Process for separating high boilers from depolymerization mixtures of polyamide 6

By combining evaporation and separation units, high-boiling-point compounds in polyamide 6 depolymerization streams are separated and purified using a stirred tank reactor and a membrane evaporator. This solves the problem of the complexity of separation and purification in existing technologies and achieves efficient separation and purification of high-boiling-point compounds and ε-caprolactam.

CN122422294APending Publication Date: 2026-07-17BASF SE
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
BASF SE
Filing Date
2024-12-20
Publication Date
2026-07-17

AI Technical Summary

Technical Problem

Existing technologies struggle to effectively separate and purify high-boiling-point compounds, especially ε-caprolactam, from the stream generated during the depolymerization of polyamide 6. Furthermore, they are difficult to handle waste streams of varying qualities, resulting in complex and unstable purification processes.

Method used

A method combining evaporation and separation units is employed. High-boiling-point compounds and ε-caprolactam are separated in the evaporation unit at a temperature higher than the flow temperature. Subsequently, the high-boiling-point compounds are further separated and cooled in the separation unit. Purification is carried out using a stirred tank reactor and a membrane evaporator, thereby achieving the separation of high-boiling-point compounds and the purification of ε-caprolactam.

Benefits of technology

It enables efficient separation and purification of high-boiling-point compounds from polyamide 6 depolymerization streams, ensuring the purity and stability of ε-caprolactam. It is applicable to waste streams of different qualities and simplifies the purification process.

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Abstract

披露了一种用于从水性液体流SL0中分离一种或多种有机化合物X的方法，该水性液体流包含单体ε‑己内酰胺和所述一种或多种化合物X，该方法包括 (i) 提供该流SL0，其具有温度TL0并且展现出该一种或多种化合物X的总浓度cL0(X) 和单体ε‑己内酰胺的浓度cL0(C)；(ii) 在蒸发单元UE1中由该流SL0产生水性至少部分蒸气流SV1和液体流SL1，该流SV1具有温度TV1，其中TV1 ≤TE1，并且展现出一种或多种化合物X的总浓度cV1(X) 和单体ε‑己内酰胺的浓度cV1(C)，其中cV1(C) > cL0(C) 并且cV1(X) < cL0(X)，并且该流SL1具有温度TL1，其中TL1=TE1，并且展现出一种或多种化合物X的总浓度cL1(X) 和单体ε‑己内酰胺的浓度cL1(C)，其中cL1(C) < cE1(C) 并且cL1(X) > cL0(X)；(iii) 在分离单元US1中由该流SV1产生水性蒸气流SV2和液体流SL2，该流SV2具有温度TV2，其中TL0 < TV2 ≤ TV1，并且展现出一种或多种化合物X的总浓度cV2(X) 和单体ε‑己内酰胺的浓度cV2(C)，并且该流SL2具有温度TL2，其中TL2=TV2，并且展现出一种或多种化合物X的总浓度cL2(X) 和单体ε‑己内酰胺的浓度cL2(C)，其中cL2(X) > cV2(X) 并且cL2(C) < cV2(C)；(iv) 将该水性流SV2传递至水分离单元UWS2。
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Citation Information

Patent Citations

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