Claims:1. A composite of Acid Activated Clay and Thermally Activated Alumina granules comprising 30-80 wt. %. Wherein, 20-80% Gamma Alumina is obtained from the Bauxite.
Wherein the Composite of Acid Activated Clay and Thermally Activated Alumina gives the better efficiency to remove the dissolved Basic Nitrogen and metallic impurities from SKO/ATF Oil.
2. The composite as claimed in claim 1, wherein the clay is Bentonite.
3. The composite as claimed in claim 1, wherein the alumina ore is selected from the group consisting of Bauxite.
4. A method for preparing a composite of Alumina based Clay Adsorbent comprising the following steps.
a. Crushing the raw Bentonite into the size of 0-15 mm by the Jaw Crusher.
b. Moist and Extrude the Bentonite into the size of 3-15 mm in the presence of 1-14 wt.% of sulphuric Acid.
c. Activate the Extruded Bentonite chemically at 75-115°C in the presence of 20-60% diluted sulphuric acid.
d. Wash and dried Activated Bentonite is fed to the fluidized bed drier where it is sieved in the range of 0.25 -2.5mm with the help of vibro-sieve shaker.
e. Alumina Sourced Bauxite is sized into the size of 0.25-2.5mm and Activated thermally at 400-900°C for a period of 0.5 to 4.0 hrs.
f. Prepare composite material of Acid Activated Bentonite in range from 30-80% and Thermally Activated Bauxite in the range from 20-80% to treat SKO & ATF purification process.
g. The Granular size of the Composite material should be in the range of 0.25-2.5mm.
, Description:FIELD OF INVENTION:
The present disclosure relates to the composition and preparation of clay adsorbent for the refining of Aromatic and Aliphatic Hydrocarbon Oil.

BACKGROUND OF INVENTION AND PRIOR ART:
Clay minerals are ubiquitous on earth and are well known for the adsorbent and catalyst in oil segments. Various sources of alumina and clay are processed to make the suitable adsorbent for selective application. Attapulgus clay is mainly used for the refining of Superior Kerosene Oil (SKO) and Aviation Turbine Fuel (ATF). The problem by using of conventional Attapulgus clay for the refining of SKO & ATF was the poor yield and color stability.

To overcome the problem of color and stability, the new adsorbent is invented by taking a blend of naturally available alumina and Clay. Bauxite is taken as a source of Alumina and Bentonite as the source of Clay. Bauxite is thermally treated to enhance its surface properties like Surface area, Pore volume and pore size. Bentonite is subjected to acid treatment in the form of noodles and then drying. Thermally treated Bauxite and acid treated Bentonite is blended in the size of 0.25 – 2.5mm. Prepared clay adsorbent is characterized and tested for purification of SKO & ATF against the color stability for prolong period.

Yield, performance and stability are drastically improved with 0.2-0.5% dosing of invented clay adsorbent.

PRIOR ART:
Prior art search and some other literature say that Attapulgus clay is mainly used for the refining of Superior Kerosene Oil (SKO) and Aviation Turbine Fuel (ATF). The performance and efficiency of invented alumina based clay adsorbent is improved many folds over the conventional Attapulgus clay. The problem by using of conventional Attapulgus clay for the refining of SKO & ATF was the poor yield and color stability. After refining process, color of the SKO & ATF starts deteriorating within a week with Attapulgus clay. The reason of color deterioration was due to the presence of some unwanted impurities like dissolved basic nitrogen, metals like Ni, Cu, Fe and phenolic compound and therefore Attapulgus clay is sufficient to purify the SKO & ATF. Out of the above said impurities, presence of dissolved basic nitrogen is more responsible for color deterioration. The color and stability was little improved by increasing the dose (2-3times) of Attapulgus clay but purification performance is not to the mark.

To overcome the problem of color and stability, the new adsorbent has been invented by taking a blend of naturally available alumina and Clay. Bauxite is taken as a source of Alumina and Bentonite as the source of Clay where in Bauxite is thermally treated to enhance its surface properties and Bentonite is subjected to acid treatment and then the thermally treated Bauxite and the acid treated Bentonite is blended.

OBJECT OF THE INVENTION:
The object of the present invention is to make clay adsorbent which can remove the maximum unwanted impurities like basic dissolve nitrogen, Nickel, Copper, Iron and phenolic compound; it provides a solution for color stability of refined SKO and ATF.

Another object of present invention is to improve the yield and reduce the dosing percentage of adsorbent.
One another object is to increase the filtration rate as compare to the existing Attapulgus clay.

Another objective is to provide the method of preparing composite clay adsorbent - comprising of Bauxite and Bentonite granules.

SUMMARY OF THE INVENTION:
The invention provides for a process for the preparation of Alumina based clay adsorbent comprising of the Bauxite and Bentonite minerals. The naturally available Alumina Sourced Bauxite is first grinded in the size of 0.25 – 2.5 mm and then thermally treated at 400-600°C. Bentonite material is sized and noodled in the presence of sulphuric acid (50-80% concentration). The nodule Bentonite is subjected to sulphuric acid treatment (20-40% concentration) for 5- 15 hours. The Thermal treatment improves the surface property of Alumina Sourced Bauxite in the terms of surface area, pore volume and pore size. Acid treated Bentonite and thermally treated Bauxite together adsorbs the impurity like dissolve basic Nitrogen, Nickel, Copper, Iron, and phenolic compound and makes the fuel stable. Size of both the material is maintained in the range of 0.25-2.5mm which helps to improve the filtration rate.

DESCRIPTION OF INVENTION:

The process of the invention is described with the help of the accompanying drawings, in which:
Figure 1 illustrates SEM image of Flattered and Porous Acid Activated Bentonite Clay.
Figure 2 illustrates the SEM image of Gamma Alumina (Thermally Activated Bauxite).
Figure 3 illustrate the XRD graph of Composite Adsorbent.
Figure 4 illustrate the BET Surface Area graph of Composite Adsorbent.

The Current invention envisages - a composite material and a method for its preparation. The composite material is an Alumina based clay adsorbent which has got an improved surface property in terms of surface area, pore volume and pore size as compare to the conventional Attapulgus clay.

In accordance with the invention the process for the preparation of the composite material is described below.
To make the Alumina based clay adsorbent, the initial raw materials required are a source of Alumina and a source of Clay. Bauxite is taken as a source of Alumina and Bentonite as a source of Clay. The entire process is comprises of the following step i.e. Sizing, Activation, Drying and Calcination.
Shape and the particle size are very important to have the proper packing of the column, contact time, to create voids between the particles and with enhanced filtration rate. Small particle size gives the good contact time but reduces the voids which in results in low filtration rate; large size creates big voids which results in good filtration rate and less contact time. Thus, it is a necessary step to optimize the clay adsorbent size by taking the combination of various fraction of particles, the packing with various particle size and shape will give the superior performance. The required particle size is obtained by Jaw Crusher and vibro-Sieve shaker. The Bauxite and Bentonite are crushed and sized separately to obtain the granules.

In accordance with this invention, the process for the preparation of the composite material is described below.
To carry out the process, the raw material is selected from at least one clay and at least one alumina ore, Bentonite is selected as a source of clay and Bauxite is selected as a source of Alumina. The amount of clay sourced Bentonite used in the composite ranges from 30 wt.% to 80 wt.% and the amount of alumina sourced Bauxite used in process for preparing the composite ranges from 20 wt.% to 80 wt.%. The particle size of the Bauxite and Bentonite after the step of crushing and sizing should be in the range of 0.25 – 2.5mm. The processing method of Bentonite and Bauxite before blending are totally different in one another.

The Bentonite clay processing includes Three major steps i.e. Extrusion, Acid Activation, and Sizing. Bentonite having a Clay 30-90 wt.% is taken into the consideration as a raw material. Raw lump Bentonite is crushed into the range of 0-15 mm at various step of processing. To avoid the attrition/abrasion loss it is important to develop the good crushing strength by means using extrusion process.
The extruded nodules of Bentonite clay are moist by water to the optimum wettability, mixed it thoroughly and ensured that it should neither be too wet nor too dry. Further, the material is extruded to size 3-15 mm with of 1-14% (wt./wt.) sulphuric acid.
To remove the certain impurities and color bodies from the SKO/ATF oil, it is very important to develop such an Adsorbent which should not only possess enhanced adsorption with good surface area, pore size, pore volume and active sties but also the flowability of adsorbate high during filtration process. The chemical and thermal treatment of the Bentonite and Bauxite improves the filtration process to remove color and other contamination. The non-limiting example of acid used for the activation is Sulphuric acid, Nitric Acid, Hydrochloric acid. For the current invention Sulphuric acid is chosen for activation.
The extruded nodules are directly fed to the Acid Activation reactor containing dilute sulphuric acid having a concentration of 20-60%. Dilute sulphuric acid and extruded Bentonite is mixed in the ratio of 30-80 wt.%. The whole mass is mixed at 75-115°C temperature. After completion of acid activation, the whole mass is filtered and washed.
The washed material is dried and fed to the fluidized bed drier where it is sieved in the range of 0.25 -2.5mm with the help of vibro sieve shaker.

The other composite material Bauxite is processed by Thermal Activation and Sieving.
In the initial raw Bauxite Sample, Alumina is present in the form of Gibbsite, which is non-porous and does not have sufficient surface area. By giving the heat treatment to the Bauxite, Gamma-Alumina phase (Boehmite) formation occurs in the temperature range from 400-900oC. The Gamma-Alumina phase with high surface area properties shows better adsorption properties.
Bauxite having an Alumina 35-55 wt.% is taken into a consideration as a starting raw material. Sizing can be done in two ways either at the starting feed material or after the thermal activation. Initial sizing helps in two ways, material is little softer so can be grind easily, second the uniform and little small size of material gets a uniform exposer of temperature with respect to time. Initial crushing of Bauxite is recommended and it is crushed in the size of 0.25-2.5mm through Jaw crusher.
The sized Bauxite material is fed to the Rotary Kiln to the temperature range of 400-900°C for 0.5-4.0 hrs. duration and allowed to cool to room temperature and kept in the non-humid atmosphere. The thermally activated Bauxite is sent to the sieving section and it is sieved through vibro-sieve shaker. The sieved material should be stored at dry place in a close container. The materiel should be sieved in the size of 0.25-2.5mm.

Now acid activated Bentonite and thermally activated Bauxite is blended in the ratio of 20-80 wt.%. The composite material comprising the acid activated Bentonite and the thermally activated Bauxite obtained in accordance with the process of this invention is characterized by various physicochemical techniques for evaluating its properties including, but not limited to, bulk density, Free Acidity, crushing strength, Oil solubility, and the granular size.
The Acid treatment of Bentonite significantly changes some of the specific properties of interest. In this process, some of the exchangeable cations are replaced by the Hydrogens ions. After Acid activation, the structure of the Bentonite becomes more flattered and become porous (refer – Image-1), which results in the increase of the surface and active site of bentonite Clay. In Bauxite (Alumina Rich), after thermal treatment, Gibbsite is converted to Gamma Alumina phase with high surface area and enhanced porosity (refer - Image 2). The decolorizing and adsorption capacity increases with the presence of Hydrogen ion on surface of the Bentonite. After Acid Activation, the pH of the Bentonite becomes acidic, the presence of Hydrogen ion further is confirmed by checking the Free and Net acidity. Presence of enhanced surface area of Bentonite along with active sites of Hydrogen has got better efficiency to remove the basic dissolve Nitrogen and other Oil-impurities like Nickel, Copper and Iron.
To remove the overall impurities, both Acid Activated Bentonite and Thermally Activated Bentonite are blended (Graph 3). The surface area of the composite material is enhanced more than 20 folds (Graph 4). After Acid and Thermal activation, the strength of the Bentonite and Bauxite also increases which helps to resist the Abrasion/Attrition loss. Further the granular size and strength helps to increase the filtration rate which enhances the filtration rate.
The composite material obtained in accordance with the process of the present invention has extensive applications including in the purification of Petroleum fraction limited to their uses in Superior Kerosene Oil and Aviation Turbine Fuel purification process.