Negative pressure steam ORC evaporator

Abstract

The utility model relates to the technical field of evaporators, in particular to a negative-pressure steam ORC evaporator which comprises an evaporator body, a negative-pressure steam heat exchanger and a negative-pressure steam heat exchanger. The steam inlet pipeline is communicated with the evaporator body and is used for introducing negative pressure steam into the evaporator body; the heat exchange tube bundle is mounted in the evaporator body and is used for exchanging heat with the negative pressure steam; the recovery pipeline is connected to the evaporator body and used for recovering condensed water in the evaporator body; the condensate pump is arranged on the recovery pipeline and is used for controlling the on-off of the recovery pipeline; the air exhaust assembly is installed on the evaporator body and used for extracting air in the evaporator body. The negative pressure steam recycling device has the effect of recycling negative pressure steam.

Description

Technical Field

[0001] This application relates to the technical field of evaporators, and in particular, to a negative pressure steam ORC evaporator. Background Art

[0002] In a typical steam power generation system, the working medium is water, and its working cycle can be ideally regarded as an ideal cycle composed of two reversible constant-pressure processes and two reversible adiabatic processes, including four thermodynamic processes: a constant-pressure heat absorption process, an adiabatic expansion process, a constant-pressure heat release process, and an adiabatic pressurization process. This thermodynamic cycle theory was proposed by the Scottish engineer W.J.M. Rankine in the 19th century. To commemorate his achievements, the basic cycle of the steam power plant has also become the Rankine cycle.

[0003] The Organic Rankine Cycle (ORC) is a Rankine cycle using low-boiling organic substances as the working medium, mainly composed of four major components: a waste heat boiler (or evaporator), a turbine, a condenser, and a working fluid pump.

[0004] The organic cycle working fluid exchanges heat with an external heat source in the evaporator and changes into a high-pressure and high-temperature organic vapor, enters the turbine to do work and drive the turbine mechanical device to generate electricity. Then, the organic vapor enters the condenser to exchange heat with cooling water and returns to the liquid working fluid, and then is pumped by the working fluid pump and enters the evaporator again to complete a whole cycle.

[0005] The heat source of ORC is usually positive pressure steam, and the air pressure of the positive pressure steam is greater than the air pressure in the evaporator to ensure that the positive pressure steam can directly flow into the evaporator. However, in this way, it is difficult to directly introduce negative pressure steam into the evaporator, and there is a problem that it is difficult to reuse negative pressure steam. Utility Model Content

[0006] The purpose of this application is to provide a negative pressure steam ORC evaporator for reusing negative pressure steam.

[0007] In the first aspect, a negative pressure steam ORC evaporator provided by this application adopts the following technical solution:

[0008] A negative pressure steam ORC evaporator includes:

[0009] An evaporator body;

[0010] An inlet steam pipeline, which is connected to the evaporator body and used to introduce negative pressure steam into the evaporator body;

[0011] A heat exchange tube bundle, which is installed in the evaporator body and used to exchange heat with negative pressure steam;

[0012] A recovery pipeline, connected to the evaporator body for recovering the condensed water in the evaporator body;

[0013] A condensate pump, arranged on the recovery pipeline and used to control the on-off of the recovery pipeline;

[0014] An air extraction assembly, installed on the evaporator body and used to extract the air in the evaporator body.

[0015] By adopting the above technical solution, through the setting of the air extraction assembly, the pressure in the evaporator body is ensured to be lower than the pressure of the negative pressure steam, so that the negative pressure steam can flow into the evaporator body by itself, thereby realizing the reuse of the negative pressure steam.

[0016] Optionally, the air extraction assembly includes a starting air ejector and an operating air ejector. Both the starting air ejector and the operating air ejector are connected to the evaporator body, and the power of the starting air ejector is greater than that of the operating air ejector.

[0017] By adopting the above technical solution, only setting the starting air ejector can also achieve air extraction during normal operation. However, due to the high power consumption of the starting air ejector, it consumes more energy to use the starting air ejector both in the starting stage and the operating stage. Therefore, the starting air ejector is used in the starting stage, and the operating air ejector is used during operation, so as to be more energy-saving.

[0018] Optionally, the operating air ejector is provided with at least two interfaces, and at least two of the interfaces are symmetrically arranged with respect to the evaporator body.

[0019] By adopting the above technical solution, at least two operating air ejectors are symmetrically arranged, thereby increasing the extraction efficiency of the air leaking into the evaporator body and ensuring the negative pressure environment in the evaporator body.

[0020] Optionally, it further includes an air extraction baffle, which corresponds to the position of the operating air ejector and is used to slow down the amount of negative pressure steam flowing towards the operating air ejector.

[0021] By adopting the above technical solution, during the operation of the operating air ejector, continuous suction will be provided, causing the air flow in the evaporator body to flow towards the direction of the operating air ejector. Through the setting of the air extraction baffle, the amount of steam flowing towards the operating air ejector is slowed down, so that the steam has sufficient time to condense into condensed water.

[0022] Optionally, there is an air-cooled area between the air extraction baffle and the operating air ejector, and the heat exchange tube bundle is also arranged in the air-cooled area for cooling the steam drawn by the operating air ejector.

[0023] By adopting the above technical solution, heat exchange tube bundles are arranged in the air-cooled area. If a small amount of steam enters the air-cooled area, it is further condensed through the heat exchange tube bundles in the air-cooled area, further reducing the waste of steam.

[0024] Optionally, a cross plate is fixedly connected to the lower end of the air extraction baffle. The cross plate is arranged towards the direction close to the operating air extractor, and a gap is arranged between the cross plate and the inner wall of the evaporator body.

[0025] By adopting the above technical solution, through the arrangement of the cross plate, the amount of steam flowing into the operating air extractor is further reduced, enabling the steam to have more sufficient time for heat exchange and condensation.

[0026] Optionally, a cross plate is fixedly connected to the lower end of the air extraction baffle. The cross plate is arranged towards the direction close to the operating air extractor, and the cross plate is fixedly connected to the inner wall of the evaporator body. A plurality of holes are formed in the cross plate.

[0027] By adopting the above technical solution, by forming holes in the cross plate, the steam flows into the air-cooled area from the holes, reducing the amount of steam flowing into the air-cooled area, enabling the steam to have more sufficient time for heat exchange and condensation, and reducing the waste of steam.

[0028] Optionally, a liquid level gauge is arranged on the evaporator body, and the liquid level gauge is used to detect the liquid level of the condensed water in the evaporator body.

[0029] By adopting the above technical solution, through the arrangement of the liquid level gauge, the water level of the condensed water in the evaporator body is monitored in real time to prevent the water level of the condensed water from being too high and submerging the heat exchange tube bundles in the middle of the evaporator body, thereby affecting the heat exchange effect.

[0030] In summary, the present application includes at least one of the following beneficial technical effects:

[0031] 1. Through the arrangement of the air extraction assembly, the pressure in the evaporator body is ensured to be lower than the pressure of the negative pressure steam, so that the negative pressure steam can flow into the evaporator body by itself, thereby realizing the reuse of the negative pressure steam;

[0032] 2. Only setting the starting air extractor can also achieve air extraction during normal operation. However, due to the high power consumption of the starting air extractor, using the starting air extractor both in the starting stage and the operation stage consumes a high amount of energy. Therefore, the starting air extractor is used in the starting stage, and the operating air extractor is used during operation, thereby being more energy-saving;

[0033] 3. During the operation of the operating air extractor, continuous suction is provided, causing the air flow in the evaporator body to flow towards the direction of the operating air extractor. Through the arrangement of the air extraction baffle, the amount of steam flowing towards the operating air extractor is slowed down, so that the steam has sufficient time to condense into condensed water. Brief Description of the Drawings

[0034] Figure 1 It is a schematic diagram of the overall structure of a negative-pressure steam ORC evaporator according to an embodiment of the present application.

[0035] Figure 2 It is a schematic diagram of the internal structure of the evaporator body according to an embodiment of the present application.

[0036] In the figure, 1 is the evaporator body; 2 is the steam inlet pipe; 3 is the heat exchange tube bundle, 31 is the preheating tube bundle, 32 is the evaporation tube bundle, 33 is the superheating tube bundle; 4 is the recovery pipe; 41 is the condensate pump; 5 is the air extraction assembly, 51 is the starting air extractor, 52 is the operating air extractor; 6 is the liquid level gauge; 7 is the air extraction baffle; 8 is the cross plate; 9 is the air-cooled area. Specific embodiments

[0037] The following will be further described in detail with reference to the attached Figure 1 - attached Figure 2 drawings to further illustrate the present application.

[0038] A negative-pressure steam ORC evaporator, referring to Figure 1 and Figure 2 , includes an evaporator body 1, a steam inlet pipe 2, a heat exchange tube bundle 3, a recovery pipe 4, a condensate pump 41 and an air extraction assembly 5. The steam inlet pipe 2 is fixedly connected to the evaporator body 1 and communicates with the evaporator body 1. Specifically, the steam inlet pipe 2 is fixedly connected to the top of the evaporator body 1, and negative-pressure steam is introduced into the evaporator body 1 through the steam inlet pipe 2. The heat exchange tube bundle 3 is arranged in the evaporator body 1 to exchange heat with the negative-pressure steam entering the evaporator body 1, so that the negative-pressure steam is condensed to form condensate.

[0039] The recovery pipe 4 is fixedly connected to the bottom of the evaporator body 1 and is used to export the formed condensate from the evaporator body 1 for recovery. The recovery pipe 4 is arranged at the bottom of the evaporator body 1 so that the condensate can flow into the recovery pipe 4 under the action of its own gravity, thus eliminating the need to add extra pumps and saving costs. The condensate pump 41 is installed on the recovery pipe 4 and is used to control the on-off of the recovery pipe 4. The condensate pump 41 first controls the recovery pipe 4 to close, at this time the condensate accumulates, and when the condensate accumulates to a certain extent, the condensate pump 41 controls the recovery pipe 4 to open, and at this time the condensate is recovered through the recovery pipe 4.

[0040] Specifically, a liquid level gauge 6 is provided on the evaporator body 1. The liquid level gauge 6 is used to detect the liquid level of the condensate water in the evaporator body 1. Specifically, the liquid level gauge 6 is electrically connected to the condensate water pump 41. When the liquid level gauge 6 detects that the condensate water level is too high, it controls the condensate water pump 41 to start and recycle the condensate water. Through the setting of the liquid level gauge 6, the water level of the condensate water in the evaporator body 1 is monitored in real time to prevent the water level of the condensate water from being too high and submerging the heat exchange tube bundle 3 in the middle of the evaporator body 1, thereby affecting the heat exchange effect.

[0041] Furthermore, an alarm is provided on the evaporator body 1. The alarm is electrically connected to the liquid level gauge 6 and alarms when the heat exchange tube bundle 3 is submerged by the condensate water, reminding the staff to carry out maintenance.

[0042] The heat exchange tube bundle 3 includes a number of preheating tube bundles 31, a number of evaporation tube bundles 32, and a number of superheating tube bundles 33. A number of preheating tube bundles 31 are arranged at the lower end inside the evaporator body 1 and close to the recovery pipeline 4. A number of preheating tube bundles 31 are arranged in an inverted trapezoidal shape, and can also be arranged in other shapes in other embodiments. The evaporation tube bundles 32 are arranged in the middle of the evaporator body 1. In this embodiment, a number of evaporation tube bundles 32 are arranged in a rectangular shape, and can also be arranged in other shapes in other embodiments. A number of superheating tube bundles 33 are arranged at the upper end inside the evaporator body 1 and close to the steam inlet pipeline 2. In this embodiment, a number of superheating tube bundles 33 are arranged in a trapezoidal shape, and can also be arranged in other shapes in other embodiments.

[0043] A number of preheating tube bundles 31 are connected in sequence to form a preheating tube group, a number of evaporation tube bundles 32 are connected in sequence to form an evaporation tube group, and a number of superheating tube bundles 33 are connected in sequence to form a superheating tube group. The preheating tube group, the evaporation tube group, and the superheating tube group are connected in sequence. One end of the preheating tube group away from the evaporation tube group is used for flowing in the liquid working medium, and one end of the superheating tube group away from the evaporation tube group is used for flowing out the gaseous working medium.

[0044] The condensate water accumulates in the evaporator body 1 and submerges the preheating tube group. The setting of the liquid level gauge 6 prevents the condensate water from submerging the evaporation tube group. The liquid working medium first flows into the preheating tube group and exchanges heat with the condensate water for the first time in the preheating tube group, then flows into the evaporation tube group and exchanges heat with the negative pressure steam for the second time, and finally flows into the superheating tube group for the third time. Since the negative pressure steam flows in from the steam inlet pipeline 2, the temperature at the location of the superheating tube group is the highest, and the temperature at the location of the evaporation tube group is between the temperature at the location of the preheating tube group and the temperature at the location of the superheating tube group. The liquid working medium finally vaporizes and flows out in the superheating tube group, and the high-temperature and high-pressure organic vapor generated in the superheating tube group is transported to the organic working medium turbine to do work.

[0045] The air extraction assembly 5 includes a starting air extractor 51 and an operating air extractor 52. Both the starting air extractor 51 and the operating air extractor 52 are connected to the evaporator body 1. The power of the starting air extractor 51 is greater than that of the operating air extractor 52. In this embodiment, the operating air extractor 52 is provided with at least two interfaces, and at least one interface is provided on both sides of the evaporator body 1. Before the negative pressure steam is introduced, the starting air extractor 51 is used to quickly extract the air in the evaporator, so that the pressure in the evaporator is lower than the negative pressure steam pressure by a certain value (such as 20 Kpa.a). Due to the large power of the starting air extractor 51, the starting efficiency is high. After the start is completed, the starting air extractor 51 is closed and the operating air extractor 52 is opened to continuously extract air, and the non-condensable gas leaking into the evaporator body 1 is extracted. Because the evaporator operates under negative pressure (lower than atmospheric pressure), air leakage is likely to occur.

[0046] A hot well is arranged in the evaporator body 1. The condensed water after heat exchange and condensation is collected in the hot well and is pumped out through the recovery pipeline 4 connected to the condensate pump 41 and discharged to a designated place.

[0047] A negative pressure steam ORC evaporator further includes an air extraction baffle 7. The upper end of the air extraction baffle 7 is fixedly connected to the inner top wall of the evaporator body 1. In this embodiment, the air extraction baffle 7 is inclined and the position of the air extraction baffle 7 corresponds to the position of the operating air extractor 52. In this embodiment, one such air extraction baffle 7 is correspondingly arranged beside each operating air extractor 52. There is an air-cooled area 9 between each air extraction baffle 7 and the corresponding operating air extractor 52, and heat exchange tube bundles 3 are also arranged in each air-cooled area 9. The heat exchange tube bundles 3 in the air-cooled area 9 are connected to other heat exchange tube bundles 3 and liquid working medium is also introduced.

[0048] During the operation of the operating air extractor 52, continuous suction is provided, causing the air flow in the evaporator body 1 to flow in the direction of the operating air extractor 52. Through the setting of the air extraction baffle 7, the amount of steam flowing towards the operating air extractor 52 is slowed down, so that the steam has sufficient time to condense into condensed water. And heat exchange tube bundles 3 are arranged in the air-cooled area 9. If a small amount of steam enters the air-cooled area 9, it is further condensed through the heat exchange tube bundles 3 in the air-cooled area 9, further reducing steam waste.

[0049] A horizontal plate 8 is fixedly connected to the lower end of each air extraction baffle 7. The horizontal plate 8 is arranged towards the direction close to the operating air extractor 52. In this embodiment, there is a gap between the horizontal plate 8 and the inner wall of the evaporator body 1. Through the setting of the horizontal plate 8, the amount of steam flowing into the operating air extractor 52 is further reduced, so that the steam has more sufficient time for heat exchange and condensation.

[0050] In other embodiments, the horizontal plate 8 is fixedly connected to the inner wall of the evaporator body 1, and a plurality of holes are formed in the horizontal plate 8. Steam and the air leaking into the evaporator body 1 flow into the air-cooled area 9 through the holes.

[0051] The implementation principle of the embodiment of this application is as follows: By setting up a starting air extractor 51 and an operating air extractor 52, at startup, the starting air extractor 51 is used for rapid startup, and at operation, the operating air extractor 52 is used for energy conservation. Additionally, an air extraction baffle 7 and a cross plate 8 are set up to reduce steam waste.

[0052] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Identical components are denoted by the same reference numerals. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A negative pressure steam ORC evaporator, characterized in that, Comprising: Evaporator body (1); Steam inlet pipe (2), communicating with the evaporator body (1) for introducing negative pressure steam into the evaporator body (1); Heat exchange tube bundle (3), installed in the evaporator body (1) and used for heat exchange with negative pressure steam; Recovery pipe (4), connected to the evaporator body (1) for recovering the condensed water in the evaporator body (1); Condensate pump (41), arranged on the recovery pipe (4) and used for controlling the on-off of the recovery pipe (4); Air extraction assembly (5), installed on the evaporator body (1) and used for extracting air in the evaporator body (1).

2. The negative-pressure steam ORC evaporator according to claim 1, wherein, The air extraction assembly (5) includes a starting air extractor (51) and an operating air extractor (52). Both the starting air extractor (51) and the operating air extractor (52) are connected to the evaporator body (1), and the power of the starting air extractor (51) is greater than the power of the operating air extractor (52).

3. The negative-pressure steam ORC evaporator according to claim 2, characterized in that, The operating air extractor (52) is provided with at least two interfaces, and at least two of the interfaces are symmetrically arranged with respect to the evaporator body (1).

4. A negative pressure steam ORC evaporator according to claim 2, characterized in that, It further includes an air extraction baffle (7), which corresponds to the position of the operating air extractor (52) and is used for slowing down the amount of negative pressure steam flowing towards the operating air extractor (52).

5. A negative pressure steam ORC evaporator according to claim 4, characterized in that, There is an air-cooled area (9) between the air extraction baffle (7) and the operating air extractor (52), and the heat exchange tube bundle (3) is also arranged in the air-cooled area (9) for cooling the steam drawn by the operating air extractor (52).

6. The negative-pressure steam ORC evaporator according to claim 5, wherein, The lower end of the air extraction baffle (7) is fixedly connected with a transverse plate (8). The transverse plate (8) is arranged towards the direction close to the operating air extractor (52), and there is a gap between the transverse plate (8) and the inner wall of the evaporator body (1).

7. A negative pressure steam ORC evaporator according to claim 5, characterized in that, The lower end of the air extraction baffle (7) is fixedly connected with a transverse plate (8). The transverse plate (8) is arranged towards the direction close to the operating air extractor (52), and the transverse plate (8) is fixedly connected with the inner wall of the evaporator body (1). A number of holes are provided on the transverse plate (8).

8. A negative pressure steam ORC evaporator according to claim 1, characterized in that, A liquid level gauge (6) is arranged on the evaporator body (1), and the liquid level gauge (6) is used for detecting the liquid level of the condensed water in the evaporator body (1).

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