Natural gas gathering and transportation pipeline cooling device

Abstract

The invention relates to the field of pipeline cooling, in particular to a natural gas gathering and transportation pipeline cooling device which comprises a well mouth standard buried pipe ditch and a conveying pipeline standard heating furnace, the buried pipe ditch is provided with a pipe ditch water circulation system to form a cooling water pond, and the heating furnace is provided with a furnace body water circulation system to form a cooler. The pipe ditch water circulation system comprises a circulation water pool, a circulation pipeline is arranged between the circulation water pool and the cooling water pool, and a circulation pump is arranged on the circulation pipeline; the furnace body water circulation system comprises a heating furnace standard configuration soft water pool, a circulation pipeline is arranged between the soft water pool and a furnace body of the heating furnace, and a heating furnace standard configuration circulation pump is arranged on the circulation pipeline. According to the device, an existing device is utilized, the gas production pipeline is cooled through the water circulation system, the investment cost is low, the technological process of the water circulation system is simple and convenient to implement, and the cooling effect is good.

Description

Technical Field

[0001] This invention relates to the field of pipeline cooling, and specifically to a natural gas gathering and transmission pipeline cooling device. Background Technology

[0002] In some existing gas fields, natural gas reservoirs have the characteristics of "three highs and one deep", namely, high temperature, high pressure, high sulfur content, and deep burial. Due to the deep location of the reservoirs, the natural gas is affected by geothermal and geological factors, resulting in high temperatures. During the extraction process, water vapor or other liquids will form hydrates, which will adhere to the pipeline and cause blockages. Furthermore, excessively high temperatures will affect the stability of transportation. Therefore, it is necessary to cool down the extracted natural gas.

[0003] Existing gas production stations utilize the throttling effect to reduce the pressure and temperature of gas production pipelines. Three-stage throttling valves are installed in the gas production station. After the natural gas is throttled and depressurized, the temperature drops significantly. However, when the temperature is too low, hydrates will form. Therefore, to prevent the formation of hydrates, a water bath heating method using a heating furnace is used during the second and third stages of throttling to increase the temperature of the transported natural gas. This can prevent the natural gas from precipitating hydrates before the dehydration process.

[0004] The specific process flow of the existing gas production station is as follows: Figure 1 As shown, high-temperature, high-pressure, and high-sulfur natural gas first enters the gas production tree 22. A first-stage throttling valve 23 is installed on the gas production tree. After the first-stage throttling, the temperature of the natural gas decreases initially with the pressure. Then, it passes through the gas production pipeline 6 and the buried pipeline trench 1 under the ground surface 28. The buried pipeline trench 1 is filled with fine sand to protect the laid gas production pipeline 6. It then enters the second-stage throttling valve 24 at the inlet of the heater 2. The temperature of the natural gas decreases further with the pressure. Then, it enters the heater coil 26. The heater coil 26 is immersed in high-temperature softened water that enters from the upper heater water inlet 20 and exits from the lower heater drain outlet 21. The natural gas flowing through the heater coil 26 is heated by a water bath. In order to further reduce the pressure of the natural gas to meet the external transmission pressure requirements, the natural gas enters the heater tertiary throttling valve 25. After the tertiary throttling, it enters the heater coil 26 again for secondary water bath heating. Finally, the natural gas enters the metering separator through the shut-off valve 27, is metered, and then enters the gas gathering trunk line.

[0005] However, in the later stages of gas field development, formation pressure decreases, and wellhead pressure decreases accordingly. At the same production level, with the wellhead oil temperature remaining constant, the throttling temperature drop becomes smaller, or even unnecessary, and the heating furnace is shut down. Because the throttling cooling effect is significantly reduced, the temperature of the medium transported in the pipeline gradually rises again. As the temperature increases, pipeline displacement occurs, leading to stress concentration, increasing pipeline inspection and maintenance costs, shortening service life, and even posing a risk of pipeline failure.

[0006] A utility model patent document with authorization announcement number CN210506241U and authorization announcement date of 2020 / 05 / 12 discloses a natural gas cooling device. The device includes a refrigeration unit and a heat exchanger, which are connected by a pipeline. Condensate in the pipeline circulates between the refrigeration unit and the heat exchanger. The inlet end of the heat exchanger is connected to the high-temperature natural gas end, and the outlet end is connected to the low-temperature natural gas end. In operation, the refrigeration unit cools the condensate, and the cooled condensate flows to the heat exchanger, where it further cools the high-temperature natural gas.

[0007] The device has a simple process and few limitations, but it requires the addition of a new refrigeration and cooling equipment to the existing gas collection station, resulting in a large production investment. Furthermore, the condensate will be lost during subsequent use, requiring inspection and replenishment, which leads to high energy consumption and poor economic efficiency. Summary of the Invention

[0008] The purpose of this invention is to provide a cooling device for natural gas gathering and transmission pipelines, which solves the problem that existing cooling technologies require separate refrigeration and cooling equipment, resulting in large initial investments and poor economic efficiency.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a natural gas gathering and transmission pipeline cooling device, comprising a buried pipe trench as standard at the wellhead and a heating furnace as standard on the transmission pipeline. The buried pipe trench is configured with a pipe trench water circulation system to form a cooling water pool, and the heating furnace is configured with a furnace body water circulation system to form a cooler. The pipe trench water circulation system includes a circulating water pool, and a circulating pipeline is provided between the circulating water pool and the cooling water pool. A circulating pump is provided on the circulating pipeline. The furnace body water circulation system includes a soft water pool as standard on the heating furnace, and a circulating pipeline is provided between the soft water pool and the furnace body of the heating furnace. A circulating pump as standard on the heating furnace is provided on the circulating pipeline.

[0010] Furthermore, the circulating water tank is a standard fire-fighting water tank for gas extraction stations.

[0011] Furthermore, the soft water tank that is standardly equipped with the heating furnace includes three interconnected cavities: an inlet tank, an intermediate tank, and a return tank. A first partition with an upper opening is provided between the inlet tank and the intermediate tank, and a second partition with a lower opening is provided between the intermediate tank and the return tank.

[0012] Furthermore, the soft water tank is provided in two parallel configurations to form a one-in-one-standby structure.

[0013] Furthermore, two circulating pumps are respectively installed in the circulating water tank and the soft water tank, and are connected in parallel at the bottom of the corresponding water tanks.

[0014] Furthermore, level monitors are installed at the top of the cooling water pool, the bottom of the circulating water pool, and the bottom of the softened water pool, and the level monitors are interlocked with the circulating pumps.

[0015] Furthermore, the circulation pipeline includes an outlet pipeline and a return pipeline, one end of the return pipeline is a diversion nozzle structure, and an exhaust fan is provided on one side of the diversion nozzle.

[0016] Furthermore, the outlet pipeline is equipped with a gate valve and a check valve connected in series.

[0017] Furthermore, in the trench water circulation system, one end of the outlet pipeline is connected to the cooling water pool, and the other end is connected to the circulation pump in the circulation pool. One end of the return pipeline is connected to the cooling water pool, and the other end of the branch nozzle is connected to the circulation pool, and is set at the top of the circulation pool diagonally opposite to the circulation pump.

[0018] Furthermore, the upper end of the heating furnace is provided with a heating furnace water inlet, and the lower end is provided with a heating furnace drain outlet. The heating furnace water inlet is connected to one end of the water outlet pipeline in the furnace water circulation system, and the other end of the water outlet pipeline is connected to the circulation pump in the soft water tank. The heating furnace drain outlet is connected to the return water pipeline, and the diversion nozzle at the other end of the return water pipeline is connected to the soft water tank and is set at the top of the soft water tank diagonally opposite to the circulation pump.

[0019] Beneficial Effects: The natural gas gathering and transmission pipeline cooling device of this invention is a pioneering invention. Compared with existing cooling technologies, the natural gas gathering and transmission pipeline cooling device of this invention has been redesigned for the buried trenches standardly equipped at the wellhead and the heating furnaces standardly equipped in the transmission pipeline. The buried trenches are equipped with a trench water circulation system to form a cooling water pool, and the heating furnaces are equipped with a furnace body water circulation system to form a cooler. Only waterproofing treatment of the existing buried trenches standardly equipped at the wellhead is required for its use. The heating furnaces standardly equipped in the transmission pipeline are existing devices and do not require modification. Each of these two devices is equipped with a water circulation system to cool the gas collection pipeline, resulting in lower investment costs and cost savings. The aforementioned trench water circulation system includes a circulating water tank, with a circulation pipeline connecting the circulating water tank and a cooling water tank, and a circulation pump installed on the circulation pipeline. The furnace body water circulation system includes a soft water tank standardly equipped with the heating furnace, with a circulation pipeline connecting the soft water tank and the furnace body, and a circulation pump standardly equipped with the heating furnace installed on the circulation pipeline. The circulation pump can circulate and transport the water in the tank, which can efficiently utilize the water in the tank without continuous water replenishment, thus reducing costs. Moreover, this device has a simple structure, is easy to construct, and has a good cooling effect using the circulating water system. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the existing gas production station process. Figure 2This is a schematic diagram of the device of the present invention; Figure 3 This is a schematic diagram of a soft water tank.

[0021] In the diagram: 1. Buried trench; 2. Heating furnace; 3. Circulating water tank; 4. Outlet water pipeline; 5. Return water pipeline; 6. Gas extraction pipeline; 7. Circulating pump; 8. Gate valve; 9. Check valve; 10. Inlet water tank; 11. Intermediate tank; 12. Return water tank; 13. First baffle; 14. Second baffle; 15. Opening; 16. Liquid level monitor; 17. Diversion nozzle; 18. Exhaust fan; 19. Thermometer; 20. Heating furnace water inlet; 21. Heating furnace drain outlet; 22. Gas extraction tree; 23. Primary throttling valve; 24. Secondary throttling valve; 25. Tertiary throttling valve; 26. Heating furnace coil; 27. Shut-off valve; 28. Ground surface; 29. ​​Soft water tank. Detailed Implementation

[0022] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0023] The natural gas gathering and transmission pipeline cooling device of the present invention utilizes existing buried pipe trenches and heating furnace devices, with the addition of a water circulation cooling system, to achieve the purpose of reducing the temperature of the gas gathering pipeline. It has low investment cost, simple process flow, easy operation and good cooling effect.

[0024] As a basic solution, such as Figure 2-3 As shown, the system includes a buried trench 1 (standard configuration for wellhead) and a heating furnace 2 (standard configuration for transmission pipeline). The existing buried trench 1 is waterproofed to facilitate the subsequent injection of circulating water to cool the gas production pipeline 6. The buried trench 1 is equipped with a trench water circulation system to form a cooling water pool that can cool the section of the gas production pipeline 6. The heating furnace 2 is equipped with a furnace body water circulation system to form a cooler. The circulating water in the water circulation system is used to perform a water bath cooling of the natural gas flowing through the heating furnace coil 26. The trench water circulation system includes a circulating water pool 3, with a circulation pipeline between the circulating water pool 3 and the cooling water pool, and a circulation pump 7 installed on the circulation pipeline. The furnace body water circulation system includes a soft water pool 29 (standard configuration for heating furnace 2), with a circulation pipeline between the soft water pool 29 and the furnace body of heating furnace 2, and a circulation pump 7 (standard configuration for heating furnace 2) installed on the circulation pipeline. The circulation pump 7 can continuously and stably promote the circulation of circulating water in the circulation system.

[0025] As a preferred embodiment, the circulating water tank 3 is a standard fire-fighting water tank in the gas production station. Using the existing fire-fighting water tank eliminates the need to build another tank, saving initial investment costs and time. In other embodiments, a separate tank can be built, which is more costly but does not affect the tank's performance.

[0026] As a preferred implementation method, such as Figure 3 As shown, the soft water tank 29 of the heating furnace 2 includes three interconnected cavities: an inlet tank 10, an intermediate tank 11, and a return tank 12. A first partition 13 with an upper opening 15 is provided between the inlet tank 10 and the intermediate tank 11, and a second partition 14 with a lower opening 15 is provided between the intermediate tank 11 and the return tank 12. This design can extend the flow path of the circulating water in the soft water tank 29, allowing the circulating water to be fully cooled before the next cycle. This can avoid the unsatisfactory cooling effect on the gas extraction pipeline 6 when the circulating water is not properly cooled.

[0027] As a preferred implementation method, such as Figure 2 As shown, two soft water tanks 29 are provided and connected in parallel to form a backup structure, which facilitates the alternating use of the two soft water tanks 29. A thermometer 19 for monitoring the circulating water temperature can be placed in the soft water tank 29. When the water temperature in one soft water tank 29 is too high or there are other problems such as insufficient water level, the other can be replaced in time. This avoids the problem of having to stop maintenance when one soft water tank 29 has a problem. Two circulation pumps 7 are provided in the circulating water tank 3 and the soft water tank 29 respectively and are connected in parallel at the bottom of the corresponding tanks. Similarly, this facilitates the alternation of the two. If one circulation pump 7 fails, the other can ensure the normal operation of the circulation system. And because it is placed at the bottom of the tank, even if the water level in the tank is low, it will not be lower than the circulation pump 7, which can ensure the normal operation of the water circulation system. In other embodiments, if a backup soft water tank 29 or circulation pump 7 is not provided, manual periodic inspection is required to avoid problems that cause the water circulation system to stop working. Although manual inspection has more uncertainties, it does not affect the use effect of a water circulation system device under normal conditions.

[0028] As a preferred implementation method, such as Figure 2 As shown, level monitors 16 are respectively installed at the top of the cooling water tank, the bottom of the circulating water tank 3, and the bottom of the soft water tank 29. The level monitors 16 and the circulating pump 7 can be interlocked through the control system. When the liquid level in the cooling water tank is higher than the set value, the circulating pump 7 stops supplying water to prevent the water in the cooling water tank from overflowing due to insufficient backflow. Conversely, when the liquid level is lower than the set value, the circulating pump 7 starts in time to replenish the water in the cooling water tank. The level monitors 16 at the bottom of the circulating water tank 3 and the soft water tank 29 work in the same way. When the liquid level is lower than the set value, the circulating pump 7 stops supplying water to prevent the circulating pump 7 from running dry. Conversely, when the liquid is replenished to a level higher than the set value, the circulating pump 7 starts in time to work. In other embodiments, a water level alarm device can be set. Although it cannot automatically interlock control the cooling system, it makes it easier for staff to discover problems and deal with them in time, and can also achieve the effect of monitoring the water circulation system.

[0029] As a preferred implementation method, such as Figure 2 As shown, the circulation pipeline includes an outlet pipeline 4 and a return pipeline 5. One end of the return pipeline 5 is a diversion nozzle 17 structure. An exhaust fan 18 is provided on one side of the diversion nozzle 17. The diversion nozzle 17 structure can increase the contact area between the water and air in the return pipeline 5, thereby allowing the circulating water returning to the pool to cool down as quickly as possible. The exhaust fan 18 can accelerate the cooling speed of the discharged water, further reducing the temperature of the circulating water to facilitate the cooling of the gas collection pipeline 6 in the next cycle. In other embodiments, the diameter of the outlet pipeline 4 can be increased, or the upper part of the circulating water pool can be shaded to avoid direct sunlight, which can also achieve the effect of reducing the temperature of the circulating water.

[0030] In a preferred embodiment, the water outlet pipeline 4 is equipped with a gate valve 8 and a check valve 9 connected in series. The gate valve 8 can control the switching of liquid flow in the water circulation system, and the check valve 9 can prevent liquid backflow in the water circulation system. In other embodiments, the gate valve 8 and the check valve 9 are not provided, so the operation of the water circulation system can only be controlled by switching the circulation pump 7 on and off, but this does not affect the use of the entire device.

[0031] As a preferred implementation method, such as Figure 2 As shown, in the water circulation system of the pipe trench, one end of the outlet pipe 4 is connected to the cooling water pool, and the other end is connected to the circulation pump 7 in the circulation pool 3. One end of the return water pipe 5 is connected to the cooling water pool, and the other end of the branch nozzle 17 is connected to the circulation pool 3 and is set at the top of the circulation pool 3 diagonally opposite to the circulation pump 7. This can extend the flow path of the water in the circulation system in the circulation pool 3, so as to facilitate sufficient cooling before the next circulation. In other embodiments, the section of the return water pipe 5 near the circulation pool 3 can be bent to extend the water flow path, thereby achieving the purpose of sufficient cooling of the circulating water.

[0032] As a preferred implementation method, such as Figure 2As shown, the upper end of the heating furnace 2 is provided with a heating furnace water inlet 20, and the lower end is provided with a heating furnace drain outlet 21. The heating furnace water inlet 20 is connected to one end of the water outlet pipeline 4 in the furnace water circulation system, and the other end of the water outlet pipeline 4 is connected to the circulation pump 7 in the soft water tank 29. The heating furnace drain outlet 21 is connected to the return water pipeline 5, and the diversion nozzle 17 at the other end of the return water pipeline 5 is connected to the soft water tank 29 and is set at the top of the soft water tank 29 diagonally opposite to the circulation pump 7. This arrangement forms a low inlet and high outlet for circulating water, which is exactly opposite to the high inlet and low outlet of the medium transported in the heating furnace coil 26, forming convection. This allows for sufficient heat exchange between the inside and outside of the heating furnace coil 26. In other embodiments, the connection positions of the water outlet pipeline 4 and the return water pipeline 5 are reversed. This will reduce the cooling effect on the heating furnace coil 26 in the heating furnace 2, but it can still achieve a cooling effect.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A cooling device for natural gas gathering and transmission pipelines, characterized in that, The system includes a buried pipe trench as standard at the wellhead and a heating furnace as standard on the transmission pipeline. The buried pipe trench is equipped with a pipe trench water circulation system to form a cooling water tank, and the heating furnace is equipped with a furnace body water circulation system to form a cooler. The pipe trench water circulation system includes a circulating water tank, and a circulating pipeline is provided between the circulating water tank and the cooling water tank. A circulating pump is installed on the circulating pipeline. The furnace body water circulation system includes a soft water tank as standard on the heating furnace, and a circulating pipeline is provided between the soft water tank and the furnace body of the heating furnace. A circulating pump as standard on the heating furnace is installed on the circulating pipeline.

2. The natural gas gathering and transmission pipeline cooling device according to claim 1, characterized in that, The circulating water tank is a standard fire-fighting water tank for gas extraction stations.

3. The natural gas gathering and transmission pipeline cooling device according to claim 1, characterized in that, The soft water tank that is standardly equipped with the heating furnace includes three interconnected cavities: an inlet tank, an intermediate tank, and a return tank. A first partition with an upper opening is provided between the inlet tank and the intermediate tank, and a second partition with a lower opening is provided between the intermediate tank and the return tank.

4. The natural gas gathering and transmission pipeline cooling device according to claim 1 or 3, characterized in that, The soft water tank is provided in two parallel configurations, forming a one-in-one-standby structure.

5. The natural gas gathering and transmission pipeline cooling device according to claim 1, characterized in that, Two circulating pumps are installed in parallel at the bottom of the corresponding water tanks, one in the circulating water tank and the other in the soft water tank.

6. The natural gas gathering and transmission pipeline cooling device according to claim 1, characterized in that, The top of the cooling water pool, the bottom of the circulating water pool and the softened water pool are respectively equipped with liquid level monitors, which are interlocked with the circulating pumps.

7. The natural gas gathering and transmission pipeline cooling device according to claim 1, characterized in that, The circulation pipeline includes an outlet pipeline and a return pipeline. One end of the return pipeline is a diversion nozzle structure, and an exhaust fan is provided on one side of the diversion nozzle.

8. The natural gas gathering and transmission pipeline cooling device according to claim 7, characterized in that, The outlet pipeline is equipped with a gate valve and a check valve connected in series.

9. The natural gas gathering and transmission pipeline cooling device according to claim 7, characterized in that, One end of the outlet pipeline in the trench water circulation system is connected to the cooling water pool, and the other end is connected to the circulation pump in the circulation pool. One end of the return pipeline is connected to the cooling water pool, and the other end of the branch nozzle is connected to the circulation pool and is set at the top of the circulation pool diagonally opposite to the circulation pump.

10. The natural gas gathering and transmission pipeline cooling device according to claim 1 or 7, characterized in that, The upper end of the heating furnace is provided with a heating furnace water inlet, and the lower end is provided with a heating furnace drain outlet. The heating furnace water inlet is connected to one end of the water outlet pipeline in the furnace water circulation system, and the other end of the water outlet pipeline is connected to the circulation pump in the soft water tank. The heating furnace drain outlet is connected to the return water pipeline, and the other end of the return water pipeline is connected to the soft water tank and is set at the top of the soft water tank diagonally opposite to the circulation pump.

Images