A delayed coking process for use in a delayed coking unit that includes at least one drum (50, 150), the coking unit producing a delayed coking product stream and a coke product that is retained in the drum, the coking product stream being introduced into a coking product stream fractionator (20, 120) to produce at least a bottoms fraction, an intermediate fraction and a light naphtha fraction, the process comprising: a. analyzing a sample of fresh heavy hydrocarbon feedstock containing asphaltenes that is to be subjected to the delayed coking process, to determine the paraffinic solvent-to-asphaltenes ratio required to flocculate substantially all of the asphaltenes; b. introducing a fresh heavy hydrocarbon feedstock containing asphaltenes for preheating into the lower portion of the coking product fractionator; c. discharging the bottoms fraction that includes the preheated fresh hydrocarbon feedstock from the fractionator as a coking unit combined feedstream; d. introducing a separate paraffinic solvent having the formula C n H 2n+2, where n is from 3 to 8 or a combined paraffinic and olefinic solvent, the latter having the formula C n H 2n, where n is from 3 to 8, into a mixing zone (30, 130) intermediate the coking product fractionator and the coking unit furnace and mixing the coking unit combined feedstream with the solvent in a sufficient ratio of solvent-to-feedstream that was determined in step (a) to solvent-flocculate substantially all of the asphaltenes in the coking unit combined feedstream; e. introducing the coking unit combined feedstream containing flocculated asphaltenes into the coking unit furnace for heating to a predetermined coking temperature; f. passing the heated combined feedstream containing the solvent-flocculated asphaltenes and solvent to the at least one drum to produce the delayed coking product stream having an increased portion of liquids and depositing a reduced amount of coke on the interior of the drum, as compared to the amount of coke deposited in the absence of the addition of the solvent to the same heavy hydrocarbon feedstock. a. analyzing a sample of fresh heavy hydrocarbon feedstock containing asphaltenes that is to be subjected to the delayed coking process, to determine the paraffinic solvent-to-asphaltenes ratio required to flocculate substantially all of the asphaltenes; b. introducing a fresh heavy hydrocarbon feedstock containing asphaltenes for preheating into the lower portion of the coking product fractionator; c. discharging the bottoms fraction that includes the preheated fresh hydrocarbon feedstock from the fractionator as a coking unit combined feedstream; d. introducing a separate paraffinic solvent having the formula C n H 2n+2, where n is from 3 to 8 or a combined paraffinic and olefinic solvent, the latter having the formula C n H 2n, where n is from 3 to 8, into a mixing zone (30, 130) intermediate the coking product fractionator and the coking unit furnace and mixing the coking unit combined feedstream with the solvent in a sufficient ratio of solvent-to-feedstream that was determined in step (a) to solvent-flocculate substantially all of the asphaltenes in the coking unit combined feedstream; e. introducing the coking unit combined feedstream containing flocculated asphaltenes into the coking unit furnace for heating to a predetermined coking temperature; f. passing the heated combined feedstream containing the solvent-flocculated asphaltenes and solvent to the at least one drum to produce the delayed coking product stream having an increased portion of liquids and depositing a reduced amount of coke on the interior of the drum, as compared to the amount of coke deposited in the absence of the addition of the solvent to the same heavy hydrocarbon feedstock.