Startup of a reactive distillation process with a decanter

A pressure-driven, dynamic model for distillation columns with smooth reformulations for flexible operation

“…Our formulation for thermodynamic equilibrium and energy balances contains two different temperatures, one denoting the temperature of phase equilibrium, the other the actual temperature on a tray. This separation of temperatures was already suggested in prior work, e.g., by Forner et al (2008). It allows for the decoupling of energy balance and phase equilibrium.…”

“…However, Forner et al (2008) used an if-else switch in their model. Here, the smooth formulation via a sigmoidal ψ t is used, which switches to 1 as soon as the tray temperature reaches the boiling point at the given composition.…”

“…A similar approach was also taken by Elgue et al (2004). Wendt et al (2003) investigated this approach for continuous heat-integrated distillation while Tran et al (2002) looked at distillation columns with liquid-liquid phase separation whereas Reepmeyer et al (2003Reepmeyer et al ( , 2004 and Forner et al (2008) studied reactive distillation columns with trays and packings. Their models also considered the aforementioned transition phase.…”

“…The models presented in (Wang et al, 2003;Reepmeyer et al, 2004;Forner et al, 2008) are formulated based on if-else conditions. In addition, equations are exchanged during the dynamic simulation, e.g., when the bubble point is reached.…”

Development of a Dynamic Modeling Approach to Simulate a Segmented Distillation Column for Flexible Operation

“…A typical equilibrium stage model requires modifications, as it is not able to describe the transition from a dry and cold state to operating conditions. In the literature, a frequently used approach is to implement mathematical switches in the model structure to change between the different thermodynamic and hydrodynamic states [23,24,26,36].…”