2019 AIChE Annual Meeting

(480e) A Study of Unexpected Autoignition Temperature Trends for Pure N-Alkanes

Authors

Mark E. Redd - Presenter, Brigham Young University
Wade Vincent Wilding, Brigham Young University
Thomas A. Knotts, Brigham Young University
Neil Giles, Brigham Young University
An experimental study of minimum autoignition temperatures (AIT) reveals unexpected behavior of pure, high-carbon-number n-alkanes (C16 and larger) not predicted by current AIT prediction methods. The well-documented behavior of n-alkanes shows AIT starting higher for the smaller members of the family and then decreasing to a roughly constant value with little change between members of the family from C7 and larger. Our measurements show that values start to increase again at C16 and show a dramatic increase between C25 and C26.

Measured values for several n-alkanes using the ASTM E-659 method are reported and compared to data from other sources. The impact of measurement method on AIT values is discussed. A mechanistic explanation of the unexpected behavior is proposed. Finally, the implications of this behavior on estimation techniques and on the trend with carbon number for other chemical families are discussed.