Controlling thermal coking

A method for producing a distillate boiling range product, which comprises:

• hydroprocessing a feedstock substantially composed of hydrocarbons in a hydroprocessing reaction zone which includes a hydrocracking catalyst containing a promoting metal selected from the group consisting of molybdenum, nickel, cobalt, or copper or a mixture thereof to produce a hydroprocessed residuum, wherein at least a portion of the hydrocracking catalyst becomes a fugitive catalyst which passes from the hydroprocessing reaction zone with the hydroprocessed residuum;
• blending the hydroprocessed residuum and the fugitive catalyst with an attenuating agent which includes an attenuating metal selected from the group consisting of antimony, lead, tin, bismuth or a mixture thereof to produce a treated residuum, wherein the attenuating agent is present in the treated residuum as dispersed solid particles, and;
• thermal coking the treated residuum at reaction conditions including a hydrogen partial pressure of about 0.01 to about 2 atmospheres, a temperature in the range of about 400 to about 500 degrees C., and a residence time of about one to about forty hours to produce coke and a distillate boiling range product;
• and
• recovering the distillate product in a measurable proportion, based on the total weight of the hydroprocessed residuum and the fugitive catalyst, which is greater than the proportion recoverable without blending the hydroprocessed residuum and the fugitive catalyst with the attenuating agent.

A method for controlling thermal coking in a petroleum residuum containing a coke promoting compound, which comprises:

• blending a petroleum residuum containing a coke promoting compound with an attenuating agent to produce a treated residuum, wherein the coke promoting compound is in the form of a dispersed particulate and includes a sulfide of molybdenum and the attenuating agent is selected from the group consisting of antimony dithiocarbamate, antimony dithiophosphate, lead dithiocarbamate, tin dialkyldicarboxylate, bismuth dithiocarbamate or a mixture thereof;
• thermal coking the treated residuum at conditions including a hydrogen partial pressure of about 0.01 to about 2 atmospheres, a temperature in the range of about 400 to about 500 degrees C., and a reaction time of about one to about forty hours to produce coke and a distillate boiling range product;
• and
• recovering the distillate product in a measurable proportion, based on the amount of the petroleum residuum blended, which is greater than the proportion recoverable without blending the petroleum residuum with the attenuating agent.