NOVELTY - The method involves providing reflux to a distillation column (162) by condensing a portion of the overhead vapor (164) from the distillation column in a condenser heat exchanger (154). A LNG stream (186) is formed from bottom liquid withdrawn from the distillation column. The refrigeration for the main heat exchanger and condenser heat exchanger is provided by a closed loop refrigeration system. The refrigerant circulated by the closed loop refrigeration system is passed through and warmed in the main heat exchanger and condenser heat exchanger.    USE - Method for liquefying natural gas feed stream and removing nitrogen.    ADVANTAGE - Since the apparatus is efficiently and easily operated, and the production of both high purity LNG product and high purity nitrogen streams are achieved even with natural gas feed compositions of relatively low nitrogen concentration. The nitrogen-rich vapor product of significantly higher purity is obtained easily by separating partially liquefied nitrogen-enriched natural gas stream in the distillation column so that compact and cost efficient process is achieved.    DETAILED DESCRIPTION - The method involves passing natural gas feed stream through main heat exchanger to cool the natural gas stream (100) and liquefy all or portion of stream for producing first LNG stream (112). The first LNG stream is withdrawn from the main heat exchanger. The liquefied or partially liquefied natural gas stream is expanded and partially vaporized. The stream is introduced into a distillation column in which the stream is separated into vapor and liquid phases. The liquefied or partially liquefied natural gas stream is the first LNG stream, or is partially liquefied nitrogen-enriched natural gas stream formed from separating nitrogen-enriched natural gas stream from the first LNG stream or from the natural gas feed stream and partially liquefying stream in the main heat exchanger. A nitrogen-rich vapor product (170) is formed from overhead vapor withdrawn from the distillation column. The warmed refrigerant that is obtained after refrigeration is provided to the main heat exchanger and to the condenser heat exchanger. The compressed refrigerant is passed through and cooled in the main heat exchanger to form cooled compressed refrigerant that is withdrawn from the main heat exchanger. The cooled compressed refrigerant is divided with portion of the refrigerant which is expanded and returned directly to the main heat exchanger to pass through and warmed in the main heat exchanger, and with another portion of the refrigerant which is expanded and sent to the condenser heat exchanger to pass through and warmed in the condenser heat exchanger. The refrigerant circulated by the closed loop refrigeration system is a mixed refrigerant. The warmed mixed refrigerant that is obtained after refrigeration is provided to the main heat exchanger and the condenser heat exchanger, and is compressed and cooled in the main heat exchanger to provide several liquefied or partially liquefied cold refrigerant streams of different compositions. The cold refrigerant stream with the highest concentration of lighter components obtained from the cold end of the main heat exchanger is divided and expanded to provide stream of refrigerant that is warmed in the condenser heat exchanger and stream of refrigerant that is returned to the cold end of the main heat exchanger to be warmed. An INDEPENDENT CLAIM is included for an apparatus for liquefying natural gas feed stream and removing nitrogen, has main heat exchanger that is provided with cooling passage for receiving natural gas feed stream and passing the natural gas feed stream through the heat exchanger to cool the stream, and liquefy the stream to produce first LNG stream. The expansion device and distillation column is provided in fluid flow communication with the main heat exchanger for receiving, expanding and partially vaporizing liquefied or partially liquefied natural gas stream and separating stream in the distillation column into vapor and liquid phases. The liquefied or partially liquefied natural gas stream is the first LNG stream, or is partially liquefied nitrogen-enriched natural gas stream formed from separating nitrogen-enriched natural gas stream from the first LNG stream or from the natural gas feed stream and partially liquefying stream in the main heat exchanger. The condenser heat exchanger is arranged for providing reflux to the distillation column by condensing portion of the overhead vapor obtained from the distillation column. The closed loop refrigeration system is arranged for providing refrigeration to the main heat exchanger and condenser heat exchanger. The refrigerant circulated by the closed loop refrigeration system is warmed in the main heat exchanger and condenser heat exchanger.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the apparatus for liquefying natural gas feed stream and removing nitrogen.    Natural gas stream (100)    LNG streams (112,186)    Condenser heat exchanger (154)    Distillation column (162)    Overhead vapor (164)    Nitrogen-rich vapor product (170)