Formation of Ni and Mg vanadates during the flameless oxy-combustion of heavy fuels

Role of nickel on vanadium poisoned FCC catalyst: A study of physiochemical properties

“…Nevertheless, the exact product cannot be ascertained in this report due to the use of rather small concentrations of the metals typical in FCC feedstock. Judging from the result of this 51 V MAS NMR and other analyses, it can be concluded that nickel inhibit vanadium effects on the catalyst by reaction of nickel species with vanadium species to form high melting point refractory nickel vanadate (which could be any of NiV 2 O 6 , 720 °C; [46,47] at reaction temperatures. The above reactions ( Eqs.…”

“…Any of the above nickel vanadate is a possible formation during cracking reaction depending on the amount of the metals and Ni/V ratio in the composition [46] . Nevertheless, the exact product cannot be ascertained in this report due to the use of rather small concentrations of the metals typical in FCC feedstock.…”

High Temperature Corrosion of Nickel in NaVO3-V2O5Melts

“…The high initial reactivity of Ni in the presence of vanadium salts has a beneficial effect because it forms a highly stable refractory phase, Ni 3 V 2 O 8 , which reduces the corrosiveness of the melt by trapping the vanadium and blocking the migration of nickel ions [3,23,26], and the stability of the refractory phase still prevails in the presence of Na 2 SO 4 [2]. The results obtained are congruent with other studies where NiO has been proposed as a corrosion inhibitor in vanadium-rich molten salts [2,3,24], or Ni-derivatives to remove vanadium compounds [26]. Notwithstanding the above, in the case of nickel-based alloys with a multielement chemical composition the results may be different due to synergistic dissolution reactions between the different oxides developed [11,[27][28][29].…”

Rare Earth-Based Compounds as Inhibitors of Hot-Corrosion Induced by Vanadium Salts

“…Through this reaction, lanthanum oxide stabilizes the vanadium cation and reduces the ionic exchange that favors the dissolution process of the protective layer [7,9] by reducing the acid character of the melt according to the following reaction [9,10]:VO3−+O2−↔VO43−.…”

“…The main objective of corrosion inhibitors is to stabilize V by trapping it in new compounds with a high melting point and low chemical reactivity. To date, the most commonly used corrosion inhibitor is based on magnesium compounds that, when reacted with vanadium salts, form the refractory compound Mg 3 (VO 4 ) 2 (melting point of 1074 °C) [7,8,9,10,11]. However, its inhibition capacity is compromised if the S content of the fuel is high [12,13].…”