METHOD AND SYSTEM FOR REMOVAL OF NITROGEN FROM LNG Russian patent published in 2019 - IPC F25J3/00 

FIELD: chemistry.

SUBSTANCE: disclosed are methods and systems for removal of nitrogen from hydrocarbon-containing gas. Recovery of methane from hydrocarbon-containing gas is carried out using a cooling system. Crude stream containing hydrocarbon-containing gas is cooled and partially condensed through indirect heat exchange with flow of one mixed refrigerant in a closed-loop refrigerating cycle. At least a portion of the cooled fed stream in the distillation column is fractionated at pressure in range of 1–8 MPa to thereby form a lower stream with low nitrogen content and an upper stream with high nitrogen content. Portion of the bottom stream with a reduced content of nitrogen is cooled through indirect heat exchange with the flow of one mixed refrigerant in a closed-loop refrigeration cycle to thereby form an LNG enriched stream.

EFFECT: technical result is reduction of nitrogen concentration in hydrocarbon-containing gas.

49 cl, 1 dwg, 1 tbl