Abstract: A shell-and-tube heat exchanger, for removing volatile substances from a polymer solution by degasification, includes a bundle of tubes arranged vertically and parallel to each other in a shell chamber through which a fluid heat-transfer medium flows. The upper end of each tube is fixed in an upper tube sheet and the lower end of each tube is fixed in a lower tube sheet, and the polymer solution flows through the tubes in the direction of gravity. One feature is that a multilayer woven wire fabric is attached to the top of the upper tube sheet. The finest meshed layer of the fabric has a mesh width of 50 ?m to 1000 ?m. The invention also relates to a method for removing volatile substances from a polymer solution by degasification in a shell-and-tube heat exchanger and use of the shell-and-tube heat exchanger.

Abstract: A shell-and-tube heat exchanger, for removing volatile substances from a polymer solution by degasification, includes a bundle of tubes arranged vertically and parallel to each other in a shell chamber through which a fluid heat-transfer medium flows. The upper end of each tube is fixed in an upper tube sheet and the lower end of each tube is fixed in a lower tube sheet, and the polymer solution flows through the tubes in the direction of gravity. One feature is that a multilayer woven wire fabric is attached to the top of the upper tube sheet. The finest meshed layer of the fabric has a mesh width of 50 ?m to 1000 ?m. The invention also relates to a method for removing volatile substances from a polymer solution by degasification in a shell-and-tube heat exchanger and use of the shell-and-tube heat exchanger.

Abstract: A chemical reaction is performed by first adding the incoming stream to a shear zone of an apparatus by way of a feed upstream of the shear zone. The apparatus includes a rotor and a stator, with the shear zone being formed by facing surfaces of the rotor and the stator. The shear zone is followed by a mixing zone having an outlet toward an outside of the apparatus. A gage pressure of at least 1 bar is generated in the shear zone. The gaseous phase is mixed into the mixing zone through the aperture and into the incoming stream under the generated gage pressure to create a reaction mixture. The reaction mixture is fed to a residence-time zone via a downstream outlet from the mixing zone, where a reaction takes place, and pressure in the mixing zone is controlled using a downstream pressure-control valve.

Abstract: Pelletized materials based on at least one thermoplastically processable polymer, where the pellets have less than 10% of concave regions and otherwise are convex in every other region, this being determined by means of incident-light interference-contrast spectroscopy, by taking the average value for the ratios of the outline area to the entire outline area for an assembly of pellets.

Abstract: An apparatus intended for extruding thermoplastics and having at least one devolatilization orifice and, if desired, also at least one dewatering orifice, which has been equipped with a metal-wire-mesh composite sheet, with a finely perforated metal sheet, or with a slit diaphragm.