Abstract: In view of the influence of nickel deposited on the contact agent during residue contact cracking and coke gasification process, the effect of different valence nickel on the coke gasification reaction on the contact agent was studied. The nickel contaminants were analyzed by XRD, XRF, BET and TPR methods, and the effect of different valence nickel deposited on the contact agent on the coke gasification reaction was investigated in a small fixed fluidized bed device. The results showed that high-valence nickel (less than 2% by mass fraction) promoted the CO selectivity of coke gasification under oxygen-poor condition, but low-valence nickel had a negative effect on the CO selectivity. In the experiment of CO oxidation, the reaction of CO oxidation to CO₂ was inhibited by high valence nickel, but promoted by the low valence nickel. When the temperature reached 730 ℃, the CO oxidation reaction rate increased rapidly. Increasing the volume fraction of reactant O₂ promoted the formation of CO₂, while increasing the volume fraction of CO₂ had little effect on the n(CO)/n(CO₂) ratio of the product.

Key words: coke, gasification, contact agent, nickel, carbon monoxide