Dynamic Modeling of the Reactive Twin-Screw Corotating Extrusion Process: Experimental Validation by Using Inlet Glass Fibers Injection Response and Application to Polymers Degassing

Abstract

In this paper is described an original dynamic model of a reactive co-rotating twinscrew extrusion (TSE) process operated by the Rhodia company for the Nylon-66 degassing finishing step. In order to validate the model, dynamic experiments have been performed on a small-scale pilot plant. These experiments consist in a temporary injection of glass fibers at the inlet of the extruder after it has reached a given operating point. The outlet glass fibers mass fraction time variation is then measured. This experiment does not lead to the RTD measurement. As a matter of fact, due to the high quantity of glass fibers that is introduced, the behavior of the flow through the extruder is perturbed so that the glass fibers cannot be considered as an inert tracer. The dynamic model that we have published elsewhere (Choulak et al., Ind. Eng. Chem. Res., 2004, 43(23), 7373-7382) is adapted to take into account this nonlinear behavior of the extruder with respect to the glass fibers injection and is favorably compared to experimental results. The description of the degassing operation is also included in the model. The model allows simulations of the complete dynamic behavior of the process. When the steady state is reached, the good position of the degassing vent with respect to the partially and fully filled zones positions can also be checked, thus illustrating the way the model can be used for design purposes.

Contribution of Reactive Extrusion to Technological and Scientific Challenges of Eco-Friendly Circular Economy

“…The extruder is considered as a continuous chemical reactor, in which polymers with different viscosities are mixed, chemical reactions develop and heat transfer phenomena occur [5]. The first attempt in modelling reactive extrusion is based on an engineering approach, such as residence time distribution (RTD) and flow conditions described for an ideal chemical reactor.…”

A Review of Dynamic Models of Hot-Melt Extrusion

“…In the literature, a constant density is often used and the shear viscosity is modeled by an empirical equation [56][57][58] or a rheological law [35,[52][53][54][55].…”