| abstract |
The present invention relates to a process for liquefying a pressurized gas stream (10). The essence is that (a) a gas stream (10) having a starting pressure of greater than about 3103 kPa is provided; (b) the gas stream (10) is expanded to a pressure lower than the initial pressure, thereby producing a vapor phase and a liquid phase product having a pressure of about -112 ° C and a fluid phase that is retained in the liquid phase or below; (c) separating the vapor phase and the liquid phase product; and (d) introducing the liquid phase product into a storage unit (90) and storing at a temperature of about -112 ° C. Another aspect of the method of the invention is (a) separating the gas stream (10) into a first steam phase current and a first fluid phase stream; (b) feeding the first fluid phase to a methane separation column; (c) compressing and cooling the first vapor phase stream to form a vapor phase and a liquid phase; (d) separating the vapor phase and the liquid phase obtained in step (c) thereby generating a second vapor phase stream and a second fluid phase stream; (e) expanding at least a portion of the second vapor phase stream to a lower pressure, thereby further cooling; (f) feeding the second liquid phase stream and the expanded second-phase stream to the methane separation column; (g) generating a third vapor phase stream predominantly of methane from the upper region of the amethane separating column, which is then guided and heated in a heat exchanger; (h) discharging a third liquid phase stream from the methane separation column, which is then fed into a fractionation system comprising at least one fractionation column, wherever a steam vapor stream is produced; (i) combining the heated third vapor phase stream obtained in step (g) with the vapor phase distillation stream obtained in step (h) and then compressing the combined stream; (j) cooling the compressed, combined stream, (k) splitting the cooled and compressed stream obtained in step (j) into a first cooled current and a second cooled stream, the first cooled current being passed through the heat exchanger (g), thereby further cooling the first cooled current ; (l) expanding the first cooled stream to create a vapor phase and a liquid phase; (m) separating the vapor phase and the liquid phase in step (1) from a phase separator, thereby producing a pressure-free liquefied natural gas having a temperature of about -112 ° C and a pressure in the liquid phase or below; (n) expanding said second cooled stream (k) to a lower pressure, thereby further cooling and introducing a vapor phase and a liquid phase; (o) separating the vapor phase and the liquid phase mixture formed in step (n); and (p) is transferred to the phase separator of the liquid phase phase (m) obtained in step (o). Atalálmá |