Patent ID: 8997519
Filing Date: 2015-04-07
Classification: F25J

Abstract:
1. A method for the cryogenic separation of a methane-rich feed flow also comprising carbon dioxide and a second impurity selected from the group consisting of nitrogen, oxygen, and a combination thereof, said method comprising the steps of: i) sending the methane-rich feed flow to an adsorption purification unit to produce a carbon dioxide-lean flow having less carbon dioxide relative to the methane-rich feed flow; ii) cooling at least part of the carbon dioxide-lean flow to produce a cooled flow; iii) sending at least part of the cooled flow to a distillation column; iv) withdrawing a methane-rich product flow from the distillation column, the methane-rich product flow being richer in methane relative to the methane-rich feed flow; v) withdrawing a flow rich in the second impurity from the distillation column, the flow rich in the second impurity being richer in the second impurity relative to the methane-rich feed flow, vi) vaporizing at least part of the methane-rich product flow; vii) regenerating the adsorption purification unit using a regeneration fluid comprising at least part of the vaporized methane-rich product flow, such that a second product stream comp sing methane and carbon dioxide is produced; viii) monitoring the carbon dioxide content of the second product stream; and ix) maintaining the carbon dioxide content of the second product stream within a given threshold.