Abstract: A process is disclosed for conveying gas stream rich in methane, such as natural gas. In the first step of the process, gas is supplied to a pipeline at an entry pressure that is substantially higher than the output pressure of the pipeline. The drop in pressure in the pipeline causes a lowering of the gas temperature, preferably to a temperature below about −29° C. (−20° F.). The entry pressure of the gas to the pipeline is controlled to achieve a predetermined output pressure of the gas from the pipeline. Output gas from the pipeline is then liquefied to produce liquefied gas having a temperature above about −112° C. (−170° F.) and a pressure sufficient for the liquid to be at or below its bubble point temperature. The pressurized liquefied gas is then further transported in a suitable container.

Abstract: A process is disclosed for reliquefying boil-off gas produced by pressurized liquid natural gas. In this process, refrigeration duty is provided to a heat exchanger by means of a refrigeration cycle. Pressurized natural gas is cooled by the heat exchanger and then expanded to a lower pressure to produce a liquid stream that is passed to a first phase separator. A boil-off vapor is passed through the heat exchanger and it is then compressed and cooled before being recycled back through the heat exchanger. The compressed, cooled boil-off gas is then expanded and passed to a second phase separator. A vapor stream produced by the second separator is removed from the process. A liquid stream produced by the second phase separator is passed to the first phase separator to produce a pressurized liquid having a temperature above about −112° C. and a pressure sufficient for the liquid to be at or below its bubble point.