膜分离技术在聚丙烯尾气回收中的应用

介绍了应用膜分离技术从聚丙烯尾气回收装置释放的不凝气中回收丙烯的情况。不凝气中丙烯的平均体积分数约68.67%,用膜分离系统从不凝气中回收丙烯,丙烯回收率可达90%。膜分离系统操作简单,占地少,经济效益明显。     

膜技术在丙烯回收系统中的应用

通过对排放到低压瓦斯管网的不凝气中丙烯含量进行分析，从经济角度，探讨了这部分丙烯的回收价值，采用膜分离装置回收后，可年创效益132．539万元。     

膜法有机蒸汽回收技术在丙烯单体回收中的应用

阐述了膜法有机蒸汽回收的基本原理，介绍了压缩冷凝膜系统相耦合的工艺在回收尾气中丙烯单体的应用。有机蒸汽膜分离系统可以从不凝气中回收90％以上丙烯，通过比较膜系统加入后和去年同期丙烯的回收量，证明了膜系统的有效性。膜系统操作简单，占地少，没有二次污染。     

具有回收丙烯氮气双功能的膜技术在聚丙烯尾气回收系统中的应用

本文对小本体聚丙烯装置原尾气回收系统存在的问题进行了分析,通过具有回收丙烯及N2双功能膜分离技术与压缩/冷凝液化回收技术的组合,回收聚丙烯装置尾气中的丙烯及N2,效果显著。     

气体膜分离技术在尾气丙烯回收中的应用

对于间歇式液相本体法聚丙烯生产中产生的含大量丙烯、氮、氧的尾气 ,在常用的冷凝法回收的基础上提出了一种新的分离法 ,即以气体膜分离法进一步回收尾气中的丙烯。该法以膜两侧气体的压差为推动力 ,通过溶解、扩散、脱附等过程 ,利用其中产生的各组分传递速率的差异来实现尾气中丙烯气体的充分回收。     

膜分离技术在丙烯-氮气体系的应用及发展

简要介绍了膜分离技术，并对膜分离技术应用于聚丙烯装置的丙烯-氮气系统的现状进行了分析。指出：今后重点应开发膜的合成制作技术；在研究新膜时，把提高回收率和纯度作为开发目标。建议膜回收技术向高密度聚乙烯及线型低密度聚乙烯装置推广延伸，制成适合于回收乙烯的膜技术。     

有机蒸气膜分离过程

绍了有机蒸气渗透膜原理和分离过程特点,根据各生产过程工艺特点,概述了应用膜分离一压缩冷凝集成技术,分离与回收乙烯、丙烯、氯甲烷和氯乙烯等有机蒸气过程。     

蒸气渗透膜法回收有机蒸气

蒸气渗透过程属于气体膜分离技术,是回收分离有权蒸气很有效的方法.简要论述了蒸气渗透过程的分离权理-溶解扩散机理,以及其膜的选择-一般采同橡胶态膜,并且列举了应用蒸气渗透技术回收几种有机蒸气的工业化应用,如氯氟烃、丙烯、丁烯等.最后展望了蒸气渗透技术的发展前景.     

聚丙烯装置不凝气中丙烯回收技术方案

在液相小本体聚丙烯工业生产中，聚合后闪蒸出料时，总会有相当数量的丙烯随着闪蒸釜的减压以及置换而被放出。闪蒸所排放的气体中主要成分是丙烯和氮气，丙烯的含量约为60％～80％。传统上，这部分丙烯是被一个湿式气柜收集起来，然后用压缩机升压到2．0MPa，再经水冷却器，冷凝为液相丙烯后，回收到储罐中。由于闪蒸排放气中含有大量的氮气，因此丙烯储罐的压力会逐渐上升，在压缩时必须进行一定量的放空，以保证系统安全。     

膜分离及深冷分离技术在聚丙烯装置的应用

气相法聚丙烯装置排放气回收系统排放至火炬系统的尾气含有大量烃类和氮气,应用膜分离和深冷分离组合技术高效回收尾气中的乙烯、丙烯和氮气等组分,减少火炬排放,降低装置物耗和能耗。实际应用效果显著,总烃回收率达到92%以上,氮气回收率75%,聚丙烯装置废气排放量减少2 591 t/a,平均能耗下降0. 24 kg/t,实现了节能降耗和清洁生产的目的。     

应用膜分离技术回收VCM精馏尾气

介绍了锦化化工(集团)有限责任公司树脂厂采用膜分离技术回收VCM精馏尾气的情况,阐述了气体膜分离技术的原理,并对该技术的各项工艺参数进行了优化、调试,总结出一套最佳控制方案,彻底解决了循环气在系统中的累积、膜组件传递动力等工艺参数影响膜分离效果的问题,可使精馏尾气中的VCM、C2H2回收率达到95%、85%以上,回收VCM 303 t/a、C2H289 t/a,获经济效益202万元/a。     

有机蒸气膜回收系统在PE装置上的应用

有机蒸气膜回收技术首次在气相法聚乙烯(PE)装置上应用,取得了良好效果,排放的尾气中1-丁烯体积分数由投用前的5％～6％下降到4％;冷剂的体积分数由1．5％下降到0．7％,而排放量基本保持不变。该回收系统投用后,共聚单体1-丁烯的消耗量可以降低1．0 kg/t。     

膜分离技术在乳液聚合尾气回收中的应用

介绍了上海氯碱化工股份有限公司聚氯乙烯厂糊状树脂装置应用有机蒸气膜分离技术从聚合排放的不凝性尾气中回收VCM的情况,阐述了膜分离技术的原理,并介绍了对工艺流程和控制系统优化的方案,最终实现了回收后的尾气中VCM体积分数低于2%,VCM回收率超过95%,每年可回收275 t VCM。     

膜分离-变压吸附联合工艺生产燃料电池氢气

将膜分离技术和变压吸附两种气体分离与净化技术相结合．充分发挥了两种工艺模式的优点．使得装置整体性能指标在稳定性、产品品质和氧气回收率上均有优异的表现，最终使得单位原料气的获利大幅挺高。另外，联合工艺具有广泛的适应性，能够灵活采用各种运行模式以适用于各种不同的气源。     

Facilitated Transport Membrane Hybrid Systems for Olefin Purification

Abstract

A new membrane system has been developed by BP for refinery and chemical plant olefin purification and recovery. This facilitated transport system, coupled with distillation, offers lower capital and operating costs than conventional distillation alone. Initial results on lab scale hollow fiber devices indicate membrane flux ranging from 8.75×10^?6 to 8×10^?5 m³/m²/sec (2.5 to 23 scfd/ft²) and selectivities from 150 to 300. Pilot plant experiments on propylene/propane and ethylene purge gas recovery over three to six months duration show membrane stability and product purity of 98.5% or greater using refinery grade propylene feed. Hybrid system optimization data for membranes and distillation indicate that using a side draw from the distillation tower provides advantages in terms of membrane area, purity of feed to the membrane, and low per-pass recovery coupled with high overall propylene recovery. Membrane performance data under various conditions will also be presented. In addition to performance data, economic evaluation and energy savings will be discussed.     

Membrane application for recovery and reuse of water from treated tannery wastewater

Secondary treated tannery wastewater contains high concentrations of Total Dissolved Solids (TDS) and other residual organic impurities, which cannot be removed by conventional treatment method. A pilot plant membrane system with a designed processing capacity of 1 m³/h, comprising of nano and reverse osmosis (RO) membrane units, accompanied by several pre-treatment operations, was evaluated in order to further treat and reuse the tannery wastewater. The maximum TD S removal efficiency of the polyamide RO membrane was more than 98%. The permeate recovery of about 78% was achieved. The water recovered from the membrane system, which had very low TDS concentration, was reused for wet finishing process in the tanneries. The reject concentrate obtained from the operation was sent to solar evaporation pans. It was evident from the study that the membrane system can successfully be applied for recovery of water from secondary treated tannery effluent, provided a suitable and effective pretreatment system prior to membrane system is employed. Combining nano and RO membranes improved the life of the membranes and permeate recovery rate.     

MBR污水处理工艺长期运行中的膜强化清洗方式

基于上海城镇污水处理厂AAO-MBR膜工艺长期运行中膜不可逆污染严重、离线化学清洗难以恢复理想通量的问题,对其清洗方式进行改进.在原清洗方式的基础上增加草酸二次清洗,探究污染膜产水能力恢复情况,并通过中试试验进行验证.结果表明:膜清洗方式改进后,离线清洗对膜污染物的去除更加彻底,清水通量可恢复至新膜的95.1％,较原清...     

膜吸收法处理焦化厂废水中的氨及苯酚

采用膜吸收法进行了焦化厂剩余氨水中氨和苯酚的脱除和回收试验.实验结果表明,利用氨和苯酚酸碱性的差异和各自对pH要求的不同,可消除两者相互间的干扰,实现两者分别单独分离和回收.在适当的酸度、温度和流速条件下,氨和苯酚的回收率均超过99.5%.采取有效的预过滤并在运行中采用质量分数2%NaOH溶液清洗等措施,可有效抑制膜污染.     

Analysis of a solar-powered membrane distillation system

Nowadays, in dry and rural areas, solar-powered membrane distillation (SPMD) technology is considered a feasiblemeans for the production of pure water from brackish water. Prior to the design and construction of a SPMD pilot plant, there is a need to predict its performance theoretically by means of a computational simulation program. Unlike previous approaches followed by other investigators to develop a mathematical model that can describe the components of a SPMD pilot plant, the developed mathematical model in this study is based on the fact that the SPMD process by nature is unsteady. The performance of a proposed SPMD pilot plant is then obtained by means of a numerical solution of the model with the aid of a simulation computer program. The results reveal that the proposed SPMD pilot plant has some unique features, which differ from a similar MD process operated at steady-state conditions in a laboratory. The analysis of the system has shown that heat recovery via an external heat exchanger is not only possible, but even effective, and an economical way to intensify the SPMD process. The plant productivity can be improved by increasing the heat-exchanger capacity (KA), decreasing the flow rates of both feed and permeate or otherwise by increasing the effective surface area of the membrane. The achieved enhancements in the SPMD pilot plant productivity are directly related to an improved heat recovery rate in the heat exchanger. However, further analysis reported in this paper shows that the increase in KA and membrane area should be optimized for any planned capacity in the design of a SPMD pilot plant.     

Effect and mechanism of ultrafiltration membrane fouling removal by ozonation

This study is aimed using ozonation to remove the fouling that occurs on ultrafiltration membranes. Polyvinylidene fluoride (PVDF) was utilized for the membrane material. The tertiary effluent from industrial park wastewater plant was treated by an ultrafiltration membrane process. A bench-scale system was performed to evaluate the efficiency of fouling removed by an ozonation process. The results should be a valuable reference encouraging the recovery of tertiary effluent by the membrane process. The ozonation process was done via the direct continuous dosing of ozone into the influent. The ozone gas mass flow rate was 8.79 mg/min; the residual ozone concentration in the influent flow was maintained at about 4.02 mg/L throughout the test. It was demonstrated that without ozonation the permeate flux dropped to 60% after 1 h, but that with ozonation it could be maintained at 90% through the test. The SEM observations showed that much fouling that had clogged the membrane was effectively removed by ozonation. The mechanism of fouling removed was also illuminated by the IR analysis. It was observed that the ozone could oxidize and destroy the organic fouling, and the cross flow could flush away any loose fragments on the filtration cake.