Natural gas buried pipe anti-frost heaving system combining solar energy and geothermal energy

Abstract

The invention relates to a natural gas buried pipe anti-frost heaving system combining solar energy and geothermal energy. The natural gas buried pipe anti-frost heaving system comprises a pipe heat exchange device, a solar heat collecting device and a ground source heat pump. The pipe heat exchange device is composed of a natural gas buried pipe and a heat exchange medium channel used for exchanging heat with the natural gas buried pipe. The two ends of the heat exchange medium channel are connected with a main heat exchange medium pipeline, and a first branch pipe and a second branch pipe are connected to the main heat exchange medium pipeline in parallel. The first branch pipe is provided with the solar heat collecting device, and the heat exchange branch pipe is provided with the ground source heat pump. Compared with the prior art, the solar heat collecting device and the ground source heat pump are reasonably combined, and the win-win situation that the natural gas buried pipe is effectively protected against frost heaving, renewable energy sources are fully utilized, and high-grade electric energy consumption is reduced can be achieved; moreover, the environmental benefits of the natural gas buried pipe anti-frost heaving system are remarkable, long-distance heat conveying is not needed, and the basic national policy of saving energy and reducing emission of China is met; and the natural gas buried pipe anti-frost heaving system has good energy saving space and higher practical value.

Description

Technical field [0001] The invention belongs to the technical field of natural gas pipelines, and specifically relates to a frost heave prevention system for buried natural gas pipelines that combines solar energy and geothermal energy. Background technique [0002] Natural gas is a high-efficiency and clean energy, and its proportion in the energy structure is increasing. Due to the unbalanced distribution of natural gas resources and markets, the transportation of natural gas has become an important link in the development of the natural gas industry. At present, large-diameter, high-pressure, and long-distance natural gas pipelines are the general development trend of the world. In the process of long-distance transportation, natural gas needs higher pressure to provide transportation power (for example, the second West-East Gas Pipeline is generally 8-12 MPa), and when natural gas reaches the distribution station, it is necessary to meet the pressure of downstream users ( G...

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Problems solved by technology

[0004] Among the methods currently available to solve the problem of natural gas frost heave, the most common passive methods are soil replacement, waterproofing or drainage. These methods reduce the possibility of frost heave by reducing the moisture in the soil, but these methods Can not completely solve the problem of frost heave

There is also the pipe trench method, which is to build waterproof cement pipes around the natural gas pipelines, but this method does not exchange heat for the natural gas pipelines, and the cooling capacity is not taken away, so the natural gas pipelines in contact with the soil outside the distribution station It will still absorb the heat of the soil, and it will still cause pipeline frost heave; the most commonly used active method is to install an electric heater before the pressure regulating valve of the natural gas pipeline, but because the minimum amount in the heating process is uncertain, the fixed heating method is adopted Cause a lot of primary energy waste; In addition, there is also a method of using heat pipe components to transfer the heat of the underground constant temperature layer to the location of frost heaving. This method does not consume high-grade electric energy and heats the soil near the natural gas pipeline relatively uniformly. However, during the implementation of this method, Due to the large thermal resistance of the soil layer and the slow heat exchange with the heat pipe, the natural gas pipeline will still cause frost heaving due to the lack of timely geothermal compensation

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