Catalytic Cracking Process Inhibits The Catalyst Of Heavy Metal Pollution

In China, the main process for oil processing is catalyzing and cracking. There were totally 77 catalyzing and cracking plants in SINOPEC and PertroChina in the year 2004, and the processing capacity has reached to over 75 million tons. It becomes a very important research topic as to how to improve the heavy-oil-cracking capacity and the anti-metal-contamination capacity of the cracking catalyst.In order to decrease the effect of heavy metal contamination in the fluid catalytic cracking process, a method has been adopted in this article to modify the matrix of FCC catalyst by using the phosphorous-modified alumina and a kind of metal complex oxide, which dramatically improved the metal tolerance ability of the cracking catalyst. The modification on active component of FCC catalyst can increase the ability of metal resistance by treating it with NH⁴⁺,RE³⁺ or other metal element singly or jointly, by calcining it with hydrothermal vapor to increase SiO₂/Al₂O₃, improve pore distribution and obtain second level pore. ZC-7000MM catalyst prepared by using the new matrix and the modified active component have showed the good ability of metal tolerance in commercial application.A study has also been made in this article to discuss the effects of reductive dry gas on metal resistance by injecting pre-lift dry gas into riser in the fluid catalytic cracking operation. The pre-lifting of dry gas could restrain the catalyst from metal V contamination, but with little effect on resisting metal Ni.