| 摘要 |
System and method for transporting oil by pipe line under or over frozen ground, e.g., permanently frozen terrain, without melting or softening the ground by heat transfer from the oil, by passing oil through a pipe line supported by such frozen ground or terrain, placing a second pipe line for carrying a fluid refrigerant, particularly liquid natural gas, along and closely adjacent to the oil pipe line but spaced therefrom, the second pipe line also being supported by the frozen ground, and being disposed adjacent to the frozen ground, providing insulation between the oil and refrigerant, e.g., liquid natural gas, pipe lines, as by placing the oil pipe line in an excavation in the ground and positioning the liquid natural gas pipe line in such excavation below and parallel to the oil pipe line, with gravel, for example, filling the spaces in the excavation and between the two pipe lines, passing a liquid refrigerant such as liquid natural gas through the second pipe line at a temperature substantially below the temperature of the adjacent frozen ground, thereby maintaining the ground around the pipe lines frozen without cooling the oil in the oil pipe line down to a temperature which substantially retards flow of the oil in the oil pipe line. As a feature of the invention, a minor portion of the liquid natural gas at each pumping station can be used for operating both the oil pump or pumps and liquid natural gas pump or pumps at the respective stations. The result is that the ground supporting or surrounding the oil pipe line remains in permanently frozen condition to firmly support such pipe line at all times, and at the same time liquid natural gas can be transported to market and a portion thereof employed to operate the pumping stations.
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