Abstract: 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.

Abstract: A natural gas compression heating process for regulating the operating temperature of the natural gas flowing through long pipelines in continuous permafrost and discontinuous permafrost regions. The heat obtained through compression of the natural gas, instead of actually heating as performed conventionally, is utilized to raise the temperature of the natural gas to only the desired operating temperature. Consequently, the locations of the natural gas compression heating process and compression stations along the pipeline in a permafrost region are determined by the flowing temperature profile of the pipeline instead of the conventional standard compression cost versus pipeline diameter analysis.