Method to control the extraction rate in a membrane based biogas upgrading plant
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l’Exploitation des Procedes Georges Claude
InventorsJean-Marc CHAREYRE, Veronique GRABIE, Golo ZICK
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Abstract
A facility and method for membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide that includes a compressor, a gas analyser, at least one valve, and first, second, third, and fourth membrane separation units for separation of CO2 from CH4 to permeates enriched in CO2 and retentates enriched in CH4, respectively. A pressure of the feed gas flow is adjusted according to a CH4 concentration of the second retentate.
Claims15
A facility for the membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide, comprising:
- a compressor for compressing the feed gas flow;
- a first membrane separation unit able to receive a flow of gas coming from the compressor and supply a first permeate and a first retentate;
- a second membrane separation unit able to receive the first retentate and supply a second permeate and a second retentate;
- a third membrane separation unit able to receive the first permeate and supply a third permeate and a third retentate;
- a fourth membrane separation unit able to receive the third retentate and supply a fourth permeate and a fourth retentate;
- a first gas analyzer adapted to measure a CH4 concentration of the second retentate;
- and
- a pressure adjustment means for adjusting the pressure of the feed gas flow according to the CH4 concentration measured by the first gas analyzer, wherein each membrane separation unit comprising at least one membrane that is more permeable to carbon dioxide than to methane.
A method for the membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide, comprising the steps of:
- compressing the feed gas flow with a compressor;
- receiving a flow of gas coming from the compressor at a first membrane separation unit that supplies a first permeate and a first retentate;
- receiving the first retentate at a second membrane separation unit that supplies a second permeate and a second retentate;
- receiving the first permeate at a third membrane separation unit that supplies a third permeate and a third retentate;
- receiving the third retentate at a fourth membrane separation unit that supplies a fourth permeate and a fourth retentate;
- with a first gas analyser, measuring a CH4 concentration of the second retentate;
- adjusting the pressure of the feed gas flow according to the CH4 concentration measured by the first gas analyzer, wherein each membrane separation unit comprising at least one membrane that is more permeable to carbon dioxide than to methane;
- comparing a CH4 concentration measured by the first gas analyzer against a setpoint CH4 concentration and determining a difference therebetween;
- and
- adjusting a pressure of the feed gas flow in such a way as to reduce the determined difference.
Dependencies are inferred from the claim text.