Abstract:
Commercial aluminas are commonly used for cracking hydrocarbons in both fixed and fluidised bed reactors and for the dehydration of liquids and high pressure gases in absorbers. The activity of the alumina decreases during use because of the deposition of carbonaceous material and it is necessary to regenerate at intervals to maintain a satisfactory performance. Regeneration is most commonly performed by controlled heating in a current of air to oxidise the carbonaceous deposits. The activity of the alumina is never fully restored by regeneration and this gradual deterioration has been attributed to the effect of elevated temperature during both operation and regeneration. Indirect evidence obtained from physical techniques (1, 2) suggested that heat treatment initially caused shrinkage of the grain size with subsequent coalescence on recrystallisation after prolonged heating. In the present study, an attempt was made to obtain direct evidence by the application of electron microscopy.
Page(s):
253-256
DOI:
DOI not available
Published:
Journal: Journal of Chemical Society of Pakistan, Volume: 7, Issue: 3, Year: 1985