Method for ethane liquefaction
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorMichael A. TURNEY
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Abstract
The process for ethane liquefaction can include a mixed refrigerant containing heavy hydrocarbons (e.g., butane and/or pentane) using compression without interstage cooling, or cooling only after the first compression stages where there is no liquid formation yet, such that the number of liquid recycle loops are reduced. The lack of cooling in the compressor reduces the compressor's mechanical efficiency; however, this is offset by having a more thermodynamically efficient process cycle because the cycle can operate as a mixed refrigerant rather than cascade.
Claims11
A method for the liquefaction of ethane, the method comprising the steps of:
- (a) providing a stream of gaseous ethane under pressure, wherein the stream of gaseous ethane comprises at least 90% ethane;
- and
- (b) condensing the stream of gaseous ethane to produce liquid ethane by exchanging heat with a mixed refrigerant within a heat exchanger, wherein the mixed refrigerant is subjected to a mixed refrigerant refrigeration cycle,
- wherein the mixed refrigerant refrigeration cycle comprises the steps of:
- compressing the mixed refrigerant in a first compression section to produce a first compressed stream;
- compressing the first compressed stream in a second compression section to produce a second compressed stream;
- compressing the second compressed stream in a third compression section to produce a third compressed stream;
- cooling the third compressed stream to approximately ambient temperature to form a cooled third compressed stream, wherein the cooled third compressed stream is a two phase fluid;
- separating the cooled third compressed stream into a liquid refrigerant and a gas refrigerant;
- expanding the gas refrigerant to produce a cooled refrigerant;
- and
- introducing the cooled refrigerant to the heat exchanger under conditions effective for absorbing heat from the gaseous ethane such that the gaseous ethane condenses to form the liquid ethane.
A method for the liquefaction of ethane, the method comprising the steps of:
- (a) providing a stream of gaseous ethane under pressure;
- and
- (b) condensing the stream of gaseous ethane to produce liquid ethane by exchanging heat with a mixed refrigerant within a heat exchanger, wherein the mixed refrigerant is subjected to a mixed refrigerant refrigeration cycle,
- wherein the mixed refrigerant refrigeration cycle comprises the steps of:
- compressing the mixed refrigerant to produce a first compressed stream;
- compressing the first compressed stream to produce a second compressed stream;
- compressing the second compressed stream to produce a third compressed stream;
- cooling the third compressed stream to approximately ambient temperature to form a cooled third compressed stream, wherein the cooled third compressed stream is a two phase fluid;
- separating the cooled third compressed stream into a liquid refrigerant and a gas refrigerant;
- expanding the gas refrigerant to produce a cooled refrigerant;
- and
- introducing the cooled refrigerant to the heat exchanger under conditions effective for absorbing heat from the gaseous ethane,
- wherein the mixed refrigerant refrigeration cycle further comprises an absence of a formation of a liquid phase of the mixed refrigerant at a point that is located both downstream the first compression step and upstream the final compression step.
Dependencies are inferred from the claim text.