Shear separation method and system

A shear separation method comprising:

• generating a permeate flow through a permeable membrane having a pore size or molecular weight cutoff substantially larger than a predetermined separation size and establishing permeate drag forces;
• creating a turbulent flow of a process fluid adjacent a permeable membrane including generating a shear flow having a shear rate of about 100,000 sec−1 or more including establishing shear lift forces;
• and
• balancing the permeate drag forces and shear lift forces to retard the passage of substances to be retained on the upstream surface of the permeable membrane.

A shear separation method comprising:

• generating a permeate flow through a smooth permeable membrane and establishing permeate drag forces;
• creating a turbulent flow of a process fluid across a permeable membrane having a shear rate of about 100,000 sec−1 or more including generating a shear flow boundary layer having a viscous sublayer adjacent to the upstream surface of the permeable membrane, and establishing shear lift forces;
• and
• balancing the permeate drag forces and shear lift forces to retard the passage of particles smaller than the viscous sublayer thickness rough the permeable membrane.

A method of concentration comprising:

• generating a permeate flow through a permeable membrane from an upstream surface to a downstream surface and establishing permeate drag forces;
• creating a turbulent flow of a process fluid adjacent a permeable membrane including generating a shear flow having a shear rate of about 100,000 sec−1 or more at the surface and establishng shear lift forces;
• and
• balancing the permeate drag forces and shear lift forces to retard the passage through the permeable membrane of substances having a size greater than a predetermined separation size and to allow passage through the permeable membrane of substances having a size less than the predetermined separation size, thereby concentrating at least one of:
• (i) the substances having a size greater than the predetermined separation size at the upstream surface of the permeable membrane, and
• (ii) the substances having a size less than the predetermined separation size at the downstream surface of the permeable membrane.

A shear separation system for treating a process fluid to concentrate or separate substances having a size less than a predetermined separation size and substances having a size greater than the predetermined separation size comprising:

• a housing;
• a process fluid inlet arranged to direct process fluid into the housing;
• a permeate outlet arranged to direct permeate from the housing;
• at least one separation element disposed within the housing and including a permeable membrane having a downstream surface which communicates with the permeate outlet, to establish a permeate flow through the permeable membrane and generate permeate drag forces at the upstream surface of the permeable membrane;
• and
• the separation element and the process fluid being arranged to create a turbulent flow of process fluid adjacent to the permeable membrane including generating a shear flow having a shear rate of about 100,000 sec−1 or more and establishing shear lift forces in the process fluid to balance the permeate drag forces and retard the passage of the substances to be retained upstream of the permeable membrane.

A method for controlling a shear separation system comprising:

• generating a permeate flow through a permeable membrane;
• creating a turbulent flow of process fluid across the permeable membrane including generating a shear flow having a shear rate of about 100,000 sec−1 or more;
• generating a permeate drag on substances in the process fluid;
• generating a shear lift on the substances in the process fluid;
• balancing the permeate drag and shear lift to establish a separation cutoff size;
• and
• adjusting at least one of the shear lift and permeate drag to control the separation cutoff size.