USOO5858.205A United States Patent (19) 11 Patent Number: 5,858,205 Huebner (45) Date of Patent: Jan. 12, 1999 54 MULTIZONE CATALYTIC REFORMING 4,929,332 5/1990 Moser et al. .............................. 208/65 PROCESS 4,929,333 5/1990 Moser et al..... ... 208/65 4,985,132 1/1991 Moser et al. .............................. 208/65 75 Inventor: Aronson L. Huebner, Palatine, Ill. Primary Examiner-Helane Myers Attorney, Agent, or Firm Thomas K. McBride; John F. 73 Assignee: UOP LLC, Des Plaines, Ill. Spears, Jr.; Richard E. Conser 21 Appl. No.: 855,232 57 ABSTRACT 22 Filed: May 13, 1997 A hydrocarbon feedstock is catalytically reformed in a (51) Int. Cl. ............................................... C10G 35/06 process which comprises at least three catalyst Zones. The feedstock contacts a catalyst comprising platinum, a 52) ... 208/65; 208/137; 208/138 halogen, and a metal promoter on a Solid catalyst Support in 58 Field of Search ................................................. 208/65 a first catalyst Zone. Effluent from the first catalyst ZOC contacts a catalyst comprising platinum, germanium and 56) References Cited halogen on a Solid catalyst Support in an intermediate U.S. PATENT DOCUMENTS catalyst Zone to obtain an intermediate effluent, which contacts a catalyst having the essential absence of germa 3,578,584 5/1971 Hayes ...................................... 208/139 nium and comprising platinum, halogen and a metal pro 4,645,586 2/1987 Buss........................................... 208/65 moter on a Solid catalyst Support in a terminal catalyst Zone 4,663,020 5/1987 Fleming .................................... 208/65 to obtain a reformate 4,722,780 2/1988 Franck et al. ... 208/65 4,737.262 4/1988 Franck et al. ... 208/65 4,764,267 8/1988 Chen et al. ............................... 208/65 18 Claims, No Drawings 5,858,205 1 2 MULTIZONE CATALYTIC REFORMING (3) Stability refers to the rate of change of activity or PROCESS Selectivity per unit of time or of feedstock processed. Activity Stability generally is measured as the rate of BACKGROUND OF THE INVENTION change of operating temperature per unit of time or of feedstock to achieve a given Cs product octane, with Field of the Invention a lower rate of temperature change corresponding to This invention relates to an improved proceSS for the better activity Stability, Since catalytic reforming units conversion of hydrocarbons, and more specifically for the typically operate at relatively constant product octane. catalytic reforming of gasoline-range hydrocarbons. Selectivity Stability is measured as the rate of decrease 1O of Cs" product or aromatics yield per unit of time or of feedstock. General Background Higher catalyst activity is required to meet the need for The catalytic reforming of hydrocarbon feedstocks in the high octane gasoline components at reasonable operating gasoline range is an important commercial process, prac conditions, and improved catalyst Selectivity becomes more ticed in nearly every significant petroleum refinery in the 15 important as higher operating Severities reduce the yield of World to produce aromatic intermediates for the petrochemi desired product. cal industry or gasoline components with high resistance to Higher operating Severities also accelerate the deactiva engine knock. The widespread removal of lead antiknock tion of the catalyst. The principal cause of deactivation of a additive from motor fuels, Subsequent gasoline reformula dual-function catalyst in a catalytic reforming operation is tion and the rising demands of high-performance internal the aforementioned formation of coke on the Surface of the combustion engines are increasing the need for gasoline catalyst. Alternative approaches to reactivation of the cata "octane', or knock resistance of gasoline blending compo lyst are well known to those skilled in the art. Regeneration nents. Furthermore, the demand for aromatic hydrocarbons of the catalyst may be carried out during a periodic shut for chemical Syntheses continues to increase throughout the down of the unit, i.e., a “semiregenerative' operation, or by industrial world. The catalytic reforming unit must operate 25 isolation and regeneration of individual reactors, i.e., a at higher Severities in order to meet these increased octane “Swing-reactor System. In a “continuous operation, cata and aromatics needs. This trend creates a need for more lyst is withdrawn by means of a slowly moving bed, effective reforming catalysts and catalyst combinations. regenerated, reactivated, and returned to the reactors. The The multi-functional catalyst composite employed in “hybrid” System is a combination of regeneration catalytic reforming contains a metallic hydrogenation techniques, in which a reactor associated with continuous dehydrogenation component on a porous, inorganic oxide catalyst regeneration is added to an existing fixed-bed Sys Support which provides acid Sites for cracking and isomer tem. The reactants may contact the catalyst in individual ization. Catalyst composites comprising platinum on highly reactors in either upflow, downflow, or radial-flow fashion, purified alumina are particularly well known in the art. with the radial-flow mode being preferred. Those of ordinary skill in the art are also aware of metallic 35 The problem facing workers in this area of the art, modifiers, Such as rhenium, iridium, tin, and germanium therefore, is to develop catalyst Systems with improved which improve product yields or catalyst life in platinum activity, Selectivity, and Stability for a variety of feedstocks, catalyst reforming operations. product requirements, and reactor Systems. This problem has The composition of the catalyst, feedstock properties, and become more challenging due to the aforementioned Selected operating conditions affect the relative importance 40 increase in required catalytic reforming Severity. Multi and Sequence of the principal reactions: dehydrogenation of catalyst-Zone Systems, in which different catalyst compos naphthenes to aromatics, dehydrocyclization of paraffins to ites are employed in the Sequential Zones of the reactor aromatics, isomerization of paraffins and naphthenes, hydro System, may comprise one Solution to the problem. The cracking of paraffins to light hydrocarbons, and formation of activity, Selectivity, and Stability characteristics of individual coke which is deposited on the catalyst. Naphthene dehy 45 catalyst composites are complementary to the Specific reac drogenation takes place principally in the first catalyst tions occurring in the different Zones of the multi-Zone Zones, while hydrocracking is largely accomplished in later System. catalyst Zones. High yields of desired gasoline-range prod Two-catalyst Systems have been disclosed in the reform ucts are favored by the dehydroge nation, ing art. U.S. Pat. Nos. 4,929,332 and 333 disclose a first 50 catalyst comprising germanium and at least one platinum dehydrocyclization, and isomerization reactions. group metal on a Solid catalyst Support. The Second catalyst The performance of catalysts employed in the catalytic comprises platinum and another promoter which preferably reforming of naphtha range hydrocarbons is measured prin is rhenium. The first catalyst of 332 consists essentially of cipally by three parameters: Pt-Ge on a support. The 333 patent differs in that the second (1) Activity is a measure of the ability of the catalyst to 55 catalyst has the essential absence of Ge. Related U.S. Pat. convert hydrocarbon reactants to products at a desig No. 4,985,132 introduces a terminal catalyst Zone compris nated Severity level, with Severity level representing a ing a moving-bed System with continuous catalyst regen combination of reaction conditions: temperature, eration. preSSure, contact time, and hydrogen partial pressure. Reforming catalysts containing germanium are known in Activity typically is designated as the octane number of 60 the prior art. For example, U.S. Pat. No. 3,578,584 describes the pentanes and heavier (“Cs”) product stream from a catalyst comprising germanium, a platinum group metal, a given feedstock at a given Severity level, or con and a halogen on a porous carrier material particularly useful versely as the temperature required to achieve a given in the reforming of a gasoline fraction. octane number. The benefits of three Stages of catalyst with a germanium (2) Selectivity refers to the yield of petrochemical aro 65 containing catalyst in the middle Zone have not been matics or Cs product from a given feedstock at a described in the prior art. Surprising yield improvements particular activity level. from the use of a first-Zone catalyst containing germanium 5,858,205 3 4 are notably applicable in Semi-regenerative and cyclic cata hydrogen-rich gas are preheated and charged to a reforming lytic reforming units, where germanium-containing catalysts Zone containing generally two or more, and typically from are commercially proven. two to five, reactors in Series. Suitable heating means are provided between reactors to compensate for the net endot SUMMARY OF THE INVENTION hermic heat of reaction in each of the reactors. It is an object of the present invention to provide an The individual first, intermediate and terminal catalyst improved process for the catalytic reforming of hydrocar Zones respectively containing the first, intermediate and bons. A corollary objective of the invention is to increase the terminal catalytic composites are typically each located in yield of petrochemical