Ethane extraction process for a hydrocarbon gas stream
First Claim
1. A process for recovering ethane from a hydrocarbon gas stream having methane, ethane and propane comprising:
- providing the hydrocarbon gas stream;
cooling the hydrocarbon gas stream by refrigeration to form a cooled hydrocarbon gas stream;
separating the cooled hydrocarbon gas stream into a methane-rich stream and an ethane/propane-rich stream, said methane-rich stream having a first pressure and a first temperature;
expanding said methane-rich stream from said first pressure to a second pressure to lower the temperature of said methane-rich stream from said first temperature to a second temperature to provide a cooling source for said refrigeration, wherein said second pressure is lower than said first pressure and further wherein said second temperature is lower than said first temperature;
separating said ethane/propane-rich stream into an ethane-rich stream and a propane-rich stream; and
recovering said ethane-rich stream.
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Accused Products
Abstract
A process for ethane extraction from a gas stream based on turboexpansion and fractionation with no mechanical refrigeration is provided. The feed gas is sweetened and dehydrated by a conventional amine process and by a molecular sieve unit, to remove carbon dioxide and water. After this pretreatment, the feed gas undergoes to a series of cooling steps through a cryogenic brazed aluminum heat exchanger and fed to a demethanizer column. A stream rich in methane is recovered from the top of this column and fed to a centrifugal compressor and subsequently routed to a booster/turboexpander. The temperature of the methane gas is greatly reduced by the expansion allowing the cooled methane stream to be a cooling source for cryogenic heat exchanger. Feed for a de-ethanizer column comes from the bottom liquids of the de-methanizer column. Ethane is recovered overhead at the de-ethanizer column.
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Citations
15 Claims
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1. A process for recovering ethane from a hydrocarbon gas stream having methane, ethane and propane comprising:
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providing the hydrocarbon gas stream;
cooling the hydrocarbon gas stream by refrigeration to form a cooled hydrocarbon gas stream;
separating the cooled hydrocarbon gas stream into a methane-rich stream and an ethane/propane-rich stream, said methane-rich stream having a first pressure and a first temperature;
expanding said methane-rich stream from said first pressure to a second pressure to lower the temperature of said methane-rich stream from said first temperature to a second temperature to provide a cooling source for said refrigeration, wherein said second pressure is lower than said first pressure and further wherein said second temperature is lower than said first temperature;
separating said ethane/propane-rich stream into an ethane-rich stream and a propane-rich stream; and
recovering said ethane-rich stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15)
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12. A process for recovering ethane from a methane, ethane and propane containing gas stream comprising:
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providing the hydrocarbon gas stream;
cooling the hydrocarbon gas stream in a cryogenic heat exchanger to form a cooled hydrocarbon gas stream;
distilling the cooled hydrocarbon gas stream in a demethanizer column to form a methane-rich stream and an ethane/propane-rich stream;
compressing said methane-rich stream to form a compressed methane-rich stream;
cooling said compressed methane-rich stream to form a compressed methane-rich stream;
turboexpanding said compressed methane-rich stream to a lower pressure to provide a cooling source for said cryogenic heat exchanger;
distilling said ethane/propane-rich stream in a de-ethanizer column to form an ethane-rich stream and a propane-rich stream; and
recovering said ethane-rich stream.
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14. A process for providing a methane-rich stream from a hydrocarbon stream containing methane, ethane and propane comprising:
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providing the hydrocarbon gas stream;
cooling the hydrocarbon gas stream by refrigeration to form a cooled hydrocarbon gas stream;
separating the cooled hydrocarbon gas stream into a methane-rich stream and an ethane/propane-rich stream, said methane-rich stream having a first pressure and a first temperature;
expanding said methane-rich stream from said first pressure to a second pressure to lower the temperature of said methane-rich stream from said first temperature to a second temperature to provide a cooling source for said refrigeration, wherein said second pressure is lower than said first pressure and further wherein said second temperature is lower than said first temperature;
recovering said methane-rich stream.
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Specification