| 摘要 |
A process for liquefying methane-rich gases comprises providing a stream of feed methane-rich gas 1 at a pressure of from 40 to 120 bar and containing higher hydrocarbons; providing a stream of methane-rich recycle gas 3 at a pressure of from 40 to 120 bar; mixing the feed gas with a first part 4 of the recycle gas; passing the resulting mixture 5 to a gas expander C, the expander outlet having a pressure of between 3 bar and 50 bar, so as to form a mixture of vapour and a condensed liquid 7 containing higher hydrocarbons; separating E the expander outlet stream into a liquid stream 9 and a vapour stream 10; reheating F and compressing G said vapour stream to a pressure of from 40 to 120 bar to form a first constituent of the above-said recycle gas; cooling F a second part 13 of the said recycle gas to a temperature higher than the outlet temperature of the said expander; passing said cooled second part of the recycle gas into a liquefaction unit N to form liquefied methane 17, 21and a second vapour stream 23; reheating F and compressing G said second vapour stream to a pressure of from 40 to 120 bar to form a second constituent of the above-said recycle gas. |
