Method and system for producing rPET bottle-grade polyester chips

Abstract

The invention discloses a method and a system for producing rPET bottle-grade polyester chips. The method comprises the following steps: an esterification step, a pre-polycondensation step, a final polycondensation step and a solid-phase polycondensation step, in the esterification step, raw materials including waste PET polyester bottle fragments, terephthalic acid and ethylene glycol are added into an esterification device, the waste PET polyester bottle fragments are subjected to an alcoholysis reaction, and meanwhile, terephthalic acid and ethylene glycol are subjected to an esterificationreaction. The method is low in investment, simple in technical route, low in raw material requirement and good in product quality; an original polyester bottle chip production device is adopted, thewaste polyester bottle fragments are subjected to alcoholysis by utilizing ethylene glycol which is one of polyester bottle production raw materials, so that the closed circulation of the ethylene glycol is realized, the esterification reaction kettle has a dual-purpose function, and the PET polyester chips meeting the national standard level of raw materials can be produced by utilizing the wastePET polyester bottles.

Description

technical field [0001] The invention belongs to the technical field of recycling of bottle-grade polyester chips, and in particular relates to a method and a system for producing rPET bottle-grade polyester chips using waste polyester bottle chips as a raw and auxiliary material. Background technique [0002] Polyester PET bottle-to-bottle recycling technology currently mainly consists of three recycling processes: physical method, chemical method, and semi-chemical-physical method. The problem with the bottle-level chips produced by the physical method and semi-chemical / physical method is that the quality is far inferior to that of the original Material slicing, the physical method is relatively strict on raw materials, most of the impurities inside the bottle after crushing, such as PP / PVC / PE and some metals, rubber, label glue, etc. cannot be effectively removed, because waste polyester cannot be effectively removed Various impurities and toxic and harmful substances brou...

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Problems solved by technology

[0002] Polyester PET bottle-to-bottle recycling technology currently mainly consists of three recycling processes: physical method, chemical method, and semi-chemical-physical method. The problem with the bottle-level chips produced by the physical method and semi-chemical / physical method is that the quality is far inferior to that of the original Material slicing, the physical method is relatively strict on raw materials, most of the impurities inside the bottle after crushing, such as PP / PVC / PE and some metals, rubber, label glue, etc. cannot be effectively removed, because waste polyester cannot be effectively removed Various impurities and toxic and harmful substances brought in by bottle flakes cannot be used according to domestic laws, and in some foreign countries, they can only be mixed with virgin PET bottle-grade chips, and cannot completely replace native PET bottle-grade chips; the same is true for semi-chemical and physical methods. Affected by this, although the impact is slightly smaller than that of the physical method, in addition to impurities, it is also difficult to control the quality of the primary particles themselves, such as color value, viscosity, etc.; the current production of rPET by the chemical method in the world is also from the latter. The process of melting and extruding to add chips has higher requirements on the raw materials of the product, and at the same time has a greater impact on the quality of the rPET product produced.

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