New sorption enhanced reaction technologies (SMBR and PermSMBR) for the production of diesel blends and green solvents
Chromatographic reactors, where reaction and separation processes are combined into single equipment, are a way of achieving better energy efficiency, productivity improvement and lower solvent consumption. In this perspective two innovative technologies are presented: the Simulated Moving Bed Reactor (SMBR) and the recently developed Simulated Moving Bed Membrane Reactor (PermSMBR). Potential applications for these technologies are addressed and their performance for the synthesis of some important oxygenates, such as acetals (1,1-diethoxyethane, 1,1-dibutoxyethane, 1,1-dimethoxyethane) used on diesel blends and ethyl lactate used as green solvent. Future challenges are highlighted.
Traditionally, compounds involving equilibrium limited reactions (as acetals, esters, ethers, among others) are synthesized in a batch reactor fed with excess of one of the reactants and followed by various separation units (mainly energy-intensive distillation steps) in order to recover the desired product, to remove the by-product(s), and to recycle the unconverted reactants to the reactor, which represents high costs (Figure 1). Process intensification, regarding the integration of reaction and separation steps into a single unit, provides the most feasible engineering solution for sustainable synthesis of this type of compounds since the products are separated as they are formed overcoming by this way the equilibrium conversion, leading to highe