The metals passivation is the process of mitigating the deleterious effects of contaminant metals, thereby improving the catalyst activity and/or selectivity to more desired products. Metals passivation is accomplished today in two ways: (1) metering the metals passivation agent, usually via the fresh feed, into the cracker where it deposits on the catalyst or (2) incorporating additives during manufacture into the catalyst formulation or into a separate carrier particle, which is blended with the catalyst. Passivation additives are normally referred to as “metal traps.” In the case of passivation of vanadium, the average life of the cracking catalyst particle is prolonged. With nickel, passivation decreases dehydrogenation activity. The refiner usually has several ways to utilize the benefits of reduced yields of hydrogen and coke achieved through metals passivation. One economically attractive option for many refiners has been to crack resid blended with the traditional gas oil feed. © 1993, Elsevier Science & Technology. All rights reserved.
Nielsen, R. H., & Doolin, P. K. (1993). Metals passivation. Studies in Surface Science and Catalysis, 76(C), 339–384. https://doi.org/10.1016/S0167-2991(08)63833-1