Development of a Novel Membrane for Extraction of Oxygen from Air

几乎所有的聚合物膜对氧的渗透性都大于对氮的渗透性。在目前的商业膜中，氧与氮的渗透率之比在2到5之间。在这种低选择性条件下，单膜工艺可获得的最高纯度富氧空气约为50%，更典型的是，膜工艺可产生30%至35%的氧气。这项研究致力于开发一种新型膜，该膜应具有高达200的氧对氮选择性，从而使膜工艺在单阶段可以产生纯度高达98%的氧气。此外，初步计算表明，对于一个日产量为10吨的工厂，膜法生产氧气的成本为15至25美元/吨，而商业氧气的成本约为90美元/吨，通过变压吸附生产氧气的成本为120美元/吨。在第一阶段的研究中，合成了一种新型聚合物，其对氧的吸附选择性约为100。在第二阶段的研究中，将开发由类似的高选择性聚合物的极薄薄膜组成的膜。将努力通过这些选择性聚合物薄膜获得高速率的氧转移。多年来，人们已经认识到需要一种廉价的方法来生产高纯度的氧气。生产纯氧的标准方法是在很低的温度下蒸馏空气。然而，这项技术已经过时，而且在经济上或效率上的改进似乎不太可能。相比之下，一种基于膜的方法似乎很有前途，特别是对于小规模的氧气生产。本研究旨在开发一种新的方法来生产用于上述目的的特殊涂层膜。

Virtually all polymeric membranes are more permeable to oxygen than to nitrogen. In current commercial membranes the ratio of oxygen-to-nitrogen permeabilities is between 2 and 5. With these low selectivities, the highest-purity oxygen- enriched air obtainable in a single membrane stage is about 50%--and more typically, membrane processes make 30% to 35% oxygen. This research addresses the development of a new type of membrane that should exhibit an oxygen-over-nitrogen selectivity of up to 200, leading to a membrane process that can produce oxygen at a purity as high as 98% in a single stage. Furthermore, preliminary calculations show that for a 10-ton-per-day plant, the membrane process should produce oxygen at a cost of $15 to $25/ton, compared with a cost of about $90/ton for merchant oxygen and $120/ton for oxygen produced via pressure-swing adsorption. During Phase I research a novel polymer was synthesized that had a selectivity toward sorption of oxygen over nitrogen of about 100. During this Phase II research, membranes will be developed that consist of extremely thin films of similar, highly selective polymers. Efforts will be directed toward obtaining high rates of oxygen transfer through these selective polymer films. The need for an inexpensive method of producing high purity oxygen has been recognized for many years. The standard method for producing pure oxygen is by distillation of air at very low temperatures. However, this technology is old, and improvements in the economics or the efficiency of the process seem unlikely. In contrast, a process based on membranes seem promising, particularly for small scale production of oxygen. This research seeks to develop a novel method to produce a specially coated membrane for the above purpose.