Kinetic and thermodynamic studies of the Bunsen reaction in the sulfur-iodine thermochemical process

摘要

This work presents the kinetic and thermodynamic studies of the Bunsen reaction in the sulfur-iodine thermochemical cycle for hydrogen production by water splitting. A series of experimental runs have been carried out by feeding the gas mixture SO_2/N_2 in an I_2/H_2O medium in the temperature range of 336-358 K. The effects of the various operating parameters on the SO_2 conversion ratio have been evaluated. The results showed that the efficiency of SO_2 conversion into H_2SO_4 increased with the amount of I_2 or H_2O increase. The increasing reaction temperature impeded SO_2 conversion into H_2SO_4. A kinetic model has been developed to fit to the experimental data obtained in a semi-batch reactor. A good fitting can be observed for each experiment, which discloses the overall kinetic mechanism of the complex Bunsen reaction. The apparent activation energies were found to be 23.513 kJ mol~(-1) and 9.212 kJ mol~(-1) for the sequential reactions (5) and (6), respectively.