Catalyst sulfidation and passivation in hydrocracking units

1. Once ammonia penetrates, adjust the injection rate of anhydrous liquid ammonia to maintain an ammonia concentration of approximately 0.8 w% in the highly acidic water. Continue to raise the temperature at the inlet of the refining reactor steadily at a rate of ≯8℃/h until it reaches 290℃, then maintain this temperature for 6 hours ； When all the ammonia has been injected, the ammonia concentration in the highly acidic water remains at approximately 0.8 w%, at which point catalyst deactivation is complete. 2. After maintaining the temperature at 290°C, the inlet temperature of the refining reactor was gradually increased to 325°C at a rate of ≤6°C/h. If the temperature rise of any bed in the cracking reactor exceeds 5°C, the heating of the cracking reactor is stopped. At the same time, adjust the injection rate of the vulcanizing agent so that the hydrogen sulfide concentration in the cyclic hydrogen reaches 1.0–1.5 v%, and maintain this temperature for 2 hours ； Based on the test analysis results, open the waste hydrogen valve at the appropriate time to maintain a hydrogen purity of over 85% in the circulating hydrogen. When all the vulcanizing agent has been injected and the hydrogen sulfide concentration in the recycled hydrogen remains constant at 1.0–1.5 v%, the pre-vulcanization of the catalyst is complete.