Thermodynamic study of hydrogen production from glycerol via supercritical water reforming

L.J. ROVETTO; M.E. FRONTANÉ; A.R. VELEZ; L.E. MOYANO

Foz do Iguazu

Conferencia; PPEPPD 20013 – 13th International Conference on Properties and Phase Equilibria for Products and Process Design; 2013

The emerging “hydrogen economy” promotes the development of alternative, sustainable and clean hydrogen production processes to build an efficient energy system. The technology of supercritical water reforming (SCWR) is currently under investigation for hydrogen production form biomass and other biomass or bio-fuels derivatives with promising results as one of the most promising alternatives. This work presents a thermodynamic study of supercritical water reforming (SCWR) of glycerol into hydrogen as the main product. The phase behavior of the compounds involved in this chemical transformation (mainly glycerol, H2O, H2, CH4, CO, CO2) is studied in order to define the supercritical region to carry out the process. The Group Contribution with Association Equation of State (GCA-EoS) is the thermodynamic model chosen to investigate the phase behavior of this system. The GCA-EoS model, takes into account molecular self and cross-association effects, and shows accurate results in predicting phase behavior of asymmetric and polar systems at high pressures and temperatures, required for the SCWR process. Different phase behavior scenarios of selected binary and ternary mixtures present throughout the glycerol conversion process towards hydrogen are presented. The hydrogen yield is function of the reaction route and operating conditions, equilibrium calculations were performed using the Gibbs free energy minimization method, to evaluate the reactor feed, temperature and pressure which maximize the hydrogen production.