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Mathematical Modelling of Temperature Response of Low‐rank Coal Particles During Pyrolysis
Author(s) -
Heidenreich C. A.,
Yan H. M.,
Zhang D.K.
Publication year - 1999
Publication title -
developments in chemical engineering and mineral processing
Language(s) - English
Resource type - Journals
eISSN - 1932-2143
pISSN - 0969-1855
DOI - 10.1002/apj.5500070512
Subject(s) - pyrolysis , moisture , work (physics) , inert gas , coal , heat flux , thermodynamics , particle (ecology) , materials science , flux (metallurgy) , dry bulb temperature , thermal conduction , atmosphere (unit) , particle size , inert , mechanics , chemistry , humidity , heat transfer , composite material , metallurgy , organic chemistry , physics , oceanography , geology
A mathematical model has been developed to predict the temperature response of dry low‐rank coal particles during pyrolysis in an inert atmosphere. The model is based on the unsteady‐state heat conduction equation in spherical coordinates and uses the Distributed Activation Energy Model to predict volatiles evolution. Measurements of the temperature response at the centre of 10mm Bowmans coal particles were conducted in a horizontal tube furnace using nitrogen as the heating medium at furnace temperatures of 150d̀C, 350d̀C, 600d̀C, 700d̀C, and 800d̀C. A sensitivity analysis was performed to assess the influence of the heat of pyrolysis and the flux of volatiles leaving the particle on the temperature response. The heat of pyrolysis can influence the predicted temperature response, however the uncertainty surrounding the magnitude and nature of its value remains a problem. The gaseous flux has no significant effect on the model predictions. Measurements of the temperature response of particles with varying moisture contents indicate that the presence of moisture significantly influences the temperature response. The effect of moisture is greater than that of the heat of pyrolysis and further work is required to incorporate moisture into the current model.