Demethanizing method and apparatus

Claim 2

A process, as set forth in claim 1, further including passing the third gas stream to the cooling zone for cooling the first gas stream.

Claim 3

A process, as set forth in claim 1, further including passing the second liquid stream to the cooling zone for cooling the first gas stream.

Claim 4

A process, as set forth in claim 4, including regulating the flow of the second liquid stream for changing the temperature of the first gas stream passing through the cooling zone.

Claim 5

A demethanizing apparatus, comprising; a demethanizer having a feed inlet, a bottoms product outlet, an overhead product outlet, and a reflux inlet; a first cooling means for cooling the demethanizer overhead product; a first separating means for separating the cooled overhead product into a first liquid stream and a first gas stream; means for passing the resultant first liquid stream to the reflux inlet of said demethanizer; a second cooling means for receiving and cooling the first gas stream; a first liquid knockout means for receiving the first gas stream and separating said stream into a second liquid stream and a second gas stream; a gas expanding means for receiving and expanding the second gas stream; a second liquid knockout having an overhead outlet, a bottoms product outlet, and a gas stream inlet for receiving the expanded second gas stream and separating said stream into a third liquid stream and a third gas stream; a first conduit means for passing the second gas stream from the first liquid knockout means, through the gas expanding means, and to the gas stream inlet of the second liquid knockout; injecting means for passing a stream of dry ethane into the second gas stream at a location downstream of the gas expanding means; and means for passing the third liquid stream to the reflux inlet of said demethanizer.

Claim 6

An apparatus, as set forth in claim 6, wherein the second cooling means comprises a first heat exchanger associated with the first gas stream and with the third gas stream for receiving and cooling the first gas stream; a second heat exchanger connected to the first heat exchanger, the gas stream inlet of the first liquid knockout, and a bottoms product outlet of the first liquid knockout for altering the temperature of the first gas stream flowing from the first separating means into the first liquid knockout means.

Claim 7

An apparatus, as set forth in claim 7, including controlling means associated with the second liquid stream flowing from the first liquid knockout means to the second heat exchanger for controlling the rate of flow of said second liquid stream and regulating the temperature change of said first gas stream passing through said second heat exchanger.

Claim 8

An apparatus, as set forth in claim 6, including a flow rate sensor associated with the first conduit means at a location upstream of said gas expanding means for measuring the flow of the second gas stream discharging from the first liquid knockout means and delivering a signal representative of said measurement; a controlling valve in the injecting means bEing associated with the dry ethane stream and connected to the flow rate sensor for receiving the signal from said sensor and controlling the rate of injection of the ethane stream into the second gas stream in response to said signal.

Claim 9

An apparatus, as set forth in claim 7, including a conduit associated with the third gas stream and the first heat exchanger for passing the third gas stream to said first heat exchanger for changing the temperature of said first gas stream.

Claim 10

A process, as set forth in claim 5, including measuring the flow rate of the second gas stream and controlling the flow rate of the ethane stream into the expanded second gas stream in response to the rate of flow of the second gas stream and passing the second gas stream to the cooling zone for cooling the first gas stream.

Claim 11

An apparatus, as set forth in claim 8, including a flow rate sensor associated with the first conduit means as a location upstream of said gas expanding means for measuring the flow of the first gas stream discharging from the first liquid knockout means and delivering a signal representative of said measurement; a conduit associated with the third gas stream and the first heat exchanger for passing the third gas stream to said first heat exchanger for changing the temperature of said first gas stream; and a controlling valve in the injecting means being associated with the dry ethane stream and connected to the flow rate sensor for receiving the signal from said sensor and controlling the rate of injection of the ethane stream into the second gas stream in response to said signal.

Claim 12

In an apparatus for separating a hydrocarbon having 1 carbon atom per molecule from a mixture containing said hydrocarbon wherein said mixture is fractionated in a demethanizing zone with the gaseous effluent from the demethanizing zone being cooled, condensed, separated into a first liquid stream and a first gaseous stream, said first liquid stream being passed to a reflux inlet of the demethanizing zone, said first gas stream being passed to and cooled in a cooling zone and separated in a separating zone into a second gas stream and a second liquid stream with said second gas stream being thereafter expanded, the improvement comprising: means for injecting a stream of dry ethane into the second gas stream after said second stream has been expanded; means for passing the expanded resultant mixture into a second separating zone; means for separating the mixture into a third gas stream and a third liquid stream; and means for recycling the third liquid stream into the demethanizing zone.

Claim 13

An apparatus, as set forth in claim 13, further including means for measuring the flow rate of the second gas stream and controlling the flow rate of the ethane stream into the expanded second gas stream in response to the rate of flow of the second gas stream.

Claim 14

An apparatus, as set forth in claim 13, including means for passing the third gas stream to the cooling zone for cooling the first gas stream.

Claim 15

An apparatus, as set forth in claim 13, including means for passing the second liquid stream to the cooling zone for cooling the first gas stream.

Claim 16

An apparatus, as set forth in claim 16, including means for regulating the flow of the second liquid stream for changing the temperature of the first gas stream passing through the cooling zone.

Claim 17

An apparatus, as set forth in claim 17, including means for measuring the flow rate of the second gas stream and controlling the flow rate of the ethane stream into the expanded second gas stream in response to the rate of flow of the second gas stream; and means for passing the third gas stream to the cooling zone for cooling the first gas stream.