Abstract A method for separating heavier hydrocarbon components of a normally gaseous mixture, e.g., natural gas, from a relatively more volatile component, e.g., methane is accomplished by cooling the gas under pressure to effect condensation, adding to the cooled feed a small amount of heavier hydrocarbons, flash separating the mixture, e.g., in a first flash drum, adding to the separated gas phase a small amount of heavier hydrocarbons, and again flash separating the mixture, e.g., in an auxiliary flash drum. Desirably, the heavier hydrocarbons added to the feed gas before the first separation may be the liquid recovered from the auxiliary flash separation. The liquid recovered from the first and auxiliary flash separations is desirably chilled and subjected to a second flash separation at lower pressure to volatilize most of the lighter component, e.g., methane, recovered in the liquid with the heavier components. The liquid resulting from the second flash separation may then be fractionated into such components as ethane, propane, butane and gasoline. The methane-containing gasiform phases from the auxiliary and second flash separations are desirably combined with the fractionated ethane and supplied as the treated natural gas product.
The process of claim 1, wherein said second condensate phase is said first mixture of said higher molecular weight components.
Claim 2
Dependent Claim
137 words
A process for the separation of methane from methane containing natural gas having higher molecular weight components than methane which comprises the steps of: a. cooling said natural gas to a temperature between about -100* and about -40* F. at a pressure between about 500 and about 1,100 p.s.i.g.; b. adding to said natural gas a first mixture of said higher molecular weight components; c. separating said natural gas mixture into a gasiform phase and a condensate phase; d. adding to said gasiform phase a second mixture of said higher molecular weight components to form a final combined mixture; and e. separating said final combined mixture at between about -100* and -40* F. and at between about 500 and 1,100 p.s.i.g. into a second gasiform phase and a second condensate phase; f. recovering a methane containing product.