AM-97-29 PASSIVATE VANADIUM ON FCC CATALYSTS FOR IMPROVED REFINERY PROFITABILITY

Description:

Process licensers have tried to engineer away its impact. Catalyst suppliers have invested considerable resources to try and mitigate its deleterious effect. Refinery planning departments have had to purchase and route’ feedstocks in less than an ideal manner to avoid its consequences. Refinery research centers and specialty chemical suppliers have attempted to formulate additives to protect against it. All are concerned with the same thing: high metals in the feed to the Fluid Catalytic Cracking Unit (FCCU). Contaminant nickel and vanadium are the primary threats. These metals enter the unit with the feed, bound up in large, heterocyclic complexes. As these complexes are subjected to extreme temperatures and catalytic conditions, the metals crack out of the-hydrocarbon and deposit on the cracking catalyst -- with resultant negative consequences; the deterioration of FCC operating yields. Unit throughput is limited, operating costs become excessive, and refinery flexibility and profitability decline. Catalyst coolers and two-stage regeneration have helped, while specially designed catalyst matrices and solid particle vanadium traps are improving every year. Antimony and bismuthbased liquid feed additives (passivators) have worked to reduce up to 60%. of the impact of nickel in particular, with tin-based passivators proving somewhat effective against vanadium. However, no means are available to entirely alleviate the impact of these metals. This paper discusses a recent innovation in the FCC metals management arena. Nalco/Exxon Energy Chemicals, L.P., in conjunction with Refining Process Services, Inc. (RPS), has introduced to the refining industry an improved metals passivation agent designed to specifically target the contaminant vanadium in the feed. A series of laboratory, pilot scale and full commercial unit applications has now proven the viability of this approach. In addition, a capability to improve the sodium tolerance of an FCC catalyst has been observed. The additive is being marketed under the tradename MVP’“, for Maximum Vanadium Protection.