对位芳纶溶剂回收尾气处理技术研究分析

对位芳纶纤维(PPTA)是一种高性能的纤维,其生产过程中的溶剂回收工段产生含有氯仿的尾气,传统的处理方法氯仿未能得到有效的回收,一方面造成原料的损耗,另一方面也造成了环境污染。本文结合对位芳纶的实际生产工艺,开发出一种新的尾气处理技术,采用溶剂吸收加活性炭吸附相结合的方式,使氯仿的回收效率提高到99.4%,活性炭年消耗量降低97.7%,最终排放的尾气满足当地环保要求。该计算结果可为同类装置的工程设计提供参考。

3—氨基—5—甲基异(口恶)唑中回收氯仿工艺的改进

生产磺胺甲恶唑(又称新明磺、新诺明)工艺的第二步,3—氨基—5—甲基异恶唑(简称氨基物)回收氯仿溶剂的常规操作法是搪玻璃反应锅夹层加热。这种操作法要求操作者具有高度的责任心和技术水平,如果操作时不严格遵守操作法或者操作不慎,在后处理时将乳化物、铁质等带入蒸发锅中进行蒸馏,一旦在其持续高温130℃,经过一定时间,将会发生严重的爆炸事故。3—氨基—5—甲基异恶唑是以5—甲基异恶唑—3甲酰胺通过 Hofmann 降介反应转化而得。

PVDMS-Al2O3 Composite Hollow Fibre Membranes for Chloroform Recovery from Gas Streams

Sorption isotherm of chloroform in polyvinyl dimethylsiloxane (PVDMS) polymer film was measured via the gravimetric method, and this film was confirmed experimentally to be good membrane material to recover chloroform from gas stream with high sorption capacity. A new PVDMS-Al2O3 composite hollow fibre membrane was further prepared by coating a PVDMS film on the outer surface of Al2O3 hollow fibre porpous substrate prepared by a dry/wet phase inversion method. Microstructure of the composite membranes was examined by scanning electron microscopy (SEM), indicating the PVDMS coating layer was uniform, free of defects, and around 15μm thick. Performance of the PVDMS-Al2O3 composite hollow fibre membranes for chloroform recovery was investigated. By comparing the experimental data that derived from a mathematical model, the permeabilities of chloroform and nitrogen in the PVDMS polymer membrane were obtained. The effects of temperature and feed flow rate on the chloroform recovery and permeate concentration were investigated both experimentally and theoretically.