Continuous Caprolactam Polymerization Kettle

Abstract

A continuous-processing caprolactam polymerization kettle is characterized by comprising two kettle bodies, wherein the first segment is a pressure kettle body and the second segment is a normal-pressure kettle body. The first pressure kettle body is a reactor with a taper outlet, a feed inlet and a reflux mouth are arranged at a kettle cover head, a tubular heat exchanger is arranged below the kettle cover head in the kettle, and the taper outlet is connected with the second normal-pressure kettle body via a gear melt pump. The second normal-pressure kettle body is a reactor with a taper outlet, a feed inlet and a reflux mouth are arranged at a kettle cover head, the feed inlet in connected with the first pressure kettle body via a gear melt pump, a taper slit pressure-releasing device is arranged at the inlet end in the kettle, a tubular heat exchanger and a coaxial multilayer convex perforated plate are successively arranged below the pressure-releasing device, and a inverse-taper baffle plate is arranged in the taper outlet. By employing the above structure design, the flow and the mixing of material fluid in the polymerization kettle are effectively improved, and the problems are solved that the reaction is not uniform and the synthesized product is not uniform in molecular weight and molecular weight distribution.

Description

technical field [0001] The invention relates to a polymerization kettle, in particular to a polymerization kettle for continuous caprolactam polymerization. Background technique [0002] At present, most of the polymerization kettles used in the field of polyamide industrial production are tubular polymerization kettles, which are heated in sections with heat transfer oil as the heat carrier, and the moisture generated during the reaction process is continuously discharged from the top of the reactor. With the continuous expansion of the polyamide fiber market in my country, higher requirements are put forward for the production capacity and product quality of polyamide, especially the molecular weight and distribution of polyamide, and then the capacity, heat transfer efficiency and pressure rating of the reactor And the multi-applicability of stirring and mixing puts forward higher requirements. [0003] Chinese invention patent ZL200610016937.3 discloses a polymerization ...

AI Technical Summary

Problems solved by technology

[0008] The existing traditional reactor structure can no longer meet the needs of large-scale production, as well as the new requirements for reactor efficiency and product quality

In traditional reactors, gear pumps are usually used to transport materials. If this method is still used in large-capacity reactors, it will inevitably lead to uneven mixing, and due to the influence of wall effects in the diameter direction, it will be in a non-Newtonian fluid state. There is a difference in the residence time of the material in the kettle, resulting in a corresponding difference in the quality of the polymerized product

On the other hand, the use of segmented insert heaters has low heat transfer efficiency and a relatively small heat transfer area, which is also not conducive to material flow and mixing in the reaction system.

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