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US 5,659,109 AGranted
Method for removing mercaptans from LNG
AssigneeThe M. W. Kellogg Company
InventorsFelix J. Fernandez de la Vega, Charles A. Durr
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Abstract
A process for liquefying natural gas containing mercaptans. Mercaptans are concentrated into a distillate stream by distilling the feed gas stream without specific pretreatment for mercaptans removal. Thus, the mercaptans removal equipment is much smaller since mercaptans treatment can take place at a point in the process where the flowrate is much lower. A portion of the treated distillate stream can be reinjected to the upstream distilling stage to facilitate mercaptan absorption.
Claims20
A method for separating mercaptans from a natural gas feed stream to be liquefied, comprising the steps of:
- (a) introducing the feed stream to a refluxed scrub column to form an overhead methane stream and a liquid bottoms stream rich in ethane and heavier hydrocarbons;
- (b) fractionating the bottoms stream from step (a) to form a natural gas liquids stream comprising pentane and heavier hydrocarbons, and one or more overhead streams comprising primarily ethane, propane and butane;
- (c) removing mercaptans from at least one of the overhead streams from step (b) to form a mercaptan-lean stream;
- (d) partially condensing and separating the overhead stream from step (a) to form vapor and liquid streams;
- (e) recycling at least a portion of the liquid stream from step (d) as at least a portion of the reflux to the scrub column in step (a);
- (f) cooling the vapor stream from step (d) to form a liquefied natural gas stream.
3 more elements
Dependencies are inferred from the claim text.