Fundamental Studies of Polymerization Processes

传统上，聚合物的制造是在间歇式反应器中完成的，对动力学和输运现象的相互作用缺乏基本的了解。随着聚合物需求的增长和价格竞争的加剧，人们正在开发更有效的聚合方法。大批量商品聚合物的制造商现在的生产线更少，并且已经转向使用连续反应器。相对小批量，高质量（和价值）聚合物的生产商发现，他们的竞争优势来自于对聚合条件和产品质量之间关系的更深入的理解。通过他的研究努力，PI希望设计和控制能够生产更均匀和更高质量聚合物的反应器。新的可控反应器设计的一个关键方面是需要提高对聚合反应器动力学的理解。聚合反应通常具有热释放大、高粘度和热去除困难的特点，所有这些都给控制反应器的动态行为带来了困难。聚合反应工程中第二个特别重要的领域是开发用于生产聚烯烃（例如聚乙烯、聚丙烯和共聚物）的连续液相和气相工艺。第三个具有巨大工艺改进潜力的领域是开发用缩聚法制备聚合物的新工艺。这类聚合物包括许多纤维和工程塑料。在这个项目中，PI将通过连续聚合反应器的实验和定量理论研究来研究这些问题。他计划发展对控制化学和物理现象的定量理解（即，通过实验数据证实的详细数学模型），并利用这种新的理解(1)设计改进的反应器设计，以更好地控制聚合物性质，并最大限度地减少困难的动力学。通过定量地确定产生振荡和稳定性问题的操作条件和系统参数的范围，他希望提供满足聚合物产品规格并具有良好经济性的设计程序，同时避免那些导致困难动态行为的参数组合。（ii）为反应器和聚合物颗粒开发新型在线传感器，以便对产品进行更密切的质量控制，并将这些新的在线聚合物特性传感器与反馈策略结合起来，提供控制方案，从而实现安全的动态操作和对产品质量的密切控制。（iii）为现有和新出现的各类聚合物产品设计新的反应器。* * * //

Traditionally, manufacture of polymers was done in batch reactors with little fundamental understanding of the interaction of kinetics and transport phenomena. With the growth of demand for polymers and increased price competition, more efficient polymerization methods are being developed. Manufacturers of high volume commodity polymers now have fewer product lines and have moved to the use of continuous reactors. Producers of relatively low volume, high quality (and value) polymers are finding that their competitive edge comes from a deeper understanding of the relationship between polymerization conditions and product quality. Through his research efforts, the PI expects to design and control reactors capable of producing a more uniform and higher quality polymer. One crucial aspect of new, controllable reactor designs is the requirement for improved understanding of the dynamics of polymerization reactors. Polymerization is often characterized by large heat release, high viscosity, and difficult heat removal--all of which contribute to difficulties in controlling the dynamic behavior of the reactor. A second area of particular importance in polymerization reaction engineering is the development of continuous liquid and gas phase processes for polyolefin production (e.g., polyethylene, polypropylene, and copolymers). A third area with great potential for process improvements is in developing new processes for polymers made by polycondensation. This class of polymers encompasses many fibers and engineering plastics. In this project the PI will pursue research on these problems through both experimental and quantitative theoretical studies of continuous polymerization reactors. He plans to develop a quantitative understanding of the governing chemical and physical phenomena (i.e., through detailed mathematical models comfirmed by experimental data) and to use this new understanding (i) To devise improved reactor designs which provide better control of polymer properties and also minimize difficult dynamics. By quantitatively determining the ranges of operating conditions and system parameters for which oscillations and stability problems arise, he expects to provide design procedures which satisfy the polymer product specifications and have good economics but which avoid those parameter combinations leading to difficult dynamic behavior. (ii) To develop new types of on-line sensors for the reactor and polymer particles which allow closer quality control of the product and to combine these new on-line polymer property sensors with feedback strategies to provide control schemes which lead to safe dynamic operation and close control of product quality. (iii) To devise new reactor designs for existing and emerging classes of polymer products. * * * //