Abstract: The recovery of distillate products from a hydrocracking process includes passing the liquid-phase portion of the reaction zone effluent into a stripping column. A naphtha sidecut stream is recovered off the stripping column and combined with the net overhead liquid of the column. These combined streams are then combined with the naphtha recovered from the primary product recovery column. This minimizes the hydrogen sulfide present in the total naphtha product.

Abstract: Potential problems associated with the formation of polynuclear aromatic compounds during hydrocracking of residual oils are eliminated by operating at high conversion rates with a high hydrogen concentration followed by a unique separation method. The feed to the final product recovery column is preferably highly vaporized before or within the column. All of the net bottoms stream of the product recovery column, which is equal to less than 5 vol. percent of the feed, is withdrawn from the process. Only PNA free distillate is recycled.

Abstract: Potential problems associated with the formation of polynuclear aromatic compounds during hydrocracking of residual oils are eliminated by operating at high conversion rates with a high hydrogen concentration followed by a unique separation method. The feed to the final product recovery column is highly vaporized. All of the net bottoms stream of the product recovery column, which is equal to less than 5 vol. percent of the feed, is withdrawn from the process. Only PNA free distillate is recycled.

Abstract: An integrated hydrocarbon conversion process wherein two different heavy oil feed streams are thermally processed is disclosed. Preferably a vacuum gas oil is charged to a thermal cracking zone and a reduced crude fraction is charged to a visbreaking heater. The effluent of each thermal operation is separated into vapor and liquid fractions, with the vapor fractions being fed to a product fractionator. The liquid fractions each enter separate but interconnected subatmospheric pressure separation zones, one of which is a vacuum column. The bottoms of a product fractionator and distillate from the vacuum column are also charged to the thermal cracking zone.

Abstract: A multiple-stage process for the conversion of a heavy hydrocarbonaceous charge stock, contaminated by the inclusion of sulfurous and nitrogenous compounds, into lower-boiling hydrocarbon products. Fresh feed and hydrogen are introduced into a catalytic hydrorefining reaction zone to convert the contaminants into ammonia and hydrogen sulfide. Hydrorefined product effluent is admixed with the effluent from a catalytic hydrocracking reaction zone, and separated into various product streams. Hydrocarbons boiling above the predetermined end boiling point of the desired end product and hydrogen are introduced into the catalytic hydrocracking reaction zone for conversion to lower-boiling hydrocarbons. Hydrocracked effluent is admixed with the hydrorefined effluent as aforesaid.