New Coating Techniques for Composite Membranes

膜扩散是一个固有的缓慢过程。 因此，基于膜的分离方法只能是 经济上可行的，如果非常薄，无缺陷的膜 被使用。 具有选择透过性的薄膜复合膜 可以通过目前的方法制造低至约0.5 μ m的层厚度 可用的技术。 具有选择性渗透层的膜 比这更薄的，将大大提高经济效益， 膜分离 该计划的目标是开发 制造工业规模复合膜的技术 其中选择性渗透层厚度低至0.1 μ m或更低。 膜将通过改变溶液涂层来制备 用于施加薄的选择性渗透层的工艺。 的 使用的涂层溶液的特征在于 在低聚合物浓度下具有高粘度。 先前 实验数据表明，使用这种溶液 能够施加比现有技术更薄的无缺陷涂层， 是可以用传统技术实现的。 如果该技术 可以应用于许多不同的聚合物，它将使 经济上可行的基于膜的分离系统， 制造并应用于广泛的气体分离问题。 通过所提出的方法制备的膜可以具有 对许多工业气体分离产生重大影响， 例如，氧/氮分离，酸性气体的去除 从流出物流或从许多来源回收氢气。 工艺经济性可能足够吸引人， 与常规分离竞争的膜系统 在这些和其他应用中的方法。

Membrane diffusion is an inherently slow process. Consequently, membrane-based separation processes can only be economically viable if extremely thin, defect-free membranes are used. Thin-film composite membranes with a permselective layer thickness down to about 0.5 um can be made by presently available techniques. Membranes with permselective layers thinner than this would dramatically improve the economics of membrane separation. The goal of this program is to develop the technology for making industrial-scale composite membranes with permselective layer thicknesses down to 0.1 um or below. The membranes will be made by modifying the solution coating process used to apply the thin permselective layer. The coating solutions to be used will be characterized in having high viscosity at low polymer concentration. Previous experimental data indicate that the use of such solutions enables a much thinner defect-free coating to be applied than is possible with conventional techniques. If the technique can be applied to many different polymers, it will enable economically viable membrane-based separation systems to be made and applied to a broad range of gas separation problems. Membranes made by the proposed process could have a significant impact on many industrial gas separations, for example, oxygen/nitrogen separation, removal of acid gases from effluent streams, or hydrogen recovery from many sources. The process economics could be sufficiently attractive to make membrane systems competitive with conventional separation methods in these and other applications.