TY - JOUR
T1 - Oxy-coal combustion in an entrained flow reactor: Application of specific char and volatile combustion and radiation models for oxy-firing conditions
AU - Álvarez, L.
AU - Yin, Chungen
AU - Riaza, J.
AU - Pevida, C.
AU - Pis, J. J.
AU - Rubiera, F.
PY - 2013/12
Y1 - 2013/12
N2 - The deployment of oxy-fuel combustion in utility boilers is one of the major options for CO2 capture. However, combustion under oxy-firing conditions differs from conventional air-firing combustion, e.g., in the aspect of radiative heat transfer, coal conversion and pollutants formation. In this work, a numerical study on pulverised coal combustion was conducted to verify the applicability and accuracy of several sub-models refined for oxy-fuel conditions, e.g., gaseous radiative property model, gas-phase combustion mechanism and heterogeneous char reaction model. The sub-models were implemented in CFD (Computational Fluid Dynamics) simulations of combustion of three coals under air-firing and various oxy-firing (21-35% vol O2 in O2/CO2 mixture) conditions in an EFR (entrained flow reactor). The predicted coal burnouts and gaseous emissions were compared against experimental results. A good agreement between the simulations and experiments was achieved, indicating a good applicability and reliability of the refined sub-models and suitability of use of the experimentally derived kinetic data in coal devolatilisation and char oxidation sub-models. The sub-models and the practices implemented in this work can be used in large-scale oxy-fuel combustion processes for reliable design and optimization.
AB - The deployment of oxy-fuel combustion in utility boilers is one of the major options for CO2 capture. However, combustion under oxy-firing conditions differs from conventional air-firing combustion, e.g., in the aspect of radiative heat transfer, coal conversion and pollutants formation. In this work, a numerical study on pulverised coal combustion was conducted to verify the applicability and accuracy of several sub-models refined for oxy-fuel conditions, e.g., gaseous radiative property model, gas-phase combustion mechanism and heterogeneous char reaction model. The sub-models were implemented in CFD (Computational Fluid Dynamics) simulations of combustion of three coals under air-firing and various oxy-firing (21-35% vol O2 in O2/CO2 mixture) conditions in an EFR (entrained flow reactor). The predicted coal burnouts and gaseous emissions were compared against experimental results. A good agreement between the simulations and experiments was achieved, indicating a good applicability and reliability of the refined sub-models and suitability of use of the experimentally derived kinetic data in coal devolatilisation and char oxidation sub-models. The sub-models and the practices implemented in this work can be used in large-scale oxy-fuel combustion processes for reliable design and optimization.
KW - Computational fluid dynamics
KW - Oxy-coal combustion
KW - Radiative heat transfer
KW - Char combustion
UR - http://www.scopus.com/inward/record.url?scp=84886638958&partnerID=8YFLogxK
U2 - 10.1016/j.energy.2013.08.063
DO - 10.1016/j.energy.2013.08.063
M3 - Journal article
SN - 0360-5442
VL - 62
SP - 255
EP - 268
JO - Energy
JF - Energy
ER -