FIELD: technological processes.
SUBSTANCE: invention relates to a method of producing liquefied hydrocarbon gas with low nitrogen content. Method of producing liquefied hydrocarbon-rich fraction (product fraction) with nitrogen content ≤1 mol% is performed as follows. Hydrocarbon-rich fraction is liquefied and overcooled with the help of a refrigerating circuit, and then subject to rectification removal of nitrogen. Method is characterized by that: a) liquefied and supercooled fraction (2) enriched with hydrocarbon is expanded (V1) and nitrogen is distilled into column (T1), b) product fraction (4) is removed from its lower part, c) nitrogen-enriched fraction (5) is removed from its upper part, compressed (C1), liquefied and overcooled (E1-E3) by means of refrigerating circuit (K), expanded (V2) and supplied to high-pressure nitrogen (T2) column, d) part of stream of nitrogen-enriched fraction from high-pressure nitrogen column (T2), which was cooled by refrigerating circuit (K), is supplied as reboiler current (9), e) nitrogen-depleted fraction (11) is removed from its lower part and nitrogen is distilled into column (T1), f) wherein two columns (T1, T2) are in thermal contact through heat exchanger (E4), which serves as reboiler for nitrogen distillation column (T1) and as light fraction condenser for high-pressure nitrogen column (T2), wherein, g) between two columns (T1, T2) there is a reflux collector (D1), from which is removed gaseous and / or liquid nitrogen stream of high purity.
EFFECT: method enables to avoid the nitrogen / hydrocarbon mixture recovery, the method is characterized by low operating costs, the enriched hydrocarbon fraction has nitrogen content equal to or less than 1 mol%, the other product is a highly concentrated nitrogen fraction with nitrogen content of at least 98 mol%.
9 cl, 1 dwg
