In‐Line Monitoring of Emulsion Polymerization Reactions Combining Heat Flow and Heat Balance Calorimetry

Abstract

In‐line monitoring of semi‐batch vinyl acetate emulsion polymerizations was performed combining heat flow and heat balance calorimetry to re‐estimate the overall heat transfer coefficient between the reactor and jacket. The initial UARJ was obtained applying a constant power through an electrical heater to the initial reactor charge. As UARJ changed during the reaction, it was re‐estimated combining the mass and energy balances of the jacket and the reactor and minimizing an objective function in terms of TJ_out. Results showed that good in‐line estimations of conversion can be performed without requiring the use of experimental conversion data to re‐estimate UARJ during the reaction.

The Autocovariance Least-Squares Method for Batch Processes: Application to Experimental Chemical Systems

“…A schematic of the experimental setup is shown in Figure (see ref for a detailed description of this setup). Temperature data are obtained at constant intervals (10 s) by thermoresistances (PT100) positioned at the jacket inlet and outlet, in the reaction medium and surroundings.…”

A Non-Adiabatic Model for Jacketed Agitated Batch Reactors Experiencing Thermal Losses

“…Consequently, there is no process-side heat generation or dissipation, Q̇ s → 0, and the physical properties of the process fluid will not evolve substantially during experimentation and may be approximated as constants. Under typical reactor operation, the heat-transfer model will be coupled with the reaction kinetics, dictating evolution in reagent concentrations, d C A /d t , , and the change in thermophysical properties of the reaction mixture as a function of conversion. The reaction kinetics will likely contain an Arrhenius term dictating the reaction rate to be an exponential function of process temperature, and thus, additional care must be taken to ensure that the time step is sufficiently small, and the chosen numerical model sufficiently robust, to avoid escalating numerical errors and instability.…”

Enabling technologies in polymer synthesis: accessing a new design space for advanced polymer materials

“…A direct comparison of both techniques is drawn by de Araújo and co-workers. 160 The factors that must be considered in calculating heat flows in either case are discussed in detail in reviews by Frauendorfer et al 140 and Fonseca et al 154 In terms of application, both methods have been used successfully in polymerisation monitoring, and applied in a range of reactor control applications. 161 Viscometry can be used to obtain molecular weight information within a polymerisation.…”