Alkali metal hydroprocessing of heavy oils with enhanced removal of coke products

A process for desulfurizing a hydrocarbon feedstream, comprising:

• a) mixing at least a portion of a hydrocarbon feedstream having an API gravity of less than 19 with a first aqueous alkali metal salt reagent solution to form a first mixed reactor feedstream;
• b) exposing at least a portion of the first mixed reactor feedstream to a first desulfurization reactor operated under first effective desulfurization conditions to form a first desulfurized reactor product stream comprising desulfurized oil, spent alkali metals, and coke;
• c) separating the first desulfurized reactor product stream to form at least a first low-boiling point vapor fraction and a first reactor product liquid fraction;
• d) mixing at least a portion of the first reactor product liquid fraction with a second aqueous alkali metal salt reagent solution to form a second mixed reactor feedstream;
• e) exposing at least a portion of the second mixed reactor feedstream to a second desulfurization reactor operated under second effective desulfurization conditions to form a second desulfurized reactor product stream comprising desulfurized oil, spent alkali metals, and coke;
• f) separating the second desulfurized reactor product stream to form at least a second low-boiling point vapor fraction and a second reactor product liquid fraction;
• g) mixing at least a portion of the second reactor product liquid fraction with water to form a first wash water separator feedstream;
• h) sending the first wash water separator feedstream to a first wash water separator vessel wherein in the first wash water separator vessel, the first wash water separator feedstream forms three distinct layers as flows:
• a first desulfurized oil product layer, a first emulsion phase layer, and a first aqueous spent alkali metal layer;
• i) removing each of the three distinct layers separately from the first wash water separator vessel to separately form a first desulfurized oil product stream, a first emulsion phase stream, and a first aqueous spent alkali metal stream;
• wherein at least 50 wt % of the total coke in the first and second desulfurized reactor product streams is removed in the first emulsion phase stream, and the first desulfurized oil product stream has a lower sulfur content by wt % than the hydrocarbon feedstream, and the first desulfurized oil product stream has a API gravity of at least 20 and a viscosity of less than or equal to 40 centistokes at 40° C.

A process for desulfurizing a hydrocarbon feedstream, comprising:

• a) mixing at least a portion of a hydrocarbon feedstream having an API gravity of less than 19 with an aqueous alkali metal salt reagent solution to form a first mixed reactor feedstream;
• b) exposing at least a portion of the first mixed reactor feedstream to a first desulfurization reactor operated under first effective desulfurization conditions to form a first desulfurized reactor product stream comprising desulfurized oil, spent alkali metals, and coke;
• c) separating the first desulfurized reactor product stream to form at least a first low-boiling point vapor fraction and a first reactor product liquid fraction;
• d) mixing at least a portion of the first reactor product liquid fraction with water to form a first wash water separator feedstream;
• e) sending the first wash water separator feedstream to a first wash water separator vessel wherein in the first wash water separator vessel, the first wash water separator feedstream forms three distinct layers as flows:
• a first desulfurized oil product layer, a first emulsion phase layer, and a first aqueous spent alkali metal layer;
• f) removing each of the three distinct layers separately from the first wash water separator vessel to separately form a first desulfurized oil product stream, a first emulsion phase stream, and a first aqueous spent alkali metal stream;
• g) mixing at least a portion of the first desulfurized oil product stream with water to form a second wash water separator feedstream
• h) sending the second wash water separator feedstream to a second wash water separator vessel wherein in the second wash water separator vessel, the second wash water separator feedstream forms three distinct layers as flows:
• a second desulfurized oil product layer, a second emulsion phase layer, and a second aqueous spent alkali metal layer;
• i) removing each of the three distinct layers separately from the second wash water separator vessel to separately form a second desulfurized oil product stream, a second emulsion phase stream, and a second aqueous spent alkali metal stream;
• wherein at least 50 wt % of the total coke in the first desulfurized reactor product stream is removed in the first and second emulsion phase streams, and the first and second desulfurized oil product streams each have a lower sulfur content by wt % than the hydrocarbon feedstream, and the first and second desulfurized oil product streams each have an API gravity of at least 20 and a viscosity of less than or equal to 40 centistokes at 40° C.