ABSTRACT
New legislature will make regenerative desulfurization during FBC inevitable in the near future. The sulfur route in such a process is being studied now at Delft University of Technology. In the sulfur release step the mechanism of the combustion and decomposition of pyrite has been elucidated. A model is developed to describe the sulfur release pattern. To obtain an efficient sulfur capture a good particle mixing without segregation is necessary for an optimum contact between gaseous sulfur species released and sorbent material. A model is derived which sufficiently can describe the segregation of sorbent, coal and ash particles and can be used to calculate the conditions to avoid it. A regenerative sorbent is being developed. Its preparation is based on the sol-gel method, producing strong particles which show a low attrition rate, a sufficient sulfation behaviour and a promising regenerability at only 900°C. Finally a simple SUlfur REtention (SURE) model was set up which can be used as a diagnostic tool for analysis of existing combustors as well as a predictive tool for analysis of plants under construction or design, also at low oxygen concentration as met at substoichiometric firing conditions. All models presented do not contain any fit parameters; all parameters can be calculated from generally accepted literature data or can be easily measured or controlled.
