Hydrocracking process and system including separation of heavy poly nuclear aromatics from recycle by sulfonation

A two stage hydrocracking process for hydrocracking of a vacuum gas oil, a demetallized oil, a deasphalted oil, a coker gas oil, a cycle oil or a visbroken oil hydrocarbon stream, the process comprising:

• subjecting the vacuum gas oil, demetallized oil, deasphalted oil, coker gas oil, cycle oil or visbroken oil hydrocarbon stream to a first hydrocracking stage to produce a first hydrocracked effluent;
• fractionating the first hydrocracked effluent to recover one or more hydrocracked product fractions and a bottoms fraction corresponding to the hydrocracked bottoms fraction, wherein the hydrocracker bottoms fraction contains heavy poly nuclear aromatic (HPNA) compounds that are formed during hydrocracking reactions;
• separating HPNA compounds from the hydrocracked bottoms fraction by contacting the hydrocracked bottoms fraction with an effective quantity of a sulfonation agent to promote reaction with HPNA compounds to produce corresponding sulfonated HPNA compounds and to form a sulfonated hydrocracked bottoms fraction, separating the sulfonated hydrocracked bottoms fraction into an HPNA-reduced hydrocracked bottoms portion and a sulfonated HPNA portion, and discharging the sulfonated HPNA portion;
• passing all or a portion of the HPNA-reduced hydrocracked bottoms portion to a second hydrocracking stage to produce a second hydrocracked effluent;
• and
• subjecting the second hydrocracked effluent to fractionating with the first hydrocracked effluent.