Composite porous hollow fiber membrane, production method for composite porous hollow fiber membrane, composite porous hollow fiber membrane module, and operation method for composite porous hollow fiber membrane module

A composite porous hollow-fiber membrane comprising a first layer and a second layer which each comprise a fluororesin-based polymer,

• wherein the first layer has a columnar texture oriented in a longitudinal direction of the composite porous hollow-fiber membrane,
• the columnar texture has an average value v of a Raman orientation parameter calculated with the following formula (1) of 1.5-4.0, and
• the second layer has a three-dimensional network texture and has an average surface-pore diameter of 5.0 nm to 5.0 μm:
• Raman orientation parameter=(I1270-parallel/I840-parallel)/(I1270-vertical/I840-vertical) (1),
• provided that,
• I1270-parallel:
• Raman band intensity at 1,270 cm−1 under parallel conditions,
• I1270-vertical:
• Raman band intensity at 1,270 cm−1 under vertical conditions,
• I840-parallel:
• Raman band intensity at 840 cm−1 under the parallel conditions,
• I840-vertical:
• Raman band intensity at 840 cm−1 under the vertical conditions,
• the parallel conditions:
• the longitudinal direction of the composite porous hollow-fiber membrane is parallel with a polarization direction, and
• the vertical conditions:
• the longitudinal direction of the composite porous hollow-fiber membrane is orthogonal with the polarization direction.