The invention discloses a method for
recovery of ethane from
carbon dioxide-containing
natural gas. On the basis of expander
refrigeration-partial
dry gas circulation process, the absorption principleof
propane and
butane based liquid
hydrocarbon to CO2 is applied in a low temperature
separation process, part of feed gas and part of the
liquid phase in a low temperature separator are mixed and undercooled to enter the middle-upper part of a demethanation
tower, part of outward transportation gas flows back and is mixed with part of the
liquid phase in the low temperature separator, then the mixture enters the top of the demethanation
tower after undercooling, thus increasing the content of
propane and
butane based liquid
hydrocarbon at the middle-upper part of the demethanation
tower, lowering the concentration of CO2 in a demethanation tower tray
gas phase, and strengthening the ability of an ethane
recovery device in inhibiting CO2
solid formation. At the same time, the method increases the
cooling capacity at the middle-upper part of the demethanation tower, and enhances the ethane
recovery rate. The method strengthens the ability of the demethanation tower in inhibiting CO2
solid formation, also increases the ethane recovery rate, effectively improves the
economic benefits of the ethane recovery device operation, and is suitable for ethane recovery devices with a feed gasCO2 content greater than 0.5%.