Gas separation membrane module

A method of operating a gas separation membrane module,

• the module comprising:
• at least one hollow fiber membrane element including hollow fiber membranes and a cylindrical body, the hollow fiber membranes being arranged side by side, each hollow fiber membrane including a hollow through which feed gas flows, the cylindrical body extending in a longitudinal direction of the hollow fiber membranes and accommodating the hollow fiber membranes;
• and
• a casing that covers at least part of the cylindrical body in an air-tight manner, wherein
• the hollow fiber membrane element includes:
• sweep gas introduction ports positioned on an outer periphery of the cylindrical body at one end side of the cylindrical body in a longitudinal direction of the cylindrical body, the sweep gas introduction ports being arranged dispersedly in a circumferential direction of the cylindrical body, the sweep gas introduction ports being introduction ports through which sweep gas having a lower carbon dioxide concentration and a higher oxygen concentration than the feed gas is introduced into an internal space of the cylindrical body, such that the sweep gas comes into contact with the hollow fiber membranes in the internal space;
• and
• mixed gas discharge ports positioned on the outer periphery of the cylindrical body at another end side of the cylindrical body in the longitudinal direction of the cylindrical body, the mixed gas discharge ports being arranged dispersedly in the circumferential direction of the cylindrical body, the mixed gas discharge ports being discharge ports through which mixed gas is discharged from the internal space, the mixed gas being generated as a result of the sweep gas coming into contact with the feed gas via the hollow fiber membranes in the internal space,
• the casing includes a casing-side introduction port through which the sweep gas is introduced into the casing, the casing-side introduction port being located on a peripheral surface of the casing such that the casing-side introduction port overlaps one of the sweep gas introduction ports in a radial direction of the cylindrical body,
• a first supply chamber, a first discharge chamber, a second supply chamber, and a second discharge chamber are positioned between the casing and the hollow fiber membrane element,
• the first supply chamber communicates with each of the hollow fiber membranes and is filled with the feed gas that is supplied from outside,
• the first discharge chamber communicates with each of the hollow fiber membranes and is filled with purified air that is generated as a result of the feed gas coming into contact with the sweep gas in the hollows of the hollow fiber membranes via the hollow fiber membranes,
• the second supply chamber extends continuously in the circumferential direction of the cylindrical body, communicates with each of the sweep gas introduction ports, and is filled with the sweep gas that is supplied from outside through the casing-side introduction port,
• the second discharge chamber extends continuously in the circumferential direction of the cylindrical body, communicates with each of the mixed gas discharge ports, and is filled with the mixed gas that has passed through the internal space, and
• the first supply chamber, the first discharge chamber, the second supply chamber, and the second discharge chamber are partitioned off from each other;
• and
• the method comprising
• driving the gas separation membrane module so that (i) a first gas pressure difference between a gas pressure of the second supply chamber and a gas pressure of each of the sweep gas introduction ports is less than (ii) a second gas pressure difference between the gas pressure of each of the sweep gas introduction ports and a gas pressure of each of the mixed gas discharge ports.