Evolution and Simulation of Pore Structure during the Calcinations of Limestone Pellets

Abstract:

The evolution characteristics of pore structure during the decomposition of limestone were experimental measured with nitrogen adsorption method. As a result, the pore structure of calcined limestone has a characteristic of bimodal distribution and the most probable pore sizes are about 3.8nm and 45nm. The probability ratio between the front and following humps decreases at first with the solid fractional conversion and then increases in the later stage of decomposition, and the corresponding inflection point of solid fractional conversion is about η=0.56 under the condition of calcination temperature 1133K. A probability density function with bimodal distribution for pore volume was established to construct the pore structure parameters model. As the average pore size decreased from 38.2nm to14.9nm, the effective diffusion coefficient of gaseous product through the porous solid product layer reduced from 0.0088cm².s^-1 to 0.0017cm².s^-1, which leads to an increase in the pore diffusion resistance affecting the decomposition mechanisms of limestone.

• Periodical: Advanced Materials Research (Volumes 1033-1034)
• Pages: 481-485
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1033-1034.481
• Online since: October 2014
• Authors: Ming Chun Li*, Jin Zhang, Zi Yao Yuan
• Keywords: Bimodal Distribution, Multiphase Reaction, Pore Structure Characteristics, Thermal Decomposition

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