ABSTRACT
In this work, carbonation reaction of CO2 with lime was investigated at both pellet scale and pilot reactor scale. A modified grain model was developed in order to evaluate the kinetic parameters of the reaction. Pellet-scale experiments were carried out in a thermogravimetric analysis (TGA) system providing the data for the model parameters calculation and also confirming the model with experimental data. The activation energy was about 29 kJ/mol for calcined calcium carbonate. Aspen Plus software was used to simulate the packed-bed reactor behavior in order to investigate the accuracy of the kinetic data obtained by the mathematical model.
Nomenclature
a CA/CAb, dimensionless gas concentration | = | |
CA Gas concentration in the pellet () | = | |
CAb Bulk gas concentration () | = | |
De Effective diffusivity of gas A in the pellet (m2/s) | = | |
De0 Initial effective diffusivity of gas A in the pellet (m2/s) | = | |
DP Effective diffusivity of gas A in the product layer () | = | |
DP0 Initial effective diffusivity of gas A in the product layer () | = | |
ks Surface rate constant () | = | |
L0 Thickness of pellet (m) | = | |
r** Dimensionless unreacted radius of the grain | = | |
rgo Radius of the grain (m) | = | |
MB Solid reactant molecular weight (g/gmol) | = | |
S0 Reaction surface area per unit volume (m2/m3) | = | |
y Dimensionless position in the pellet | = | |
Z Ratio of molar volume of solid product to solid reactant | = | |
Variation ratio of the pore diffusion | = | |
Pellet porosity | = | |
Initial pellet porosity | = | |
True density of the solid reactant () | = | |
Dimensionless time | = | |
Thiele modulus for the pellet, | = | |
Thiele modulus for the grain | = | |
t time (s) | = |