Nozzle/header design for polystyrene

A method comprising:

• passing a molten polymer through lateral flow tubes of a vessel header of a devolatilizer vessel, wherein the lateral flow tubes are arranged in a parallel configuration and enter the vessel header through a plurality of alternating vessel header penetrations with a single vessel header penetration per lateral flow tube;
• wherein the molten polymer exits the lateral flow tubes as strands through perforations in the lateral flow tubes within the vessel header, and wherein the lateral flow tubes have a non-circular cross-section, and wherein the non-circular cross-section has the shape of a circular sector, an elliptical sector, or an irregular quadrilateral, wherein the non-circular cross-section has two straight sides, wherein a third side of the non-circular cross-section is an arc, wherein the two straight sides connect at an angle that is equal to or more than 70-76 degrees, and wherein each straight side connects with the arc at an angle that is greater than 90 degrees;
• and
• obtaining devolatilized polymer from the devolatilizer vessel.