(302k) Multidimensional Modeling of Reactive Drying of Polymeric Films: an Integrated Process and Product Approach

Chemical system modeling is frequently referred to process modeling, i.e., the modeling for establishing relationships among process variables. Most process models are lumped and deterministic that may be sufficient for their applications. However, for a complex system, e.g., a multi-stage, multi-zone process where a geometrically sophisticated product is being manufactured, system modeling could be a very challenging task. In this case, a system model may contain a process model describing process behavior and a product model characterizing quality development. Such models will be likely distributed and dynamic.

In this work, we investigate the modeling of sophisticated reactive drying of geometrically distributed polymeric thin films. In this system, the product (i.e., thin films covering a geometrically complicated substrate) is developed through undergoing solvent transfer within the film and evaporation at the surface, film topology change, and polymeric reaction, while the process (i.e., a multi-stage oven) is operated for providing radiation and convection heat and air flow mechanics to the product. An additional layer of complexity is the ever-changing boundary condition that the system experiences. It corresponds to the nature that the product needs to go through the multi-stage operations continuously in most applications. Since product quality is addressed for every location on the substrate, and process efficiency is the energy efficiency in each operational stage, a hybrid modeling methodology is introduced which utilizes fundamental knowledge, computational fluid dynamics (CFD), and system dynamics techniques. The resulting model can characterize the spatial and temporal behavior of process and product and their interactions. Model-based simulation reveals opportunities for improving product quality as well as processing efficiency.

This methodology significantly extends scope of reactive drying process modeling, and makes an in-depth understanding of the mechanism behind. Model-based applications reveal various usually inconceivable opportunities for systematic improvements of both product quality and process efficiencies. This modeling methodology is, in general, applicable to a variety of industrial reactive drying problems, where product and process performance can be simultaneously considered.