Numerical simulation of sub-bituminous coal and bituminous coal mixed combustion employing tabulated-devolatilization-process model

• Published in: Energy (Oxford) Vol. 71; pp. 399 - 413
• Main Authors: Hashimoto, Nozomu, Shirai, Hiromi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.07.2014; Elsevier
• Subjects: Applied sciences; Bituminous coal; Coal; Coal combustion; Combustion; Computer simulation; Energy; Exact sciences and technology; Fuel processing. Carbochemistry and petrochemistry; Fuels; Furnaces; Heating rate; Mathematical models; Mixing ratios; Numerical simulation; Solid fuel processing (coal, coke, brown coal, peat, wood, etc.); Sub-bituminous coal; TDP model; Coal combustion; Numerical simulation; Sub-bituminous coal; TDP model; Combustion; Devolatilization; Lignite; Modeling; Coal
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2014.04.091

To investigate the cause of the increase in the unburned fraction when sub-bituminous coal is mixed with bituminous coal observed in previous experimental research using a 100 kg-coal/h-class coal combustion test furnace, numerical simulations of the mixed combustion of sub-bituminous coal and bituminous coal are performed. To take into account the effect of the particle heating rate on the devolatilization parameters, the tabulated-devolatilization-process model (TDP model) is employed. The results show that the simulation could qualitatively reproduce the experimental results, which are an increase in flame lift-off with increasing sub-bituminous coal mixing ratio and a maximum value of the unburned fraction at a sub-bituminous coal mixing ratio of 25%. Furthermore, it is clarified from the simulation results that the nonlinear increase in the overall unburned fraction in the case of sub-bituminous coal mixing with bituminous coal is caused by the steep increase in the unburned fraction of bituminous coal particles with increasing sub-bituminous coal mixing ratio. •We investigate a cause of unburned fraction increase with sub-bituminous coal mixing.•Numerical simulations employing the TDP model were conducted.•Flame lift-off with sub-bituminous coal mixing was reproduced by simulation.•Steep unburned fraction increase of bituminous coal particles is the cause.