Patent ID: 8312738

Claim:
A method for the separation of a feedstream in a distillation tower with a controlled freezing zone comprising: feeding a mixture of at least one acid gas and methane to a lower distillation zone comprising a dividing wall, which extends substantially vertically through the lower distillation zone to divide the lower distillation zone into a pre-fractionation zone and a product zone; producing in the lower distillation zone an enriched acid gas liquid bottoms stream and a freezing zone vapor feedstream at a temperature and pressure at which substantially no carbon dioxide solids are formed; contacting in the controlled freezing zone the freezing zone vapor feedstream with at least one freezing zone liquid feedstream containing methane at a temperature and pressure wherein both solids containing carbon dioxide and a methane-enriched vapor stream are formed; removing in an upper distillation section an acid gas component from the methane-enriched vapor stream; separating the enriched acid gas liquid bottoms stream into a liquid acid gas stream and a hydrocarbon stream; recovering from a draw tray of the lower distillation zone a portion of the hydrocarbon stream and concentrating the portion of the hydrocarbon stream using an adsorption or membrane system to produce an enriched hydrocarbon product stream and an enriched sour gas stream; and reintroducing the enriched sour gas stream into the lower distillation section.