Title of Invention

AN IMPROVED PROCESS FOR THE PREPARATION OF SUPER ACTIVE ACIDIC BIMETALLIC CONTINUOUS CATALYTIC REFORMING (CCR) CATALYST

Abstract An improved process for the preparation of a bimetallic continuous catalytic reforming catalyst by contacting a high surface area porous carrier material selected from alumina sphere with a solution of a halogen acid selected from hydrochloric acid, drying the impregnated carrier material and calcinating it in a dry atmosphere, impregnating the above halogenated porous carrier material with an organic solvent solution of chlorostannate (II) chloroplatinate anionic complex for a period of 20 min to 280 min, drying and calcining the resulting impregnated carrier material in a dry atmosphere to obtain the desired bimetallic catalyst.
Full Text The present invention relates to an improve process for the preparation of a bimetallic continuous catalytic reforming composite catalyst
The present invention particularly relates to an improved process for the preparation of a super active acidic bimetallic continuous catalytic reforming (CCR) composite catalyst.
The acidic bimetallic catalyst composite of the present invention is suitable for the conversion of low octane hydrocarbons present in naphtha to high octane hydrocarbons concentrates and to aromatic rich concentration. The invention gives a method for preparing an acidic bimetallic dual functional catalyst composite with superior activity and selectivity for use in catalytic reforming of naphtha in CCR (continuous catalyst regeneration) mode of operation. Consistent with this invention by the expression "dual functional catalyst" are intended catalysts which have both hydrogenation / dehydrogenation function and an acidic function leading to the production of high octane reformat yield for motor fuel and aromatics for the petrochemical industry. More precisely, the product of the invention essentially contains platinum as a catalytically active species, together with a second metal tin and halogen, all incorporated on a porous high surface area refractory carrier material of controlled textural and structural properties.
Preparation of catalyst of the present invention involves the use of tin, platinum and halide on a gamma alumina support in a way to substantially improve the activity and selectivity of the catalyst in CCR mode of naphtha reforming operation.
Catalysts for the continuous catalytic reforming (CCR) of naphtha consisting of platinum, tin and chlorine on alumina support are of course known in the art.
Reference may be made to US Patent 3883419. Wherein the platinum tin reforming catalyst was prepared by impregnating the support with an aqueous solution of a halogen acid containing a platinum group metal, drying the impregnated carrier and then impregnating the dried platinum group metal impregnate with a solution of divalent tin compound.

Published US Patent 4032,434 describes a method for the preparation of a bimetallic catalytic composite containing a platinum group component, a tin component and a halogen component on a porous carrier material. The tin component was cogelled with the support material, and the platinum halogen components were impregnated on the tin containing support.
The methods followed in the above mentioned patents for the incorporation of platinum and tin on the carrier material for the preparation of the catalyst do not assure the close promineity of tin and platinum in the catalyst composite. Utilizing a platinum-tin complex for the preparation of the catalyst helps in associating tin closely with platinum in the catalyst which assures a high beneficial effect of tin on the catalytic performance of platinum catalysts utilizing a platinum-tin complex are however disclosed in the art.
It is known [Graciela T et al Appl. Cat. 19 (1985) 77-85] that the interaction between H2Pt(IV)Cl6, and Sn(II)Cl2 in a hydrochloric acid solution leads to the formation of Sn (IV) and Pt (II) species and a complex [PtCl2 (SnCl3)2]2- structure.
Reference may be made to US patent 3, 998, 950 which disclosed a dehydrogenation catalyst comprising a alkali or alkaline earth component with a catalytic composite consisting essentially a tin component in combination with a platinum component on a carrier material.
The platinum tin containing composite was prepared by impregnating a high surface area porous carrier material with a solution of a complex Chlorostannate (II) Chloroplatinate anionic species stabilized with aqueous halogen acid. The catalyst was utilized for the dehydrogenation of hydrocarbons.
The patent does not describe the suitability of the catalyst for the reforming of naphtha, which involves several reactions other than dehydrogenation. Moreover along with platinum and tin the catalyst also contains alkali or alkaline earth metals.

US patent 3840475 discloses a method for making supported bimetallic hydrocarbon conversion catalyst by simultaneously depositing platinum and tin on a nonacidic alumina support using a platinum-tin complex. The catalyst was evaluated for the dehydrocyclization of n-octane. Its suitability for the reforming of naphtha was not disclosed.
Published US Patent, 3844938 discloses a process for reforming a hydrocarbon feed stock by contacting it under reforming conditions with a catalytic composite prepared by impregnating a high surface area porous carrier material with a solution comprising a tinchlorostannate (II) chloroplatinate anionic species, the said solution being stabilized in contact with the carrier material with an aqueous halogen acid.
By using of contrast method of preparation of the platinum-tin catalytic composite has been disclosed in the present invention which utilizes tin chlorostannate (II) chloroplatinate complex in acetone solution to incorporate the tin and platinum component on pre-chlorinated alumina support. The impregnating solution does not require the addition of hydrochloric acid for stabilizing the complex. The uniqueness of the method of preparation of the highly active and selective catalyst for the reforming of naphtha will be illustrated hereinafter.
In the prior art referred to herein before the CCR catalyst is prepared by utilizing an aqueous solution of a tin-platinum anionic complex stabilized by hydrochloric acid for incorporating platinum and tin on the carrier material. The hydrochloric acid obviates instability of the complex anionic species upon contact with the carrier material, an instability believed to result from carrier material adsorption of halogen from the complex and thus preserves the intimate association of the tin and platinum components.
On the contrary the present invention utilizes an acetone solution of a platinum-tin complex for the incorporation of the metals on prechlorinated alumina spheres. The prechlorination of the alumina spheres assures that it does not adsorb chlorine from the impregnating solution when brought in contact with it. The present invention thus does not require the addition of hydrochloric acid to the impregnating solution for stabilizing

the tin-platinum complex. This renders the impregnating solution less acidic which reduces the solubility of alumina from the carrier material when brought in contact with the solution. The textural properties of the carrier material are thus not altered.
The main object of the present invention is to provide a process for the preparation of a bimetallic continuous catalytic reforming (CCR) catalyst which obviates the drawbacks as detailed above.
Another object of the present invention is to provide a process for the preparation of this catalyst composite having superior activity selectivity when employed in a low pressure reforming process.
Yet another object of the present invention is to provide improvement in activity characteristics of the reforming catalyst by utilizing a relatively inexpensive component such as tin to promote and stabilize the platinum metal. Still another object of the present invention is to provide a process for the preparation of he catalyst utilizing an impregnating solution comprising platinum-tin anionic complex prepared by commingling the acetone solution of stannous chloride and chloroplatinic acid.
Accordingly, the present invention provides an improved process for the preparation of a bimetallic continuous catalytic reforming catalyst, the said process comprising:
a) contacting a high surface area porous carrier material selected
from alumina sphere with a solution of a halogen acid selected
from hydrochloric acid, drying the impregnated carrier material
and calcinating it in a dry atmosphere,
b) impregnating the above halogenated porous carrier material
with an organic solvent solution of chlorostannate (II)
chloroplatinate anionic complex for a period of 20 min to 280
min,
c) drying and calcining the resulting impregnated carrier material in
a dry a4mo§pTiere to obtain the desired bimetallic catalyst.

In an embodiment at the present invention the porous carrier material used is a refractory inorganic oxide in gamma alumina spheres.
In yet another embodiment of the present invention the halogen acid used is hydrochloric acid.
In yet another embodiment of the present invention the halogen containing carrier material used is chlorinated alumina spheres
In yet another embodiment of the present invention the chlorostannate (11) chloroplatinate anionic complex is a reaction product of stannous chloride and chloroplatinic acid.
In yet another embodiment of the present invention the volume ratio of a solution of chlorostannate (11) chloro platinate anionic complex to pore volume of chlorinated alumina sphere is in the range of 1:1 to 1:2.
In yet another embodiment of the present invention the organic solvent used is selected from acetone and methyl ethyl ketone.
In still another embodiment of the present invention the catalyst prepared contains on an elemental basis 0.1 wt% to 1.0wt% of platinum and tin and about 0.8 wt% to 1.2wt% chlorine.
Accordingly the refractory porous support utilized in the present invention is considered first. It is preferred that the material should be adsorptive, have a high surface area and should be relatively refractory to the condition utilized in the hydrocarbon conversion process. The carrier material used in the present invention is porous high surface area (150-250m2/g) gamma alumina spheres which is traditionally used as support for dual functional catalysts utilized in the hydrocarbon conversion process. The gamma alumina sphere support may have an apparent bulk density of 0.5-0.7 g/ml and pore volume 0.3-

0.7 ml/g. In the present invention alumina spheres of diameter 1.0 to 2.0 mm are preferred to suit the moving bad operation. In general best results are obtained with a gamma alumina earner material in the form of spherical particles having a diameter typically 1.5 mm, an apparent bulk density of about 0.6 g/ml; a pore volume of about 0.6 ml/g and a BET surface area 175 to 200 m2/g. The spheres should be relatively strong and the attrition loss should be less than 1.0 per cent.
The other aspect of the catalyst composite is the incorporation of an essential component chlorine (0.8-1.2 wt %) on the alumina carrier. This chlorine should be stable on the support and should not be easily leached out during calcination or subsequent reduction in hydrogen, at elevated temperatures around 530°C. The halogen pick up depends upon the surface area of the support and the number of hydroxyl groups present on the surface which are replaced by the halide group. The halogen may be added to the carrier during its preparation or afterwards or even during the impregnation of active metal ingredients in the form of a water soluble halogen compound preferably hydrochlroic acid. In the present invention the halogen was added to the formed support prior to the addition of active metal ingredients by dipping the support in aqueous hydrochloric acid solution. Conditions for the halogen uptake like the concentration and volume of the hydrochloric acid solution; duration of uptake, and temperature of solution were optimized to get the desired uptake of the halogen.
The other essential constituents of the superactive composite of the present invention are a tin and platinum component. These components may be incorporated into the catalytic composite in any suitable manner known to efficiently disperse these components throughout the chlorinated carrier material soluble decomposable. Compounds of tin and platinum are used to impregnate the carrier with tin and platinum. Solvent used in this impregnation is selected on the basis of its capability to dissolve the described compounds so that it is uniformly distributed over the carrier surface. Aqueous or organic solvents may be used.

In accordance with the present invention prechlorinated spherical alumina support of high surface area is impregnated with a solution comprising a complex tin-platinum group metal anionic species. The impregnating solution is prepared to contain complex trichlorostannate (II) chloroplatenate anionic species containing tin in the +2 valance state. Thus stannous chloride is reacted with chloroplatinic acid at ambient temperature to yield a suitable complex tin-platinum anionic species. Preferably the impregnation solution containing the tin-platinum anionic complex is prepared by moistening stannous chloride with hot hydrochloric acid, adding acetone to the moist stannous chloride and commingling it with an acetone solution of chloroplatinic acid at room temperature. The concentration of tin and platinum is so chosen to yield a final catalyst composite containing from about 0.1 to 1 wt% each of tin and platinum on an elemental basis.
Impregnation conditions employed herein involve conventional impregnation techniques known to the art. Thus the catalytic components are adsorbed on the chlorided spherical alumina carrier by soaking, dipping, suspending or immersing in the impregnation solution suitably at room temperature conditions. The carrier material is maintained in contact with the impregnating solution at room temperature for 15 to 30 minutes and the impregnating solution thereafter evaporated at an elevated temperature. As an example a volume of chlorinated alumina spheres are immersed in a substantially equal volume of impregnation solution at room temperature agitated for a brief period, thereafter heated on a steam bath to essentially remove the acetone solvent and recover the partially dried impregnated earner material.
In summary one preferred embodiment of the impregnating step of the present invention utilized an impregnating solution comprising a complex trichlorostannate (II) chloroplatinate anionic species prepared by commingling acetone solutions of stannous chloride and chloroplatinic acid. The concentration of tin and platinum in the impregnating solution is selected to yield a final catalyst composite containing from about 0.1 to 1 wt% each of platinum and tin calculated on an elemental basis. The prechlorinated alumina sphere support is immersed in the impregnating solution of volume equal to the volume of support left for 15 to 30 minutes thereafter heated on a steam bath to remove the solvent acetone. The partially dried impregnated carrier is

further dried at 110-150°C for 20-40 hours prior to calcination at 500-550°C for 4 to 10 hours in an oxygen containing atmosphere.
The method aspect of the present invention is contacting a hydrocarbon charge stock (naphtha) and hydrogen with the catalyst in a fixed bed system. In this system a hydrogen rich gas and chargestock are preheated to the desired reaction temperature and are then passed into a reforming zone containing a fixed bed of catalyst. A preferred chargestock of reforming operation are those consisting essentially of naphthenes, paraffins and also aromatics.
In the reforming embodiment the effluent stream is withdrawn from the reforming zone and passed through a cooler to a separation zone. The hydrogen rich gas is separated from high octane liquid product. A measured portion of hydrogen rich gas stream is then recycled through suitable compressing means back to reforming zone.
In the reforming embodiment of the present invention the pressure utilized is in the range of 3.5 to 12 kg/cm2 with best results obtained at about 6 kg/cm2. The present invention requires a temperature in the range of about 480-535°C and preferably about 510°C. The present invention typically utilizes sufficient hydrogen to provide an amount of about 1 to 10 moles of hydrogen per mole of hydrocarbon entering the reforming zone. Excellent results are obtained when 5 moles of hydrogen are used per mole of hydrocarbon. Likewise the present invention utilizes a weight hourly space velocity (WHSV) of 1.0 to 3.0 with a value of 2.0 being preferred.
The novelty of the present invention lies in preparation of CCR catalyst by utilizing an acetone solution of a platinum-tin complex for the incorporation of the metals on prechlorinated alumina spheres. The prechlorination of the alumina spheres assures that it does not adsorb chlorine from the impregnating solution when brought in contact with it. The present invention thus does not require the addition of hydrochloric acid to the impregnating solution for stabilizing the tin-platinum complex as reported in prior art. This renders the impregnating solution less acidic which reduces the solubility of alumina

from the carrier material when brought in contact with the solution. The textural properties of the carrier material are thus not altered.
The following examples are given to illustrate further the preparation of the superactive CCR catalyst of the present invention. The examples should not be construed to limit the scope of the present invention.
EXAMPLE-I
This example demonstrates the method for the chlorination of alumina sphere utilized as carrier material for the preparation of the CCR catalysts.
Weighed amount of alumina spheres of average diameter 0.165 cms were chlorinated by immersing it in a volume of N/15 hydrochloric acid solution ten times its weight for 24 hours. After this the acid was decanted and the wet spheres were dried at 110°C for 16 hours. The dried spheres were subsequently calcined in a dry atmosphere at 450°C for 4 hours. The resulting chlorinated alumina spheres were utilized for the preparation of the catalyst.

EXAMPLE -2 [Catalyst-A]
100 gins of prechlorinated alumina spheres of example-I were used as support for the preparation of the catalyst. An acetone impregnation solution was prepared as follows. 0.81 Ig of stannous chloride was moistened with hot hydrochloric acid and mixed with acetone. This mixture was commingled with an acetone solution of 0.875g of chloroplatinic acid to obtain a final catalyst-B containing on elemental basis about 0.35 wt% platinum., 0.43 wt% tin and 1.0 wt% Chlorine. The volume of solution was taken equal to the pore volume of the spheres.
The impregnation step was performed by adding the chlorinated alumina spheres to the impregnation solution. The impregnation solution was maintained in contact with the alumina spheres for a period of 30 minutes at room temperature. The wet spheres were first dried on a water bath to remove acetone partially and then dried at 110°C for 16 hours. The dried spheres were subjected to a calcination step in an air atmosphere at 550°Cfor4hours.
The resulting catalyst-A on analysis had a nominal loading of 0.35 wt% of pt, 0.42 wt% of Sn and 0.97 wt% of chlorine. The catalyst had a surface area of 185 m2/g and apparent bulk density of 0.61 g/ml. The platinum metal dispersion as determined by oxygen titration was 90%.
EXAMPLE -3 [Catalyst-B]
100 gms of prechlorinated alumina spheres of example-I were used as support for the preparation of the catalyst. An acetone impregnation solution was prepared as follows. 0.81 Ig of stannous chloride was moistened with hot hydrochloric acid and mixed with acetone. This mixture was commingled with an acetone solution of 0.875g of chloroplatinic acid obtain a final catalyst-B containing on elemental basis about 0.35 wt% platinum., 0.43 wt% tin and 1.0 wt% Chlorine. The volume of the solution was taken greater than the pore volume of the spheres impregnation was done by dipping the chlorinated alumina spheres in the impregnating solution prepared as above at room

temperature. After 9 hours of immersion, the excess solution was decanted and the wet spheres were first heated on a steam bath for 2 hours followed by further drying at 110°C for 16 hours. The dried spheres were finally calcined at 500°C for 4 hours. Analysis indicated that the resulting catalyst-B contained 0.346 gms of platinum, 0.425 gms tin and 1.04 gms chlorine. The platinum metal dispersion was 90%.
EXAMPLE -4 [Catalyst-C]
100 gms of chlorinate alumina spheres of example-1 were dipped in an aqueous solution of 0.875g of chloroplatinic acid to have a loading of 0.35 gms platinum in the final catalyst. After 20 hours the solution was decanted and the wet spheres were dried at 120°C for 4 hours. The platinum loaded spheres were then dipped in an aqueous solution of stannous chloride having tin in an amount to have 0.3 gms tin in the final catalyst. After 6 hours the excess solution was decanted. The wet spheres were first dried at 110°C for 20 hours and then calcined at 550°C for 4 hours in an oxygen containing atmosphere. Analysis indicated that the final catalyst contained 0.35 gms of platinum, 0.28 gms of tin and 0.98 gms of chlorine. The platinum metal dispersion as determined by oxygen titration was 56 per cent.
EXAMPLE -5 Performance of the catalyst
The prepared catalysts A,B and C were separately subjected to catalytic reforming evaluation test designed to simulate conditions encountered in commercial continues catalytic reforming (CCR) process and to emphasis their relative activity and selectivity. The runs were conducted under essentially sulphur free conditions. Analysis of the charge stock is given in Table-1. The list was designed to determine whether a catalyst being evaluated has superior characteristics for use in high severity low pressure reforming operation. Each catalyst was evaluated for a period of 160 hours approximately.

During this period the products from reforming zone were collected and analyzed. Test runs were performed under identical conditions which comprises a weight hourly space velocity of 2hr-1, reactor pressure of 6 kg/cm2 and a gas/oil ratio of 5.0 results are given in Table-2.
TABLE -I
(Table Removed)
TABLE-II TEST RESULTS

(Table Removed)
It will be seen from table-2 that the activity of catalyst-A of example-4 as measured by RONC (Research Octane number clear) of the liquid product is highest.
The catalyst formulated according to the concept of the present invention materially accelerates the rate of reforming reactions and is more active for promotion of the beneficial upgrading reaction of catalytic reforming than the other catalyst.
However, activity is only one of the necessary characteristics needed in order for a catalyst to demonstrate superiority. Activity characteristics must be coupled with superior selectivity in order to demonstrate improved in order to demonstrate improved performance. Selectivity is measured directly by C5+ liquid yield. The date presented in Table-2 indicate that catalyst-C produced slightly lower C5+ liquid yield as compared to catalysts C and B. This result is greatly expected in view of the fact that established relationship for activity-selectivity generally recognizes that decreased selectivity accompanies increased activity. The other additional advantage of this catalyst-A is that it gives the highest aromatic yield compared to the catalysts C and B.
In summary the bimetallic CCR catalyst of the present invention is a significant advance over the other bimetallic catalysts prepared by following examples 2 and 3.



We claim :
1. An improved process for the preparation of a bimetallic continuous
catalytic reforming catalyst, the said process comprising:
a) contacting a high surface area porous carrier material selected
from alumina sphere with a solution of a halogen acid selected
from hydrochloric acid, drying the impregnated carrier material
and calcinating it in a dry atmosphere,
b) impregnating the above halogenated porous carrier material
with an organic solvent solution of chlorostannate (II)
chloroplatinate anionic complex for a period of 20 min to 280
min,
c) drying and calcining the resulting impregnated carrier material in
a dry atmosphere to obtain the desired bimetallic catalyst.

2. An improved process as claimed in claim 1 wherein the halogen
containing carrier material used is chlorinated alumina spheres.
3. An improved process as claimed in claims 1-2 wherein the chlorostannate
(II) chloroplatinate anionic complex is a reaction product of stannous
chloride and chloroplatinic acid.
4. An improved process as claimed in claims 1-3 wherein the organic solvent
used is selected from acetone and methyl ethyl ketone.

5. An improved process for the preparation of a bimetallic continuous catalytic reforming catalyst substantially as herein described with reference to the examples.

Documents:

986-del-2000-abstract.pdf

986-del-2000-claims.pdf

986-del-2000-correspondence-others.pdf

986-del-2000-correspondence-po.pdf

986-del-2000-description (complete).pdf

986-del-2000-form-1.pdf

986-del-2000-form-19.pdf

986-del-2000-form-2.pdf


Patent Number 242142
Indian Patent Application Number 986/DEL/2000
PG Journal Number 34/2010
Publication Date 20-Aug-2010
Grant Date 16-Aug-2010
Date of Filing 03-Nov-2000
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 DAYAL SINGH RAWAT INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248 005 INDIA.
2 RAGHUNATH PRASAD MEHROTRA INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248 005 INDIA.
3 ASHOK KUMAR SAXENA INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248 005 INDIA.
4 VIJAI SINGH DANGWAL INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248 005 INDIA.
5 TURUGA SUNDARA RAMA PRASADA RAO INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248 005 INDIA.
PCT International Classification Number B01J 23/42
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA