TY - JOUR
TI - Novel fragmentation model for pulverized coal particles gasification in low temperature air thermal plasma
AU - Jovanović Rastko D
AU - Cvetinović Dejan B
AU - Stefanović Predrag Lj
AU - Škobalj Predrag D
AU - Marković Zoran J
JN - Thermal Science
PY - 2016
VL - 20
IS - 11
SP - 207
EP - 221
PT - Article
AB - New system for start-up and flame support based on coal gasification by low  temperature air thermal plasma is planned to supplement current heavy oil  system in Serbian thermal power plants in order to decrease air pollutions  emission and operational costs. Locally introduced plasma thermal energy  heats up and ignites entrained coal particles, thus starting chain process  which releases heat energy from gasified coal particles inside burner  channel. Important stages during particle combustion, such as particle  devolatilisation and char combustion, are described with satisfying accuracy  in existing commercial CFD codes that are extensively used as powerful tool  for pulverized coal combustion and gasification modeling. However, during  plasma coal gasification, high plasma temperature induces strong thermal  stresses inside interacting coal particles. These stresses lead to "thermal  shock" and extensive particle fragmentation during which coal particles with  initial size of 50-100 μm disintegrate into fragments of at most 5-10 μm.  This intensifies volatile release by a factor 3-4 and substantially  accelerates the oxidation of combustible matter. Particle fragmentation, due  to its small size and thus limited influence on combustion process is  commonly neglected in modelling. The main focus of this work is to suggest  novel approach to pulverized coal gasification under high temperature  conditions and to implement it into commercial comprehensive code ANSYS  FLUENT 14.0. Proposed model was validated against experimental data obtained  in newly built pilot scale D.C plasma burner test facility. Newly developed  model showed very good agreement with experimental results with relative  error less than 10%, while the standard built-in gasification model had error  up to 25%.