CA1065270A - Shaped catalysts for naphtha reforming - Google Patents

Abstract

SHAPED CATALYST FOR NAPHTHA REFORMING
ABSTRACT OF THE DISCLOSURE
The present invention is the use of amphora shaped cata-lysts in the known process of naphtha reforming. Catalysts employed in naphtha reforming have been found to be unexpectedly superior to other commercial catalyst forms when placed in the amphora shape, which is a substantially spherical outer surface with a void center having a cavity in the external surface com-municating with the void center.

Description

BACKGROUND OF THE INVENTION
The present invention is the use of a particular shaped catalyst in the naphtha reforming process. Naphtha reforming is conducted on a large commercial scale. In naphtha reforming, the refinery stream called naphtha is contacted with hydrogen at an elevated temperature in the presence of a catalyst. The naphtha stream may vary significantly, but it is a complex mixture of hydrocarbons boiling in the range of about 30C. to 230C. The hydrocarbon stream contains hydrocarbons of 5 to 14 carbon atoms.
The composition of catalysts employed in the reforming process have varied widely. Any of these catalysts could be employed in the invention. The shape of the catalyst in the in-vention is different and produces the unexpectedly desirable results with these catalyst materials.
SUMMARY OF THE INVENTION
The invention is in the process of naphtha reforming wherein naphtha is reacted with hydrogen at an elevated tempera-ture in the presence of a catalyst, the improvement comprising using as the catalyst a catalyst having a substantially spherical shape with a void center and an opening in the external surface communicating with the void center. Using catalysts of , .. ', ~

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-this amphora shape gives a reforming reaction of unexpecteddesirability. The catalysts are easily prepared and used in a reforming reaction on a commercial scale.
The central aspect of the invention is the amphora shape of the catalyst. The catalyst shape is shown in the drawing.
; The figure shows the outer surface of the amphora from a side view with a cut-away portion that shows the void interior.
:- The amphora shaped catalysts are most conveniently pre-- pared from a powder of the support material~ generally an alumina or alumina hydrate, which may incorporate promoter metals and additional acidic components, such as aluminosilicates. The powdered support material is mixed with a solvent such as water to form a slurry. A portion of the well calcined powder, or preferably some other powdered material not wet by the solvent, is placed in an open container. Droplets of the slurry are then ;
formed and dropped into the powder in such a manner that the droplets do not fall through the powder but rather lay with the top portion of the droplet exposed to the atmosphere while the bottom portion is in contact with the powder. The droplets may be allowed to air dry or suitably, the drying rate could be increased by use of a heat lamp or some other such device. The -amphora aggregates are removed from the powder, and powder cling-ing to the amphora is removed by gentle mechanical vibration or washing.
Normally, the catalyst composition itself can be made into suitable amphora shaped particles by the process described above.
In some cases, it may be desirable to add a suitable binder to improve the stability of the amphora. It is also possible to pre-pare a support material in the amphora form and then impregnate this catalyst support with active ingredients.

~)6S2!70 The active ingredients of the catalyst used in the amphora form may be taken from any of the elements used in the art. A preferred catalyst is one that contains ~-alumina.
Besides ~-alumina, other acid agents such as ~-alumina - zeolites such as acid-treated mordenite, other alumino-silicates, and halides may be incorporated~ Also preferred are catalysts containing platinum alone or in combination with other elements.
When such other elements are present, platinum may be found in the form of an alloy, a small group of atoms known as a cluster, or in the form of separate patches. The non-platinum components of this combination might be in the zero or positive oxidation state.
Examples of optional components include Pt with Ge, Sn, Pb, In, ~
Cu, Au, Re, Cr, Mo, W, rare earth and group VIII elements or mix- ;
tures thereof. Group VIII metals, such as Ir, Pd or Co might be - substituted for Pt. In any case, the advantages of the amphora shape are increasingly apparent as the intrinsic activity of the catalyst is improved by adding the above promoting materials.

The reforming process using amphora shaped catalysts is conducted within the parameters of the art process, and the useful ranges are not modified generally by this invention except that the more advantageous low pressure, low recycle ratio con-ditions can be applied more easily to the longer lived amphora catalyst. Substantially improved results, however, are obtained by this invention for art reforming processes.
The advantages of the invention are best seen from the following specific examples.
SPECIFIC EMBODIMENTS

Comparative Examples A_& B and Examples_l 2 - Reforming of methylcyclopentane.
Two alumina based reforming catalysts were prepared--one in the amphora form and one in the form of an extrudate. The .

1(~65Z70 catalysts contained platinum, tin and chloride and were prepared from identical starting materials as described below.
- Amphora Preparation An alumina support material was formed in amphora shape from a slurry of 175 g. Harshaw U-10199-82 alumina hydrate (less than 325 mesh) and 175 g. Philadelphia Quartz A-30 Q-loid alumina sol (30% Wt. A12O3). The slurry was dropped onto a bed of powdered fluorinated graphite supplied by Air Products and Chemicals, Inc., and dried by heating with a lamp until hard amphora particles formed. A syringe with a 22 gauge needle was used to obtain a suitable drop size. The particles were further dried at 100C., calcined 3-1/2 hours at 425c., cooled, washed with distilled water to remove adhering graphite and re-dried at 100C. before a final calcination at 425C. for 2 hours. A portion of the cool, dry amphora particles (115 g. 162 cc.) was impregnated ;~ with a solution containing Pt and Sn chlorides. Stannous chloride hydrate (SnC12.2H2O, 0.56 g.) was added to 8.4 cc. concentrated HCl (37%) solution, and 11.5 cc. of 10% platinic chloride solution (0.43 g. Pt) was added to the tin solution. A further 6.8 cc.
concentrated HCl was added and the total diluted to 69 cc. The ` solution was added to the amphora at room temperature in air, and the mixture tumbled for 10 minutes to distribute the impregnant evenly. The catalyst was dried at 110C. for 16 hours and calcined at 425C. for 27-1/2 hours.
Extrudate Preparation An extrudate shaped alumina support material was formed from a slurry identical to that used in the amphora prepara-tion. Water was evaporated from this slurry by heating until a consistency suitable for extrusion was reached. The resulting paste was extruded from a 50 cc. "Plastipak" syringe onto clean enameled pans. The extrudate was dried 16 hours at 110C. and calcined ;

5-1/2 hours at 425C. before impregnation. A portion of the cool, dry extrudate (115 g, 168 cc.) was impregnated in exactly the same manner as the amphora, dried at 110C~ and calcined along side of the amphora portion for 27-1/2 hours at 425C.
The catalysts had the following properties: -Amphora Form Extrudate Form -Composition 0.46% Pt, 0.26% Sn, 0.51% Pt, 0.27% Sn, , 1.3% Cl 1.4% Cl Size 2.5 mm diameter, 1.55 mm diameter, 0.7 mm wall 3-10 mm long Surface area 177 m2/g. 178 m2/g Pore volume 0.42 cc./g. 0.43 cc./g.

After air drying and hydrogen reduction in a 130 cc.
reactor constructed of stainless steel each of the catalysts was equilibrated by reforming Mid-Continent naphtha at 100 p.s.i.g., a liquid hourly space velocity of 2, a molar ratio of hydrogen to hydrocarbon of 4 and a temperature of 480-510C. for a period of 10 hours. In each case a total catalyst volume of 130 cc. was employed; the weight of amphora used was 95.4 g.; the weight of the extrudate was 85.0 g. Methylcyclopentane was reformed to benzene at the same pressure and liquid hourly space velocity above, but a hydrogen to hydrocarbon molar ratio of 3.2 was used.
The results of reforming methylcyclopentane (MCP) to benzene are given in Table I. The results are stated as follows:

% conversion = moles of reactant reacted x 100 moles of reactant fed % selectivity = moles of product found x 100 moles of reactant reacted single pass yield _ moles of product found x 100 ~ moles of reactant fed : ' - ~
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~065Z70 Table I

Reforming of Methylcyclopentane to Benzene Using Amphora as Compared to Extrudate .
'Results, %
CatalystTemp, Single Pass Example Form C. Convers'ion Selectivity Yield Comp. AExtrudate 450 11 87 9.6 1 Amphora" 58 78 45.2 Comp. BExtrudate 480 26 73 19.0 10 2 Amphora" 80 76 60.8 Comparative Example C' and Example' 3 - Reforming of cyclohexane.
The catalysts prepared above were used in the reform-ing of cyclohexane to benzene. At a pressure of 100 p.s.i.g., a temperature of 400C. and a liquid hourly space velocity of 4, the amphora form was shown to be substantially superior to extrudate as shown in Table II.

, Table II

Reforming of Cyclohexane to Benzene with'Amphora and Extrudate ' '___ Results', %' Single Pass Example Catalyst Form Conversion Se'lectivity Yield . . . _ Comp C Extrudate 64 88 56.3 .: .
3 Amphora 81 78 63.2 , Comparative Examples D & E and Examples 4-5 - Reforming of Mid-Continent Naphtha.
The catalysts prepared above were employed in the reforming of Mid-Continent naphtha containing 48% paraffins, 42%
naphthenes, 10% aromatics. The Mid-Continent naphtha had the following boiling range.

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; 'Mid-Continent Naphtha Distillati n ASTM D-86 Initial Boiling Point190 F. 88 C.
, 10% recovered 222F.105C.
' 20% recovered 233F.112C.
50% recovered 263 F.128 C.
60% recovered 275F.135C. ~-90% recovered 325 F.163 C.
95% recovered 340F.171 C. ' , 10 End point 360F.182C. '~ -,' The reforming experiment was conducted at 100 p.s.i.g., ;
an LHSV of 2 and a hydrogen to hydrocarbon ratio of 4. The product from the experiments was tested for Research Octane Number (RON).
The results of these tests are shown in Table III.

Table III
.
Reforming of Mid-Continent Naphtha to Improve Research Octane Number' . : .
On Stream , Temp, Time, RON
~,~, 20 Example Catalyst Shape C. H of Product -, Comp. D Extrudate 480 3 87.6 -, 4 Amphora " " 99,5 Comp. E Extrudate 510 6 96.6 5 Amphora " " 103.7 It is seen that the amphora shape when used at 480C. gives a ' product that is better than the extrudate used at 510C. Further, it has been found that the product formed with amphora at 480C.

is substantially better in terms of blending value (yield x octane) ~' than the product prepared with the extrudate shape. The operation at lower temperature will also result in substantial savings of heat and catalyst~life.

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.: - :, : :. . . ~ : -106S~70 Comparative Examples F and G_and Examples '6-7 - Selectivity of amphora.
In the reforming of Mid-Continent naphtha described above, the selectivity of the reaction was measured by monitoring the hydrogen production--the higher the hydrogen production, the ~' ' higher the selectivity. The production of hydrogen in the '' experiments is shown in Table IV.

TABLE IV
Determining the Selectivity of Reforming by Monitoring Hydrogen'Produc'tion' H2 Generated per -' Temp,Barrel of Naphtha Example 'Catalyst'Shape ''C. Reformed, SCF
Comp. F Extrudate 480 ~ 980 6 Amphora " 1890 Comp. G Extrudate 510 1540 7 Amphora " 2140 ' SCF = Standard Cubic Foot It is seen that the reforming is much more selective with the 20 amphora shaped catalyst.
Example 8 - Addition of mordenite and reforming Mid-Continent naphtha.
A support material was formed in amphora shape from - a slurry of 200 g. "Dispal M" powdered alumina hydrate and 200 g.H2O. A 1 g. portion of Norton Zeolon (HB-23) mordenite which had - been exchanged with NH4NO3 solution and washed with 6N HCl for 6 hours at 100C. was added to the slurry of "Dispal." Imprbgnated amphora partic~es were formed as in Example 1. After air drying ~' and H2 reduction in a 130 cc. stainless steel reactor, the amphora 30 shaped catalyst containing Pt, Sn and mordenite was used to reform k Mid-Continent naphtha. At a pressure of 100 p.s.i.g., a tempera-ture of 450C., a LHSV of 2 and a hydrogen to hydrocarbon ratio of 4, the specific gravity changed from 54.7 to 43.9 indicating that the reformate had a RON in the range of 95-100.

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Claims (8)

WE CLAIM:

1. In the process of naphtha reforming wherein naphtha 18 reacted with hydrogen at an elevated temperature in the presence of a catalyst, the improvement comprising using as the catalyst a catalyst having a substantially spherical shape with a void center and an opening in the external surface communicating with the void center.

2. The process of Claim 1 wherein the catalyst contains .alpha.-alumina alone or in admixture with other acid agents.

3. The process of Claim 1 wherein the catalyst contains platinum metal.

4. The process of Claim 3 wherein the platinum of the catalyst is present in an alloy, cluster or patch.

5. The process of Claim 1 wherein the catalyst contains Pt and additional elements selected from the group of Ge, Sn, Pb, In, Cu, Au, Re, Cr, Mo, W, rare earths, Group VIII elements or mixtures thereof in the zero or positive valence state.

6. The process of Claim 1 wherein the catalyst contains a Group VIII metal alone or ln combination with Pt.

7. The process of Claim 1 wherein the Group VIII
metal is Ir, Pd or Co.

8. The process of Claim 1 wherein the catalyst has a diameter of between 1/32" and 1/2".