Melt Polycondensation In A Rotating Disc Reactor

旋转盘式反应器中的熔融缩聚

• 批准号: 9209187
• 负责人: Kyu Yong Choi
• 金额: $ 12.3万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-10-15 至 1995-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9209187&HistoricalAwards=false
• 关键词: Melt; Polycondensation; Rotating; Disc; Reactor

Melt condensation polymerization techniques are used in the polymer industry for the synthesis of thermoplastics and specialty polymers. For example, saturated polyesters (such as poly(ethylene terephthalate) - PET and poly(butylene terephthalate) - PBT), polyamides, polyarylates, and polycarbonates are manufactured in either semi-batch or continuous polycondensation reactors. Many of these processes are characterized by multiple reaction stages and complex reaction networks that give rise to various unwanted side products. The pure molten monomers are polymerized in the absence of added solvents - a more environmentally friendly process than other industrial polymerization processes. The process is also advantageous because the polymers can be directly pelletized or spun into fibers. A common feature of industrial melt polycondensation processes is that multiple reaction stages are employed using several reactors in series. For PET production, the sequential reaction procedure includes: (a) monomers, low molecular weight oligomers, and low molecular weight prepolymers are synthesized in continuous stirred tank reactors, and (b) the prepolymers are then polymerized to higher molecular weight polymers in finishing polymerization reactors (often rotating disc reactors) where large vapor-liquid surface areas are provided. The final polymer product properties are mostly regulated in this finishing polymerization stage, therefore the optimal design and operation of this reactor is important and is the objective this research. Specifically, the PI will address the following questions: (1) What are the major factors that affect the formation of polymer films on a rotating disc? What are the quantitative relations between the disc design/operating variables and film thickness? (2) What is the role of gas bubbles of condensation byproducts in the mass transfer process? How can one quantify the effect of gas bubbles on the total vapor- liquid mass transfer rate? (3) What interactions occur between the neighboring discs and what will be the optimal layout of multiple discs on the agitator shaft? What will be the optimal angle of disc immersion in the liquid pool? (4) What is the overall liquid (polymer melt) flow pattern in the reactor? (5) How does the continuous finishing reactor behave under various reactor operating conditions and feed conditions at steady state and transient state? What polymer properties are most strongly influenced by what reactor variables? How should one pair the polymer property parameters with reactor operating conditions for the design of product quality control systems? Both experimental work and reactor modeling will be done.***//

熔融缩聚技术在聚合物工业中用于合成热塑性塑料和特种聚合物。例如，饱和聚酯（如聚（对苯二甲酸乙酯）- PET和聚（对苯二甲酸丁二酯）- PBT）、聚酰胺、聚芳酯和聚碳酸酯可以在半间歇或连续缩聚反应器中生产。许多这些过程的特点是多反应阶段和复杂的反应网络，产生各种不需要的副产物。纯熔融单体在没有添加溶剂的情况下聚合-比其他工业聚合工艺更环保的工艺。该工艺也很有利，因为聚合物可以直接成球或纺成纤维。工业熔体缩聚过程的一个共同特点是采用多个反应器串联的多个反应阶段。对于PET生产，顺序反应程序包括：(a)单体、低分子量低聚物和低分子量预聚物在连续搅拌槽式反应器中合成，(b)预聚物随后在提供大汽液表面积的精加工聚合反应器（通常是转盘反应器）中聚合成更高分子量的聚合物。最终聚合物产品的性能主要在最后聚合阶段进行调节，因此反应器的优化设计和运行是本研究的目标。具体来说，PI将解决以下问题：(1)影响旋转圆盘上聚合物薄膜形成的主要因素是什么？圆盘设计/操作变量与薄膜厚度之间的定量关系是什么？(2)冷凝副产物气泡在传质过程中的作用是什么？如何量化气泡对总汽液传质速率的影响？(3)相邻圆盘之间的相互作用是什么？多圆盘在搅拌轴上的最佳布置是什么？圆盘浸入液池的最佳角度是什么？(4)反应器内整体液体（聚合物熔体）的流动模式是怎样的？(5)连续精加工反应器在各种反应器工况和进料工况下的稳态和暂态性能如何？哪些反应器变量对聚合物的性能影响最大？在产品质量控制系统的设计中，如何将聚合物性能参数与反应器操作条件配对？实验工作和反应堆建模将同时进行