Modeling on the pyrolysis of particles of low-rank coal and CaO mixture

•Pyrolysis of mixture particle of coal and CaO was studied with a model.•The model coupled intraparticle transport phenomena and pyrolysis reaction kinetics.•The addition of CaO to mixture coal particle can promote coal pyrolysis.•Smaller particle size and larger porosity are favorable for efficient pyrolysis.•Higher temperature and purge rate of nitrogen gas can improve pyrolysis process.