Flue gas waste heat recovery power generation device

Abstract

The invention discloses a flue gas waste heat recovery power generation device, which comprises a waste heat recovery heat exchanger for collecting flue gas waste heat generated by a flue gas device and carrying out heat exchange between the flue gas waste heat and a heating medium to increase the temperature of the heating medium; the expansion machine uses the high-temperature heat medium to do work to drive the generator to generate electric energy; and the heating medium storage tank is used for receiving the heating medium after acting of the expansion machine and pumping the heating medium back to the waste heat recovery heat exchanger for continuous heat exchange circulation. According to the invention, heat exchange is carried out between the heating medium and the waste flue gas, the structure is simple, the application is flexible, the miniaturization arrangement is convenient, the waste heat in the flue gas with a smaller gas volume can be efficiently recycled, the heat recovery efficiency of high-temperature flue gas discharged by various furnaces is improved, and the energy utilization rate is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas waste heat recovery power generation, and in particular to a flue gas waste heat recovery power generation device. Background Art

[0002] High-temperature flue gas discharged from various furnaces often takes away 20-50% of the furnace's heat supply. Flue gas is the main way for general energy-consuming equipment to waste energy. Recycling flue gas waste heat is one of the ways to improve energy utilization.

[0003] At present, the system that uses waste heat from flue gas to generate electricity mainly includes a waste heat boiler, a steam turbine and a deaerator. The waste heat boiler is provided with a flue gas inlet and a flue gas outlet, and a high-pressure heat exchange device and a low-pressure heat exchange device are arranged in the waste heat boiler. Its working principle is as follows: the cold water after deoxygenation by the deaerator is sent to the high-pressure heat exchange device and the low-pressure heat exchange device; the high-temperature flue gas enters the waste heat boiler from the flue gas inlet and exchanges heat with the high-pressure heat exchange device and the low-pressure heat exchange device. The high-pressure steam generated by the high-pressure heat exchange device after heat exchange is used to be sent to the steam turbine for power generation. After power generation is completed, the steam is condensed into cold water by the condenser and then sent to the deaerator again to supply water to the high-pressure heat exchange device and the low-pressure heat exchange device. The low-pressure steam or hot water generated by the low-pressure heat exchange device after heat exchange is used to return to the deaerator for deoxygenation operation.

[0004] Patent document No. CN106321174B discloses a power generation system using waste heat from high-temperature flue gas, including a double-pressure waste heat boiler equipped with a reheater, wherein the high-pressure steam from the double-pressure waste heat boiler is passed into a back-pressure steam turbine generator set to generate electricity, and the steam after power generation from the steam turbine generator set is returned to the double-pressure waste heat boiler and heated by the reheater, and the reheated steam passes through a steam pipe and enters the steam turbine generator set to generate electricity. However, its technical solution currently mainly relies on flue gas heating to generate steam, and the steam drives the steam turbine to generate electricity, but its scale is large, and it is not suitable for recovering a small amount of flue gas, and the overall waste heat recovery efficiency is low.

[0005] Patent document No. CN102374514B discloses a flue gas waste heat dual-pressure power generation system, including a power generation system formed by a waste heat boiler, a steam turbine and a deaerator, a waste heat boiler is provided with a flue gas inlet and a flue gas outlet, a high-pressure heat exchange device and a low-pressure heat exchange device are sequentially arranged from the flue gas inlet to the flue gas outlet in the waste heat boiler, the high-pressure outlet of the high-pressure heat exchange device is connected to the steam turbine, the high-pressure inlet of the high-pressure heat exchange device is connected to the water supply port of the deaerator, the low-pressure outlet of the low-pressure heat exchange device is connected to the steam inlet of the deaerator, the low-pressure inlet of the low-pressure heat exchange device is connected to the water supply port of the deaerator, and a steam outlet pipeline is provided in the power generation system, and the steam outlet pipeline is provided on the pipeline between the low-pressure outlet of the low-pressure heat exchange device and the steam inlet of the deaerator. This application also has the problem that it mainly generates steam by heating flue gas, and the steam drives the steam turbine to generate electricity, but its scale is large, and it is not suitable for recovering flue gas with a small amount of gas. Summary of the invention

[0006] The purpose of the present invention is to provide a flue gas waste heat recovery power generation device with simple structure, flexible application, convenient miniaturization and layout, which can efficiently recover and utilize the waste heat in a small amount of flue gas and improve the heat recovery efficiency of high-temperature flue gas discharged from various furnaces.

[0007] The object of the present invention can be achieved by the following technical scheme: a flue gas waste heat recovery power generation device, comprising a waste heat recovery heat exchanger, which collects the flue gas waste heat generated by the flue gas device, utilizes the flue gas waste heat to exchange heat with a heat medium, and increases the temperature of the heat medium;

[0008] The expander uses the high-temperature heat medium to drive the generator to generate electricity;

[0009] The heat medium storage tank receives the heat medium after the expander has done work, and pumps the heat medium back to the waste heat recovery heat exchanger to continue the heat exchange cycle.

[0010] Optionally, the waste heat recovery heat exchanger is connected to the flue gas device through pipeline one, the waste heat recovery heat exchanger is connected to the venting device through pipeline seven, the waste heat recovery heat exchanger is connected to the expander through pipeline two, the expander is connected to the heat medium storage tank through pipeline three, the heat medium storage tank and the waste heat recovery heat exchanger are directly provided with a circulating pump, the heat medium storage tank is connected to the circulating pump through pipeline five, and the circulating pump is connected to the waste heat recovery heat exchanger through pipeline six.

[0011] Optionally, a speed limit protection device is also included:

[0012] The speed limiting protection device includes a condenser, and the condenser is used for heat exchange between the hot medium and the cold medium;

[0013] The condenser is connected to the heat medium through pipeline 3, and the condenser sends the heat medium after heat exchange into the heat medium storage tank through pipeline 4;

[0014] The condenser is connected to the cold medium through a pipeline 12, and the condenser discharges the cold medium after heat exchange through a pipeline 13.

[0015] Optionally, the expander is provided with a speed limiter, and the operation of the condenser is interlocked with the speed limiter.

[0016] Optionally, a voltage limiting protection device is also included.

[0017] The pressure limiting protection device comprises a safety relief device, which is arranged on pipeline 2, and the pressure relief port of the safety relief device is connected to the heat medium storage tank through pipeline 11.

[0018] Optionally, a pressure gauge is also provided on the pipeline 2, and the pressure gauge is interlocked with the circulation pump.

[0019] Optionally, it also includes a medium preheating device,

[0020] The medium preheating device includes a temperature riser, which is used to perform heat exchange between flue gas waste heat and supplementary heat medium;

[0021] The temperature booster is connected to the supplementary heat medium through pipeline 9, and the temperature booster replenishes the supplementary heat medium after heat exchange into the heat medium storage tank through pipeline 10;

[0022] The temperature booster is connected to the flue gas generated by the flue gas device through a pipeline seven, and the temperature booster discharges the flue gas after heat exchange into the venting device through a pipeline eight.

[0023] Optionally, a regulating valve is provided on the pipeline nine, a liquid level gauge is provided on the heat medium storage tank, and the regulating valve is interlocked with the liquid level gauge.

[0024] Optionally, pipeline 14 is connected between pipeline 1 and pipeline 10.

[0025] Beneficial effects of the present invention:

[0026] 1. The present invention exchanges heat with waste flue gas through a heat medium, has a simple structure, flexible application, and convenient miniaturization and layout. It can efficiently recycle waste heat in a small amount of flue gas, improve the heat recovery efficiency of high-temperature flue gas discharged from various furnaces, and improve energy utilization.

[0027] 2. The present invention increases the speed limit protection for the expander by setting a speed limit protection device, and uses the speed limiter to detect the speed of the expander. When the speed of the expander is too high, the expander is slowed down. At the same time, the speed limiter interlocks and controls the operation of the condenser to perform heat exchange and cooling of the heat medium, which can reduce the temperature and pressure of the heat medium, further increase the control of the expander, and is beneficial to the stable operation of the expander and reduce the failure rate of the entire device.

[0028] 3. The present invention increases the protection of pipeline pressure by setting a pressure limiting protection device to ensure the safe operation of the entire device. The pressure gauge is interlocked with the circulation pump to reduce the speed of the circulation pump, further increasing the protection of the pipeline, which is beneficial to the stable operation of the entire system.

[0029] 4. The present invention increases the waste heat of the supplementary heat medium by arranging a medium preheating device, further recovers and utilizes the flue gas heat, and improves the recovery efficiency of the flue gas heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a flue gas waste heat recovery power generation device according to the present invention;

[0031] Figure 2 Another structural schematic diagram of a flue gas waste heat recovery power generation device of the present invention;

[0032] Figure 3 Another structural schematic diagram of a flue gas waste heat recovery power generation device of the present invention;

[0033] Figure 4 Another structural schematic diagram of a flue gas waste heat recovery power generation device of the present invention;

[0034] Figure 5 This is another structural schematic diagram of a flue gas waste heat recovery power generation device of the present invention.

[0035] 100, waste heat recovery heat exchanger; 200, expander; 300, generator; 400, heat medium storage tank; 400a, circulation pump; 500, venting device;

[0036] 600, speed limiting protection device; 610, condenser; 620, speed limiter;

[0037] 700, pressure limiting protection device; 710, safety relief device; 720, pressure gauge;

[0038] 800, medium preheating device; 810, temperature riser; 820, regulating valve; 830, liquid level gauge;

[0039] 910, pipeline one; 920, pipeline two; 930, pipeline three; 940, pipeline four; 950, pipeline five; 960, pipeline six; 970, pipeline seven; 980, pipeline eight; 990, pipeline nine; 9100, pipeline ten; 9110, pipeline eleven; 9120, pipeline twelve; 9130, pipeline thirteen; 9140, pipeline fourteen. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0041] like Figure 1-Figure 5 As shown, the present invention discloses a flue gas waste heat recovery power generation device, comprising

[0042] The waste heat recovery heat exchanger 100 collects the waste heat of the flue gas generated by the flue gas device, and uses the waste heat of the flue gas to perform heat exchange with the heat medium to increase the temperature of the heat medium;

[0043] The expander 200 utilizes the high-temperature heat medium to drive the generator 300 to generate electrical energy;

[0044] The heat medium storage tank 400 receives the heat medium after the expander 200 has done work, and pumps the heat medium back to the waste heat recovery heat exchanger 100 to continue the heat exchange cycle.

[0045] Embodiment 1, as Figure 2 As shown, the waste heat recovery heat exchanger 100 is connected to the flue gas device through pipeline one 910, the waste heat recovery heat exchanger 100 is connected to the expander 200 through pipeline two 920, the expander 200 is connected to the heat medium storage tank 400 through pipeline three 930, the heat medium storage tank 400 and the waste heat recovery heat exchanger 100 are directly provided with a circulation pump 410a, and the waste heat recovery heat exchanger 100 is connected to the venting device 500 through pipeline seven 970.

[0046] The system operation process is as follows: the flue gas from the flue gas device enters the waste heat recovery heat exchanger 100 through the pipe 1 910. In the waste heat recovery heat exchanger 100, the flue gas heats up the heat medium through heat exchange. The heated heat medium goes to the expander 200 through the pipe 2 920 to work and drive the generator 300. The generator 300 generates electric energy and provides it to the energy user. The heat medium after working in the expander 200 passes through the pipe 3 930 and returns to the heat medium storage tank 400. The heat medium in the heat medium storage tank 400 passes through the pipe 5 950, is pressurized by the circulation pump 410a, and then goes to the waste heat recovery heat exchanger 100 through the pipe 6 960 to continue circulating. The flue gas after heat recovery and utilization enters the venting device 500 through the pipe 7 970 for venting.

[0047] The device can perform heat exchange with waste flue gas through a heat medium, and can efficiently recycle waste heat in a relatively small amount of flue gas.

[0048] Embodiment 2, as Figure 3 As shown, on the basis of Example 1, a speed limiting protection device 600 is added to the expansion machine 200. The speed limiting protection device 600 may include a condenser 610. The hot medium after the expansion machine 200 does work enters the condenser 610 through the pipeline three 930, and the cold medium (cold water may be used) enters the condenser 610 through the pipeline twelve 9120. The condenser 610 performs heat exchange on the hot medium and the cold medium. The hot medium after the heat exchange is sent to the heat medium storage tank 400 through the pipeline four 940, and the cold medium after the heat exchange is discharged through the pipeline thirteen 9130.

[0049] Furthermore, a speed limiter 620 may be provided on the expander 200 , and the speed limiter 620 is interlocked with the condenser 610 .

[0050] When in use, the speed limiter 620 detects the rotation speed of the expander 200. When the rotation speed of the expander 200 is too high, the speed of the expander 200 is reduced. At the same time, the speed limiter 620 interlocks and controls the operation of the condenser 610 to perform heat exchange and cool the heat medium, which can reduce the temperature and pressure of the heat medium and further increase the control over the expander 200.

[0051] Embodiment 3, as Figure 4 As shown, a pressure limiting protection device 700 for the heat medium can be added on the basis of Embodiment 1 or 2 to ensure the safe operation of the entire device. The pressure limiting protection device 700 includes a safety relief device 710 (such as a safety pressure relief valve), which can be set on the pipeline 2 920. When the pressure of the heat medium is too high, the heat medium will break through the pressure relief port of the safety relief device 710 and enter the heat medium storage tank 400 through the pipeline 11 9110, thereby playing a role in protecting the pipeline from overpressure.

[0052] Furthermore, a pressure gauge 720 may be provided on the second pipeline 920. When the second pipeline 920 is over-pressured, the pressure gauge 720 is interlocked with the circulation pump 410a to reduce the speed of the circulation pump 410a, thereby further reducing the pressure in the second pipeline 920 and increasing the protection of the pipeline.

[0053] Embodiment 4, as Figure 5 As shown, on the basis of Example 1, 2 or 3, a medium preheating device 800 for supplementing the heat medium can be added. The medium preheating device 800 can include a heater 810. The heater 810 is connected to the supplementary heat medium through a pipeline 990. The flue gas discharged from the waste heat recovery heat exchanger 100 still has a lot of heat. The flue gas enters the heater 810 through a pipeline 970. The heater 810 performs heat exchange on the flue gas and the supplementary heat medium. The supplementary heat medium after the heat exchange is supplemented into the heat medium storage tank 400 through a pipeline 9100. The flue gas after the heat exchange enters the emptying device through a pipeline 980 for emptying.

[0054] The medium preheating device 800 can further increase the recovery and utilization of heat in the flue gas.

[0055] Furthermore, a regulating valve 820 is provided on the pipeline 990, and a liquid level gauge 830 is provided on the heat medium storage tank 400. The regulating valve 820 is interlocked with the liquid level gauge 830. When the liquid level gauge 830 detects that the amount of heat medium in the heat medium storage tank 400 is insufficient, the regulating valve 820 is automatically interlocked to open to replenish the heat medium. When the liquid level gauge 830 detects that the amount of heat medium in the heat medium storage tank 400 is large, the regulating valve 820 is automatically interlocked to close.

[0056] Furthermore, if Figure 1 As shown, pipeline fourteen 9140 is connected between pipeline one 910 and pipeline ten 9100 and controlled by a valve (not shown in the figure). After the device stops, the smoke can directly enter the venting device 500 through pipeline fourteen 9140 and pipeline eight 980 for venting.

[0057] The present invention exchanges heat between a heat medium and waste flue gas, has a simple structure, is flexible in application, and is convenient to arrange in a small size. It can efficiently recycle and utilize the waste heat in a relatively small amount of flue gas, thereby improving the heat recovery efficiency of high-temperature flue gas discharged from various furnaces and improving energy utilization. By setting a speed limiting protection device 600, the speed limiting protection for the expander 200 is increased, which is beneficial to the stable operation of the expander 200 and reduces the failure rate of the entire device. By setting a pressure limiting protection device 700, the protection for the pipeline pressure is increased to ensure the safe operation of the entire device. By setting a medium preheating device 800, the waste heat of the supplementary heat medium is increased, the flue gas heat is further recycled and utilized, and the recovery efficiency of the flue gas heat is improved.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0059] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0060] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0061] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

Claims

1. A flue gas waste heat recovery power generation device, characterized in that: include: A waste heat recovery heat exchanger (100) collects waste heat of flue gas generated by the flue gas device, and utilizes the waste heat of flue gas to perform heat exchange with a heat medium, thereby increasing the temperature of the heat medium; The expander (200) utilizes the high-temperature heat medium to drive the generator (300) to generate electric energy; The heat medium storage tank (400) receives the heat medium after the expander (200) has done work, and pumps the heat medium back to the waste heat recovery heat exchanger (100) to continue the heat exchange cycle.

2. The flue gas waste heat recovery power generation device according to claim 1, characterized in that: The waste heat recovery heat exchanger (100) is connected to the flue gas device via a first pipeline (910), the waste heat recovery heat exchanger (100) is connected to the venting device (500) via a seventh pipeline (970), the waste heat recovery heat exchanger (100) is connected to the expander (200) via a second pipeline (920), the expander (200) is connected to the heat medium storage tank (400) via a third pipeline (930), the heat medium storage tank (400) and the waste heat recovery heat exchanger (100) are directly provided with a circulation pump (410a), the heat medium storage tank (400) is connected to the circulation pump (410a) via a fifth pipeline (950), and the circulation pump (410a) is connected to the waste heat recovery heat exchanger (100) via a sixth pipeline (960).

3. The flue gas waste heat recovery power generation device according to claim 2, characterized in that: Also included is a speed limiting protection device (600): The speed limiting protection device (600) comprises a condenser (610), and the condenser (610) is used to perform heat exchange between a hot medium and a cold medium; The condenser (610) is connected to the heat medium through the pipeline three (930), and the condenser (610) sends the heat medium after heat exchange into the heat medium storage tank (400) through the pipeline four (940); The condenser (610) is connected to the cold medium through pipeline 12 (9120), and the condenser (610) discharges the cold medium after heat exchange through pipeline 13 (9130).

4. The flue gas waste heat recovery power generation device according to claim 3 is characterized in that: The expander (200) is provided with a speed limiter (620), and the condenser (610) operates in an interlocking manner with the speed limiter (620).

5. The flue gas waste heat recovery power generation device according to claim 4, characterized in that: It also includes a pressure limiting protection device (700), The pressure limiting protection device (700) comprises a safety relief device (710), wherein the safety relief device (710) is arranged on pipeline two (920), and a pressure relief port of the safety relief device (710) is connected to the heat medium storage tank (400) via pipeline eleven (9110).

6. The flue gas waste heat recovery power generation device according to claim 5, characterized in that: The second pipeline (920) is also provided with a pressure gauge (720), and the pressure gauge (720) is interlocked with the circulation pump (410a).

7. The flue gas waste heat recovery power generation device according to claim 6, characterized in that: It also includes a medium preheating device (800), The medium preheating device (800) comprises a temperature increaser (810), and the temperature increaser (810) is used to perform heat exchange between flue gas waste heat and supplementary heat medium; The temperature booster (810) is connected to the supplementary heat medium through the pipeline nine (990), and the temperature booster (810) replenishes the supplementary heat medium after heat exchange into the heat medium storage tank (400) through the pipeline ten (9100); The temperature booster (810) is connected to the flue gas generated by the flue gas device through the pipeline seven (970), and the temperature booster (810) discharges the flue gas after heat exchange into the venting device (500) through the pipeline eight (980).

8. The flue gas waste heat recovery power generation device according to claim 7, characterized in that: The pipeline nine (990) is provided with a regulating valve (820), the heat medium storage tank (400) is provided with a liquid level meter (830), and the regulating valve (820) is interlocked with the liquid level meter (830).

9. The flue gas waste heat recovery power generation device according to claim 6, characterized in that: Pipeline 14 (9140) is connected between pipeline 1 (910) and pipeline 10 (9100).

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