Multi-scale dynamic mathematical model of CO2 and fly ash mineralization

Abstract

The multi-scale structural characteristics of micro-nano pores of fly ash are the core factors affecting the mechanisms of physical transport and chemical reaction of CO2. The existing theoretical models of mineralization do not take such characteristics into account. it is difficult to describe the mechanisms of physical transport and chemical reaction of CO2. In order to address this scientific problem, a theoretical model of multi-scale structures of pore series is established. A mathematical dynamic model of multi-scale internal diffusion-mineralization is also established for accurately describing the concentration variation law in physical transport and chemical reaction processes of CO2 in micro-nano pores of fly ash under natural static conditions. The model is simulated to analyze the key parameters affecting the transport-mineralization reaction rate in the evolutionary mechanism of CO2. The simulated results showed that if the initial apparent diffusion-mineralization coefficient is reduced by 100 times, the concentration of CO2 at the center of the particles is reduced by 25 order in magnitude. The attenuation coefficient is reduced by 2 order in magnitude and the concentration of CO2 at the center of the particles is changed by 9 order in magnitude. These findings indicate that the initial apparent diffusion-mineralization coefficient and attenuation coefficient are the factors affecting the diffusion-mineralization reaction in the evolution of CO2. The reason for the phenomenon of multi-scale evolution and mechanism of diffusion mineralization reaction of CO2 in the micro-nano pores of fly ash is revealed.