Abstract: A method and a device for the production of polyamide 6 pellets wherein an intermediate drying is not necessary and a combined pelletizing and extraction take place. Depending on the intended use, the pellets may directly be used or subjected to further treatment steps. A device for the production of polyamide 6 pellets includes a melt device for providing a melt of polyamide 6, an underwater pelletizing system which is operable under increased pressure, and a vertical vessel having a cylindrical section and a tapered bottom section. The tapered bottom section is provided with a cooling device and is connected to a pipe comprising a screw and/or a rotary gate valve for conveying pellets. The device includes a circuit for circulating an aqueous solution of ? caprolactam through the underwater pelletizing system and the vertical vessel.

Abstract: Heat exchanger tubes which are immersed in a fluidized bed of a combustion fluidized bed installation are provided with flow deflectors which reduce erosion of the fluidized materials in the bed on the tubes. The flow deflectors are preferably fins or pins, which protrude from the surface of the tubes and which disturb the erosive flow against the outer walls of the tubes. The flow deflectors also increase the surface areas of the tubes and thereby improve heat transfer from the combustion in the fluidized bed to a fluid heat exchanging medium within the tubes.