EMPLEO DE LA ESPECTROSCOPIA INFRARROJA Y LA DIFRACCION DE RAYOS-X EN LA CARACTERIZACION DE CATALIZADOR DE CRAQUEO FCC SOMETIDO A PROCESO DE DESACTIVACION HIDROTERMICA

Abstract

Infrared spectroscopy, powder X-ray diffraction and microactivity test were used to study a laboratory process of hydrothermal deactivation of FCC cracking catalyst REY type . In the evaluation of the deactivation process by means of Xray diffraction, two analysis were used: the cristallinity percentage analysis associated: ALAS the eoliLe faujasite concentration, active phase of the catalyst, and the analysis to calculate the unit cell of the abovementioned zeolite. As a result, the cristalograthic parameter a• goes
down as the deactivation process takes place, which means that the zeolite cell is shrinking due to the dealumination effect. The present study shows that the analytic procedure used to determine the crystalline percentage by X-ray diffraction leads to an over determination of this parameter whenever the dealumination of zeolite faujasite is present in the deactivation process. The objective of the present work was to study the use of infrared spectroscopy as an alternative method to follow the deactivation process, specially the variation of the absorption band intensity in the range 400-700 cm^-1 associated with the vibration of deformed tetrahedron Al,Si0₄ individual bonds and A1,Si04 bonds as a whole. The micro-activity measurements show the hydrothermal deactivation behaviour according to the exposure time and proved the obtained results by using X-ray diffraction and infrared spectroscopy.