Startup procedure for reforming catalysts

Process for reforming a hydrocarbon charge under reforming conditions in a reforming zone containing a sulfur-sensitive metal containing reforming catalyst wherein over-cracking of the charge stock and excessive temperature rise in the reforming zone is suppressed by pre-conditioning the catalyst, prior to contact with the charge, with a reformate of specified octane number and aromatics content.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a catalytic reforming process wherein a suitable 
charge stock, such as a petroleum naphtha, is converted to a gasoline of 
high octane number. More particularly, the invention described herein is 
concerned with a startup procedure for treating a metal-containing 
reforming catalyst, normally sulfur-sensitive under conventional 
conditions of reforming operation. 
2. Description of the Prior Art 
Catalysts intended for use in reforming processes wherein hydrocarbon 
fractions, e.g., naphthas or gasoline or mixtures thereof are converted to 
improve the anti-knock characteristics thereof are well known in the 
petroleum industry. 
It has heretofore been proposed to employ metal-containing catalysts, 
notably those containing a platinum metal, for promoting reforming. Such 
catalysts are necessarily characterized by a certain amount of acidity. 
One type of reforming catalyst which has been used commercially consists 
of an alumina base material having platinum metal impregnated thereon, 
with the acidity characteristics being contributed by a small amount of 
halogen incorporated in the catalyst. 
In more recent years, multimetallic reforming catalysts, for example, 
bimetallic catalysts, have come into use. These catalysts generally 
contain platinum, together with one or more additional metals such as 
rhenium, germanium, iridium, palladium, osmium, ruthenium, rhodium, 
copper, silver, tin or gold deposited on a refractory support which also 
contains a specified amount of halogen. Representative of multimetallic 
reforming catalysts are those containing platinum and rhenium, such as 
described in U.S. Pat. No. 3,415,737; those containing platinum and 
iridium, such as described in U.S. Pat. Nos. 2,848,377 and 3,953,368 and 
those containing platinum, rhenium and iridium such as described in U.S. 
Pat. No. 3,487,009. 
Reforming generally initially produces an excessive amount of light gases, 
e.g., methane and ethane, unless proper pretreatment or startup procedures 
are utilized. The light hydrocarbon gases, produces as a result of high 
hydrocracking activity or metal-cracking activity of the catalyst, are 
particularly to be avoided during reforming since they serve to decrease 
the yield of gasoline boiling products. It is known that hydrocracking 
activity can be diminished if the catalyst is sulfided prior to contact 
with the charge stock. The presulfiding can be accomplished, for example, 
by passing a sulfur-containing gas e.g., H.sub.2 S, through the catalyst 
bed. Other presulfiding treatments utilizing various other 
sulfur-containing compounds are known from prior art, such as U.S. Pat. 
No. 3,415,737. 
While generally any of the aforenoted metal-containing reforming catalysts 
are adversely affected by the presence of an excess amount of sulfur, 
i.e., greater than about 15 ppm, those in which iridium is a catalytically 
active component are known to be extremely sensitive to the presence of 
sulfur. Thus, it has been reported, for example, in U.S. Pat. No. 
3,507,781, that reforming catalysts comprising catalytically active 
amounts of platinum and iridium supported on a porous solid carrier, for 
example, alumina, are extremely sensitive to sulfur concentrations, 
exceeding about 2 ppm. At such concentrations, the increase in catalyst 
temperature necessary to maintain conversion of the chargestock to a 
constant octane number gasoline product increases very substantially. 
During the startup period of a reforming unit, utilizing a metal, e.g., a 
platinum-iridium-containing catalyst, that is, when the catalyst is 
initially or immediately after regeneration contacted with hydrogen and 
naphtha at reforming conditions, the catalyst causes excessive 
hydrocracking which has been termed "hydrogenolysis". As a consequence of 
such high hydrocracking activity, an excessive temperature rise or heat 
front, travels through the catalyst as naphtha is initially contacted with 
the catalyst in the presence of hydrogen and at reforming conditions. 
Although the occurring temperature rise only exists in the initial period 
of contact with the naphtha feed, such could be the cause of a temperature 
runaway in a commercial reforming plant. The temperatures in the bed may 
increase as high as several hundred degrees above the temperature of the 
naphtha introduced to the reaction zone. Obviously, such a severe 
temperature increase can damage the reactor and/or catalyst and is to be 
strictly avoided. 
One method of controlling the hydrocracking activity of the 
platinum-containing reforming catalyst, e.g., platinum in combination with 
iridium and/or rhenium catalyst, would be to add a quantity of sulfur to 
the feed during the startup period. However, such catalyst, as indicated 
above, is very sensitive to the presence of sulfur and other means of 
control have accordingly been sought. 
One alternative suggested method is that described in U.S. Pat. No. 
3,507,781 wherein a reforming process using a catalyst containing platinum 
and iridium on a porous solid carrier is started up by contacting the 
naphtha with the catalyst in the presence of an inert gas, for example, 
nitrogen. Utilizing such technique, it has been indicated that the 
pressure in the reforming zone should be about 200 psig and the catalyst 
temperature about 650.degree. F. when the naphtha is first contacted with 
the catalyst at a space velocity of about 1 volume/volume/hour. 
Thereafter, the temperature is increased to about 900.degree. F. over a 
2-3 hour period while building up autogeneous pressure of produced 
hydrogen. 
Another method is that described in U.S. Pat. No. 4,148,758 wherein 
excessive hydrocracking or hydrogenolysis of a sulfur sensitive reforming 
catalyst is suppressed by incorporating within the reforming catalyst at 
the time of its preparation a sulfurous acid or sulfuric acid component. 
Such prior suggested alternative techniques have had the disadvantage of 
requiring extremely careful control of treating conditions or with respect 
to the method described in the latter patent the use of corrosive 
chemicals. 
SUMMARY OF THE INVENTION 
In accordance with the invention described herein, it has been found that 
temperature runaways in the catalytic reforming unit and overcracking of 
the chargestock, i.e., hydrogenolysis, can be very substantially reduced 
or even completely eliminated, when the metal-containing reforming 
catalyst, during initial use or in a freshly regnerated state, is 
contacted in a preliminary step, prior to contact with the chargestock, 
with a reformate characterized by an octane number (R+O) between about 90 
and about 100 and an aromatics content within the approximate range of 40 
to 50 mole percent for a specified period of time, generally at least 
about 0.5 hour and not more than about 3 hours at a temperature between 
about 600.degree. F. and about 750.degree. F. and preferably between about 
650.degree. F. and about 700.degree. F. 
After such pretreatment of the catalyst, chargestock, i.e., naphtha, may be 
admitted to the unit as in a normal startup. It has been found that the 
procedure of this invention serves to limit temperature increases to 
insignificant levels, generally not in excess of about 30.degree. F., 
while maintaining the maximum activity and selectivity. In contrast, the 
temperature of a comparable reforming catalyst increased from 650.degree. 
F. to 1300.degree. F. in one minute when normal C.sub.6 -330.degree. F. 
charge naphtha was passed over the catalyst. 
It is contemplated that metal-containing reforming catalysts, normally 
sensitive to sulfur, may be beneficially affected by the startup procedure 
of the invention described herein. Thus, while Group VIII noble metal 
supported reforming catalysts, e.g., platinum on alumina, may be 
advantageously treated utilizing the startup procedure described herein, 
the latter is particularly applicable for and treatment of multi-metallic 
catalysts, e.g., platinum-rhenium, platinum-iridium and 
platinum-rhenium-iridium, particularly fresh or regenerated reactivated 
catalysts of such type, which are known to be especially sensitive to 
sulfur. 
The reforming catalyst undergoing treatment in accordance with the startup 
procedure of this invention generally comprises a Group VIII noble metal 
component, notably platinum in concentrations ranging from about 0.01 to 
about 3 percent, based on the weight of the catalyst, a component 
comprised of iridium or rhenium, or both, in concentration ranging from 
about 0.01 to about 3 percent, based on the weight of the catalyst and a 
halogen component in concentration ranging from about 0.1 to about 3 
percent, based on the weight of the catalyst. 
Reforming, utilizing the described catalyst, is conducted in the presence 
of hydrogen under reforming conditions. The latter include a temperature 
between about 700.degree. F. and 1100.degree. F. and more usually between 
about 800.degree. F. and about 1000.degree. F.; a pressure within the 
range of about 50 to about 1000 psig and preferably between about 100 and 
700 psig and a liquid hourly space velocity of between about 0.1 and about 
10 and preferably about 0.5 and about 4. The molar ratio of hydrogen to 
hydrocarbon charge is generally between about 0.5 and about 20 and 
preferably between about 2 and about 12. 
The startup technique, constituting the subject matter of this invention, 
is particularly directed to avoiding temperature runaways in the reforming 
unit and overcracking of the chargestock without paying a penalty in 
irreversible activity loss. The procedure involved is economically 
attractive and does not entail the use of or introduction into the 
catalyst or reforming system of additional extraneous chemicals. The new 
startup procedure simply involves exposure of the catalyst to reformate at 
a temperature within the approximate range of 600.degree. to 750.degree. 
F. for a period of time followed by incremental replacement of the 
reformate with increasing amounts of charge naphtha until all the 
reformate has been replaced. Once this has been achieved and the bed 
temperatures of the reactors have equilibrated, the startup is capable of 
proceeding, with avoidance of catalyst presulfiding, in a conventional 
manner.

DESCRIPTION OF SPECIFIC EMBODIMENTS 
Chargestocks undergoing reforming, in accordance with the process described 
herein, are contemplated, as those conventionally employed. These include 
virgin naphtha, cracked naphtha, gasoline, including FCC gasoline or 
mixtures thereof boiling within the approximate range of 70.degree. to 
500.degree. F. and, preferably within the range of about 120.degree. to 
about 450.degree. F. The charge should be essentially free; that is, the 
feed should contain less than about 10 ppm sulfur and preferably less than 
5 ppm and still more preferably less than 1 ppm. The presence of sulfur in 
the charge decreases the activity of the catalyst as well its stability. 
In instances where the chargestock is not already low in sulfur, acceptable 
levels can be reached by hydrogenating the chargestock in a pretreatment 
zone wherein the chargestock is contacted with a hydrogenation catalyst 
which is resistant to sulfur poisoning. A suitable catalyst for this 
hydrodesulfurization process, is, for example, an alumina-containing 
support and a minor proportion of molybdenum oxide and cobalt oxide. Such 
hydrodesulfurization is ordinarily accomplished at 700.degree.-850.degree. 
F. at 200 to 2000 psig and at a liquid hourly space velocity of 1 to 5. 
The sulfur contained in the chargestock is converted to hydrogen sulfide, 
which can be removed by suitable conventional methods prior to reforming. 
In a preferred embodiment, hydrogen production and hydrogen purity are 
maximized while localized hydrocracking and methane production are 
minimized by inclusion in the reformate of a small amount not exceeding 
about 10 ppm, of sulfur and maintaining contact between the catalyst and 
such sulfur-containing reformate until the bed temperatures line out. 
Charge naphtha, which is thereafter substituted for the reformate, 
preferably contains about 2 to about 10 ppm of sulfur and particularly 
preferred about 4 to about 8 ppm of sulfur. Charge naphtha with such 
sulfur level or with sulfur additives to this level is preferably employed 
while the inlet temperatures are gradually increased to operating 
conditions. The time during which the catalyst is exposed to the above 
treatment is generally in the approximate range of 5 to 24 hours. 
After such exposure time, the sulfur can either be withdrawn completely or 
reduced to a lower level, not exceeding about 2 ppm. This method of 
streaming a catalyst is superior to presulfiding since it is much more 
selective. The utilization of the above procedure results in bringing on 
stream, a catalyst with near optimum activity, yield and hydrogen 
production and purity in a reliable and reproducible manner. 
The reforming catalysts employed are contemplated as being those Group VIII 
metal-containing, e.g., platinum, catalysts normally sensitive to sulfur 
under conditions encountered in reforming, and, as aforenoted, 
particularly multimetallic catalysts containing in addition to platinum, 
iridium and/or rhenium. Such catalysts may be made by conventional well 
known techniques in which the metal components are deposited on a single 
suitable refractory support. Also, reforming catalysts may be used wherein 
a minor proportion of platinum is deposited on one support and a minor 
proportion of another metal, such as iridium, is deposited on a separate 
support. The latter type reforming catalysts are more particularly 
described in copending application Ser. No. 076,047, filed Sept. 17, 1979. 
When the reforming catalyst is made up of separate particles containing 
platinum or platinum-rhenium and those containing a second metal, e.g., 
iridium, the relative weight ratio of the separate particles is generally 
between about 10:1 and about 1:10. The dimensions of the separate 
particles may range from powder size, e.g., 0.01 micron up to particles of 
substantial size, e.g., 3000 microns. Preferably, the particle size is 
between about 1 and about 100 microns. 
The refractory support is contemplated as being an inorganic oxide and 
usually alumina, of the gamma or eta variety. Halogen may be chlorine, 
bromine or fluorine, with particular preference being accorded chlorine. 
Generally, the refractory support of the catalyst is a porous adsorptive 
material having a surface area exceeding 20 square meters per gram and 
preferably greater than about 100 square meters per gram. Refractory 
inorganic oxides are preferred supports, particularly alumina or mixtures 
thereof with silica. Alumina is particularly preferred and may be used in 
a large variety of forms including alumina, precipitate or gel, alumina 
monohydrate, sintered alumina and the like. Various forms of alumina 
either singly or in combination, such as eta, chi, gamma, theta, delta or 
alpha alumina may be suitably employed as the alumina support. Preferably, 
the alumina is gamma alumina and/or eta alumina. The above nomenclature 
used in the present specification and claims with reference to alumina 
phase designation is that generally employed in the United States and 
described in "The Alumina Industry: Aluminum and its Production" by 
Edwards, Frary and Jeffries, published by McGraw-Hill (1930). 
Halogen may be added to the support, preferably alumina, in a form which 
will readily react therewith in order to obtain the desired results. One 
feasible method of adding the halogen is in the form of an acid, such as 
hydrogen fluoride, hydrogen bromide, hydrogen chloride and/or hydrogen 
iodide. Other suitable sources of halogen include salts, such as ammonium 
fluoride, ammonium chloride and the like. When such salts are used, the 
ammonium ions will be removed during subsequent heating of the catalyst. 
Halogen may also be added as fluorine, chlorine, bromine or iodine or by 
treatment in gaseous hydrogen halide. The halogen, preferably a chlorine 
or fluorine moiety, may be incorporated into the catalyst at any suitable 
stage in the catalyst manufacture. Thus, halogen may be added before, 
after or during incorporation of the platinum or platinum-rhenium and 
iridium on the refractory support. Halogen is conveniently incorporated 
into the catalyst when impregnating the support with halogen-containing 
metal compounds, such as chloroplatinic acid and chloroiridic acid. 
Additional amounts of halogen may be incorporated in the catalyst by 
contacting it with materials, such as hydrogen fluoride and hydrogen 
chloride, either prior to or subsequent to the metal impregnation step. 
Halogen may also be incorporated by contacting the catalyst with a gaseous 
stream containing the halogen, such as chlorine or hydrogen chloride. One 
feasible way to halogenate the alumina is by the addition of an alkyl 
halide, such as tertiary butyl chloride during the reforming operation. 
The amount of halogen introduced into the support is such that the halogen 
content of the overall catalyst is between about 0.1 and about 5 weight 
percent. 
The platinum metal may be deposited on the support, desirably alumina, in 
any suitable manner. Generally, it is feasible to mix particles of support 
with a platinum compound such as chloroplatinic acid, platinum 
tetrachloride, bromoplatinic acid, or the ammonium salt of chloroplatinic 
or bromoplatinic acid. 
The iridium metal may be deposited on the support, desirably alumina, by 
contacting with an appropriate iridium compound such as the ammonium 
chloride double salt, tribromide, tetrachloride or chloroiridic acid. 
Iridium amine complexes may also suitably be employed. 
The impregnated particles may then be dried in air at an elevated 
temperature generally not exceeding 250.degree. C. prior to introduction 
of the catalyst into the reforming unit. Optionally, the catalyst may be 
exposed to a hydrogen atmosphere to reduce a substantial portion of the 
platinum component to the elemental state. 
It is to be noted that the catalyst of the present invention may contain in 
addition to platinum, iridium and/or rhenium one of several additional 
catalytic components such as silver, osmium, copper, gold, palladium, 
rhodium, gallium, germanium or tin or compounds thereof. The amounts of 
the added catalytic components may be in the approximate range of 0.01 to 
2 weight percent, preferably between about 0.1 and about 1.0 weight 
percent. The platinum content, rhenium content, iridium content and 
halogen content of catalysts is in the same range as set forth 
hereinabove, with the preferred support being alumina. 
In a typical commercial reforming process, reaction temperature is 
increased during the course of the run to maintain a constant product 
octane level. Increasing the reaction temperature becomes necessary since 
the catalyst is continuously deactivated. Generally, the reaction 
temperature cannot exceed about 1000.degree. F. before rapid deactivation 
of the catalyst is encountered. Accordingly, as the reaction temperature 
approaches about 1000.degree. F., it is usually necessary to regenerate 
the catalyst. Regeneration is accomplished by burning the coke deposit 
from the catalyst and then treating with chloride, HCl-oxygen mixtures or 
organic chloride-oxygen mixtures to rejuvenate the catalyst and thereby 
restore its activity and selectivity. 
It is contemplated that the catalyst described hereinabove may be employed 
in any of the conventional types of processing equipment. Thus, the 
catalyst may be used in the form of pills, pellets, extrudates, spheres, 
granules, broken fragments or various other shapes dispersed as a fixed 
bed within a reaction zone. The charge stock may be passed through the 
catalyst bed as a liquid, vapor or mixed phase in either upward or 
downward flow. The catalyst may also be used in a form suitable for moving 
beds. In such instances, the chargestock and catalyst are contacted in a 
reforming zone wherein the chargestock may be passed in concurrent or 
countercurrent flow to the catalyst. Alternatively, a suspensiod-type 
process may be employed in which the catalyst is slurried in the 
chargestock and the resulting mixture conveyed to the reaction zone. The 
reforming process is generally carried out in a series of several 
reactors. Usually, three to five reactors are used. The catalyst of the 
invention may be employed in just one of the reactors, e.g., the first 
reactor or in several reactors or in all reactors. After reaction, the 
product from any of the above processes is separated from the catalyst by 
known techniques and conducted to distillation column where the various 
desired components are obtained by fractionation. 
A typical catalytic reforming unit is shown in FIG. 1. Referring more 
particularly to this Figure, reformer feed, constituting desulfurized 
naphtha is combined with hydrogen recycle gas, heated and reformed over 
catalyst contained in the three reactors. Heat is adsorbed during the 
reforming reactions which requires the stream to be reheated in the first 
and second interpass heaters. Upon exiting the last reactor the effluent 
is cooled then split in a fresh separator, after which some of the 
recycled gas is returned to the unit. The product is stabilized to the 
desired vapor pressure and the reformate obtained as part of the motor 
gasoline or aviation fuel pool. The vapor effluent from the last reactor 
of the series is a gas rich in hydrogen, which usually contains small 
amounts of gaseous hydrocarbons and is separated from the C.sub.5+ liquid 
product and recycled to the process to minimize coke production, which 
forms and deposits on the catalyst during the reaction. 
In one embodiment of the present invention, a stream of reformate produced 
is recycled in the overall catalytic reforming system shown in FIG. 1, 
through lines 10, 11 and 12 to the first reforming reactor, where it 
serves, in accordance with the desired startup procedure to pre-condition 
the catalyst preliminary to further contact with reformer charge stock. It 
will be understood that the reformate recycle stream is controlled in 
amount and maintains contact with the catalyst undergoing treatment for a 
desired period of time by means of suitable valve controls, which, for 
purposes of simplicity, have been omitted from the drawing. Also, it will 
be understood that during the period of pre-conditioning of the catalyst 
by contact with the reformate recycle stream, the flow of reformer charge 
stock is discontinued to the initial reforming reactor by suitable control 
means. 
The following examples will serve to illustrate the start up procedure of 
this invention without limiting the same. 
EXAMPLE 1 
One hundred (100) grams of gamma-alumina beads were impregnated by soaking 
overnight in 145 ml of aqueous hexachloroplatinic acid solution containing 
0.6 gram of platinum. By the following day, the support had adsorbed the 
aqueous solution, including the platinum. The catalyst was then dried 
overnight at 110.degree. C. in air. Similarly, the iridium component was 
made by impregnating 62.2 grams of gamma-alumina beads with 90 ml of a 
solution containing 1 gram of H.sub.2 IrCl.sub.6.6H.sub.2 O (37.3 weight 
percent Ir). Following adsorption of this solution by the support, the 
iridium containing component was dried at 110.degree. C. overnight in air. 
Finally, the catalyst consisting of 0.3 wt. % platinum and 0.3 wt. % 
iridium was made by mixing equal amounts of the 0.6 wt. % platinum and 0.6 
wt. % iridium catalyst. 
EXAMPLE 2 
The catalyst of Example 1 was presulfided with hydrogen containing 400 ppm 
of hydrogen sulfide. The catalyst was apportioned as follows: 12 
grams--first reactor, 22 grams--second reactor and 25 grams--third 
reactor. With the catalyst at 750.degree. F., 200 psig and the recycle at 
6 standard cubic feet per hour, the presulfiding gas was put into the 
first of three reactors in series for one hour (2.0055 cu. ft.). 
Breakthrough was not detected after the last reactor. Following this, 
charge naphtha was pumped at 190 ml/hour with 10 ml/hour of 1% tert.-butyl 
chloride in naphtha for 200 minutes. The 1% solution of ter.-butyl 
chloride was then replaced with a solution containing 1500 cc of naphtha 
and 30 cc of 1% tert.-butyl chloride in naphtha and the catalyst was on 
stream. 
EXAMPLE 3 
The catalyst of Example 1 was pretreated at 650.degree. F., 100 psig and 
recycle of 10 standard cubic feet per hour with 98 R+O reformate. The 
catalyst was loaded with 9 grams in the first reactor, 17 grams in the 
second reactor and 19 grams in the third reactor. Initially, 76 ml/hr of 
promoter I, composed of 1 gram tert.-butyl chloride in 130 grams of 98 R+O 
reformate, was pumped for 20 minutes. This was then replaced with promoter 
II, composed of 1 gram tert.-butyl chloride in 1300 grams of reformate, 
also pumped at 76 ml/hr. Simultaneously with this charge, 10 ml/hr of 
charge naphtha was begun and the rate was increased 15 ml/hr at 20 minute 
intervals to 100 ml/hr. After this was attained, the rate of promoter II 
was decreased to 7.5 ml/hr and the charge naphtha was increased to 145 
ml/hr. Following this adjustment, promoter II was replaced with a solution 
containing 1500 cc of naphtha and 30 cc of 1% tert.-butyl chloride in 
naphtha. The catalyst was then on stream and subsequently adjusted to 
operating conditions. 
EXAMPLE 4 
The catalyst of Example 4 was prepared by mixing equal amounts by weight of 
0.6% platinum and 0.2% iridium-containing 1/16 inch gamma-alumina beads. 
This resulted in an overall compositions of 0.3% platinum and 0.1% 
iridium. The components were prepared by impregnating the beads with 
aqueous H.sub.2 PtCl.sub.6 or H.sub.2 IrCl.sub.6 solutions. The platinum 
catalyst was dried for one hour at 950.degree. F. in air and the iridium 
catalyst was dried for one hour at 700.degree. F. in nitrogen. 
EXAMPLE 5 
The catalyst of Example 4 was presulfided at 750.degree. F. with gas 
containing 400 ppm of hydrogen sulfide in hydrogen. The catalyst was 
distributed as follows: 12 grams in the first reactor, 22 grams in the 
second reactor and 25 grams in the last reactor. The presulfiding gas was 
first introduced into the top of the last reactor at 2 standard cubic feet 
per hour. Addition was continued until the breakthrough of H.sub.2 S was 
detected after the last reactor. When breakthrough occurred, H.sub.2 S 
addition was stopped and the amount of gas was noted (2.269 cu. ft.). The 
first and second reactor were similarly presulfided in series. Two 
standard cubic feet per hour of presulfiding gas were introduced into the 
first reactor while breakthrough was monitored between the second and last 
reactor. When breakthrough occurred (1.547 cu. ft.), the presulfiding gas 
addition was stopped. The catalyst was then streamed with 33.3 ml of a 
solution containing charge naphtha with 1% tert.-butyl chloride. This was 
followed by charge naphtha along with a solution containing 1500 cc of 
naphtha and 30 cc of 1% tert.-butyl chloride in naphtha resulting in 1-10 
ppm chloride being added. 
EXAMPLE 6 
The catalyst of Example 4 was pretreated at 650.degree. F., 100 psig and a 
recycle of 10 standard cubic feet per hour with 98 R+O reformate. The 
catalyst was loaded by placing 12 grams in the first reactor, 22 grams in 
the second reactor and 25 grams in the last reactor. The catalyst was 
initially pretreated by adding 33.3 ml of a solution composed of 130 grams 
of reformate and 1 gram tert.-butyl chloride. This was followed by the 
addition of a solution (Promoter II) composed of 1300 grams of reformate 
and 1 gram of tert.-butyl chloride charged at 100 ml/hr. Simultaneously, 
the addition of 10 ml/hr of charge naphtha was begun and the rate was 
increased 15 ml/hr at 20 minute intervals to a final rate of 100 ml/hr. 
After this was attained, the rate of addition of Promoter II was decreased 
to 10 ml/hr and the rate of charge naphtha was increased to 190 ml/hr. 
Promoter II, containing reformate, was then replaced by a solution 
containing 1500 cc of naphtha and 30 cc of 1% tert.-butyl chloride in 
naphtha and the catalyst was on stream. 
Reforming of C.sub.6 -330.degree. F. Arab Light Naphtha was accomplished in 
a adiabatic pre-reactor system at a pressure of 200 psig, a recycle mole 
ratio of hydrogen to charge of 5 and a weight hourly space velocity of 
2.5. 
The results obtained are shown graphically in FIGS. 2 and 3 where inlet 
temperature necessary to obtain a product having an octane number of 98 
R+O is plotted against time on stream. Comparative results obtained using 
the catalyst of Example 1 wherein a presulfided start up and a reformate 
start up are shown in FIG. 2. After the start up both the presulfided and 
reformate treated catalyst were run identically. It will be seen from the 
results presented graphically in FIG. 2 that the amount of activity gained 
due to the reformate start up was approximately 20.degree. F. 
Comparative results obtained using the catalyst of Example 4 in a 
presulfided start up and in a reformate start up are shown in FIG. 3. 
Referring more particularly to the results presented graphically in the 
latter Figure, it will be seen that the catalyst which was pre-sulfided 
was unable to recover with the iridium level at 0.1%. Such result is 
presumably due to the rapid rate of coking on the platinum sites. The 
catalyst which was started up with reformate treatment, on the other hand, 
without presulfiding, lined out between 945.degree.-950.degree. F. Such 
level of activity is presumed due to the iridium concentration of 0.1%. 
It is to be understood that the above description is merely illustrative of 
preferred embodiments of the invention, of which many variations may be 
made within the scope of the following claims by those skilled in the art 
without departing from the spirit thereof.