US 11,052,345 B2
Membrane permeation treatment with adjustment of the number of membranes used as a function of the pressure of the feed gas flow
Jean-Marc Chareyre, Voiron (FR); Veronique Grabie, Coublevie (FR); and Golo Zick, Fontaine (FR)
Assigned to L'Air Liquide Societe Anonyme Pour L'Etude Et L'Exploitation Des Procedes Georges Claude, Paris (FR)
Filed by L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude, Paris (FR)
Filed on Aug. 8, 2019, as Appl. No. 16/536,307.
Claims priority of application No. FR 1857384 (FR), filed on Aug. 8, 2018.
Prior Publication US 2020/0047113 A1, Feb. 13, 2020
Int. Cl. B01D 53/22 (2006.01); C07C 7/00 (2006.01); C07C 7/144 (2006.01)
CPC B01D 53/226 (2013.01) [C07C 7/005 (2013.01); C07C 7/144 (2013.01); B01D 2053/221 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method for membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide, comprising:
compressing the feed gas flow with a compressor;
receiving the compressed feed gas flow from the compressor at a first membrane separation unit and supplying therefrom a first permeate and a first retentate, the first membrane separation unit comprising a plurality of membranes more permeable to carbon dioxide than methane;
receiving the first retentate at a second membrane separation unit and supplying therefrom a second permeate and a second retentate, the second membrane separation unit comprising a plurality of membranes more permeable to carbon dioxide than methane;
receiving the first permeate at a third membrane separation unit and supplying therefrom a third permeate and a first retentate, the third membrane separation unit comprising a plurality of membranes more permeable to carbon dioxide than methane;
receiving the third retentate at a fourth membrane separation unit and supplying therefrom a fourth permeate and a fourth retentate, the fourth membrane separation unit comprising a plurality of membranes more permeable to carbon dioxide than methane;
measuring a pressure of either the compressed feed gas flow received from the compressor by the first membrane separation unit or a pressure of the second retentate;
comparing the measured pressure with a setpoint pressure and determining a difference therebetween; and
adjusting, through use of at least one valve, a number of the plurality of membranes of at least one of the membrane separation units that receive a flow of gas as a function of the determined difference between the measured pressure and the setpoint pressure so as to keep a methane concentration of the second retentate constant.