Effect of matrix acidity on resid cracking activity of FCC catalysts

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:370742

Alerasool, S; Doolin, P K; Hoffman, J F ^[1]

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1. Ashland Petroleum Company, Ashland, KY (United States)

The importance of matrix acid sites on the cracking of large resid molecules in heavy crude fractions is discussed. The challenge of measuring fresh matrix acidity was overcome by first destroying the zeolite by treating the catalyst with concentrated acid and then titrating the acid sites by thermogravimetry of pyridine. Due to differences in hydrothermal stability, the acidity of matrix in its fresh form did not correlate with the commercial resid cracking activity on an equilibrated catalyst. To overcome this drawback, the zeolite was destroyed by steaming at 870{degrees}C. Such severe treatment created a matrix that closely resembled that of the commercially equilibrated catalyst. Changes in the nature of acid sites were investigated by performing diffuse reflectance infrared spectroscopy (DRIFTS) measurements on fresh and steamed matrices. While Lewis acid sites were predominant on most fresh matrices, the population of Bronsted acid sites increased as a result of hydrothermal deactivation. The correlations between each type of acidity and commercial resid cracking are discussed. The incorporation of acid density, type, and stability into a comprehensive model is shown to be an important prerequisite for designing robust resid cracking catalysts.

• OSTI ID: 370742
• Report Number(s): CONF-960376--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
BROENSTED ACIDS
CATALYSTS
CATALYTIC CRACKING
CHEMICAL PROPERTIES
DEACTIVATION
LEWIS ACIDS
MOLECULES
PETROLEUM
PETROLEUM RESIDUES
REFINING
ZEOLITES