LIQUEFIED NATURAL GAS PROCESSING

摘要

A process and apparatus for the recovery of ethane, ethylene, propane, propylene, and heavier hydrocarbons from a liquefied natural gas (LNG) stream is disclosed. The LNG feed stream is directed in heat exchanger relation with a warmer distillation stream rising from the fractionation stages of a distillation column, whereby the LNG feed stream is partially heated and the distillation stream is partially condensed. The partially condensed distillation stream is separated to provide volatile residue gas and a reflux stream, whereupon the reflux stream is supplied to the column at a top column feed position. A portion of the partially heated LNG feed stream is supplied to the column at an upper mid-column feed point, and the remaining portion is heated further to partially or totally vaporize it and thereafter supplied to the column at a lower mid-column feed position. The quantities and temperatures of the feeds to the column are effective to maintain the column overhead temperature at a temperature whereby the major portion of the desired components is recovered in the bottom liquid product from the column.