Comprehensive Design of a Gas/Liquid/SolidMembrane-based Polymerisation Reactor

随着对更节能和可持续工艺的需求，同时提高产品质量，即使是已建立的化学工艺也必须重新评估和重新设计。虽然连续反应器提供了显着更高的传热和传质能力相比，间歇式反应器，许多过程仍然使用间歇式反应器。特别是气液反应，这往往是有限的热量和质量传递，可以受益于连续操作。通常，气-液反应通过在搅拌釜反应器中分散气泡来实现。搅拌器使气泡破碎以增加液相和气相之间的界面面积。虽然是常见的做法，但这种方法具有非常低的机械效率，并且不能产生限定的界面面积。另一方面，膜接触器可以在气相和液相之间产生稳定的界面面积，并具有高的表面积与体积比。因此，膜接触器是许多气液反应的有前途的反应器系统。在这里，我们建议开发一种新的连续膜为基础的气液反应系统。作为第一反应，将实施作为气态离析物进料的偏二氟乙烯到聚偏二氟乙烯（PVDF）的乳液聚合，聚偏二氟乙烯将在液相中形成固体颗粒。除了节省能源外，PVDF的连续聚合还可以使用更少的有害表面活性剂，减少废水排放。此外，VDF乳液聚合中的聚合反应发生在表面活性剂形成的胶束中，因为液体本体相中单体分子的浓度不足以进行链增长反应。因此，在本项目中，将研究气态单体通过膜进入具有胶束的液相的详细传质机制和限制，并开发克服这些限制的方法。

With the need for more energy-efficient and sustainable processes at simultaneously improved product quality, even established chemical processes have to be reevaluated and newly designed. Although continuous reactors offer a significantly higher heat and mass transfer capacity compared to batch reactors, many processes are still using batch reactors. Especially gas-liquid reactions, which are often limited by heat and mass transfer, could benefit from the continuous operation. Usually, gas-liquid reactions are realized by dispersing gas bubbles in a stirred tank reactor. An agitator breaks the gas bubbles up to increase the interfacial area between the liquid and the gaseous phase. Although common practice, this method has a very low mechanical efficiency and can not create a defined interfacial area. Membrane contactors, on the other side, can create a stable interfacial area between gas and liquid phase combined with a high surface-to-volume ratio. Hence, membrane contactors are promising reactor systems for many gas-liquid reactions.Here, we propose to develop a new continuous membrane based reactor system for gas-liquid reactions. As a first reaction, the emulsion polymerization of vinylidene fluoride, which is fed as gaseous educt, to polyvinylidene fluoride (PVDF), which will form as solid particles in the liquid phase, will be implemented. In addition to energy savings, a continuous polymerization of PVDF would also be accompanied by the use of less harmful surfactants and a reduction of wastewater.Further, the polymerization reaction in the emulsion polymerization of VDF occurs in micelles, formed by surfactants, as the concentration of monomer molecules in the liquid bulk phase is not sufficient for chain propagation reactions. Hence in this project, the detailed mass transfer mechanisms and limitations of a gaseous monomer through a membrane into a liquid phase with micelles will be studied, and methods to overcome such limitations will be developed.