WO2004062794A1

WO2004062794A1 - Attrition resistant catalyst for hydrocarbon conversion

Info

Publication number: WO2004062794A1
Application number: PCT/US2003/000257
Authority: WO
Inventors: Mark D. Moser; Robin E. Shepherd; Andrzej J. Ringwelski; John Y.G. Park
Original assignee: Uop Llc
Priority date: 2003-01-06
Filing date: 2003-01-06
Publication date: 2004-07-29
Also published as: AU2003201827A1

Abstract

A catalyst and a process for using the catalyst are disclosed generally for the conversion of hydrocarbons. By the use of at least one high temperature calcination under dry conditions, a catalyst with a beneficial combination of lowered surface area and excellent piece crush is created. X-ray diffraction pattern information is used to distinguish the resulting product.

Description

ATTRITION RESISTANT CATALYST FOR HYDROCARBON CONVERSION

FIELD OF THE INVENTION

[0001] This invention relates to a shaped catalyst prepared by using a dry high

temperature calcination that gives a characteristic x-ray pattern, and a process for using

the catalyst for hydrocarbon conversion. The controlled adjustment of a significant

hydrocarbon conversion catalyst property of surface area has been found to be possible

along with the maintenance and even improvement of another significant catalyst

property of piece crushing strength. Surface area can allow acidic and metal supported

reactions to occur, while piece crush strength permits catalyst particles to maintain their

integrity, and thus their useful life.

[0002] US-A-3,920,615 discloses a calcination treatment of at least 800°C which is

used to reduce the surface area of an alumina catalyst to between 10 m²/gm and 150

m²/gm. The catalyst displays improved selectivity in a process for long chain mono-

olefin dehydrogenation from paraffins as part of the production of alkylaryl sulfonates.

No mention is made of the resulting piece crushing strength from the procedure.

[0003] Canadian Patent No. 1,020,958 discloses a catalyst consisting of at least one

platinum group component used in a reaction zone with a hydrocarbon and hydrogen

under conditions causing coke deposition on the catalyst. The catalyst is regenerated by

oxidation and the process is repeated until the surface area is between 20 and 90% of the

original value. The catalyst is then treated to incorporate at least one promoter metal

selected from the group of Re, Ge, Ir, Sn, Au, Cd, Pb, rare earths, or a mixture thereof.

The resulting catalyst shows increased stability in use thus requiring less frequent

regeneration or replacement. Again, no mention is made of the resulting piece crushing

strength from this procedure. [0004] Applicants have found that piece crushing strength is a very important

property for catalysts. This has been recognized in the art pertaining to hydrotreatment

as disclosed in US-A-4,767,523 and US-A-4,820,676 where a solution of ammonium

sulfate is used to treat alumina such that after calcination the strength of the alumina is

increased when measured under high pressure fixed bed hydrotreating conditions.

[0005] Piece crushing strength is an even more important property for moving bed

applications. When catalyst particles are moving through a reaction zone, higher piece

crushing strength leads to less catalyst attrition and deterioration to fines. Catalysts with

poor strength more often fracture, generating dust and catalyst fines that can become

trapped against reactor screens. This can lead to blocked flow of reactants and products,

which often may require a reforming unit to shut down for screen cleaning. Many

commercial moving bed systems require catalyst make up in order to replace catalyst

inventory lost to fines, dust, or cracked chips.

[0006] US-A-5,552,035 discloses a method for hydro-thermally calcining an

extruded bound zeolitic catalyst that can be used in a fixed bed reforming process, where

calcination improves catalyst strength. In contrast to Potter et al., applicants have found

that dry calcination gives even better retention of catalyst strength. By studying the

controlled use of steam as part of the state-of-the-art Potter et al. disclosed hydro-thermal

calcination evaluation, applicants obtained a surprising result by removing the Potter et

al. disclosed 30 volume % to 100 volume % water from the calcination atmosphere. In

fact, it was found that this water was causing substantial loss of piece crushing strength

in achieving a desired reduction in catalyst surface area. By conducting a calcination at

substantially dry conditions such that the moisture level remains less than 4 mass %, and

preferably less than 3 mass %, an excellent combination of piece crushing strength and reduced surface area was obtained.

[0007] US-A-4,483,693 discloses a process for steam reforming of hydrocarbons in

the presence of greater than 1 ppm sulfur using a catalyst comprising an alumina with a

surface area from 30 to 160 m²/g formed by calcination of pure single phase boehmite.

No information is provided regarding calcination water content or catalyst strength

SUMMARY OF THE INVENTION

[0008] A broad embodiment of the present invention is a shaped catalyst comprising an

alumina support where the catalyst is treated with a dry high temperature calcination at a

time and temperature sufficient to produce a catalyst characterized with a X-ray powder

diffraction pattern such that the ratio of peak intensities at respective two-Θ Bragg angle

values of 32.5:34.0 is at least 1.2, and the ratio of peak intensities at respective two-Θ

Bragg angle values of 46.0:45.5 is at most 1.1. The catalyst has a surface area from 140

m²/gm to 210 m²/gm and a piece crush strength of at least 34 N/mm. This amounts to a

surface area reduction from 5% to 30% of the original support as analyzed prior to the dry

high temperature calcination with a concomitant maintenance of piece crush strength of

greater than 95% of the original support as analyzed prior to the dry high temperature

calcination.

[0009] Optionally, the catalyst has at least one platinum group metal dispersed thereon

along with a halogen component, especially chlorine, and further optionally an additional

promoter metal element selected from the group consisting of rhenium, tin, germanium,

cerium, europium, indium, and phosphorous. A preferred shape is substantially spherical.

[0010] The catalyst is useful in a catalytic reforming process for converting gasoline-

range hydrocarbons, especially in the presence of less than 1 ppm sulfur. When the catalyst contains an alkali or alkaline-earth metal, the catalyst is useful in a dehydrogenation

process.

[0011] Additional objects, embodiments and details of this invention can be obtained

from the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 shows an X-ray diffraction pattern for a catalyst of the invention

(Base D) compared to a reference (Base A) over the range 2-theta 43 to 26.

[0013] FIG. 2 shows an X-ray diffraction pattern for a catalyst of the invention

(Base D) compared to a reference (Base A) over the range 2-theta 50 to 42.

DETAILED DESCRIPTION OF THE INVENTION

[0014] A broad embodiment of the present invention, therefore, is a shaped alumina

catalyst which is prepared by calcining shaped alumina particles at a time, temperature, and

moisture level sufficient to produce a catalyst with a characteristic X-ray pattern that has

desirable surface area and excellent piece crush strength.

[0015] Suitable alumina materials are the crystalline aluminas known as the gamma,

eta, and theta phase aluminas, with gamma or eta phase aluminas giving best results. A

preferred alumina is that which has been characterized in US-A-3,852,190 and US-A-

4,012,313 as a by-product from a Ziegler higher alcohol synthesis reaction as described in

Ziegler's US-A-2,892,858. For purposes of simplification, such an alumina will be

hereinafter referred to as a "Ziegler alumina". Ziegler alumina is presently available from

the Vista Chemical Company under the trademark "Catapal" or from Condea Chemie

GmbH under the trademark "Pural." This material is an extremely high purity pseudoboehmite which, after calcination at a high temperature, has been shown to yield a

high purity gamma-alumina.

[0016] The preferred form of the present catalyst is a sphere. Alumina spheres may be

continuously manufactured by the well known oil-drop method which comprises: forming

an alumina slurry with Ziegler alumina or an alumina hydrosol by any of the techniques

taught in the art and preferably by reacting aluminum metal with hydrochloric acid;

combining the resulting hydrosol or slurry with a suitable gelling agent; and dropping the

resultant mixture into an oil bath maintained at elevated temperatures. The droplets of the

mixture remain in the oil bath until they set and form gelled spheres. The spheres are then

continuously withdrawn from the oil bath and typically subjected to specific aging and

drying treatments in oil and an ammoniacal solution to further improve their physical

characteristics. The resulting aged and gelled particles are then washed and dried at a

relatively low temperature of 150°C to 205°C and subjected to a calcination procedure at a

temperature of 450°C to 700°C for a period of 1 to 20 hours. This treatment effects

conversion of the alumina hydrogel to the corresponding crystalline gamma-alumina. US-

A-2,620,314 provides for additional details and is incorporated herein by reference thereto.

The use of the term "substantially spherical" refers to the geometric properties of most of

the spheres being round and includes slight deviations.

[0017] An alternate form of the present catalyst is a cylindrical extrudate. A

"substantially cylindrical" catalyst, defined with geometric properties of most of the

cylinders being circular in one direction and linear in another, and including slight

deviations therefrom, can be prepared by any of the well known to the art forming methods

such as extrusion. The preferred extrudate form is prepared by mixing Ziegler alumina

powder with water and suitable peptizing agents, such as nitric acid, acetic acid, alurninum nitrate and like materials, to form an extrudable dough having a loss on ignition (LOI) at

500°C of 45 to 65 mass-%. The resulting dough is extruded through a suitably shaped and

sized die to form extrudate particles, which can be dried at a relatively low temperature of

150°C to 205°C and subjected to a calcination procedure at a temperature of 450°C to

700°C for a period of 1 to 20 hours.

[0018] Moreover, spherical particles can also be formed from the extrudates by rolling

the extrudate particles on a spinning disk. An average particle diameter can vary from 1

mm to 10 mm, with the preferred particle diameter being approximately 3 mm.

[0019] After shaping, the catalyst is subjected to at least one calcination treatment.

Preferably, this calcination is conducted at conditions selected to create a product catalyst

comprising a calcined alumina with a characteristic X-ray pattern and desired physical

properties in terms of surface area and piece crushing strength. This calcination typically

takes place at a temperature of from 700°C to 900°C, a moisture level of less than 4 mass

% steam and a time of 15 minutes to 20 hours. More preferably the calcination conditions

comprise a temperature from 800°C to 900°C, a moisture level of less than 3 mass % steam

and a time limit of 30 minutes to 6 hours. An oxygen atmosphere is employed typically

comprising dry air. Dry air is considered air with no added moisture or steam, ranging

from air that has been dried using chemical means such as molecular sieves or silica gels to

ambient moisture levels. Generally the exact period of time being that required in order to

reach the desired calcined alumina physical properties of surface area and piece crush

strength. The relative amount of surface area reduction will be approximately between 5 to

30%. Further, the piece crush strength will be reduced at most to 95% of the original value.

The piece strength can also increase due to this calcination such that greater than a 100% of

the original value may be obtained. [0020] Therefore, if the alumina prior to this calcination treatment has a surface area

between 200 and 220 m²/gm, then the calcined alumina will have a surface area between

140 m7gm and 210 m7gm (measured by BET/N₂ method, ASTM D3037, or equivalent).

Preferably the calcined alumina will have a surface area from between 150 m²/gm and 180

m²/gm. Likewise, if the piece crush strength of the alumina prior to this calcination

treatment is 36 N/rnrn, then the calcined alumina obtained is at least 34 N/mm (average

reported by ASTM D4179 or equivalent). Preferably the calcined alumina will have a

piece crush strength greater than 36 N/mm, and more preferably greater than 40 N/mm.

Note that this time requirement will, of course, vary with the calcination temperature ,

employed and the oxygen content of the atmosphere employed. Note also that the alumina

prior to this calcination treatment can have a surface area range from between 180 m²/gm

and 240 m²/gm, with the preferred range being from 200 m²/gm to 220 m²/gm as illustrated

above.

[0021] The best results are achieved when the catalyst has an X-ray diffraction pattern

showing characteristic intensities of peaks at specified Bragg angle positions. Specifically,

the preferred catalyst has an X-ray powder diffraction pattern such that the ratio of peak

intensities at respective two-Θ Bragg angle positions of 32.5:34.0 is at least 1.2 and the

ratio of peak intensities at respective two-Θ Bragg angle values of 46.0:45.5 is at most 1.1.

The X-ray pattern may be obtained by standard X-ray powder diffraction techniques, of

which a suitable example is described hereinbelow. Typically, the radiation source is a

high-intensity, copper-target, X-ray tube operated at 45 KV and 35 n A. Flat compressed

powder samples illustratively are scanned in a continuous mode with a step size of 0.030°

and a dwell time of 9.0 seconds on a computer-controller diffractometer. The diffraction

pattern from the copper K radiation may be recorded with a Peltier effect cooled solid-state detector. The data suitably are stored in digital format in the controlling computer. The

peak heights and peak positions are read from the computer plot as a function of two times

theta (two-Θ), where theta is the Bragg angle.

[0022] An optional ingredient of the catalyst is a platinum-group-metal component.

This component comprises platinum, palladium, ruthenium, rhodium, iridium, osmium or

mixtures thereof, with platinum being preferred. The platinum-group metal may exist

within the final catalytic composite as a compound such as an oxide, sulfide, halide,

oxyhalide, etc., in chemical combination with one or more of the other ingredients of the

composite or as an elemental metal. The best results are obtained when substantially all the

platinum-group metal component is present in the elemental state and it is homogeneously

dispersed within the carrier material. The platinum-group metal component may be

present in the final catalyst composite in any amount that is catalytically effective; the

platinum-group metal generally will comprise 0.01 to 2 mass % of the final catalytic

composite, calculated on an elemental basis. Excellent results are obtained when the

catalyst contains 0.05 to 1 mass % platinum.

[0023] The platinum-group metal component may be incorporated in the support in

any suitable manner, such as coprecipitation, ion-exchange or impregnation. The preferred

method of preparing the catalyst involves the utilization of a soluble, decomposable

compound of a platinum-group metal to impregnate the carrier material in a relatively

uniform manner. For example, the component may be added to the support by

commingling the support with an aqueous solution of chloroplatinic or chloroiridic or

chloropalladic acid. Other water-soluble compounds or complexes of platinum-group

metals may be employed in impregnating solutions and include ammonium chloroplatinate,

bromoplatinic acid, platinum trichloride, platinum tetrachloride hydrate, platinum dichlorocarbonyl dichloride, dinifrodiarninoplatinum, sodium tetranitroplatinate (LT),

palladium chloride, palladium nitrate, palladium sulfate, diamminepalladium (II)

hydroxide, teframminepalladium (II) chloride, hexamminerhodium chloride, rhodium

carbonylchloride, rhodium trichloride hydrate, rhodium nitrate, sodium hexachlororhodate

(III), sodium hexanitrorhodate (HI), iridium tribromide, iridium dichloride, iridium

tetrachloride, sodium hexanitroiridate (III), potassium or sodium chloroiridate, potassium

rhodium oxalate, etc. The utilization of a platinum, iridium, rhodium, or palladium

chloride compound, such as chloroplatinic, chloroiridic or chloropalladic acid or rhodium

trichloride hydrate, is preferred since it facilitates the incorporation of both the platinum-

group-metal component and at least a minor quantity of the preferred halogen component

in a single step. Hydrogen chloride or the like acid is also generally added to the

impregnation solution in order to further facilitate the incorporation of the halogen

component and the uniform distribution of the metallic components throughout the carrier

material. In addition, it is generally preferred to impregnate the carrier material after

calcination in order to minimize the risk of washing away the valuable platinum-group

metal.

[0024] Generally the platinum-group metal component is dispersed homogeneously in

the catalyst. Preferably, homogeneous dispersion of the platinum-group metal is

determined by Scanning Transmission Electron Microscopy (STEM), comparing metals

concentrations with overall catalyst metal content. In an alternative embodiment one or

more platinum-group metal components may be present as a surface-layer component as

described in US-A-4,677,094, incorporated herein by reference. The "surface layer" is the

layer of a catalyst particle adjacent to the surface of the particle, and the concentration of surface-layer metal tapers off when progressing from the surface to the center of the

catalyst particle.

[0025] A Group -VAQUPAC 14) metal component is an optional ingredient of the

catalyst of the present invention. Of the Group 1NA(IUPAC 14) metals, germanium and tin

are preferred and tin is especially preferred. The component may be present as an

elemental metal, as a chemical compound such as the oxide, sulfide, halide, oxychloride,

etc., or as a physical or chemical combination with the porous carrier material and/or other

components of the catalytic composite. Preferably, a substantial portion of the Group

rVA(IUPAC 14) metal exists in the finished catalyst in an oxidation state above that of the

elemental metal. The Group WA(IUPAC 14) metal component optimally is utilized in an

amount sufficient to result in a final catalytic composite containing 0.01 to 5 mass % metal,

calculated on an elemental basis, with best results obtained at a level of 0.1 to 2 mass %

metal.

[0026] The Group INA(IUPAC 14) metal component may be incorporated in the

catalyst in any suitable manner to achieve a homogeneous dispersion, such as by

coprecipitation with the porous carrier material, ion-exchange with the carrier material or

impregnation of the carrier material at any stage in the preparation. One method of

incorporating the Group IVA(IUPAC 14) metal component into the catalyst composite

involves the utilization of a soluble, decomposable compound of a Group -VA(IUPAC 14)

metal to impregnate and disperse the metal throughout the porous carrier material. The

Group rVA(IUPAC 14) metal component may be impregnated either prior to,

simultaneously with, or after the other components are added to the carrier material. Thus,

the Group INA(ιUPAC 14) metal component may be added to the carrier material by

commingling the carrier material with an aqueous solution of a suitable metal salt or soluble compound such as stannous bromide, stannous chloride, stannic chloride, stannic

chloride pentahydrate; or germanium oxide, germanium tetraethoxide, germanium tetra-

chloride; or lead nitrate, lead acetate, lead chlorate and the like compounds. The utilization

of Group rVA(ιUPAC 14) metal chloride compounds, such as stannic chloride, germanium

tetrachloride or lead chlorate is particularly preferred since it facilitates the incorporation of

both the metal component and at least a minor amount of the preferred halogen component

in a single step. When combined with hydrogen chloride during the especially preferred

alumina peptization step described hereinabove, a homogeneous dispersion of the Group

INA(IUPAC 14) metal component is obtained in accordance with the present invention.

In an alternative embodiment, organic metal compounds such as trimethyltin chloride and

dimethyltin dichloride are incorporated into the catalyst during the peptization of the

inorganic oxide binder, and most preferably during peptization of alumina with hydrogen

chloride or nitric acid. [0027] Optionally the catalyst may also contain other components or mixtures thereof

that act alone or in concert as catalyst modifiers to improve activity, selectivity or stability.

Some known catalyst modifiers include rhenium, gallium, cerium, lanthanum, europium,

indium, phosphorous, nickel, iron, tungsten, molybdenum, zinc, and cadmium.

Catalytically effective amounts of these components may be added to the carrier material in

any suitable manner during or after its preparation or to the catalytic composite before,

during or after other components are being incorporated. Generally, good results are

obtained when these components constitute 0.01 to 5 mass % of the composite, calculated

on an elemental basis of each component.

[0028] Another optional component of the catalyst, particularly useful in hydrocarbon

conversion processes comprising dehydrogenation, dehydrocyclization, or hydrogenation reactions, is an alkali or alkaline-earth metal component. More precisely, this optional

ingredient is selected from the group consisting of the compounds of the alkali metals —

cesium, rubidium, potassium, sodium, and lithium ~ and the compounds of the alkaline

earth metals — calcium, strontium, barium, and magnesium. Generally, good results are

obtained when this component constitutes 0.01 to 5 mass % of the composite, calculated on

an elemental basis. This optional alkali or alkaline earth metal component may be

incorporated into the composite in any of the known ways by impregnation with an

aqueous solution of a suitable water-soluble, decomposable compound being prefened.

[0029] As heretofore indicated, it is necessary to employ at least one calcination step in

the preparation of the catalyst. An essential step of the invention is the high temperature

calcination step, also may also be called an oxidation step, which preferably takes place

before incorporation of any metals to the support but can be performed after incorporation

of any metals. When the high temperature calcination occurs before incorporation of any

metals, good results are obtained when a lower temperature oxidation step and an optional

halogen adjustment step follow the addition of any metals.

[0030] The conditions employed to effect the lower temperature oxidation step are

selected to convert substantially all of the metallic components within the catalytic

composite to their corresponding oxide form. The oxidation step typically takes place at a

temperature of from 370°C to 600°C. An oxygen atmosphere comprising air is typically

employed. Generally, the oxidation step will be carried out for a period of from 0.5 to 10

hours or more, the exact period of time being that required to convert substantially all of the

metallic components to their corresponding oxide form. This time will, of course, vary

with the temperature employed and the oxygen content of the atmosphere employed. [0031] In addition to the oxidation step, a halogen adjustment step may also be

employed in preparing the catalyst. The halogen adjustment step may serve a dual

function. First, the halogen adjustment step may aid in homogeneous dispersion of the

Group rVA(IUPAC 14) metal and any other metal components. Additionally, the halogen

adjustment step can serve as a means of incorporating the desired level of halogen into the

final catalytic composite. The halogen adjustment step employs a halogen or halogen-

containing compound in air or an oxygen atmosphere. Since the preferred halogen for

incorporation into the catalytic composite comprises chlorine, the preferred halogen or

halogen-containing compound utilized during the halogen adjustment step is chlorine, HCl

or precursor of these compounds. In carrying out the halogen adjustment step, the catalytic

composite is contacted with the halogen or halogen-containing compound in air or an

oxygen atmosphere at an elevated temperature of from 370°C to 600°C. Water may be

present during the contacting step in order to aid in the adjustment, hi particular, when the

halogen component of the catalyst comprises chlorine, it is preferred to use a mole ratio of

water to HCl of 5:1 to 100:1. The duration of the halogenation step is typically from 0.5 to

5 hours or more. Because of the similarity of conditions, the halogen adjustment step may

take place during the oxidation step. Alternatively, the halogen adjustment step may be

performed before or after the calcination step as required by the particular method being

employed to prepare the catalyst of the present invention. Irrespective of the exact halogen

adjustment step employed, the halogen content of the final catalyst should comprise, on an

elemental basis, from 0.1 to 10 mass % of the finished composite.

[0032] In preparing the catalyst, a reduction step may also be optionally employed. The

reduction step is designed to reduce substantially all of the platinum-group metal

component to the corresponding elemental metallic state and to ensure a relatively unifonn and finely divided dispersion of the component throughout the refractory inorganic oxide.

It is preferred that the reduction step takes place in a substantially water-free environment.

Preferably, the reducing gas is substantially pure, dry hydrogen (i.e., less than 20 volume

ppm water). However, other reducing gases may be employed such as CO, nitrogen, etc.

Typically, the reducing gas is contacted with the oxidized catalytic composite at conditions

including a reduction temperature of from 315°C to 650°C for a period of time of from 0.5

to 10 or more hours effective to reduce substantially all of the platinum-group metal

component to the elemental metallic state. The reduction step may be performed prior to

loading the catalytic composite into the hydrocarbon conversion zone or may be performed

in situ as part of a hydrocarbon conversion process start-up procedure and/or during

reforming of the hydrocarbon feedstock. However, if the in-situ technique is employed,

proper precautions must be taken to predry the hydrocarbon conversion plant to a

substantially water-free state and a substantially water-free hydrogen-containing reduction

gas should be employed.

[0033] Optionally, the catalytic composite may also be subjected to a presulfiding step.

The optional sulfur component may be incorporated into the catalyst by any known

technique.

[0034] The catalyst of the present invention has particular utility as a hydrocarbon

conversion catalyst. The hydrocarbon is to be converted is contacted with the catalyst at

hydrocarbon-conversion conditions, which include a temperature of from 40°C to 550°C, a

pressure of from 1 to 200 atmospheres absolute and liquid hourly space velocities from 0.1

to 100 hr^"1. The catalyst is particularly suitable for catalytic reforming of gasoline-range

feedstocks, and also may be used for dehydrocyclization, isomerization of aliphatics and

aromatics, dehydrogenation, hydrocracking, disproportionation, dealkylation, alkylation, transalkylation, oligomerization, and other hydrocarbon conversions. The present

invention provides greater stability and lowered coke production relative to other catalysts

known to the art when used to process gasoline-range feedstock as a catalytic reforming

catalyst. Preferably, the gasoline-range feedstock has a sulfur content less than 1 part per

million. The present invention also provides greater stability and lowered coke production

relative to other catalysts known to the art when used in a dehydrogenation process where

the catalyst comprises an alkali or alkaline earth metal component.

EXAMPLE 1

[0035] A commercially produced, spherical gamma alumina base (Base A), containing

0.3 mass % tin, had an initial surface area of 215 m²/gm. The piece crushing strength of this

support was 36.4 N/mm. The apparent bulk density (ABD) of this base was 0.5 grams/cc.

This base was subsequently calcined by two methods. The first method, a standard

steaming at elevated temperature to lower the surface area, produced Base B, properties of

which are listed below. Base C was produced to illustrate the invention. This involved

subjecting a layer of support to high temperature calcination in dry air. The moisture level

for this experiment was approximately 2.5 mass % water.

[0036] Base C retained significantly greater mechanical strength, although the surface

area was reduced by 55 m²/gm. In surprising contrast, the support that was calcined with

steam to the same 160 m²/gm surface area lost mechamcal strength. An approximate 30 %

reduction in piece crush strength was noted for the steamed base, while the dry calcination

did not negatively affect the piece crush strength.

EXAMPLE 2

[0037] The commercially produced, spherical gamma alumina Base A from example I

was used to prepare an additional base (Base D), by calcining Base A in dry air containing

approximately 2.5 mass % water at 860°C for 45 minutes.

[0038] The X-ray diffraction patterns of Base A and Base D were obtained by standard

X-ray powder techniques. The diffraction pattern from 43 two-Θ to 26 two-Θ is shown in

FIG. 1 and from 50 two-Θ to 42 two-Θ is shown in FIG. 2. These patterns show that the

catalyst of the present invention is unique from conventional gamma alumina. Particularly,

FIG. 1 shows a broad peak near 33 two-Θ, and FIG. 2 shows a peak near 46 two-Θ that is

left shifted. The peaks were characterized by taking ratios of peak intensities. The ratios of

peak intensities at respective two-Θ Bragg angle values of 32.5:34.0 and 46.0:45.5 were

determined to be 1.0 and 1.1 for Base A and 1.4 and 1.0 for Base D.

Claims

CLAIMS:

1) A shaped hydrocarbon conversion catalyst comprising an alumina having an X-ray powder diffraction pattern such that the ratio of peak intensities at respective two-Θ Bragg angle values of 32.5:34.0 is at least 1.2 and the ratio of peak intensities at respective two-Θ Bragg angle values of 46.0:45.5 is at most 1.1.

2) The catalyst of Claim 1 further comprising at least one platinum group metal dispersed onto the catalyst in an amount from 0.01 mass-% to 2.0 mass-% of the catalyst calculated on an elemental basis and optionally a halogen component present in an amount from 0.1 mass-% to 10 mass-% of the catalyst calculated on an elemental basis.

3) The catalyst of Claim 2 further comprising a metal promoter component selected from the group consisting of tin, germanium, rhenium, gallium, cerium, lanthanum, europium, indium, phosphorous, nickel, iron, tungsten, molybdenum, zinc, cadmium, and mixtures thereof, wherein the metal promoter comprises from 0.01 mass-% to 5.0 mass-% of the catalyst calculated on an elemental basis.

4) The catalyst of Claims 1 -3 wherein the catalyst has a piece crush strength of greater than 34 N/mm and preferably greater than 40 N/mm.

5) The catalyst of Claims 1-3 wherein the alumina has a surface area from 140 m²/gm to 210 m²/gm and preferably from 150 m²/gm to 180 m²/gm.

6) The catalyst of Claim 1 further comprising an alkali or alkaline-earth metal dispersed onto the shaped catalyst in an amount from 0.01 mass-% to 5.0 mass-% of the catalyst calculated on an elemental basis.

7) A hydrocarbon conversion process comprising contacting a hydrocarbon feedstock with the catalyst of claims 1, 2, 3 or 6.

8) The process of Claim 7 wherein the hydrocarbon-conversion conditions include a temperature of from 40°C to 550°C, a pressure of from 1 to 200 atmospheres absolute and liquid hourly space velocities from 0.1 to 100 hr^"1. 9) The process of Claim 7 wherein the hydrocarbon feedstock is a gasoline-range feedstock.

10) The process of Claim 7 where the process is a catalytic reforming process.