TY - JOUR
T1 - Numerical simulation of heat transfer in self-propagating high-temperature synthesis (SHS)-based calcination of limestone
AU - Volaity, Sayee Srikarah
AU - Agrawal, Shubham
AU - Kilambi, Srinivas
AU - Phelan, Patrick
AU - Kumar, Aditya
AU - Neithalath, Narayanan
N1 - Publisher Copyright:
© 2024 Elsevier Ltd
PY - 2025/4/15
Y1 - 2025/4/15
N2 - Calcination of limestone, a high temperature (∼900 °C) process that emits 44 % of the mass of limestone as CO2, is a critical process in the production of many industrially important materials. To soften the CO2-related impacts of traditional calcination, and to enable ultrafast synthesis of lime, a novel approach based on self-propagating high-temperature synthesis (SHS) has been put forward. SHS uses exothermic heat released by the combustion of fuel intermixed with the reactants to advance the reaction, and hence requires the provision of lower external temperatures. This study introduces a microstructure-guided modeling approach to understand the effect of fuel types (lignin alone or an equal combination of lignin and biomass; fuel-to-limestone ratio of 1.5, by mass) and pellet sizes (12.7 mm or 25.4 mm diameter) on the heat transfer processes in limestone-fuel pellets undergoing SHS, and to elucidate the kinetics of this reaction. The modeling framework considers different zones in a temporal temperature profile of a pellet undergoing SHS. Heat released from the combustion of fuel is explained using a heat source function, which is further validated using experiments. The use of lignin alone as the fuel results in higher pellet temperatures and consequently, higher conversion rates, even though the reaction initiation is earlier for lignin-biomass fuel combination. The simulated temperature profiles are used along with a kinetic model to determine the time-dependent degrees of conversion. The modeling approach is found to be capable of describing the effects of fuel types and pellet sizes on the initiation, duration, progress, and extent of SHS-based calcination.
AB - Calcination of limestone, a high temperature (∼900 °C) process that emits 44 % of the mass of limestone as CO2, is a critical process in the production of many industrially important materials. To soften the CO2-related impacts of traditional calcination, and to enable ultrafast synthesis of lime, a novel approach based on self-propagating high-temperature synthesis (SHS) has been put forward. SHS uses exothermic heat released by the combustion of fuel intermixed with the reactants to advance the reaction, and hence requires the provision of lower external temperatures. This study introduces a microstructure-guided modeling approach to understand the effect of fuel types (lignin alone or an equal combination of lignin and biomass; fuel-to-limestone ratio of 1.5, by mass) and pellet sizes (12.7 mm or 25.4 mm diameter) on the heat transfer processes in limestone-fuel pellets undergoing SHS, and to elucidate the kinetics of this reaction. The modeling framework considers different zones in a temporal temperature profile of a pellet undergoing SHS. Heat released from the combustion of fuel is explained using a heat source function, which is further validated using experiments. The use of lignin alone as the fuel results in higher pellet temperatures and consequently, higher conversion rates, even though the reaction initiation is earlier for lignin-biomass fuel combination. The simulated temperature profiles are used along with a kinetic model to determine the time-dependent degrees of conversion. The modeling approach is found to be capable of describing the effects of fuel types and pellet sizes on the initiation, duration, progress, and extent of SHS-based calcination.
KW - Calcination
KW - Kinetics
KW - Limestone
KW - Numerical simulation
KW - Self-propagating high-temperature synthesis (SHS)
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U2 - 10.1016/j.fuel.2024.134226
DO - 10.1016/j.fuel.2024.134226
M3 - Article
AN - SCOPUS:85213267209
SN - 0016-2361
VL - 386
JO - Fuel
JF - Fuel
M1 - 134226
ER -