METHOD FOR LIQUEFYING A STREAM RICH IN HYDROCARBONS

摘要

A method for liquefying a stream rich in hydrocarbons, in particular, a natural gas stream is disclosed, wherein the liquefying of the stream rich in hydrocarbons is carried out in a cascade comprising three refrigeration circuits and the first refrigeration circuit carries out the precooling, the second refrigerant circuit carries out the liquefying and the third refrigerant circuit carries out the supercooling of the stream rich in hydrocarbons. According to the invention, the refrigerant in the refrigerant circuit for the precooling (E1) of the stream rich in hydrocarbons contains (a - a'') C3H8, C3H6, C2H6 or C2H4 in a concentration fo at least 95 Vol. % and the temperature difference between the boiling point and the dew point of the refrigerant is less than 5 °C.