Increasing hydrocracker diesel yield, total liquid yield and pour point properties by ammonia or amine spiking

A process for operating a catalytic hydrocracker in a hydrocarbon refinery wherein the process comprises:

• selecting and installing a catalyst into a hydrocracker vessel where the catalyst has a characteristic for high naphtha selectivity;
• delivering a hydrocarbon feedstream into the hydrocracker vessel where the hydrocarbon feedstream comprises a heavy distillation hydrocarbon material where at least 50% of the feedstream has a boiling point fraction of at least 650° F.:
• delivering hydrogen into the hydrocracker vessel where both the hydrocarbon feedstream and the hydrogen are in contact with the catalyst under catalytic conditions to cause both hydrogenation and cracking of the hydrocarbon feedstream;
• producing a product slate that comprises a first desired naphtha make and a first desired distillate make;
• selectively feeding a basic compound in to the hydrocracker to partially passivate the catalyst and to thereby shift the product slate to a ratio where a higher diesel make is produced relative to the naphtha make such that the diesel make is at least 0.5% higher than when the basic compound is not fed to the hydrocracker;
• and
• selectively suspending the feed of the basic compound to the hydrocracker to shift the product slate back to near the original ratio of diesel make to naphtha make.