A vessel header includes lateral flow tubes arranged in a parallel configuration. The lateral flow tubes enter the vessel header through alternating vessel header penetrations with a single vessel header penetration per lateral flow tube. Each lateral flow tube has a perforated section within the vessel header having a non-circular cross-section having the shape of a circular sector, an elliptical sector, or an irregular quadrilateral. A method includes passing a molten polymer through the lateral flow tubes of the vessel header. The molten polymer exits the lateral flow tubes as strands through perforations in the lateral flow tubes within the vessel header. The method includes obtaining devolatilized polymer.