Modeling of the isothermal sulphation reactions of natural sorbents

Abstract The sulphation reaction of the calcines produced from four limestone and one dolomite samples were investigated and modeled. The experiments were conducted in a thermogravimetric analyzer under isothermal conditions and in a gaseous atmosphere consisting of 15 vol% CO 2 , 0.35 vol% SO 2 and balance of dry air by volume. The variation of reaction rate with temperature was determined by sulphating of calcines at three different temperatures: 1023, 1173 and 1273 K. Based on the initial sulphation rates, the apparent activation energies were calculated as 51.58, 145.20 and −37.79 kJ/mol for L01, L04 and D01 samples, respectively. The unreacted shrinking core model was chosen to describe this non-catalytic solid/gas (CaO/SO 2 ) reaction mechanism. The experimental results were found to be correlated successfully by this model and diffusion through the calcium sulphate product layer is rate limiting.

[1]  R. B. Snyder,et al.  Limestone reactivities with SO2 as determined by thermo gravimetric analysis and as measured in pilot scale fluidized-bed coal combustors , 1978 .

[2]  D. D. Perlmutter,et al.  A random pore model for fluid‐solid reactions: II. Diffusion and transport effects , 1981 .

[3]  D. D. Perlmutter,et al.  A random pore model for fluid‐solid reactions: I. Isothermal, kinetic control , 1980 .

[4]  J. M. Smith,et al.  A single‐pore model for gas‐solid noncatalytic reactions , 1977 .

[5]  A. Shaaban.  Determination of the kinetic parameters of the reaction between SO2 and CaO using the thermogravimetric technique , 1991 .

[6]  M. Hartman,et al.  Influence of Porosity of Calcium Carbonates on Their Reactivity with Sulfur Dioxide , 1978 .

[7]  R. H. Borgwardt,et al.  Properties of carbonate rocks related to sulfur dioxide reactivity , 1972 .

[8]  S. Küçükbayrak,et al.  Sulphation capacities of natural Turkish limestones and dolomites , 1993 .

[9]  Tiİmur Doǧu.  The Importance of Pore Structure and Diffusion in the Kinetics of Gas-Solid Non-catalytic Reactions: Reaction of Calcined Limestone with SO2 , 1981 .

[10]  R. L. Pigford,et al.  Rate of Diffusion-Controlled Reaction Between a Gas and a Porous Solid Sphere - Reaction of SO2 with CaCO3 , 1973 .

[11]  H. Yoon,et al.  An investigation of CaO sulfation mechanisms in boiler sorbent injection , 1989 .

[12]  Robert W. Coughlin,et al.  Reaction of sulfur dioxide with limestone and the grain model , 1976 .