Method of reducing the entrainment of polymer in the polymer-lean liquid phase of a separator

A process for producing a polymer comprising the steps of:

• (a) continuously polymerizing a monomer and optionally at least one comonomer in a solvent in a polymerization reactor to produce a polymer solution comprising the solvent, the polymer, unreacted monomer and optionally unreacted comonomer;
• (b) continuously withdrawing the polymer solution from the polymerization reactor;
• (c) heating the polymer solution;
• (d) reducing the pressure of the heated polymer solution by an amount sufficient to separate the polymer solution into a polymer-rich liquid phase comprising the polymer and a polymer-lean liquid phase comprising the solvent, the unreacted monomer and optionally the unreacted comonomer;
• (e) feeding the pressure-reduced polymer solution into a separator;
• (f) reducing the entrainment of the polymer in the polymer-lean liquid phase by:
• (i) setting a diameter range of polymer droplets in a polymer solution entering the separator;
• (ii) estimating a traveling time of the polymer droplets in the separator;
• and
• (iii) adjusting a residence time of the polymer solution in the separator to be at least the traveling time of the polymer droplets in the polymer-lean liquid phase;
• (g) withdrawing the polymer-rich liquid phase from separator and recovering the polymer from the polymer-rich liquid phase;
• and
• (h) withdrawing the polymer-lean liquid phase from the separator and directly recycling the polymer-lean liquid phase into the polymerization reactor.

A method for determining a minimum residence time of a polymer solution in a separator required to ensure efficient separation of a polymer solution into a polymer-rich phase comprising the polymer and a polymer-lean phase comprising solvent, unreacted monomer and optionally unreacted comonomer with the maximum fraction of polymer collected in the polymer-rich phase, the process comprising:

• setting a diameter range of polymer droplets in a polymer solution entering the separator;
• estimating a traveling time of the polymer droplets in the separator;
• and
• adjusting a residence time of the polymer solution in the separator to be at least the traveling time of the polymer droplets in the polymer-lean phase;
• wherein the diameter range of the polymer droplets is set by selecting a hole size of a distributor inside the separator.