Alumina-titania mixed oxide used as support for hydrotreating catalysts of Maya heavy crude-effect of support preparation methods

The main objective of this work is to study the effect of preparation methods of supports on hydroprocessing of Maya heavy crude. In this respect, we have used different procedures to prepare alumina-titania binary mixed oxide supports. A wetness incipient impregnation method is used to make PCoMo catalysts by using these binary supports. The catalysts are characterized by XRD and pore size distribution and the hydroprocessing activities of these catalysts are evaluated for a microreactor and batch reactor. Maya heavy crude and a mixture of Maya crude and hydrodesulfurized diesel are used as feedstock in the batch reactor and microreactor, respectively. The supports prepared by sodium aluminate and titanium chloride salts have higher pore volume and bigger average pore diameter compared with supports prepared by the other methods in this investigation. XRD results reveal that the titanium oxide is well dispersed over alumina in the supports prepared by the above said method. The catalysts supported on binary oxide prepared by this method exhibit higher activities and stability with time-on-stream. The activity results obtained from the microreactor are more or less comparable with those obtained from the batch reactor. The rate of deactivation is faster in the initial period of the reaction and after that it is slowed down. It is also found that the rate of hydrodemetalation deactivation is faster than that of hydrodesulfurization.