Steam turbine drainage waste heat utilization system and method

Abstract

The invention discloses a steam turbine drainage waste heat utilization system and method. The steam turbine drainage waste heat utilization system comprises a drainage pipeline, a drainage flash tank, a water-water heat exchanger, a condenser, a raw water inlet pipeline, a raw water heater, an auxiliary steam pipeline and a pipeline from the raw water heater to the condenser. An outlet of the drainage pipeline is communicated with an inlet of the drainage flash tank, a bottom outlet of the drainage flash tank is communicated with an inlet of the condenser through the shell side of the water-water heat exchanger, and an outlet of the raw water inlet pipeline is communicated with the shell side of the raw water heater through the pipe side of the water-water heat exchanger. By means of the system and method, medium-grade and low-grade steam heat can be recycled, heat loss is reduced, and the unit operation efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of energy-saving operation of units and relates to a system and method for utilizing waste heat from steam turbine drain. Background Art

[0002] The main research directions of energy conservation and emission reduction technology for thermal power units include improving combustion efficiency, reducing exhaust loss, and recycling working fluids. During the start-up and shutdown process of thermal power generating units, in order to ensure the safe operation of the units, the drain pipes of each steam pipeline will produce a large amount of medium and low-grade steam. These steams enter the drain expansion tank and condense and then are discharged to the condenser, making the steam energy unutilized. Therefore, how to effectively utilize the heat energy of these medium and low-grade steam, reduce heat energy loss, and improve the operating efficiency of the units has become the focus of attention for improving the quality and efficiency of units in the industry. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a system and method for utilizing waste heat from steam turbine drain, which can recover heat from medium and low-grade steam, reduce heat loss, and improve unit operating efficiency.

[0004] To achieve the above object, the present invention discloses a steam turbine drain waste heat utilization system, comprising a drain pipe, a drain expansion tank, a water-to-water heat exchanger, a condenser, a raw water inlet pipe, a raw water heater, an auxiliary steam pipe and a pipe from the raw water heater to the condenser;

[0005] The outlet of the drain pipe is connected to the inlet of the drain expansion tank, the bottom outlet of the drain expansion tank is connected to the inlet of the condenser via the shell side of the water-to-water heat exchanger, the outlet of the raw water inlet pipe is connected to the shell side of the raw water heater via the tube side of the water-to-water heat exchanger, and the auxiliary steam pipe is connected to the inlet of the condenser via the tube side of the raw water heater and the raw water heater to condenser pipe in turn.

[0006] Furthermore, the top opening of the hydrophobic expansion container is connected to a drain pipe.

[0007] Furthermore, it also includes a drainage pipe, a drainage pump, a condenser pipe and a heat exchanger pipe;

[0008] The bottom outlet of the drain expansion tank is divided into two paths after the drain expansion pipe and the drain pump. One path is connected to the condenser pipe through the drain expansion and the condenser inlet, and the other path is connected to the heat exchanger pipe and the shell side of the water-to-water heat exchanger through the drain expansion and the condenser inlet.

[0009] Furthermore, a condenser valve is provided on the pipeline extending from the condenser to the condenser; and a heat exchanger valve is provided on the pipeline extending from the condenser to the heat exchanger.

[0010] Furthermore, the auxiliary steam pipeline is connected to the inlet of the condenser through the pipe side of the raw water heater and the raw water heater to condenser pipeline in sequence.

[0011] Furthermore, an auxiliary steam inlet valve is provided on the auxiliary steam pipeline, and a raw water heater steam trap is provided on the pipeline from the raw water heater to the condenser.

[0012] Furthermore, the outlet of the condenser is divided into two paths after passing through the condensate pipeline, one of which is connected to the condensate output pipeline through the condensate flow control valve and the shaft seal heater, and the other is connected to the condensate output pipeline through the expansion heat exchange pipe inlet pipe, the heat exchange pipe in the drainage expansion tank and the expansion heat exchange pipe outlet pipe.

[0013] Furthermore, a condensate pump is provided on the condensate pipeline.

[0014] Furthermore, a condensate flow control valve is provided on the inlet pipe of the expansion heat exchange tube.

[0015] The method for utilizing steam turbine drain waste heat of the present invention comprises the following steps:

[0016] The drain water outputted from the drain pipe enters the drain expansion tank for expansion, the drain water outputted from the drain expansion tank enters the water-to-water heat exchanger for heat release, and then enters the condenser;

[0017] The raw water output from the raw water inlet pipe enters the water-to-water heat exchanger for heat exchange and temperature increase, and then enters the raw water heater for further heat exchange and temperature increase. The auxiliary steam output from the auxiliary steam pipe enters the raw water heater for heat exchange and temperature increase, and then enters the condenser.

[0018] The present invention has the following beneficial effects:

[0019] In the specific operation of the steam turbine drain waste heat utilization system and method described in the present invention, the drain output from the drain pipe enters the drain expansion tank for expansion, the drain output from the drain expansion tank enters the water-to-water heat exchanger for heat release, and then enters the condenser, the raw water output from the raw water inlet pipe enters the water-to-water heat exchanger for heat exchange and temperature increase, and then enters the raw water heater for further heat exchange and temperature increase. Not only can the steam pipe drain be used to heat the condensate when the unit is started, but the drain waste heat can also be deeply utilized to heat the raw water of the water production system, making full use of the heat of the steam pipe drain of the thermal power unit turbine, promoting the reuse of the heat source waste heat, and improving the energy saving and emission reduction capabilities of the unit. In the expansion tank, the steam-water heat exchange method is used to replace the original water spray cooling method, and the water side medium is condensate, thereby achieving the purpose of heating the condensate. The superheated steam of the drain expansion tank still has a certain amount of thermal energy after condensation, and exchanges heat with the raw water to increase the raw water temperature and enhance the efficiency of chemical water production. The present invention can fully utilize the heat of the steam turbine drain system, deeply utilize the medium and low-grade heat of the unit, and contribute to the energy-saving operation of the thermal power generating unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

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

[0022] Among them, 1 is a drain expansion tank, 2 is a condenser, 3 is a shaft seal heater, 4 is a condensate pump, 5 is a drain pump, 6 is a water-to-water heat exchanger, 7 is a raw water heater, 8 is a drain pipe, 9 is an emptying pipe, 10 is a condensate pipe, 11 is an expansion heat exchange pipe inlet pipe, 12 is an expansion heat exchange pipe outlet pipe, 13 is an expansion condensate flow control valve, 14 is a condensate flow control valve, 15 is an expansion drain pipe, 16 is an expansion to heat exchanger pipe, 17 is an expansion to condenser pipe, 18 is an expansion to heat exchanger valve, 19 is an expansion to condenser valve, 20 is a raw water inlet pipe, 21 is a raw water to raw water heater pipe, 22 is an auxiliary steam pipe, 23 is a raw water heater to condenser pipe, 24 is an auxiliary steam inlet valve, and 25 is a raw water heater drain valve. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. 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.

[0024] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0026] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0027] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0028] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0029] 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, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0031] Embodiment 1

[0032] The steam turbine drain waste heat utilization system of the present invention comprises a drain pipe 8, a drain expansion tank 1, a water-to-water heat exchanger 6, a condenser 2, a raw water inlet pipe 20, a raw water heater 7, an auxiliary steam pipe 22 and a pipe 23 from the raw water heater to the condenser; the outlet of the drain pipe 8 is connected to the inlet of the drain expansion tank 1, the bottom outlet of the drain expansion tank 1 is connected to the inlet of the condenser 2 via the shell side of the water-to-water heat exchanger 6, the outlet of the raw water inlet pipe 20 is connected to the shell side of the raw water heater 7 via the tube side of the water-to-water heat exchanger 6, and the auxiliary steam pipe 22 is connected to the inlet of the condenser 2 via the tube side of the raw water heater 7 and the pipe 23 from the raw water heater to the condenser in turn.

[0033] Accordingly, the method for utilizing steam turbine drain waste heat of the present invention comprises the following steps:

[0034] The drain water output from the drain pipe 8 enters the drain expansion tank 1 for expansion, the drain water output from the drain expansion tank 1 enters the water-to-water heat exchanger 6 for heat release, and then enters the condenser 2; the raw water output from the raw water inlet pipe 20 enters the water-to-water heat exchanger 6 for heat exchange and temperature increase, and then enters the raw water heater 7 for further heat exchange and temperature increase, the auxiliary steam output from the auxiliary steam pipe 22 enters the raw water heater 7 for heat exchange and temperature increase, and then enters the condenser 2.

[0035] Embodiment 2

[0036] refer to Figure 1 The steam turbine drain waste heat utilization system of the present invention comprises a drain expansion tank 1, a condenser 2, a shaft seal heater 3, a condensate pump 4, a drain pump 5, a water-to-water heat exchanger 6, a raw water heater 7, a drain pipe 8, an emptying pipe 9, a condensate pipe 10, a heat exchange pipe inlet pipe 11, a heat exchange pipe outlet pipe 12, a condensate flow control valve 13, a condensate flow control valve 14, a drain pipe 15, a heat exchange pipe 16, a condenser pipe 17, a heat exchange valve 18, a condensate valve 19, a raw water inlet pipe 20, a raw water to raw water heater pipe 21, an auxiliary steam pipe 22, a raw water heater to condenser pipe 23, an auxiliary steam inlet valve 24 and a raw water heater drain valve 25;

[0037] The outlet of the drain pipe 8 is connected to the inlet of the drain expansion tank 1. The top opening of the drain expansion tank 1 is connected to the drain pipe 9. The bottom outlet of the drain expansion tank 1 is divided into two paths after the drain pipe 15 and the drain pump 5. One path is connected to the inlet of the condenser 2 through the drain to condenser pipe 17. The drain to condenser pipe 17 is provided with a drain to condenser valve 19. The other path is connected to the inlet of the condenser 2 through the drain to heat exchanger pipe 16 and the shell side of the water-water heat exchanger 6 in sequence. The heat exchanger pipe 16 is provided with a drain-to-heat exchanger valve 18, the outlet of the raw water inlet pipe 20 is connected with the shell side of the raw water heater 7 via the tube side of the water-to-water heat exchanger 6 and the raw water-to-raw water heater pipe 21, the auxiliary steam pipe 22 is connected with the inlet of the condenser 2 via the tube side of the raw water heater 7 and the raw water heater-to-condenser pipe 23 in turn, the auxiliary steam pipe 22 is provided with an auxiliary steam inlet valve 24, and the raw water heater-to-condenser pipe 23 is provided with a raw water heater drain valve 25.

[0038] The outlet of the condenser 2 is divided into two paths after passing through the condensate pipe 10, one of which is connected to the condensate output pipe through the condensate flow control valve 14 and the shaft seal heater 3, and the other is connected to the condensate output pipe through the expansion and dilation heat exchange pipe inlet pipe 11, the heat exchange pipe in the steam expansion tank 1 and the expansion and dilation heat exchange pipe outlet pipe 12. A condensate pump 4 is provided on the condensate pipe 10, and a expansion and dilation condensate flow control valve 13 is provided on the expansion and dilation heat exchange pipe inlet pipe 11.

[0039] The method for utilizing steam turbine drain waste heat of the present invention comprises the following steps:

[0040] When the unit is operating normally, the condensate flow control valve 14 is opened, and the condensate enters the condensate pipe 10 from the condenser 2, is pumped out by the condensate pump 4, flows through the shaft seal heater 3 for heating, and then enters the subsequent process flow.

[0041] When the unit is in the startup stage, the steam from each steam pipe is drained through the drain pipe 8 to the drain expansion tank 1 for expansion and cooling. The condensate flow control valve 13 is opened to adjust the condensate flow through the drain expansion tank 1 for heat exchange, which is used to adjust the temperature of the drain expansion tank 1. Then, the condensate enters the shaft seal heater 3 through the outlet pipe 12 of the expansion heat exchange pipe, and then enters the condensate output pipe. The steam after temperature reduction, expansion and separation is discharged to the atmosphere or condenser 2 through the exhaust pipe 9. The condensed steam enters the subsequent system through the expansion and drain pipe 15. When the amount of water is small, the expansion to condenser valve 19 is opened, and the expansion to heat exchanger valve 18 is closed at this time, and the water is transported to the condenser 2 through the expansion to condenser pipe 17. When the amount of water drainage is large, the expansion to heat exchanger valve 18 is opened, and the expansion to condenser valve 19 is closed. The water drainage enters the water-water heat exchanger 6 through the expansion to heat exchanger pipe 16 for further heat exchange. The raw water output by the water production system enters the water-water heat exchanger 6 through the raw water inlet pipe 20 to exchange heat with the water drainage to increase the temperature. The raw water after heat exchange is transported to the subsequent water production system through the raw water to raw water heater pipe 21. At this time, the auxiliary steam inlet valve 24 and the raw water heater steam trap 25 on the auxiliary steam pipe 22 and the raw water heater to condenser pipe 23 are all closed.

[0042] After the unit is started, since the steam pipeline no longer needs to be drained, it is necessary to exit the operation of the drain expansion tank 1. At this time, the drain expansion condensate flow control valve 13 is closed, and the operation of the drain expansion tank 1 is cut off. At the same time, the operation of the drain pump 5 is stopped, and the drain expansion to heat exchanger valve 18 and the drain expansion to condenser valve 19 are closed. The auxiliary steam inlet valve 24 is opened, and auxiliary steam is added to heat the raw water flowing through the raw water heater 7. The auxiliary steam after heat exchange is transported to the condenser 2 through the raw water heater to condenser pipeline 23.

[0043] Embodiment 3

[0044] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for utilizing waste heat from steam turbine drain are implemented. The memory may include a memory, such as a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk memory, etc. The processor, the network interface, and the memory are interconnected through an internal bus. The internal bus may be an industrial standard architecture bus, a peripheral component interconnection standard bus, an extended industrial standard structure bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the program may include a program code, and the program code includes computer operation instructions. The memory may include a memory and a non-volatile memory, and provide instructions and data to the processor.

[0045] Embodiment 4

[0046] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the steam turbine drain waste heat utilization method are implemented. Specifically, the computer-readable storage medium includes, but is not limited to, for example, a volatile memory and / or a non-volatile memory. The volatile memory may include a random access memory (RAM) and / or a cache memory, etc. The non-volatile memory may include a read-only memory (ROM), a hard disk, a flash memory, an optical disk, a magnetic disk, etc.

[0047] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0048] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0049] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0050] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A steam turbine drain waste heat utilization system, characterized in that: It comprises a drain pipe (8), a drain expansion tank (1), a water-to-water heat exchanger (6), a condenser (2), a raw water inlet pipe (20), a raw water heater (7), an auxiliary steam pipe (22) and a pipe from the raw water heater to the condenser (23); The outlet of the drain pipe (8) is connected to the inlet of the drain expansion tank (1), the bottom outlet of the drain expansion tank (1) is connected to the inlet of the condenser (2) via the shell side of the water-to-water heat exchanger (6), the outlet of the raw water inlet pipe (20) is connected to the shell side of the raw water heater (7) via the tube side of the water-to-water heat exchanger (6), and the auxiliary steam pipe (22) is connected to the inlet of the condenser (2) via the tube side of the raw water heater (7) and the raw water heater to condenser pipe (23) in sequence.

2. The steam turbine drain waste heat utilization system according to claim 1, characterized in that: The top opening of the hydrophobic expansion container (1) is connected to a drain pipe (9).

3. The steam turbine drain waste heat utilization system according to claim 1, characterized in that: It also includes a drainage pipeline (15), a drainage pump (5), a pipeline for drainage to a condenser (17), and a pipeline for drainage to a heat exchanger (16); The bottom outlet of the drain expansion tank (1) is divided into two paths after passing through the drain expansion pipe (15) and the drain pump (5), one of which is connected to the inlet of the condenser (2) through the drain expansion to the condenser pipe (17), and the other is connected to the inlet of the condenser (2) through the drain expansion to the heat exchanger pipe (16) and the shell side of the water-to-water heat exchanger (6) in turn.

4. The steam turbine drain waste heat utilization system according to claim 3, characterized in that: The expansion-to-condenser pipeline (17) is provided with a expansion-to-condenser valve (19); and the expansion-to-heat exchanger pipeline (16) is provided with a expansion-to-heat exchanger valve (18).

5. The steam turbine drain waste heat utilization system according to claim 1, characterized in that: The auxiliary steam pipeline (22) is connected to the inlet of the condenser (2) through the pipe side of the raw water heater (7) and the raw water heater to condenser pipeline (23) in sequence.

6. The steam turbine drain waste heat utilization system according to claim 5, characterized in that: The auxiliary steam pipeline (22) is provided with an auxiliary steam inlet valve (24), and the pipeline from the raw water heater to the condenser (23) is provided with a raw water heater steam trap (25).

7. The steam turbine drain waste heat utilization system according to claim 1, characterized in that: The outlet of the condenser (2) is divided into two paths after passing through the condensate pipe (10), one of which is connected to the condensate output pipe through the condensate flow control valve (14) and the shaft seal heater (3), and the other is connected to the condensate output pipe through the expansion heat exchange pipe inlet pipe (11), the heat exchange pipe in the steam expansion tank (1) and the expansion heat exchange pipe outlet pipe (12).

8. The steam turbine drain waste heat utilization system according to claim 7, characterized in that: A condensate pump (4) is provided on the condensate pipeline (10).

9. The steam turbine drain waste heat utilization system according to claim 7, characterized in that: The inlet pipe (11) of the expansion-expansion heat exchange tube is provided with an expansion-expansion condensate flow control valve (13).

10. A method for utilizing waste heat from steam turbine drain, characterized in that: The steam turbine drain waste heat utilization system according to claim 1 comprises the following steps: The drain water outputted from the drain pipe (8) enters the drain expansion tank (1) for expansion, the drain water outputted from the drain expansion tank (1) enters the water-to-water heat exchanger (6) for heat release, and then enters the condenser (2); The raw water output from the raw water inlet pipe (20) enters the water-to-water heat exchanger (6) for heat exchange and temperature increase, and then enters the raw water heater (7) for further heat exchange and temperature increase. The auxiliary steam output from the auxiliary steam pipe (22) enters the raw water heater (7) for heat exchange and temperature increase, and then enters the condenser (2).

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