Single pass cross flow filtration module and method

A method of single pass cross-flow filtration of a viscous liquid comprising biopolymers sensitive to shear rate for controlling permeate flux, comprising:

• a. providing a fluid to be filtered;
• b. providing a fluid reservoir containing the fluid to be filtered, the fluid reservoir being fluidly connected to a means for urging fluid to a first filtration segment of a filtration module;
• c. the filtration module comprising two or more filtration segments fluidly connected in series, each filtration segment having an upstream side and a downstream side, and each having a retentate channel and a permeate channel;
• wherein each filtration segment comprises hollow fiber filter membranes;
• d. adjusting the permeate flux to reach desired values of axial velocity, shear rate and its associated shear stress, axial pressure drops and transmembrane pressure drops by providing a configuration of components, the configuration of components comprising:
• i. two or more filtration segments, each of the two or more filtration segments having a selected length;
• ii. one or more hollow fiber filter membranes in each filtration segment, the one or more hollow fiber filter membranes having a selected lumen diameter, wherein at least one of the selected lumen diameters differs from the others, and provided that the two or more filtration segments are arranged such that for a given filtration segment having a selected lumen diameter, no filtration segment on the upstream side of the given filtration segment has a selected lumen diameter that is larger;
• iii. at least one pump and at least one valve in the retentate channel of respective ones of the two or more filtration segments, the at least one pump and the at least one valve being positioned between two filtration segments with the differing lumen diameters;
• iv. at least one pump mounted in the permeate channel of each of the two or more filtration segments;
• v. a fluid line segment for exiting permeate from all permeate channels to a reservoir for depositing, which comprises at least one valve positioned between the entries of permeate channels of two filtrations segments and
• e. filtering a fluid mixture through the filtration module to obtain a retentate and a permeate,
• wherein the means for urging the fluid to the first filtration segment, all pumps mounted in the permeate channel of each of the two or more filtration segments, and the at least one valve in the fluid line segment for exiting permeate are controlled by a processor to control the permeate flux in the permeate channels of the two or more filtration segments.