Abstract A process is described for fixed bed hydrodesulfurizing a nonasphaltic oil feed or feed blend for a zeolitic FCC riser cracking system in which cracking occurs at a space velocity sufficiently high to prevent formation of a catalyst bed. It is found that sulfur dioxide emissions from the zeolite catalyst regenerator associated with the riser are reduced to a lower extent than total sulfur removal from the feed oil. This indicates uneven sulfur removal in the hydrodesulfurization step whereby a smaller portion of sulfur is removed from the heavy portion of the feed from which the coke is derived than from the lighter portion of the feed. The present invention demonstrates a synergistic effect upon sulfur removal from the heavy portion of the feed by widening the boiling range of the feed and this synergistic effect is converted to practical advantage by reducing the amount of hydrodesulfurization catalyst in proportion to said synergistic effect, thereby keeping hydrocracking to a specified low level. The hydrodesulfurization effluent is charged to the FCC process wherein the ratio of gasoline to total conversion is enhanced by reducing the amount of hydrodesulfurization catalyst and hydrocracking as permitted by said synergistic effect.
Inventors
👤 R Christman
👤 J Mckinney
👤 T Readal
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-28 00:13
CPC Classifications
C; C10; C10G; C10G69/00; C10G69/02; C10G69/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
197 words
A PROCESS FOR IMPROVING THE RATIO OF GASOLINE TO TOTAL CONVERSION IN A ZEOLITE RISER CRACKING OPERATION COMPRISING PASSING A NON-ASPHALTIC SULFUR-CONTAINING PETROLEUM HYDROCARBON FEED OIL HAVING A VOLUME AVERAGE BOILING POINT OF AT LEAST 700*F. TOGETHER WITH HYDROGEN DOWNFLOW OVER A FIXED BED OF HYDRODESULFURIZATION CATALYST COMPRISING GROUP VI AND GROUP VIII METALS ON A NON-CRACKING ALUMINA SUPPORT TO REMOVE AT LEAST 80 WEIGHT PERCENT OF THE SULTUR FROM THE FEED OIL, REGULATING THE AMOUNT OF HYDRODESULFURIZATION CATALYST IN THE BED TO AVOID EXCESSIVELY DECREASING THE BOILING CHARACTERISTICS OF THE FEED OIL WHEREBY AN INCREASE IN THE TEMPERATURE DIFFERNTIAL BETWEEN THE 10 AND 90 PERCENT BOILING POINTS OF THE FEED STREAM OCCURS BUT DOES NOT EXCEED 20*F. WHILE THE 90 PERCENT BOILING POINT OF THE FEED IS DECREASED AT LEAST 10*F., PASSING EFFLUENT FROM THE DHYDRODESULFURIZATION ZONE BOILING ABOVE THE GASOLINE RANGE TO A ZEOLITE RISER CRACKING PROCESS WHICH AVOIDS FORMATION OF A CATALYST BED IN THE REACTION FLOW PATH, AND RECOVERING A CRACKED HYDROCARBON PRODUCT HAVING AN INCREASED RATIO OF GASOLINE TO TOTAL CONVERSION AS COMPARED TO THE RATIO OBTAINABLE WITH SAID FEED OIL UNDER THE SAME CRACKING CONDITIONS IN THE ABSENCE OF SAID HYDRODESULFURIZATION.
Claim 2
Dependent Claim
197 words
A PROCESS FOR IMPROVING THE RATIO OF GASOLINE TO TOTAL CONVERSION IN A ZEOLITE RISER CRACKING OPERATION COMPRISING PASSING A NON-ASPHALTIC SULFUR-CONTAINING PETROLEUM HYDROCARBON FEED OIL HAVING A VOLUME AVERAGE BOILING POINT OF AT LEAST 700*F. TOGETHER WITH HYDROGEN DOWNFLOW OVER A FIXED BED OF HYDRODESULFURIZATION CATALYST COMPRISING GROUP VI AND GROUP VIII METALS ON A NON-CRACKING ALUMINA SUPPORT TO REMOVE AT LEAST 80 WEIGHT PERCENT OF THE SULTUR FROM THE FEED OIL, REGULATING THE AMOUNT OF HYDRODESULFURIZATION CATALYST IN THE BED TO AVOID EXCESSIVELY DECREASING THE BOILING CHARACTERISTICS OF THE FEED OIL WHEREBY AN INCREASE IN THE TEMPERATURE DIFFERNTIAL BETWEEN THE 10 AND 90 PERCENT BOILING POINTS OF THE FEED STREAM OCCURS BUT DOES NOT EXCEED 20*F. WHILE THE 90 PERCENT BOILING POINT OF THE FEED IS DECREASED AT LEAST 10*F., PASSING EFFLUENT FROM THE DHYDRODESULFURIZATION ZONE BOILING ABOVE THE GASOLINE RANGE TO A ZEOLITE RISER CRACKING PROCESS WHICH AVOIDS FORMATION OF A CATALYST BED IN THE REACTION FLOW PATH, AND RECOVERING A CRACKED HYDROCARBON PRODUCT HAVING AN INCREASED RATIO OF GASOLINE TO TOTAL CONVERSION AS COMPARED TO THE RATIO OBTAINABLE WITH SAID FEED OIL UNDER THE SAME CRACKING CONDITIONS IN THE ABSENCE OF SAID HYDRODESULFURIZATION.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the riser temperature is 900* to 1000*F.
Claim 4
Dependent Claim
21 words
The process of claim 1 wherein the residence time in the riser is at least 0.5 but less than five seconds.
Claim 5
Dependent Claim
15 words
The process of claim 1 wherein the temperature in the riser is 950* to 1050*F.
Claim 6
Dependent Claim
17 words
The process of claim 1 wherein the residence time in the riser is 0.5 to 2.5 seconds.
Claim 7
Dependent Claim
19 words
The process of claim 1 wherein said feed oil has a volume average boiling point of at least 750*F.
Claim 8
Dependent Claim
14 words
The process of claim 1 wherein the hydrodesulfurization pressure is 800 to 1200 psi.
Claim 9
Dependent Claim
25 words
The process of claim 1 wherein the hydrodesulfurization hydrogen consumption is 100 to 500 standard cubic feet per barrel of feed oil boiling above 650*F.
Claim 10
Dependent Claim
12 words
The process of claim 1 wherein the feed oil comprises gas oil.