Interview to Wim de Schepper, Researcher in Separation and Conversion Technology – Electrochemical technologies at VITO

Q: For the time being VITO has worked on the Separation and purification units for single cell reactors, what are the next steps and what challenges the company will be facing?

A: The work on downstream processing (DSP) has been a close cooperation between the project partners Hysytech, Avantium, Novamont, RadiciGroup, Perstorp, AVA Biochem, INSTM, TNO and VITO.

Numerous technology screening tests have been performed on different synthetic mixtures mimicking the actual process fluids. Very diverse DSP technologies such as freeze crystallization, extraction, precipitation, distillation were shown to be promising as well for separation of target molecules and solvent regeneration. Encouraging results were obtained for electrolyte recycling and concentration of products in single technology screening tests. Some examples include the separation of sulfuric acid electrolyte from the valeric acid product for line 1 and the separation of glucaric acid from glucose for line 2. Both separations were found to be technically feasible with electrodialysis and nanofiltration.

A few challenges remain however, specifically the separation of maleic acid from sulfuric acid remains challenging both in terms of materials requirements and performance of the unit operations. The real operational conditions that will occur in the PERFORM pilot and the actual composition of the generated streams remain uncertain for both line 1 and 2 and can be tuned to some extent. A scenario analysis will be used to assess performance under different conditions and to anticipate undesired process conditions including possible high impurity of target molecules maleic, valeric, glucaric and adipic acid.

Our next steps entail continued process characterization in the lab and material selection to allow for pilot construction and demonstration of both PERFORM reaction lines.