摘要:
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.
摘要:
An apparatus and method for the spray drying of solvent-containing compositions. A liquid or paste-form solvent-containing composition is heated to a temperature above the boiling point of the solvent, transported under excess pressure and at a temperature above the boiling point of the solvent to a relaxation space where it is sprayed to evaporate the solvent. The relaxation space is not under excess pressure and is at a temperature that is above the boiling point of the solvent.
摘要:
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.
摘要:
A process for separating a multi-component mixture containing solid or liquid organic components by treating the mixture with a gaseous entraining agent comprising a superheated carrier fluid containing a lower monohydric alcohol or a lower monohydric alcohol and water to cause constituents of the multi-component mixture to become entrained in the gaseous entraining agent, and separating the gaseous entraining agent containing constituents of the multi-component mixture from the multi-component mixture.
摘要:
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.