| 摘要 |
<p>CRYOGENIC RECOVERY OF LPG FROM NATURAL GAS In accordance with the present invention a natural gas stream predominating in methane and containing significant amounts of C2, C3, C4 and C5 and higher molecular weight hydrocarbons is cooled in a plurality of cooling stages to a temperature sufficient to produce at least one liquid phase portion predominating in C2, C3, C4 and C5 and higher molecular weight hydrocarbons, the at least one liquid phase portion predominating in C2, C3, C4 and C5 and higher molecular weight hydrocarbons is separated from the main gas stream during the course of the cooling, the thus separated liquid phase portion or portions predominating in C2, C3, C4 and C5 and higher molecular weight hydrocarbons is further separated into a vapor phase portion predominating in C2, C3, and C4 hydrocarbons and at least one liquid phase portion predominating in C5 and higher molecular weight hydrocarbons, at least one second separation step, at least one portion of the at least one vapor phase portion predominating in C2, C3 and C4, hydrocarbons is recovered as at least one product of the process and at least one portion of the remaining portion of the at least one phase portion predominating in C2, C3 and C4 hydrocarbons is recycled to and recombined with the main gas stream as a liquid phase. In another aspect, heat capacity is recovered from at least a part of the C2, C3 and C4 hydrocarbons and recycled by utilizing the same for the heating of portions of the fluids in the second separation step and/or the feed to the second separation step.</p> |
