Note: Descriptions are shown in the official language in which they were submitted.
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.
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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
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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
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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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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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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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