Nuno S. Graça

Dynamic study of the synthesis of 1,1-dibutoxyethane in a fixed-bed adsorptive reactor

The synthesis of 1,1-Dibutoxyethane in a fixed-bed adsorptive reactor using Amberlyst 15 was studied for the first time. The adsorption of non-reactive pairs was investigated experimentally, at 25°C, by frontal chromatography in a fixed-bed adsorber. In order to avoid the immiscibility of the liquid phase, the liquid-liquid equilibrium for the mixture 1-butanol/water was studied. The multicomponent equilibrium adsorption data was assumed to follow the modified Langmuir type isotherm. Reaction experiments of 1,1-Dibutoxyethane production and column regeneration were performed in the fixed-bed adsorptive reactor. This work will enable further developments in chromatographic reactors aiming at the 1,1-Dibutoxyethane process intensification.

Simulated Moving Bed Reactor

The simulated moving bed reactor (SMBR), an important chromatographic reactor, is addressed in this chapter. The SMBR mathematical model, considering external and internal mass-transfer resistances and variable velocity due to change of liquid composition, is shown. An analytical solution for linear SMBR in the presence of mass-transfer resistances, based on the steady-state equivalent true moving bed reactor analogy, is also presented. This solution allows a fast evaluation of the linear SMBR performance for different conditions. The required steps to implement an SMBR-based process, fundamental data acquisition and validation, are highlighted using the green solvent ethyl lactate as a case study. The performance of this reactor for acetals production is also discussed. For all the studied compounds, the SMBR exhibits high conversion and high productivity at moderate temperatures, but also a significant desorbent consumption, which might be reduced by using new materials with lower water affinity.