WO2008059531A2

WO2008059531A2 - Clay based catalysts for treatment of hydrocarbon

Info

Publication number: WO2008059531A2
Application number: PCT/IN2007/000528
Authority: WO
Inventors: Chetan Navnithlal Shah
Original assignee: Chetan Navnithlal Shah
Priority date: 2006-11-13
Filing date: 2007-11-07
Publication date: 2008-05-22
Also published as: WO2008059531A3; KR20090103877A; KR101268273B1

Abstract

A catalyst composition in granular form comprising an intimate mixture of smectite clay in the range of 75 - 95 % of the total composition and at least one additive selected from attapulgite and amorphous metakaolin in the range of 25 - 5 % of the total composition, said composition having a particle size of 0.25 mm to 2 mm, a total acidity greater than 22 mg KOH/g and a surface area of 300 - 350 m /g.

Description

CLAY BASED CATALYSTS FOR TREATMENT OF HYDROCARBON

Field of invention

The present invention relates to a catalyst composition. More particularly, relates to a catalyst composition used for cracking of aromatic hydrocarbons.

Definitions:

For the puipose of this specification the following terms will have the meanings assigned to them in addition to the conventional meaning of the respective terms.

Smectite: Smectite refers to a family of clays primarily composed of hydrated sodium calcium aluminum silicate. Common names for smectite include montmorillonite or sodium montmorillonite ("sodium bentonite")

Attapulgite/Palygorskite: Palygorskite (also known as attapulgite) is a magnesium aluminum silicate type of clay available in the states of Gujarat, Andhra Pradesh and Rajasthan in India. It is one of the types of fuller's earth.

Kaolinite: Kaolinite is a clay mineral with the chemical composition Al₂Si₂O₅(OH)₄. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina. Rocks that are rich in kaolinite are known as china clay or kaolin. Meta kaolinite: Kaolinite clay heated to a temperature of 750 degree C for 3 hours forms Meta kaolin.

Total acidity: The total acidity of a solution is a measure of all the hydrogen ions (H⁺) of both the fixed and volatile acids present.

Methylene blue value: This value indicates the cation exchange capacity of smectite clay. The value increases with the quantity of active clay in a composition.

Bromine index: As per ASTM D1491. Bromine number signifies the presence of un-saturation or double bond or olefins in the hydrocarbon. These olefins interfere in the further processing and have to be removed. These olefins have approximately same boiling points as aromatic compounds and separation by means of distillation is not possible. Bromine Number is expressed as the grams of Bromine (Br) available to react with 100 grams of the product. Bromine Index is expressed as the milligrams of Bromine available to react with 100 grams of the product under the specified condition.

Background and Prior Art

Naturally occurring clays such as bentonite, smectite, kieselghur and the like are widely used as adsorbents in several industrial processes during purification and decolorization, stabilization of vegetable oils or catalytic reactions including alkylation, polymerization, isomerization and the like. Clay-based catalysts have also been used in refining of petroleum and other crude oil products.

Bentonite is a native, colloidal, hydrated, mineral of the Dioctahedral Smectite Group that is primarily composed of the mineral montmorillonite, which has been processed to remove grit and non-swellable ore components. Bentonite is mined and processed into a variety of grades. The different grades of bentonite are distributed as individual products with similar applications to various industrial and consumer markets worldwide, including metal casting, well drilling, water sealant, and the emerging alternative fuel industry.

Smectite refers to a family of clays primarily composed of hydrated sodium calcium aluminum silicate. Common names for smectite include montmorillonite or sodium montmorillonite. Smectite is a clay mineral having a 2: 1 expanding crystal lattice. Its isomorphous substitution leads to the formation of the various types of smectite and causes a net permanent ¹ charge balanced by cations in such a manner that water may move between the sheets of the crystal lattice, giving a reversible cation exchange and very plastic properties. Smectite is used to slow the progress of water through soil or rocks; used in drilling mud to give the water greater viscosity; used to produce nanocomposites; used as an absorbent to purify and discolor liquids; used as filler in paper and rubber; and used as a base for cosmetics and medicines.

Often, the reactive properties of naturally occurring clays can be altered or enhanced by acid treatment/ activation or through organic modification. Such treatments or modifications are accompanied by change in key physical properties such as surface area, pore volume, and surface acidity. Acid treatment disrupts the laminar structure of the clay and exposes parts of the interlayer surface to atmospheric N₂ and non-swelling adsorbates. Thus surface area increases after dissolution of soluble lattice ions gradually in the octahedral sites. Due to the partial dissolution Of Al⁺³, Mg⁺² & Fe⁺³ ions, the protons of the hydroxyl groups at the corners of the octahedron may become more labile as a result of structural deformation and increased acidity. Typically, the organic modification of clay involves substitution of exchangeable cations in the interlayer structure of the clay. The nature and technique used in the modification of clay largely depends on the desired properties.

These catalyst compositions are used for several industrially important reactions and in particular for treatment of hydrocarbons obtained during cracking of crude oil, for the treatment of vegetable oils and the like. Several types of clay-based catalyst compositions suitable for use in the treatment of hydrocarbons are reported in the prior art. The conventional clay based catalyst have moderate catalytic activity, a relatively low life and non reusability.

For instance,

US Patent No. 5,330,946 discloses a catalytic material comprising Ca- bentonite for treatment of aromatic hydrocarbons. The clay composition consists of a major amount of Ca-bentonite and relatively minor amount of sodium bentonite (non-acid activated). Similarly, US Patent No. 5,908,500 discloses a clay-based bleaching material suitable for use as an adsorbent in bleaching of soybean and corn oil. The clay-based materials described in the '500 patent is Attapulgite (palygorskite)-smectite mixture treated with the ethanolic sulfuric acid.

Again Japanese Patent No. 1,099,645 discloses clay-based material for treatment of edible oil, which is preferably composed of Bentonite (3-15%), Attapulgite (40-60%), Perlite (3-20%) and activated alumina (35-70%).

Still further, Japanese Patent No. 1,151,937 discloses a clay composition comprising Bentonite (1-5%), Attapulgite (15-55%), Kieselghur (15-55%) and active alumina (15-55%).

The catalysts described in the prior art have limitations in terms of catalytic activity or catalyst life when used in treatment of hydrocarbons. Catalyst with low activity gets exhausted relatively quickly and the reactor needs to be replenished with the catalyst. The deactivated catalyst needs to be frequently activated resulting in frequent downtime and an additional step of replenishment and reactivation. Also the toluene generated by side reactions such as Disproportionation reaction indicates losses in valuable xylenes. The toluene generation has to be as small as possible. An activated clay satisfying both long life and lower Disproportionation reaction is unknown in the prior art. Objects of the invention

It is an object of the present invention to provide an efficient catalyst composition suitable for hydrocarbon treatment.

Another object of the invention is to provide a catalyst composition with modified Smectite clay.

Yet another object of the present invention is to provide a catalyst composition which is economical.

Yet another of the present invention is to provide a catalyst composition which is reusable.

Yet another objective of the present invention is to provide a catalyst composition which has an improved lifecycle.

Yet another objective of the present invention is to provide a catalyst composition which has an improved acid value.

Summary of the invention

The present invention discloses a novel clay-based catalyst composition suitable for use in the treatment of hydrocarbons, the catalyst having superior catalytic activity, higher life and being less expensive. In accordance with the present invention there is provided a catalyst composition in granular form comprising an intimate mixture of smectite clay in the range of 75 - 95% of the total composition and at least one additive selected from attapulgite and amorphous metakaolin in the range of 25 - 5% of the total composition, said composition having a particle size of 0.25 mm to 2 mm, a total acidity greater than 22 mg KOH/g, and a surface area of 300 - 350 m²/g.

Typically, the additives Attapulgite or metakaolin are either activated before using as additive in the catalyst composition or along with the smectite clay.

Typically, the methylene blue value of the activated smectite clay is greater than 400 mg/g.

Typically, the metakaolin is formed by heating kaolin to a temperature of 700 - 750 degree C for 2-5 hours.

Typically, the methylene blue value is in the range of 400 - 450 mg/g.

Typically, the total acidity of the catalyst composition is between 22 - 25 mg KOH/g

Typically, the composition comprises smectite clay, attapulgite and metakaolin.

Typically, the ratio of attapulgite to metakaolin is in the range of 2: 1 to 1 :1. Typically, the ratio of smectite to attapulgite is in the range of 8:1 to 4:1.

Typically, ratio of smectite to metakaolin is in the range of 8: 1 to 4:1.

Typically, the moisture content of the composition is between 3 to 5%.

Description of the invention

Accordingly, the present invention provides a catalyst composition comprising modified Smectite clay particularly suitable for use in processing of cracking products of crude oil, vegetable oils and the like.

The clay-based catalyst composition according to this invention comprises Smectite clay and at least one additive selected from a group consisting of Attapulgite and metakaolin. The Attapulgite or metakaolin is either activated before using as an additive in the catalyst composition or along with the smectite clay.

The catalyst composition in granular form preferably comprises an intimate mixture of smectite clay in the range of 75 - 95% of the total composition and at least one additive selected from attapulgite and amorphous metakaolin in the range of 25 - 5% of the total composition, said composition having a particle size of 0.25 mm to 2 mm, a total acidity greater than 22 mg KOH /g, a surface area of 300 - 350 m /g and a moisture content of 3 -5%. Preferably, the metakaolin is formed by heating kaolin to a temperature of 700 - 750 degree C for 2-5 hours.

Preferably, the methylene blue value of the smectite clay is in the range of 400 - 450 mg/g.

Preferably, the total acidity of the catalyst composition is between 22 - 25 mg KOH/g

Preferably, the composition comprises smectite clay, attapulgite and metakaolin.

Preferably, the ratio of attapulgite to metakaolin is in the range of 2: 1 to 1 : 1.

Preferably, the ratio of smectite to attapulgite is in the range of 8: 1 to 4: 1. Preferably, ratio of smectite to metakaolin is in the range of 8: 1 to 4: 1.

In one embodiment according to the present invention, the novel clay-based catalyst composition comprises a relatively major amount of Smectite clay and relatively minor amount of at least one additive selected from the group comprising Attapulgite and/or metakaolin.

According to another aspect of the invention, the Smectite clay used in the preparation of the novel catalyst of the present invention is Ca- Montmorillonite clay, which has the following characteristics and specifications: SiO₂: 46 to 54 %; Al₂O₃: 10 to 18 %; Fe₂O₃: 6.0 to 16 %; TiO₂: 1.0 to 3.5 %; CaO: 1.2 to 3.0 %; MgO: 1.5 to 3.0 %; P₂O₅: 0.01 to 0.2 %; Na₂O: 1.0 to 2.5%; K₂O: 0.1 to 0.5 %; SO₃: 0.1 to 0.3 %; LOI 9.5 to 13.5%.

The attapulgite used in the preparation of the catalyst of the present invention has the following characteristics and specifications: SiO₂: 52 %; Al₂O₃: 7 to 8 %; Fe₂O₃: 9 to 11 %; TiO₂: 1.5 to 3.0 %; CaO: 1.0 to 3.0 %; MgO: 9.0 to 15.0 %; K₂O: 0.5 to 3 %; SO₃: 0.1 to 0.3 %; LOI 9.5 to 13.5%.

The kaolin used in the preparation metakaolin of the catalyst of the present invention has the following characteristics and specifications: SiO₂: 46 to 48 %; Al₂O₃: 38 to 40 %; Fe₂O₃: 0.1 to 0.6 %; TiO₂: 0.5 to 2.0 %; CaO: 0.02 to 0.5 %; MgO: 0.01 to 0.5 %; K₂O: 0.1 to 0.5 %; LOI 9.0 to 15.0%.

The novel composition of the present invention is prepared starting with Smectite clay of desired specification as prepared in accordance with my co pending application 1876/MUM/2006. To this activated or acid treated clay, a desired amount of additive or additives is added and the uniform mixing is achieved by techniques such as slurring or dry mixing. The additive clay i.e. Attapulgite and metakaolin are typically activated or acid treated before adding to the Smectite. The metakaolin is formed by heating kaolin to a temperature of about 700 - 750 degree C for a period of 2 - 5 hours. The mixture of smectite clay with attapulgite and/or metakaolin is subjected to a granulation process by any known granulation technique to obtain granules of particle size between 0.25mm - 2mm in diameter. The methylene blue value can be checked either of the smectite clay or of the composition. Typically this value decreases by the addition of the additives. Similarly the total acidity value is checked to be at least 22 mg KOH/g. the composition is also subjected to drying to ensure that the moisture content is between 3- 5% and the surface area was between 300 - 350 m²/g. Alternatively, all the clays that is Smectite, Attapulgite and metakaolin are premixed in a desired ratio and then co-activated or co-treated with acid and granulated subsequently.

The invention will now be described with respect to the following examples which do not limit the invention in any way and only exemplify the invention.

Example 1 :

7.2 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was mixed with 2.4 kg of acid treated attapulgite and 2.4 kg of metakaolin to form an intimate mixture. The mixture was granulated using a lab granulator to obtain a catalyst composition (sample 4). The moisture content was found to be 4%. The surface area of the composition was checked by BET method as given in table 2. BET method (Brunnauer et al J. Am. Chem. Soc, 60 (1938) 309) was carried out using Quantochrome model Nova-3000 analyzer using N₂ adsorption. Samples were degassed at a temperature of 80⁰C for 12 hrs. The chemical content of the composition was checked by X - ray Fluorescence Spectrophotometer, Shimadzu EDX-700 using Fundamental parameter, and FP method with standard matrix calibration and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by titrating with KOH solution. 2 gm of the sample was suspended in 100 ml of 4 % NaCl solution & boiled at 95⁰C for 30 minutes & filtered. The filtrate was titrated with 0.05N KOH using Phenolpthalein as indicator. Total acidity was measured as mg KOH/ 100 gm of the sample and the values are as given in table 2.

Example 2:

10.2 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was mixed with 1.2 kg of acid treated attapulgite and 0.6 kg of metakaolin to form an intimate mixture. The mixture was granulated using a lab granulator to obtain a catalyst composition (sample 5). The surface area of the composition was checked by BET method as per example 1 and is given in table 2. The chemical content of the composition was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a method as per example 1 with KOH solution and values are given in table 2.

Example 3 :

9.6 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was mixed with 2.4 kg of metakaolin to form an intimate mixture. The mixture was granulated using a lab granulator to obtain a catalyst composition (sample 6). The surface area of the composition was checked by BET as per in example 1 and is given in table 2. The chemical content of the composition was checked by X - ray Fluorescence as per in example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a method as per in example 1, titrating with KOH solution and values are given in table 2.

Example 4:

9.6 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was mixed with 2.4 kg of acid treated attapulgite to form an intimate mixture. The mixture was granulated using a lab granulator to obtain a catalyst composition (sample 7). The surface area of the composition was checked by BET method and is given in table 2 The chemical content of the composition was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a process as per example 1 ; titrating with KOH solution and values are given in table 2.

Example 5 :

9.6 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was mixed with 1.2 kg of acid treated attapulgite and 1.2 kg of metakaolin to form an intimate mixture. The mixture was granulated using a lab granulator to obtain a catalyst composition (sample 8).The surface area of the composition was checked by BET method as per example 1 and is given in table 2. The mineral chemical content of the composition was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a process as per example 1; titrating with KOH solution and values are given in table 2.

Example 6:

6.0 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was mixed with 3.0 kg of acid treated attapulgite and 3.0 kg of metakaolin to form an intimate mixture. The mixture was granulated using a lab granulator to obtain a catalyst composition (sample 9). The surface area of the composition was checked by BET method as per example 1 and is given in table 2. The mineral chemical content of the composition was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a process as per example 1; titrating with KOH solution and values are given in table 2.

Example 7:

10.8 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was mixed with 0.6 kg of acid treated attapulgite and 0.6 kg of metakaolin to form an intimate mixture. The mixture was granulated using a lab granulator to obtain a catalyst composition (sample 10). The surface area of the composition was checked by BET method as per example 1 and is given in table 2. The chemical content of the composition was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a process as per example 1; titrating with KOH solution and values are given in table 2.

These catalyst were compared with 100% smectite (sample 1) 100% attapulgite 100% (sample 2) and 100% metakaolin (sample 3). The results of the analysis of the 10 samples are tabulated in tables 1 and 2 below.

Example 8:

12 kg of the smectite clay was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This smectite clay was granulated using a lab granulator to obtain a catalyst. The methylene blue value was checked by mixing 0.5 gm of sample 4 with 4.5 gm of washed graded clay-free silica sand and 5 gm silicon carbide in a 250 ml conical flask. To this 100 ml of 2 % tetra sodium pyrophosphate solution was added. This solution was stirred on a magnetic stirring plate for 10 minutes. 2 ml of 0.01 M methylene blue solution was added to the sample and stirred to mix the contents. After each addition, a drop of the suspension is placed onto a filter paper (Whatman Filter Paper No. 541) using a glass rod. This was repeated until the end point was reached. The methylene blue value was calculated by the standard equation and found to be 450 mg/g. The surface area of the composition was checked by BET method as per example 1 and is given in table 2. The mineral content of the composition (sample 1) was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a process as per example 1; titrating with KOH solution and values are given in table 2.

Example 9:

12 kg of the attapulgite was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This attapulgite clay was granulated using a lab granulator to obtain a catalyst. The surface area of the composition was checked by BET method and is given in table 2. The mineral content of the composition (sample 2) was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was adjusted to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a process as per example 1, titrating with KOH solution and values are given in table 2.

Example 10:

12 kg of the metakaolin was treated with acid in accordance with my co pending patent application number 1876/MUM/2006. This metakaolin clay was granulated using a lab granulator to obtain a catalyst. The surface area of the composition was checked by BET method and is given in table 2. The mineral content of the composition (sample 3) was checked by X - ray Fluorescence as per example 1 and was found to be as given in table 1. The particle size of the granules was found to be in the range of 0.25 mm to 2.0 mm. The total acidity of the composition was checked by a process as per example 1; titrating with KOH solution and values are given in table 2. Table 1: the Chemical analysis of the catalyst in accordance with the present invention (samples 4, 5, 6, 7, 8, 9 and 10) is compared to the Chemical analysis of the conventional catalyst (samples I₅ 2 and 3) Where in Smectite clay is (S), Attapulgite is (A) and metakaolin is (K).

Table 2: the surface area and total acidity of the catalyst in accordance with the present invention (samples 4, 5, 6, 7, 8, 9 and 10) is compared to the surface area and total acidity of the conventional catalyst (samples 1,2 and 3)

Fig 1 and IA of the accompanying drawings shows an X - ray diffraction image of the activated clay in the various combinations of the present invention (samples 4, 5, 6, 7, 8, 9 and 10) as compared with the conventional catalyst (samples 1, 2 and 3) as shown in the table 1.

Fig 2 of the accompanying drawings shows a graph of total acidity of the various samples as shown in table 1 and table 2.

Applications of the catalysts as per the samples 1 to 10 above.

The catalyst composition of the present invention can be used for several industrially important reactions and in particular for treatment of hydrocarbons obtained during cracking of crude oil. The cracking of crude oil gives several petroleum fractions containing products such as liquid petroleum gas (LPG), petrol, diesel, kerosene, naphtha stream, butadiene etc. The naphtha (petroleum) stream is further treated with cracker catalysts to get high boiler aromatic hydrocarbon products such as benzene, toluene and xylene, etc. The novel catalyst composition according to this invention can be effectively used in the treatment of this high boiler aromatic hydrocarbon stream (containing benzene, toluene and xylene) to remove any olefins contaminants so that the stream can be further subjected to xylene isomerization.

In a typical procedure, the catalyst compositions as per samples 1 to 9 were separately placed in is placed in a fixed bed reactor and the reactor is heated to about 155-195°C. The heating can be accomplished by any known methods including but not limited to electric heaters or oil heaters. The pressure in the reactor is maintained at about 9-15 bar to keep the contents in a liquid state, which helps in removal of reaction products from the clay surface. If the products are not removed from the clay surface continually, the catalyst activity may drop due to masking of active sites. The aromatic hydrocarbon stream containing about 15-35% Cg hydrocarbons is passed through the clay bed. The Liquid hourly space velocity (LHSV) is maintained at 10 hr^'1 and varied in the range of about 5-50 hr^'1. Samples are taken after fixed time interval and analyzed by Gas chromatography for toluene content and also for Bromine Index.

Fig. 3 and 3A of the accompanying drawing shows a graph of Bromine Index with the various samples as shown in table 1. A higher bromine index corresponds to a lower life of the catalyst hence BI is inversely proportional to the life of the catalyst. Fig. 4 and 4A of the accompanying drawing shows a graph of percentage of toluene generated with the various samples as shown in table 1. A higher toluene generated corresponds to a lower life of the catalyst hence toluene generation is inversely proportional to the life of the catalyst.

The graphs in fig 3, 3 A, 4 and 4 A show that the catalyst in accordance with this invention has a significantly increased life of 20% more.

Fig. 5 of the accompanying shows a graph of capacity of the catalysts of v vaarriioouuss ssaammpplleess ooff tthhee p prreesseenntt iinnvveennttiioonn..

Thus it can be seen that the novel catalyst compositions of the present invention have excellent catalytic activity for the treatment of hydrocarbons. Further, addition of Attapulgite and metakaolin also increases the catalyst life substantially.

In comparison of the cost of carrying out of the hydrocarbon cracking process using the catalyst of the present invention as compared with the cost of carrying out the process using conventional catalyst, there is a appreciable increase of 10 - 15 % savings in value terms.

While considerable emphasis has been placed herein on the specific composition of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Claims

Claims:

1. A catalyst composition in granular form comprising an intimate mixture of smectite clay in the range of 75 - 95 % of the total composition and at least one additive selected from attapulgite and amorphous metakaolin in the range of 25 - 5% of the total composition, said composition having a particle size of 0.25 mm to 2 mm in diameter, a total acidity greater than 22 mg/g and a surface area of 300 - 350 m²/g.

2. A catalyst composition as claimed in claim 1, wherein the Attapulgite or metakaolin is acid activated.

3. A catalyst composition as claimed in claim 1, in which the intimate mixture is acid activated.

4. A catalyst composition as claimed in claim 1, wherein the metakaolin is formed by heating kaolin to a temperature of 700 - 750 degree C for 2-5 hours.

5. A catalyst composition as claimed in claim 1, wherein the methylene blue value of the smectite clay is in the range of 400 - 450.

6. A catalyst composition as claimed in claim 1, having a total acidity between 22 - 25 mg KOH/g.

7. A catalyst composition as claimed in claim 1, wherein the composition comprises smectite clay, attapulgite and metakaolin.

8. A catalyst composition as claimed in claim 6, wherein the ratio of attapulgite to metakaolin is in the range of 2: 1 to 1 :1.

9. A catalyst composition as claimed in any one of the preceding claims, wherein the ratio of smectite to attapulgite is in the range of 8: 1 to 4: 1.

10. A catalyst composition as claimed in any one of the preceding claims, wherein the ratio of smectite to metakaolin is in the range of 8:1 to 4:1.

1 LA catalyst composition as claimed in any one of the preceding claims, having a moisture content between 3 to 5%,

12. A catalyst composition as described herein with reference to the accompanying examples.