Waste heat utilization system and steam conveying pipeline

Abstract

The utility model discloses a waste heat utilization system and a steam conveying pipeline, the waste heat utilization system comprises a condensation water unit, a control unit and a drainage pipe, the condensation water unit comprises a first pipe, a second pipe, a water storage tank and a drain valve; the control unit comprises an electric control valve, a liquid level sensor and a controller; the drain pipe is attached to the steam conveying pipeline, and the middle of the drain pipe extends to the position above the steam conveying pipeline. The steam conveying pipeline comprises a pipeline unit and a plurality of waste heat utilization systems, the pipeline unit comprises a steam pipe, and the waste heat utilization systems are arranged at intervals in the length direction of the steam pipe. Compared with the prior art, the waste heat utilization system provided by the utility model has the advantages that the water storage tank is used for storing condensed water, the pressure in the steam pipeline is used for pushing the condensed water to flow above the steam pipeline along the drainage pipe, and then the condensed water flows out downwards, so that a circle of thermal barrier is formed around the steam pipeline; therefore, the heat loss of the steam pipeline is greatly reduced.

Description

Technical Field

[0001] This utility model relates to the field of steam transmission technology, specifically to a waste heat utilization system and a steam transmission pipeline. Background Technology

[0002] Steam experiences significant heat loss during transport, typically decreasing in temperature by 8-10°C and pressure by about 0.08 MPa per kilometer. This pipeline loss is a major limiting factor for the economic viability of steam pipeline transportation. Furthermore, as some of the steam condenses into water due to heat loss, the accumulation of condensate over increasing distance can cause water hammer. Therefore, steam pipelines are designed with condensate drains at regular intervals, typically drained locally into sewers due to the small volume. However, the temperature of condensate is generally the saturation temperature at one atmosphere, slightly below 100°C. This wastes a significant amount of heat.

[0003] The heat loss of steam pipelines mainly depends on the steam temperature, ambient temperature, and the total thermal resistance of the insulation structure. Technical and economic analysis shows that reducing heat loss by increasing the total thermal resistance of the pipeline insulation structure is economically feasible for heating radii within 6 kilometers. Therefore, reducing the temperature difference between the steam and ambient temperatures to decrease heat loss is one approach to increasing the heating radius.

[0004] Chinese patent CN210219062U provides a condensate waste heat recovery system for long-distance steam pipelines. This system uses high-temperature condensate to heat the insulation layer, reducing the temperature difference across the insulation layer and thus minimizing steam loss. However, in this system, the condensate pipe passes under the insulation layer of the steam pipeline, preventing the formation of a thermal barrier on top of the insulation layer, resulting in an unsatisfactory effect in reducing heat loss from the steam pipeline. Utility Model Content

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a waste heat utilization system and a steam transmission pipeline to solve the technical problem that the existing technology cannot establish a comprehensive thermal barrier for steam pipelines, resulting in an unsatisfactory effect in reducing the heat loss of steam pipelines.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, this utility model provides a waste heat recovery system for steam transmission pipelines, comprising: a condensate unit, a control unit, and a drain pipe.

[0008] The condensate unit includes a first pipe, a second pipe, a water storage tank, and a steam trap. The upper ends of the first pipe and the second pipe are both connected to a steam conveying pipeline, and the lower ends of the first pipe and the second pipe are both connected to the water storage tank. The steam trap is installed on the first pipe.

[0009] The control unit includes an electrically controlled valve, a liquid level sensor, and a controller. The electrically controlled valve is installed on the second pipe, the liquid level sensor is installed inside the water storage tank and connected to the controller, and the controller is connected to the electrically controlled valve. When the condensate level in the water storage tank rises to a preset maximum value, the controller controls the electrically controlled valve to open; when the condensate level in the water storage tank drops to a preset minimum value, the controller controls the electrically controlled valve to close.

[0010] The inlet of the drain pipe is connected to the water storage tank. The drain pipe is arranged close to the steam conveying pipe and extends above the steam conveying pipe in the middle. The outlet of the drain pipe is located below the steam conveying pipe.

[0011] In some embodiments, the drain pipe includes a main pipe and multiple branch pipes. The inlet of the main pipe is connected to the water storage tank, and its outlet is located above the steam conveying pipe. The inlets of each branch pipe are connected to the outlet of the main pipe. The branch pipes are arranged close to the steam conveying pipe, and the outlets of the branch pipes are located below the steam conveying pipe.

[0012] In some embodiments, a portion of the branch pipe is located on one side of the steam conveying pipeline, and another portion of the branch pipe is located on the other side of the steam conveying pipeline.

[0013] In some embodiments, the control unit further includes a power supply module, which is connected to the electronically controlled valve, the liquid level sensor, and the controller to supply power to them.

[0014] In some embodiments, the power supply module includes a battery and a solar panel. The solar panel is disposed on a steam conveying pipeline and connected to the battery. The battery is connected to the electronically controlled valve, the liquid level sensor, and the controller.

[0015] Secondly, this utility model also provides a steam conveying pipeline, including a pipeline unit and multiple waste heat utilization systems. The pipeline unit includes a steam pipe, and the waste heat utilization systems are spaced apart along the length of the steam pipe. The first pipe and the second pipe are respectively connected to the steam pipe, and the drain pipe is arranged close to the steam pipe.

[0016] In some embodiments, the piping unit further includes a first insulation layer that wraps around the steam pipe, the first pipe and the second pipe passing through the first insulation layer and communicating with the steam pipe, and the drain pipe being arranged close to the first insulation layer.

[0017] In some embodiments, the pipe unit further includes a heat-conducting layer that wraps around the first insulation layer, and the middle portion of the drain pipe is located within the heat-conducting layer.

[0018] In some embodiments, the pipe unit further includes a second insulation layer that wraps around the heat-conducting layer. The first pipe and the second pipe pass through the first insulation layer, the heat-conducting layer, and the second insulation layer. Both ends of the drain pipe pass through the second insulation layer, and the middle part of the drain pipe is located within the heat-conducting layer.

[0019] In some embodiments, the first pipe is connected to the bottom of the steam pipe, and the second pipe is connected to the middle or upper part of the steam pipe.

[0020] Compared with the prior art, the waste heat utilization system provided by this utility model uses a water storage tank to store condensate. After accumulating enough condensate, the pressure inside the steam pipe pushes the condensate to flow along the drain pipe to the top of the steam pipe, and then flows down, thereby forming a heat barrier around the steam pipe, thus significantly reducing the heat loss of the steam pipe. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the steam conveying pipeline provided in an embodiment of the present invention;

[0022] Figure 2 This is a cross-sectional view of the steam conveying pipeline provided in an embodiment of this utility model. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0024] To address the technical problem that existing technologies are not effective enough in reducing heat loss in steam pipelines, this invention provides a waste heat utilization system and a steam transmission pipeline that can form a thermal barrier around the steam pipeline, thereby significantly reducing heat loss in the steam pipeline.

[0025] Please see Figure 1 The waste heat recovery system 100 is used on a steam transmission pipeline and includes a condensate unit 10, a control unit 20, and a drain pipe 30.

[0026] The condensate unit 10 includes a first pipe 11, a second pipe 12, a water storage tank 13, and a steam trap 14. The upper ends of the first pipe 11 and the second pipe 12 are both connected to a steam conveying pipeline, and the lower ends of the first pipe 11 and the second pipe 12 are both connected to the water storage tank 13. The steam trap 14 is installed on the first pipe 11.

[0027] The steam trap 14, also known as a condensate trap, can automatically identify steam and water, thereby achieving the purpose of automatically blocking steam and draining water. The steam trap 14 is installed on the first pipe 11, and the condensate generated in the steam transmission pipeline can be discharged into the water storage tank 13 through the first pipe 11.

[0028] The control unit 20 includes an electrically controlled valve 21, a level sensor, and a controller. The electrically controlled valve 21 is mounted on the second pipe 12, and the level sensor is located inside the water storage tank 13 and connected to the controller. The controller is connected to the electrically controlled valve 21. The electrically controlled valve 21 is normally closed. When the condensate level in the water storage tank 13 rises to a preset maximum value, the controller controls the electrically controlled valve 21 to open. When the condensate level in the water storage tank 13 drops to a preset minimum value, the controller controls the electrically controlled valve 21 to close.

[0029] The inlet of the drain pipe 30 is connected to the water storage tank 13. The drain pipe 30 is arranged close to the steam conveying pipeline and its middle part extends above the steam conveying pipeline. The outlet of the drain pipe 30 is located below the steam conveying pipeline.

[0030] Condensate from the steam delivery pipeline flows into the storage tank 13 through the first pipe 11. When the water level in the storage tank 13 rises to a preset maximum value, the solenoid valve 21 opens. The storage tank 13 is connected to the steam delivery pipeline through the second pipe 12. The high-pressure steam in the steam delivery pipeline forces the condensate in the storage tank 13 out through the drain pipe 30. The condensate first moves along the drain pipe 30 to the top of the steam delivery pipeline, and then flows to the bottom of the steam delivery pipeline. During the flow of the condensate along the drain pipe 30, because the condensate temperature is very high, close to 100°C, it heats the upper, middle, and lower areas of the steam delivery pipeline, forming a thermal barrier around the steam delivery pipeline, thereby significantly reducing the heat loss of the steam delivery pipeline.

[0031] In some embodiments, the water storage tank 13 is wrapped with an insulation structure or is made of insulation material. The condensate temperature inside the water storage tank 13 is close to 100°C. Taking insulation measures can reduce the heat loss of the condensate, thereby increasing the temperature of the thermal barrier and reducing the heat loss of the steam transmission pipeline.

[0032] In some embodiments, the liquid level sensor can be a contact-type liquid level sensor, such as a hydrostatic immersion level transmitter. Based on the principle that the measured liquid hydrostatic pressure is proportional to the liquid height, it uses an isolated diffused silicon sensing element or a ceramic capacitive pressure sensing sensor to convert the hydrostatic pressure into an electrical signal. After temperature compensation and linear correction, it is converted into a standard electrical signal and transmitted to the controller. The controller can be a common industrial controller such as a microcontroller, which presets the highest and lowest liquid level values ​​and controls the opening or closing state of the solenoid valve 21 based on the liquid level data.

[0033] In some embodiments, the control unit 20 further includes a power supply module 22, which is connected to the electronically controlled valve 21, the liquid level sensor and the controller respectively, and supplies them with power.

[0034] In some embodiments, the power supply module 22 includes a battery 221 and a solar panel 222. The solar panel 222 is disposed on a steam conveying pipe and connected to the battery 221. The battery 221 is connected to an electronically controlled valve 21, a liquid level sensor, and a controller. The solar panel 222 converts light energy into electrical energy and stores it in the battery 221. This method does not require an external power supply and is easier to implement.

[0035] In some embodiments, the drain pipe 30 includes a main pipe 31 and multiple branch pipes 32. The inlet of the main pipe 31 is connected to the water storage tank 13, and its outlet is located above the steam conveying pipe. The inlets of each branch pipe 32 are connected to the outlets of the main pipe 31. The branch pipes 32 are arranged close to the steam conveying pipe, and their outlets are located below the steam conveying pipe.

[0036] In a preferred embodiment, some branch pipes 32 are located on one side of the steam conveying pipeline, and other branch pipes 32 are located on the other side of the steam conveying pipeline. Some branch pipes 32 also extend for varying distances along the length of the steam conveying pipeline. This arrangement maximizes the coverage area of ​​the thermal barrier by maximizing the number of branch pipes 32 surrounding the steam conveying pipeline, thereby reducing heat loss in the steam conveying pipeline.

[0037] Please see Figure 1 and Figure 2 This utility model also provides a steam conveying pipeline including a pipeline unit 500 and multiple waste heat utilization systems 100. The pipeline unit 500 includes a steam pipe 510, through which high-temperature and high-pressure steam is conveyed. The waste heat utilization systems 100 are spaced apart along the length of the steam pipe 510. A first pipe 11 and a second pipe 12 are respectively connected to the steam pipe 510, and a drain pipe 30 is arranged close to the steam pipe 510.

[0038] In some embodiments, the first pipe 11 is connected to the bottom of the steam pipe 510 to facilitate the drainage of condensate. The second pipe 12 is connected to the middle or upper part of the steam pipe 510 to prevent condensate from flowing into the second pipe 12.

[0039] In some embodiments, the pipe unit 500 further includes a first insulation layer 520, which wraps around the steam pipe 510. The first pipe 11 and the second pipe 12 pass through the first insulation layer 520 and are connected to the steam pipe 510. The drain pipe 30 is arranged close to the first insulation layer 520.

[0040] In some embodiments, the pipe unit 500 further includes a heat-conducting layer 530, which surrounds the first insulation layer 520, with the middle portion of the drain pipe 30 located within the heat-conducting layer 530. The heat-conducting layer 530 can achieve a uniform heat distribution, forming a thermal barrier around the first insulation layer 520, thereby expanding the coverage area of ​​the thermal barrier and reducing heat loss in the steam transport pipe.

[0041] In some embodiments, the piping unit 500 further includes a second insulation layer 540, which surrounds the heat-conducting layer 530. The first pipe 11 and the second pipe 12 penetrate the second insulation layer 540, the heat-conducting layer 530, and the first insulation layer 520, and communicate with the steam pipe 510. Both ends of the drain pipe 30 pass through the second insulation layer 540, and the middle portion of the drain pipe 30 is located within the heat-conducting layer 530. Specifically, the main pipe 31 passes through the second insulation layer 540 and extends into the heat-conducting layer 530. Each branch pipe 52 extends downward within the heat-conducting layer 530, distributed as evenly as possible around the first insulation layer 520, and finally passes through the second insulation layer 540 to extend below the piping unit 500 for draining condensate.

[0042] As the high-temperature condensate flows along each branch pipe 32, it heats the heat-conducting layer 530. Due to the good thermal conductivity of the heat-conducting layer 530, a high-temperature barrier is quickly formed outside the first insulation layer 520, reducing the temperature difference between the two sides of the first insulation layer 520, thereby reducing the heat transfer efficiency of the first insulation layer 520 and thus reducing the heat loss of the steam pipe 510.

[0043] The specific embodiments of this utility model described above do not constitute a limitation on the scope of protection of this utility model. Any other corresponding changes and modifications made based on the technical concept of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A waste heat recovery system for use in steam transmission pipelines, characterized in that, include: The condensate unit includes a first pipe, a second pipe, a water storage tank, and a steam trap. The upper ends of the first pipe and the second pipe are both connected to a steam conveying pipeline, and the lower ends of the first pipe and the second pipe are both connected to the water storage tank. The steam trap is installed on the first pipe. The control unit includes an electrically controlled valve, a liquid level sensor, and a controller. The electrically controlled valve is installed on the second pipe, the liquid level sensor is installed inside the water storage tank and connected to the controller, and the controller is connected to the electrically controlled valve. When the condensate level in the water storage tank rises to a preset maximum value, the controller controls the electrically controlled valve to open; when the condensate level in the water storage tank drops to a preset minimum value, the controller controls the electrically controlled valve to close. A drain pipe, the inlet of which is connected to the water storage tank, is arranged close to the steam conveying pipe and extends above the steam conveying pipe in the middle, and the outlet of the drain pipe is located below the steam conveying pipe.

2. The waste heat utilization system according to claim 1, characterized in that, The drain pipe includes a main pipe and multiple branch pipes. The inlet of the main pipe is connected to the water storage tank, and its outlet is located above the steam conveying pipe. The inlets of each branch pipe are connected to the outlet of the main pipe. The branch pipes are arranged close to the steam conveying pipe, and the outlets of the branch pipes are located below the steam conveying pipe.

3. The waste heat utilization system according to claim 2, characterized in that, Some of the branch pipes are located on one side of the steam conveying pipeline, and the other part of the branch pipes are located on the other side of the steam conveying pipeline.

4. The waste heat utilization system according to claim 1, characterized in that, The control unit also includes a power supply module, which is connected to the electronically controlled valve, the liquid level sensor and the controller respectively to supply power to them.

5. The waste heat utilization system according to claim 4, characterized in that, The power supply module includes a storage battery and a solar panel. The solar panel is installed on the steam conveying pipeline and connected to the storage battery. The storage battery is connected to the electronic control valve, the liquid level sensor and the controller.

6. A steam conveying pipeline, characterized in that, It includes a piping unit and a waste heat utilization system as described in any one of claims 1-5, wherein the piping unit includes a steam pipe, the waste heat utilization system is spaced apart along the length of the steam pipe, the first pipe and the second pipe are respectively connected to the steam pipe, and the drain pipe is arranged close to the steam pipe.

7. The steam conveying pipeline according to claim 6, characterized in that, The piping unit also includes a first insulation layer, which wraps around the steam pipe. The first pipe and the second pipe pass through the first insulation layer and are connected to the steam pipe. The drain pipe is arranged close to the first insulation layer.

8. The steam conveying pipeline according to claim 7, characterized in that, The pipe unit also includes a heat-conducting layer, which wraps around the first insulation layer, and the middle part of the drain pipe is located inside the heat-conducting layer.

9. The steam conveying pipeline according to claim 8, characterized in that, The pipe unit also includes a second insulation layer, which wraps around the heat-conducting layer. The first pipe and the second pipe pass through the first insulation layer, the heat-conducting layer, and the second insulation layer. Both ends of the drain pipe pass through the second insulation layer, and the middle part of the drain pipe is located inside the heat-conducting layer.

10. The steam conveying pipeline according to claim 6, characterized in that, The first pipe is connected to the bottom of the steam pipe, and the second pipe is connected to the middle or upper part of the steam pipe.

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