초록 ▼

The present invention is directed to methods and apparatus for improving the recovery of the relatively less volatile components from a methane-rich gas feed under pressure to produce an NGL product while, at the same time, separately recovering the relatively more volatile components which are liqu

The present invention is directed to methods and apparatus for improving the recovery of the relatively less volatile components from a methane-rich gas feed under pressure to produce an NGL product while, at the same time, separately recovering the relatively more volatile components which are liquified to produce an LNG product. The methods of the present invention improve separation and efficiency within the NGL recovery column while maintaining column pressure to achieve efficient and economical utilization of the available mechanical refrigeration. The methods of the present invention are particularly useful for removing cyclohexane, benzene and other hazardous, heavy hydrocarbons from a gas feed. The benefits of the present invention are achieved by the introduction to the NGL recovery column of an enhanced liquid reflux lean on the NGL components. Further advantages can be achieved by thermally linking a side reboiler for the NGL recovery column with the overhead condenser for the NGL purifying column. Using the methods of the present invention, recoveries of propane and heavier components in excess of 95% are readily achievable.

대표청구항 ▼

1. A process for recovering the relatively less volatile components from a methane-rich gas feed under pressure to produce an NGL product while rejecting the relatively more volatile components which are subsequently liquified to produce LNG, comprising the steps of:cooling at least a portion of a g

1. A process for recovering the relatively less volatile components from a methane-rich gas feed under pressure to produce an NGL product while rejecting the relatively more volatile components which are subsequently liquified to produce LNG, comprising the steps of:cooling at least a portion of a gas feed in one or more heat exchangers by means of a mechanical refrigeration cycle; introducing said gas feed into an NGL recovery column at one or more feed stages for separation into a first gas stream primarily comprising relatively more volatile components and a first liquid stream primarily comprising relatively less volatile components; introducing said first liquid stream into an NGL purifying column at one or more feed stages to produce an NGL product stream comprising desirable less volatile components from the bottom and a second gas stream comprising more volatile components from the overhead of said NGL purifying column; cooling said second gas stream and thereafter introducing said cooled, second gas stream to the top portion of said NGL recovery column as an overhead reflux to enhance recovery of desirable less volatile components; and liquefying said first gas stream to produce a pressurized LNG stream, wherein at least one mechanical refrigeration cycle is used in the cooling of said second gas stream and in the liquefying of said first gas stream.