Multiple-stage cascade hydrorefining of contaminated charge stocks

Claim 1

A PROCESS FOR HYDROREFINING A HYDROCARBON CHARGE STOCK COMPRISING HYDROCARBON BOILONG ABOVE THE GASOLINE BOILING RANGE, AND CONTAINING A CONTAMINANT SELECTED FROM THE GROUP CONSISTING OF NITROGENOUS COMPOUNDS AND SULFUROUS COMPOUNDS, WHICH PROCESS COMPRISES THE STEPS OF: (A) HYDROCRACKING AND HYDROREFINING SAID CHARGE STOCK IN ADMIXTURE WITH HYRDOGEN AT A TEMPERATURE IN THE RANGE OF FROM ABOUT600*F. TO ABOUT 850*F. IN A FIRST REACTION ZONE CONTAINING A HYDROREFINING CATALYTIC COMPOSITE; (B) SEPARATING THE NORMALLY LIQUID PRODUCT EFFLUENT FROM SAID FIRST REACTION ZONE INTO A FIRST LIGHT FRACTION, HAVING AN END BOILING POINT OF FROM ABOUT 400* F. TO ABOUT 650*F. AND A HEAVIER FRACTION; (C) COMBINING AT LEAST A PORTION OF SAID FIRST LIGHT FRACTION WITH A HYDROCARBON MIXTURE HAVING AN INITIAL BOILING POINT OF FROM ABOUT 300*F. TO ABOUT 450*F. AND CONTAINING AT LEAST ONE OF THE AFORESAID CONTAMINANTS, AND REACTING THE RESULTING MIXTURE WITH HYDROGEN AT A TEMPERATURE WITHIN SAID RANGE IN A SECOND REACTION ZONE CONTAINING A HYDROREFINING CATRALYTIC COMPOSITE AND MAINTAINED UNDER LESS SEVERE CONVERSION CONDITIONS THAN SAID FIRST ZONE; (D) SEPARATING THE NORMALLY LIQUID PRODUCT EFFLUENT FROM SAID SECOND REACTION ZONE INTO A SECOND LIGHT FRACTION, HAVING AN END BOILING POINT WITHIN THE RANGE OF FROM ABOUT 300*F. TO ABOUT 450*F., AND A HYDROREFINED SECOND HEAVY FRACTION; (E) COMBINING AT LEAST A PORTION OF SAID SECOND LIGHT FRACTION WITH A HYDROCARBON MIXTURE, HAVING AN END BOILING POINT OF FROM 300*F. TO ABOUT 450*F. AND CONTAINING AT LEAST ONE OF THE AFORESAID CONTAMINANTS, REACTING THE RESULTING MIXTURE WITH HYDROGEN AT A TEMPERATURE WITHIN SAID RANGE IN A THIRD REACTION ZONE CONTAINING A HYDROREFINING CATALYTIC COMPOSITE AND MAINTAINED UNDER CONDITIONS TO EFFECT HYDROGENATIVE HYDROREFINING OF SAID MIXTURE WITH MINIMUM HYDROCRACKING; AND, (F) SEPARATING THE PRODUCT EFFLUENT FROM SAID THIRD REACTION ZONE INTO A NORMALLY GASEOUS PHASE AND A HYDROREFINED THIRD HEAVY FRACTION.