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Developments in Catalyti Cracking of Reduced Crudes

IP.com Disclosure Number: IPCOM000219852D
Publication Date: 2012-Jul-17

Publishing Venue

The IP.com Prior Art Database

Abstract

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DEVELOPMENTS IN CATALYTIC CRACKING OF REDUCED CRUDES

    U, S, REFINERIES ARE CURRENTLY OPERATING AT LESS THAN 70~ OF CAPACITY WITH NO INDICATIONS OF ANY INCREASE, IN ADDITION, THE

DEMAND FOR RESIDUAL FUEL IS RAPIDLY DECLINING,I)THE REDUCTION IN

CRUDE RUNS HAS FREED SOME FCC CAPACITY FOR CONVERSION OF THE RE- SIDUA TO LIGHTER PRODUCTS, INCLUDING VARIOUS AMOUNTS OF ATMOS-

PHERIC OR VACUUM TOWER BOTTOMS IN CHARGE TO FCC UNITS HAS BECOME AN ESTABLISHED OPERATION IN THE UNITED STATES. A SURVEY TAKEN EARLIER THIS YEAR SHOWED THAT ABOUT 25 FCC UNITS IN THE U.S. ARE PROCESSING RESID. IN ADDITION, A NEW HEAVY 01L CRACKING UNIT,

SPECIFICALLY DESIGNED FOR CRACKING A DESULFURIZED RESID, HAS RE- CENTLY STARTED UP AT THE PHILLIPS REFINERY IN SWEENY, TEXAS,

KELLOGG IS IN THE MIDST OF DESIGNING ANOTHER GROSS ROOTS HEAVY 01L CRACKING FACILITY FOR SABER 01L AT CORPUS CHRISTI, TEXAS. CURRENT REVAMPS OF FCC UNITS GENERALLY INCLUDE SOME CONSIDERATION OF RESIDUAL CRACKING. RECENT DEVELOPMENTS REGARDING DESIGN OF BOTH NEW UNITS AND REVAMPS, CATALYSTS AND PASSIVATORS, HEAT REMOVAL SYSTEMS AND OPERATING VARIABLES IN CATALYTIC CRACKING
OF REDUCED CRUDES ARE PRESENTED IN THIS PAPER.

FEEDSTOCKS

   THE QUALITY OF REDUCED CRUDES, PARTICULARLY WITH RESPECT TO THEIR ASPHALTENE CONTENT, VARIES CONSIDERABLY. THEREFORE, THE

DESIGN OF NEW H0C uNITS WILL VARY ACCORDING TO THE QUALITY OF THE RESID. KELLOGG CATEGORIZES FEEDSTOCKS AS FOLLOWS:


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1, HIGH QUALITY REDUCED CRUDES

   THIS INCLUDES REDUCED CRUDES OF METALS CONTENTS LESS THAN ABOUT 10 PPM AND CARBON RESIDUES OF LESS THAN 5~ FEEDSTOCKS

OF THIS QUALITY CAN BE HANDLED IN A MODIFIED FCC UNIT, THE USUAL PROBLEM IS DEVELOPING A DESIGN WHICH WILL MINIMIZE COKE FORMATION SO THAT EXTERNAL MEANS TO REMOVE HEAT FROM THE REGEN- ERATOR ARE NOT REQUIRED, CATALYST AND OPERATING VARIABLES TO ACHIEVE THE LOW COKE YIELD INCLUDE HIGH CATALYST ACTIVITY, USE OF METALS PASSIVATORS~ LOW PRESSURES~ LOW CONTACT TIME AND LIGHT OIL RECYCLE, AN ILLUSTRATION OF THE YIELDS THAT CAN BE ACHIEVED

WITH SUCH FEEDSTOCKS IS SHOWN IN TABLE I FOR B6TH HIGH AND LOW SEVERITY OPERATIONS, WHEREIN IT IS DESIRED TO MAXIMIZE GASOLINE

OR MIDDLE DISTILLATE,

   THIS FEEDSTOCK HAS A 3,9% CARBON RESIDUE AND A 5,7 PPM METALS CONTENT, AND A 23,3┬░API. THE NORMAL COKE YIELD IN AN FCC UNIT

WHIC~ EASILY SATISFIES THE HEAT REQUIREMENTS IS ABOUT ~, WITH THE 3,9% CARBON RESIDUE FEED~ WE ARE PRODUCING AN ADDITIONAL

2 TO 3~ COKE WHICH REQUIRES SPECIALIZED CONDITIONS TO AVOID EXCESSIVE REGENERATOR TEMPERATURES,

    ~OTE ALSO THAT THERE IS A GOOD FLEXIBILITY FOR VARYING CONVERSION AND YIELDS IN H0C UNITS, THESE PILOT PLANT DATA SHOW THE MAXIMUM GASOLINE OPERATION PRODUCES ABOUT 64% GASOLINE AT 80~ CONVERSION, AT MILDER SEVERITIES, A 32% YIELD OF LIGHT

CATALYTIC GAS OIL IS ACHIEVED, IN BOTH CASES, LIQUID RECOVERIES GREATER THAN 105~ ARE REALIZED,


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2, REDUCED CRUDES WITH METALS CONTENT UP TO AB ~T 30 PPM AND

CARBON RESIDUES OF 5 TO 10%.

   THIS CATEGORY IS ILL...