Davy International Aktiengesellschaft

Zimmer Aktiengesellschaft

Ovidiu Dicoi

Hans Wewer

Erwin Doerr

Ronald P Wainberg

High molecular weight polyethylene terephthalate (PET) is obtained by solid state polycondensation of low molecular weight polymer granulate or chips. The present invention relates to a moving bed reactor wherein the crystallized, low molecular weight polymer granulate or chips move by gravity flow from the top to the bottom of a cylindrical, vertical reactor. By means of an automatic sampling system, samples of the polymer chips are taken from different points in the moving bed and analyzed to continuously establish the intrinsic viscosity, i.e. molecular weight, of the chips. A countercurrent flow of cold and/or heated gas and the chip residence time are then adjusted in response to the viscosity profile in the reactor in order to control and achieve a desired chip quality.

Continuous moving bed reactor for manufacture of high molecular weight

A new process for use with continuously operated plants for the production of polyester polymers suitable for producing fibers, bottles and film, by reacting ethylene glycol and terephthalic acid in the presence of a catalyst so that the vapour by-products from the esterification, prepolycondensation and polycondensation stages are continuously rectified in two in-line columns yielding ethylene glycol of high purity (99.85%) which is returned to the process, waste water with 400 ppm ethylene glycol, and a heavy fraction containing oligomers, diethylene glycol, etc. Moreover, an improvement in the quality of the esterified product is attained as it contains less than 0.6% diethylene glycol without the use of diisopropylamine, a poisonous additive.

Column system process for polyester plants

A process for the continuous recovery of caprolactam from either solid polycaprolactam waste by depolymerization or from liquid polycaprolactam extraction water from an extraction zone where, in either instance, a caprolactam water vapor mixture is produced and subsequently upgraded in a distillation zone to provide a dilute mixture of caprolactam and water vapor. A minor portion of this dilute caprolactam water vapor is condensed and recycled to the distillation zone. The remaining, major portion of this mixture is compressed and admixed with fresh steam, superheated and passed to either the extraction zone or depolymerization reaction.

Growing community of inventors

Offenbach, Germany

Ovidiu Dicoi