recovery of natural gas liquids (amelioru00c9e group) by means of refrigeration and reflux from facilities for liquefied natural gas (lng)

摘要

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.