摘要 |
Ethane is separated from a carbon dioxide-containing feed gas in a demethanizer that receives a rich subcooled reflux stream at very low temperature. Freezing of carbon dioxide is prevented by feeding a temperature-controlled vapor portion of the feed gas to the column, wherein the temperature of the vapor portion is adjusted by routing a portion of the expander discharge through a heat exchanger in response to the tray temperature in the demethanizer. Thus, high separation efficiency is achieved at reduced, or even eliminated carbon dioxide freezing.
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