OCPEC

The proposed SBO project aims at developing an electrochemical system which , besides the production of chemicals, generates electricity by means of fuel cell operations in stead of generating steam. In order to achieve favourable reaction kinetics and high selectivity for the electrochemical partial reactions, it is crucial to use adapted heterogeneous electrocatalysts, electrolyte/matrix/membrane and electrode potentials and to tailor process parameters. The initial boundary operational conditions for the system are an aqueous medium and a maximum temperature of 120°Cs. Key technological requirements for the success of the project are: 1. the use of an electrode catalyst (with or without carrier) that has a highly selective activity and a stable/corrosion resistant nature; 2. the use of ion conducting material between and in the electrodes that conduct (1) H+-ions in an proton exchange membrane fuel cell (pemFC) at low temperature (ion exchange membrane, 50°C to 200°C) or (2) for OH anions in alkaline fuel cells (AFC) at low temperature (electrolyte solution, 50°C of higher); 3. depending of the type of reaction, the electrodes should be optimised for (1) ion and electron conductivity, (2) micro and macro porosity and (3) hydrophilic or hydrophobic nature to optimally support the internal mass transports. Hence, the 2- or 3-phase contacts at the catalyst are maximized in number and activity; 4. electrode and cell construction must support the desited reaction selectivity, so that a uniform electrochemical voltage is present in the entire electrode. In this way, the incidence of the parasitic side reactions taking place at a different electrochemical potential is minimised. Electrode structures could be built as mono layers, gas porous layers, metallic matrixes, 3-dimensional packed beds or fluidized beds; 5. heat and water mangement, supply and evacuation of reactants and products, conduction of electricity, in the fuel cell stacks should be optimised in order to achieve the highest reaction homogeneity in the entire reactor; 6. the implementation of modern tools as modelling and computer simulations for the design and upscaling of electrodes, cells, stacks and the final system.

Trefwoorden:Electrochemical systems