METHOD FOR REMOVAL OF VOLATILE COMPONENTS FROM NATURAL GAS Russian patent published in 2004 - IPC

FIELD: removal at least of one component possessing a high volatility, such as nitrogen, from natural gas under pressure for production of liquefied natural gas under pressure, which has a low content of nitrogen and a temperature above approx. - 112C (-170F). SUBSTANCE: the source natural gas containing nitrogen is expanded under pressure and fed to a fractionating rectifying column. A flow of primary vapor is formed in the fractionating rectifying column, which has a high content of nitrogen, and a flow of primary liquid. The vapor flow is cooled down for formation of the vapor phase and liquid phase. After that the vapor and liquid phases are subjected to phase separation for formation of the flow of secondary vapor and flow of the secondary liquid. The flow of the secondary liquid is returned to the fractionating rectifying column as phlegm. The flow of the secondary vapor is preferably used for cooling of the delivered flow of the source raw material. The flow of the primary liquid is discharge from the plant for fractionation as a flow of product having a low content of nitrogen. EFFECT: provided production of a liquid product under pressure with a low content nitrogen with the aid of only one rectifying column. 9 cl, 1 dwg, 2 tbl, 1 ex