cycle power generation system further comprises a working fluid pump for pumping the organic working fluid in the condensing working fluid tank into the working fluid channel of the heat exchanger.

[0011] Preferably, the first heat-to-power conversion device is a steam turbine.

[0012] Preferably, the second heat-to-power conversion device is a turbine expander.

[0013] Preferably, the power generation device further comprises a working fluid cooling system for cooling the organic working fluid vapor;

[0014] The working medium cooling system comprises a cooling tower, and the cooling water outlet of the cooling tower is returned to the water inlet of the cooling tower through the water phase channel of the machine pump and the condenser.

[0015] Preferably, a flow regulating valve is installed on the pipeline between the water pump and the water steam inlet of the waste heat boiler, and a pulsation damper is connected through a branch pipe.

[0016] Preferably, a flow regulating valve is also installed on the pipeline between the working fluid pump and the organic working fluid inlet of the heat exchanger, and is also connected to a pulsation damper through a branch pipe.

[0017] Preferably, a flow regulating valve is also installed on the pipeline between the pump and the water phase channel inlet of the condenser, and a pulsation damper is also connected through a branch pipe.

[0018] Preferably, the power generation device further comprises a plurality of temperature detectors for respectively detecting the temperature of flue gas, water, water vapor, organic working fluid, and organic working fluid vapor.

[0019] The beneficial effects of the utility model are:

[0020] By superimposing the water vapor Rankine cycle power generation and the organic Rankine cycle power generation, the high temperature flue gas can be utilized in a cascade manner, which can effectively improve the utilization rate of the heat energy of the high temperature flue gas; and the water vapor (exhaust steam) in the water vapor Rankine cycle power generation system is cooled by an organic working fluid (the boiling point is lower than that of water), and there is no need to set up an additional cooling system specifically for cooling the water vapor (exhaust steam), which has good synergy and reduces costs; at the same time, the organic working fluid can also absorb the heat of the water vapor (exhaust steam) in the water vapor Rankine cycle power generation system, so as to achieve a more effective utilization of energy. Furthermore, a pulsation damper is provided on the pump outlet pipe to improve the stability of the fluid flow, and can effectively protect the pipe and downstream equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a system schematic diagram of a power generation device.

[0022] The main reference numerals in the figure have the following meanings:

[0023] 1. Condensate tank, 2. Water pump, 3. Waste heat boiler, 4. First heat-to-power conversion device, 5. Heat exchanger, 6. First generator, 7. Condensate working fluid tank, 8. Working fluid pump, 9. Heat exchanger, 10. Second heat-to-power conversion device, 11. Condenser, 12. Second generator, 13. Cooling tower, 14. Machine pump, 15. Flow regulating valve, 16. Pulsation damper; 17. Temperature detector. DETAILED DESCRIPTION

[0024] The utility model is specifically introduced below in conjunction with the accompanying drawings and embodiments.

[0025] This embodiment provides a water steam-organic Rankine cascade cycle cascade power generation device, such as Figure 1 As shown, it includes a water vapor Rankine cycle power generation system, an organic Rankine cycle power generation system and a working medium cooling system; and the water vapor Rankine cycle power generation system and the organic Rankine cycle power generation system both include a heat exchanger 5 for condensing water vapor using an organic working medium, and the organic Rankine cycle power generation system and the working medium cooling system both include a condenser 11 for cooling the organic working medium vapor. The working medium cooling system includes a cooling tower 13 and a pump 14, and the cooling water outlet of the cooling tower 13 is returned to the water inlet of the cooling tower 13 through the pump 14 and the water phase channel of the condenser 11.

[0026] The water vapor Rankine cycle power generation system comprises a condensate tank 1, a water pump 2, a waste heat boiler 3, a first heat-to-power conversion device 4 (steam turbine), the above-mentioned heat exchanger 5 and a first generator 6. The water vapor outlet of the waste heat boiler 3 is connected to the water vapor inlet of the waste heat boiler 3 through the first heat-to-power conversion device 4, the water phase channel of the heat exchanger 5 and the condensate tank 1 in sequence; and the first heat-to-power conversion device 4 is connected to the first generator 6.

[0027] Specifically, the water pump 2 pumps the water in the condensate tank 1 to the water phase inlet of the waste heat boiler 3. The high-temperature flue gas (350-380°C) passes through the waste heat boiler 3 to heat the water in the water phase pipeline, thereby generating high-temperature and high-pressure water vapor and entering the first heat-to-power conversion device 4. The water vapor drives the first heat-to-power conversion device 4 to do work and drives the first generator 6 connected thereto to generate electricity. The water vapor (exhaust steam) after doing work enters the heat exchanger 9 to exchange heat with the low-temperature organic working medium (the boiling point is lower than that of water), and then condenses and is directed to the condensate tank 1 for storage. The water pump 2 continues to pump the cooling water in the condensate tank 1 into the water phase channel of the waste heat boiler 3 to absorb heat and vaporize again, thereby realizing water vapor Rankine cycle power generation.

[0028] The organic Rankine cycle power generation system includes a condensing medium tank 7, a medium pump 8, the above-mentioned heat exchanger 5, a heat exchanger 9, a second heat-to-power conversion device 10 (turbine expander), the above-mentioned condenser 11 and a second generator 12. The organic medium vapor outlet of the heat exchanger 9 is connected to the organic medium inlet of the heat exchanger 9 through the second heat-to-power conversion device 10 (turbine expander), the medium channel of the condenser 11 for cooling the organic medium, the condensing medium tank 7, and the medium channel of the heat exchanger 5 in sequence; and the second heat-to-power conversion device 10 is connected to the second generator 12.

[0029] Specifically, the working fluid pump 8 pumps the low-temperature organic working fluid in the condensing working fluid box 7 into the working fluid channel in the heat exchanger 5, and then exchanges heat with the water vapor (exhaust steam) in the water phase channel to realize the condensation of the water vapor (exhaust steam); the organic working fluid after heat exchange further enters the working fluid channel of the heat exchanger 9, and the high-temperature flue gas is reduced to 200-250°C (medium-temperature flue gas) after heat exchange with the water in the water phase channel through the waste heat boiler 3. This part of the flue gas is introduced into the flue gas channel of the heat exchanger 9 through a pipeline, and then the organic working fluid in the working fluid channel can be heated and vaporized. The generated organic working fluid steam enters the second thermal power conversion device 10 and drives the second thermal power conversion device 10 to do work to drive the second generator 12 connected thereto to generate electricity. The low-temperature flue gas after heat exchange is discharged from the heat exchanger 9 and discharged after treatment. The organic working fluid vapor (exhaust steam) after work enters the working fluid channel of the cooler, exchanges heat with the cooling water pumped into the water phase channel of the condenser 11 by the machine pump 14, and then condenses and flows into the condensation working fluid tank 7 for storage. The cooling water in the water phase channel of the condenser 11 enters the cooling tower 13 for cooling after absorbing heat. The working fluid pump 8 continues to pump the low-temperature organic working fluid in the condensation working fluid tank 7 into the working fluid channel of the heat exchanger 9 to condense the water vapor (exhaust steam) in the water phase channel of the heat exchanger 5, thereby realizing the cascade and circulation of the water vapor Rankine cycle power generation and the organic Rankine cycle power generation system, and achieving the cascade utilization of high-temperature flue gas.

[0030] Furthermore, in order to improve the stability of fluid flow and effectively protect the pipeline and downstream equipment, flow regulating valves 15 are installed on the pipeline between the water pump 2 and the water vapor inlet of the waste heat boiler 3, on the pipeline between the working fluid pump 8 and the organic working fluid inlet of the heat exchanger 9, and on the pipeline between the machine pump 14 and the water phase channel inlet of the condenser 11, and pulsation dampers 16 are connected through branch pipes. In order to facilitate temperature monitoring, temperature detectors 17 are also installed on multiple pipelines of the power generation device.

[0031] The above is only a preferred implementation of the utility model patent. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model patent. These improvements and modifications should also be regarded as the protection scope of the utility model patent.

Claims

1. A water steam-organic Rankine cascade cycle cascade power generation device, characterized in that: The power generation device includes a water vapor Rankine cycle power generation system and an organic Rankine cycle power generation system; and the water vapor Rankine cycle power generation system and the organic Rankine cycle power generation system both include a heat exchanger for condensing water vapor using an organic working medium; The water steam Rankine cycle power generation system also includes a waste heat boiler, which is used to heat water with high-temperature flue gas to obtain water vapor and medium-temperature flue gas; the water vapor outlet of the waste heat boiler is connected to the water phase inlet of the waste heat boiler through the first heat-to-power conversion device, the water phase channel of the heat exchanger, and the condensate tank in sequence; and the first heat-to-power conversion device is connected to the first generator, which is used to drive the first generator to generate electricity; The organic Rankine cycle power generation system also includes a heat exchanger, which is used to heat the organic working fluid using the medium-temperature flue gas discharged after the waste heat boiler heats the water, obtains low-temperature flue gas and discharges it, and obtains organic working fluid steam; the organic working fluid steam outlet of the heat exchanger is connected to the organic working fluid inlet of the heat exchanger in sequence through the second heat-to-power conversion device, the working fluid channel of the condenser for cooling the organic working fluid, the condensing working fluid box, and the working fluid channel of the heat exchanger; and the second heat-to-power conversion device is connected to the second generator to drive the second generator to generate electricity.

2. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 1, characterized in that: The water steam Rankine cycle power generation system further includes a water pump, which is used to pump water in the condensate tank into the water steam inlet of the waste heat boiler.

3. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 1, characterized in that: The organic Rankine cycle power generation system also includes a working fluid pump for pumping the organic working fluid in the condensation working fluid box into the working fluid channel of the heat exchanger.

4. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 1, characterized in that: The first heat-to-power conversion device is a steam turbine.

5. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 1, characterized in that: The second heat-to-power conversion device is a turbine expander.

6. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 1, characterized in that: The power generation device also includes a working fluid cooling system for cooling the organic working fluid vapor; The working medium cooling system comprises a cooling tower, and the cooling water outlet of the cooling tower is returned to the water inlet of the cooling tower through the water phase channel of the machine pump and the condenser.

7. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 2, characterized in that: A flow regulating valve is installed on the pipeline between the water pump and the water steam inlet of the waste heat boiler, and a pulsation damper is connected through a branch pipe.

8. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 3, characterized in that: A flow regulating valve is also installed on the pipeline between the working fluid pump and the organic working fluid inlet of the heat exchanger, and is also connected to a pulsation damper through a branch pipe.

9. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 6, characterized in that: A flow regulating valve is also installed on the pipeline between the pump and the inlet of the water phase channel of the condenser, and is also connected to a pulsation damper through a branch pipe.

10. The water steam-organic Rankine cascade cycle cascade power generation device according to claim 6, characterized in that: The power generation device also includes a plurality of temperature detectors for detecting the temperature of flue gas, water, water vapor, organic working fluid, and organic working fluid vapor respectively.

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