Novel Separation Processes using Solvents with a Critical Point of Miscibility

该建议涉及最近开发的一种新的分离过程，它可以为过程设计器添加一个有价值且功能强大的工具。它涉及多级逆流分离过程。该方法的基本思想是基于使用具有互溶临界点的溶剂对。通过在临界点附近运行并改变系统温度，人们可以选择创建两种溶剂形成均相溶液的区域，而在其他区域，两种溶剂分离成两个不同的相。这种溶剂已用于分离，但目前它们的使用距离混相的临界点还很远。通过在各截面的临界点上操作，有利于混合区的传质和聚结过程。这允许设计低强度的混合，这将是有用的分离，其中有乳化或泡沫的趋势，由于杂质。它也适用于具有低扩散系数和高传质阻力的高分子量化合物的分离。这允许一些新颖的设计选择，并将允许分离，目前不经济可行与现有的溶剂分离方法。对基本概念进行了论证，并成功地运行了一个小塔。然而，为了有效地应用这些过程，需要更好地理解所涉及的科学原理。本提案的目标是提供理解，以及为未来的设计提供更好的科学基础。

This proposal deals with a novel separation process recently developed that could add a valuable and powerful tool to the process designer. It is concerned with multistage countercurrent separation processes. The basic idea underlying the approach is based on using pairs of solvents that have a critical point of miscibility. By operating close to the critical point and changing the temperature of the system, one can alternatively create regions where the two solvents form homogeneous solution and others in which they separate into two distinct phases. Such solvents are already used in separations, but at present they are used far from the critical point of miscibility. By operating across the critical point in each section, the mass transfer in the mixing zone as well as the coalescence process is facilitated. This allows design with low intensity of mixing, and this will be useful for separations in which there is a tendency to emulsification or foaming due to impurities. It is also suitable for separation of high molecular weight compound which have low diffusivities and therefore high mass transfer resistance. This allows some novel design options and will allow separations which are at present not economically feasible with existing solvent separation methods. The basic concept has been demonstrated and a small column has been successfully operated. However, in order to apply these processes in an efficient way, a better understanding of the scientific principles involved is required. The goal of this proposal is to provide understanding, as well as to provide a better scientific base for future design.