Patent ID: 6237365
Filing Date: 2001-05-29
Classification: F25J,Y10S

Abstract:
An apparatus for cryogenically separating an inlet hydrocarbon gas stream comprising at least methane and ethane into a residue gas stream comprising a major portion of the methane and a heavier hydrocarbon fraction comprising principally ethane and other heavier hydrocarbons, the apparatus comprising:(1) a main inlet for the hydrocarbon mixture;(2) a main stream connected to the main inlet and including a first separator for separating liquid and vapour phases, the first separator having a liquid phase outlet and a vapour phase outlet;(3) a liquid phase stream connected to the liquid phase outlet and a vapour phase stream connected to the vapour phase outlet;(4) a branch stream connected to the main inlet;(5) a fractionation column including first, second and third inlets, the first inlet being connected to the liquid phase stream, the second inlet being connected to the vapour phase stream and the third inlet being connected to the branch stream, whereby the flow through the third inlet has substantially the same composition as the inlet gas, the second inlet being provided above the first inlet and the third inlet being provided above the second inlet;(6) a first outlet means located at the bottom of the fractionation column for the heavier hydrocarbon fraction and a second outlet means at the top of the fractionation column for the residue stream;(7) an outlet conduit connected to the second outlet means;(8) first means for cooling the branch stream, including a first heat exchanger means provided between the outlet conduit and the branch stream for heat exchange therebetween, for cooling the incoming hydrocarbon gas branch stream and heating the residue gas stream in the outlet conduit; and(9) second means for expanding and cooling the main stream.