Abstract
A kinetic study of sulphur dioxide capture by calcined limestone at 1123K was conducted by thermogravimetric analysis over a relatively wide range of diameter of limestone particles and concentrations of oxygen as well as sulphur dioxide. The experimental conditions were chosen by taking into consideration the practical operating conditions of a fluidized-bed coal combustor. Results are reported in particular on the effects of oxygen concentration on the rate of sulphur dioxide retention; these effects are of practical importance for staged air firing operation of the bed. A formula which took into account the oxygen and sulphur dioxide concentrations could predict the rate of sulphur dioxide retention at various degree of utilization of sulphur sorbent by defining an approximate maximum utilization level as solid reactivity. This parameter could be expressed by a linearly and monotonously decreasing function of the rate. Detailed effects of particle size on the expression were investigated.
