Heat transfer to fine coal particles in flash pyrolysis

✍ Scribed by K.R. Doolan; J.C. Mackie; R.G. Weiss

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 823 KB
• Volume: 49
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(83)90165-7

✦ Synopsis

Heat transfer to fine bituminous coal particles suspended in argon has been studied by recording infrared emission from the coal as a function of time at wavelengths 3.42 and 2.26/am when the coal was subjected to very rapid heating by a shock wave. The rate of particle beating was found to fit a Nusselt model of conductive heat transfer. Light extinction studies on coal suspensions showed that particles of diameters ~5/am undergo velocity relaxation behind the shock front in less than 30/as. Allowance for forced convective heat transfer to the coal particles in the velocity relaxation zone was made in the heat transfer analysis but forced convection was found to be unimportant in these studies. The Nusselt heat conduction model has been found to hold for heat transfer to micron-sized coal particles up m 1200K; above this temperature infrared emission from soot produced from products of devolatilization of the coal becomes important.