A discrete-pore-size-distribution-based gas–solid model and its application to the CaO+CO2 reaction

Abstract Experimental data obtained in both atmospheric and pressurized thermogravimetric reactors indicate that carbonation is insensitive to the CO 2 partial pressure in terms of final conversion and apparent carbonation rate. A new gas–solid model is formulated to describe the entire experimental carbonation history, with measured rate constant and pore size distribution data as input. The effective diffusivity in the product layer is the only fitting parameter, dependent on the evolution of the pores. The model is able to predict atmospheric and pressurized thermogravimetric reactor carbonation data with fitted activation energies of 215 and 187 kJ/mol for the limestone and dolomite tested.

[1]  J. Szekely,et al.  A structural model for gas solid reactions with a moving boundary—VI: The effect of grain size distribution on the conversion of porous solids , 1975 .

[2]  R. German.  Sintering theory and practice , 1996 .

[3]  Muhammad Sahimi,et al.  Statistical and continuum models of fluid-solid reactions in porous media , 1990 .

[4]  J. Carlos Abanades,et al.  Determination of the Critical Product Layer Thickness in the Reaction of CaO with CO2 , 2005 .

[5]  J. Grace,et al.  Characterization of steam reactivation mechanisms in limestones and spent calcium sorbents , 2001 .

[6]  R. Barker,et al.  The reversibility of the reaction CaCO3 ⇄ CaO+CO2 , 2007 .

[7]  E. H. Baker,et al.  87. The calcium oxide–carbon dioxide system in the pressure range 1—300 atmospheres , 1962 .

[8]  George R. Gavals.  A Random Capillary Model with Application to Char Gasification at Chemically Controlled Rates , 1980 .

[9]  M. Avrami.  Kinetics of Phase Change. II Transformation‐Time Relations for Random Distribution of Nuclei , 1940 .

[10]  J. C. Abanades.  The maximum capture efficiency of CO2 using a carbonation/calcination cycle of CaO/CaCO3 , 2002 .

[11]  G. Simons,et al.  The kinetic rate of SO2 sorption by CaO , 1987 .

[12]  John P. Longwell,et al.  Product Layer Diffusion during the Reaction of Calcium Oxide with Carbon Dioxide , 1999 .

[13]  T. Edgar,et al.  Distributed pore‐size model for sulfation of limestone , 1983 .

[14]  Kevin R. Bruce,et al.  Pore-distribution changes of calcium-based sorbents reacting with sulfur dioxide , 1987 .

[15]  J. C. Abanades,et al.  In-Situ Capture of CO2 in a Fluidized Bed Combustor , 2003 .

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

[17]  D. D. Perlmutter,et al.  Effect of the product layer on the kinetics of the CO2‐lime reaction , 1983 .

[18]  J. Grace,et al.  Sorption-enhanced steam reforming of methane in a fluidized bed reactor with dolomite as CO2-acceptor , 2006 .

[19]  J. Szekely,et al.  A structural model for gas-solid reactions with a moving boundary-II: The effect of grain size, porosity and temperature on the reaction of porous pellets , 1971 .

[20]  J. C. Abanades,et al.  Conversion Limits in the Reaction of CO2 with Lime , 2003 .

[21]  Douglas P. Harrison,et al.  Hydrogen Production Using Sorption-Enhanced Reaction , 2001 .

[22]  T. Shimizu,et al.  A twin fluid-bed reactor for removal of CO2 from combustion processes , 1999 .

[23]  G. Simons,et al.  Small pore closure and the deactivation of the limestone sulfation reaction , 1986 .

[24]  D. P. Harrison,et al.  CHARACTERISTICS OF THE REVERSIBLE REACTION BETWEEN CO2(g) AND CALCINED DOLOMITE , 1996 .

[25]  G. Simons,et al.  The Structure of Coal Char: Part I—Pore Branching , 1979 .

[26]  P. L. Silveston,et al.  Gasification: Part I. Isothermal, kinetic control model for a solid with a pore size distribution , 1973 .

[27]  M. W. Santana,et al.  NON-ISOTHERMAL. IN SITU XRD ANALYSIS OF DOLOMITE DECOMPOSITION , 1989 .

[28]  Yoshizo Suzuki,et al.  Developing an innovative method, HyPr-RING, to produce hydrogen from hydrocarbons , 2002 .

[29]  D. D. Perlmutter,et al.  The effect of pore structure on fluid‐solid reactions: Application to the SO2‐lime reaction , 1981 .

[30]  E. Petersen.  Reaction of porous solids , 1957 .

[31]  Robert S. Boynton.  Chemistry and Technology of Lime and Limestone , 1966 .

[32]  Arthur M. Squires,et al.  Cyclic Calcination and Recarbonation of Calcined Dolomite , 1977 .

[33]  S. Lowell,et al.  Powder surface area and porosity , 1984 .

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

[35]  J. Carlos Abanades,et al.  Pore-Size and Shape Effects on the Recarbonation Performance of Calcium Oxide Submitted to Repeated Calcination/Recarbonation Cycles , 2005 .

[36]  S. Bhatia.  Analysis of distributed pore closure in gas‐solid reactions , 1985 .

[37]  K. Bischoff.  Accuracy of the pseudo steady state approximation for moving boundary diffusion problems , 1963 .

[38]  K. Dam-Johansen,et al.  High-temperature reaction between sulphur dioxide and limestone—III. A grain-micrograin model and its verification , 1991 .

[39]  J. Szekely,et al.  A changing grain size model for gas—solid reactions , 1979 .

[40]  James W. Evans,et al.  Gas-solid reactions , 1976 .

[41]  D. D. Perlmutter,et al.  Unified treatment of structural effects in fluid‐solid reactions , 1983 .