Which metals can poison catalysts

Heavy metals such as vanadium and nickel, among which vanadium has the greatest impact on catalysts; metal passivators must have the ability to passivate vanadium

Iron, nickel, copper, vanadium, and zinc are all metals that can poison catalysts, but vanadium and nickel have the greatest impact; vanadium forms compounds that destroy the crystal structure of the catalyst.

In the raw materials, heavy metals are mainly iron, nickel, vanadium, and sodium, which are the most common and have the greatest impact. The metal compounds in the raw materials are further decomposed during the reaction, with the metals depositing on the catalyst; after regeneration, they turn into oxides. A high content of metal oxides affects the catalyst’s activity and selectivity. 1) Iron-based oxidation catalysts are present in large quantities, but their harm is minimal. They facilitate the formation of CO2/CO in the flue gases during coking; iron essentially deposits on the surface of the catalyst, blocking its pores and leading to a decline in the catalyst’s cracking performance. 2) Both nickel and vanadium possess dehydrogenation properties; the unsaturated hydrocarbon molecules resulting from dehydrogenation tend to condense and form coke. As a result, nickel and vanadium reduce the selectivity of the catalyst, leading to an increase in the hydrogen content in the dry gas among the reaction products and an increase in the yield of coke. 3) V can also form low-melting eutectics with alumina, reducing the specific surface area of the catalyst; at the same time, it destroys the crystal structure of the catalyst, thereby causing permanent deactivation of the catalyst. 4) Na poses a significant hazard; it can neutralize the acidic centers in the catalyst, thereby reducing its activity. It can also combine with elements such as silicon and aluminum present on the catalyst to form soluble compounds, resulting in permanent loss of activity. Additionally, Na acts in synergy with V, and together they form low-melting-point oxide eutectics on the catalyst surface, which cover the active centers and weaken the structure of the catalyst carrier, thus reducing the catalyst’s thermal stability. 、

Thank you, but I think there should also be copper, arsenic, lead, mercury, especially arsenic. . . . . . . .

Different catalysts are sensitive to different metal or non-metal elements; it depends on the specific catalyst, and no generalization can be made.

Thank you, I checked and there is indeed a difference; thank you

Iron, nickel, copper, vanadium. Mainly nickel and vanadium. Nickel mainly plays a role in dehydrogenation, while vanadium can destroy the crystal structure of zeolites.

What catalyst? The poster seems to be referring to a reforming catalyst.

Yes, it’s the reforming catalyst, R-264