文章在以往研究基础之上,进一步确定了废旧尼龙6在亚超临界水中解聚的主要产物种类,考察了不同的反应温度、反应压力、反应时间对液相产物收率的影响,并提出了解聚进程.实验结果表明:液相产物为氨基己酸和己内酰胺,最大收率分别为6.6％和96％;解聚反应为连续反应,尼龙6先被水解为氨基己酸,后经环化脱水为己内酰胺或进一步分解为低分子物质.研究得出了每一种反应进程下的速率常数k和表观活化能Ea的值.

Supercritical water oxidation(SCWO) is mainly applied in the study of low concentration organic waste water.The process of SCWO was simulated under the supercritical thermodynamic condition so as to make the SCWO process self-compensation from the viewpoint of energy.The process of SCWO was modeled through the Aspen Plus process simulator and SCWO energy self-compensation process was realized by closed Brayton cycle(CBC).The results show that the energy loss in the SCWO energy self-compensation process is far less than the energy release(QR-QH>p),and the energy self-compensation process of supercritical water oxidation with CBC is realizable,and the energy balance point for n-hexane is 2.4% in such process.

Degradated products of nylon 6 in supercritical water were analyzed by GC-MS.The composition of degradated products was identified andε-caprolactam was determined quantitatively.The test results showed that the main product of degradated nylon 6 wasε-caprolactam and other products were some low molecular weight substances.The sample preparation is simple,rapid and easy to operate.The reproducibility of the method is good,the RSD of retention time is 0.64% and the RSD of peak area is 3.58%.

The depolymerization of waste nylon 6 in subcritical and supercritical water was investigated.GC-MS,ultraviolet spectrometry were used to analyze the products in liquid qualitatively and quantitatively.The influences of temperature,pressure,and reaction time on the yield of the products were studied.The results showed that the main products in liquid were caprolactam,and the optimized conditions of the reaction were found to be 370 ℃,25 MPa,60 min of reaction times,with the maximum recovery of 96%.An active energy of 64.4 kJ/mol was calculated according to Arrhenius relationship and the kinetic analysis.

本文综述了超临界流体技术在废旧塑料如聚对苯二甲酸乙二醇脂(PET)和聚酰胺6(尼龙6)解聚回收利用中的研究进展。介绍了解聚工艺方法,包括超临界水法、超临界甲醇法,并对各种工艺的优缺点进行了比较。可为此领域的工作者提供较为详尽的参考依据。