Hydrocracking process for the production of high quality distillates from heavy gas oils

A method for hydroprocessing a hydrocarbon feedstock, said method employing multiple reaction zones within a single reaction loop, comprising the following steps:

• (a) passing a hydrocarbonaceous feedstock to a first hydroprocessing zone having one or more beds containing hydroprocessing catalyst, the hydroprocessing zone being maintained at hydroprocessing conditions, wherein the feedstock is contacted with catalyst and hydrogen;
• (b) passing the effluent of step (a) directly to a hot high pressure separator, wherein the effluent is contacted with a hot, hydrogen-rich stripping gas to produce a vapor stream comprising hydrogen, hydrocarbonaceous compounds boiling at a temperature below the boiling range of the hydrocarbonaceous feedstock, hydrogen sulfide, ammonia, and a bottoms stream comprising hydrocarbonaceous compounds boiling in approximately the same range of said hydrocarbonaceous feedstock along with a portion of the hydrocarbonaceous compounds boiling in the diesel boiling range;
• (c) passing the vapor stream from step (b) after cooling and partial condensation to a hot hydrogen stripper containing at least one bed of hydrotreating catalyst, where it is contacted countercurrently with hydrogen, while the liquid stream of step (b) is passed to a second stage reactor;
• (d) passing the overhead vapor stream from the hot hydrogen stripper of step (c), after cooling and contacting with water, to a first cold high pressure separator where hydrogen, hydrogen sulfide and light hydrocarbonaceous gases are removed overhead and a liquid stream comprising naphtha and middle distillates is passed to fractionation, thereby removing most of the ammonia and some of the hydrogen sulfide (as ammonium bi-sulfide in the sour water stream as it leaves the cold high-pressure separator);
• (e) passing the liquid stream from the hot hydrogen stripper of step (c) to a bed of hydroprocessing catalyst in the second reactor stage wherein the liquid is contacted under hydroprocessing conditions with the catalyst, in the presence of hydrogen;
• (f) passing the overhead from the cold high pressure separator of step (d) to an amine absorber, where hydrogen sulfide is removed before hydrogen is compressed and recycled to hydroprocessing vessels within the loop;
• (g) passing the separator bottoms of step (b) to a second reaction stage where it is contacted with at least one bed of hydrocracking catalyst in the presence of hydrogen to produce a vapor stream and liquid effluent;
• (h) passing the vapor stream of step (g) after cooling to a second cold high-pressure separator where a vapor stream is removed comprising primarily hydrogen and light hydrocarbonaceous gases;
• (i) passing the liquid effluent of step (g) after cooling to the cold high-pressure separator of step (h) to separate hydrogen and light hydrocarbonaceous gases from the liquid effluent;
• (j) passing the vapor stream from steps (h) and (i) after further cooling and separation of condensate, to the make-up hydrogen compressor;
• (k) passing the compressed hydrogen from the make-up hydrogen compressor to the primary reactor loop;
• and
• (l) passing the liquid effluent from steps (h) and (i) to the fractionation system.