Numerical studies of the flash pyrolysis of cellulose

✍ Scribed by Virendra Kothari; Michael Jerry Antal Jr

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 892 KB
• Volume: 64
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(85)90361-8

✦ Synopsis

Numerical simulations reveal that the time required for rapid pyrolysis of cellulosic biopolymer particles (diameter d 0.5 mm) is composed of a heatup time th and a devolatilization time fd. Approximations of fh and td are given by the time required for radiative and convective heat transfer to raise the particle's temperature to a pyrolysis temperature Tp ('sensible' heat requirement) and to provide the endothermic heat of reaction AH ('latent' heat requirement). The value of 7 is specified by the chemical rate law governing pyrolysis. Recently reported rate laws place a practical upper limit on Tp of : 500°C and provide for the complete vaporization of cellulose at high heating rates. Strong analogies exist between the time required for a given power input to provide both the sensible and latent heat requirements of a solid undergoing a phase change and the time required for heat transfer to effect cellulose pyrolysis. Correction factors reported here permit an accurate estimate of the time required for cellulose pyrolysis, based on the times required for the rate of heat transfer (power input) to provide the 'sensible' and 'latent' heats of pyrolysis at the ('melting point') temperature q.