| 摘要 |
An apparatus and process for cooling gas flow in a pressurized pipeline, comprises the installation of one or more Joule-Thomson expansion valves along the length of the pipeline. The valve permit precise control of the temperature of the gas in the line, and accordingly the line itself, for passage through continuous or discontinuous areas of permafrost. The present invention allows precise control of the temperature of such a gas pipeline at predetermined points, to operate either in a warm mode (above the freezing point of water) or cold mode (below the freezing point of water). It is important that the temperature characteristics of the pipeline closely match those of the adjacent terrain or soil, to preclude settling of a warm pipe by melting adjacent permafrost soil, and to preclude frost heaves caused by ice buildup around a cold pipe in thawed ground. The present invention provides for the installation of Joule-Thomson expansion valves at predetermined points where precise control of the temperature from warm to cold mode is critical. The valves may be installed in series with the line, or in parallel with isolation shutoff valves required at various points in the line.
|
