Claims:WE CLAIM:
1. An FCC additive comprising;
i. a phosphorous modified zeolite in an amount in the range of 20 to 50 wt%;
ii. a clay in an amount in the range of 15 to 35 wt%;
iii. an alumina in an amount in the range of 1 to 20 wt%;
iv. a silica in an amount in the range of 10 to 20 wt%; and
v. a promoter metal in an amount in the range of 0.01 to 2.0 wt%.
2. The FCC additive as claimed in claim 1, wherein the zeolite is ZSM-5.
3. The FCC additive as claimed in claim 1, wherein the promoter metal is at least one selected from the group consisting of copper, tin, niobium and tungsten.
4. The FCC additive as claimed in claim 1 has an average bulk density in the range of 0.7 to 0.8 g/cc, a BET surface area in the range of 130 to 150 m2/g and an attrition index less than 2.
5. A process for preparing the FCC additive, the process comprising the following steps:
a. mixing a source of phosphorous with water to obtain a solution;
b. adding at least one zeolite in the solution and stirring for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a zeolite slurry;
c. separately mixing in water, at least one precursor of alumina and acetic acid, and stirring for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain an alumina slurry;
d. adding at least one precursor of clay to the alumina slurry, followed by addition of water and stirring for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a first mixture;
e. adding at least one precursor of silica to the first mixture and stirring for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a second mixture;
f. mixing the zeolite slurry and the second mixture to obtain a third mixture;
g. adding a precursor of at least one promoter metal in the third mixture and stirring for a time period in the range of 1 to 5 hours, at a temperature range of 25 to 80 oC to obtain a fourth mixture; and
h. spray drying the fourth mixture, followed by calcining to obtain the FCC additive.
6. The process as claimed in claim 5, wherein the precursor of phosphorous is selected from the group consisting of di-ammonium hydrogen phosphate (DAHP), phosphoric acid, di-hydrogen ammonium phosphate (DHAP).
7. The process as claimed in claim 5, wherein the weight ratio of the zeolite to the precursor of phosphorous is in the range of 1: 1 to 1: 4.
8. The process as claimed in claim 5, wherein the precursor of the clay is selected from the group consisting of kaolin clay, holloysite, and bentonite.
9. The process as claimed in claim 5, wherein the precursor of the alumina is selected from the group consisting of colloidal alumina, pseduoboehmite alumina, bayrite alumina, and gamma alumina.
10. The process as claimed in claim 5, wherein the precursor of the silica is selected from the group consisting of silica sol, colloidal silica, and tetraethyl orthosilicate.
11. The process as claimed in claim 5, wherein the precursor of the promoter metal is at least one salt of the metal selected from the group consisting of nitrate, sulfate, acetonitrile, alkoxide, chloride, acetylacetonate, and acetate.
12. The process as claimed in claim 11, wherein the metal is at least one selected from the group consisting of copper, tin, niobium and tungsten.
13. The process as claimed in claim 5, wherein the step of spray drying is carried out at a temperature in the range of 100 to 500 °C.
14. The process as claimed in claim 5, wherein the step of calcining is carried out at a temperature in the range of 500 to 600 °C.
Dated this 6th day of September, 2019

MOHAN DEWAN
of R.K. DEWAN & COMPANY
IN/PA-25
APPLICANT’S PATENT ATTORNEY

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI
, Description:
FIELD
The present disclosure relates to an FCC additive and a process for preparation thereof.
DEFINITIONS
As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which it is used to indicate otherwise.
Equilibrium catalyst (E-CAT): Equilibrium catalyst is a partially deactivated Fluidized Catalytic Cracking Catalyst which has spent an equilibration time in the FCC reactor and represents a catalyst having particles of average age and activity. The equilibrium catalyst (E-CAT) composition depends on the fresh catalyst, catalyst make up and additive composition and typically contains silica, alumina, phosphorous pentoxide, rare earth oxide and metals originating from the feed such as Nickel, Vanadium, Iron, Sodium, Calcium and the like.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Fluidic Catalytic Cracking units are playing an increasingly important role for converting heavy hydrocarbons to light hydrocarbons. In the FCC unit, the heavy hydrocarbons are subjected to cracking in the presence of an FCC catalyst such as E-CAT to obtain a light hydrocarbon such as propylene. However, the yield of propylene is low.
Conventionally, the use of Y-zeolites in conjunction with pentasil zeolites has led to increase in the yield of propylene. However, such combination of Y-zeolites in conjunction with pentasil zeolites have comparatively less yield of propylene.
Other types of dopants have been tried, however many of them are responsible for reduced rate of conversion, giving rise to overall efficiency considerations.
There is, therefore, felt a need for the development of an additives to further increase the propylene yield.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide an FCC additive.
Another object of the present disclosure is to provide an FCC additive, when used in combination with an FCC catalyst, is capable of providing enhanced propylene yield.
Still another object of the present disclosure is to provide a process for preparation of an FCC additive.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to an FCC additive. The FCC additive comprises a phosphorous modified zeolite in an amount in the range of 20 to 50 wt%; clay in an amount in the range of 15 to 35 wt%; an alumina in an amount in the range of 1 to 20 wt%; silica in an amount in the range of 10 to 20 wt%; and a promoter metal in an amount in the range of 0.01 to 2.0 wt%.
The present disclosure further provides a process for the preparation of the FCC additive. Initially, a source of phosphorous is mixed with water to obtain a solution, to which at least one zeolite is added and the slurry is stirred for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a zeolite slurry. Separately, at least one alumina is mixed with water along with a pre-determined quantity of acetic acid and the slurry is stirred for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain an alumina slurry. At least one clay is added to the alumina slurry, followed by addition of water, and stirring continued for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a first mixture. At least one silica is then added to the so obtained first mixture and stirred for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a second mixture. In the next step, the zeolite slurry and the second mixture are mixed together to obtain a third mixture. At least one precursor of the promoter metal is added to the third mixture, followed by stirring for a time period in the range of 1 to 5 hours, at temperature range of 25 to 80 oC to obtain a fourth mixture. The fourth mixture is subjected to spray drying, followed by calcining to obtain the FCC additive.
The FCC additive of present disclosure is capable providing the enhanced yield of propylene, when used in combination with FCC catalyst.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a graphical representation of Temperature-Programmed Desorption (TPD) analysis. Graph a represents Temperature-Programmed Desorption (TPD) analysis of the FCC additive of the present disclosure comprising the combination of copper and tin. Graph b represents Temperature-Programmed Desorption (TPD) analysis of the comparative additive without copper and tin.
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details, are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Vacuum gas oil/crude oil is upgraded into lighter fractions such as propylene and LPG by using the FCC process. There is a continuous increase in the demand of propylene and LPG due to their wide range of applications. Therefore, there is a need to enhance the yields of propylene.
The present disclosure provides an FCC additive, when used in combination with an FCC catalyst for cracking heavy hydrocarbon feed, is capable of providing enhanced propylene yield.
In one aspect, the present disclosure provides an FCC additive comprising a phosphorous modified zeolite in an amount in the range of 20 to 50 wt%; clay in an amount in the range of 15 to 35 wt%; an alumina in an amount in the range of 1 to 20 wt%; silica in an amount in the range of 10 to 20 wt%; and a promoter metal in an amount in the range of 0.01 to 2.0 wt%.
The zeolite present in phosphorous modified zeolite is ZSM-5. Typically, the phosphorous is present in the form of oxide in an amount in the range of 10 to 12 wt%.
The promoter metal is at least one selected from the group consisting of copper, tin, tungsten and niobium.
In accordance with the present disclosure, the FCC additive has average bulk density in the range of 0.7 to 0.8 g/cc, a BET surface area in the range of 130 to 150 m2/g.
In accordance with the embodiments of the present disclosure, the attrition index of the FCC additive is in the range of 0.5 to 2.0. In accordance with the present disclosure, the attrition index is measured using ASTM D5757.
In accordance with one exemplary embodiment of the present disclosure, the FCC additive comprises phosphorous modified zeolite, wherein zeolite is present in an amount of 40 wt% and phosphorous pentoxide is present in an amount of 10 wt%; clay in an amount of 31.5 wt%; alumina in an amount of 8 wt%; silica in an amount of 10 wt%; and a combination of copper and tin, wherein copper is present in an amount of 0.4 wt%, and tin is present in an amount of 0.1 wt%.
In accordance with another exemplary embodiment of the present disclosure, the FCC additive comprises phosphorous modified zeolite, wherein zeolite is present in an amount of 40 wt% and phosphorous pentoxide is present in an amount of 10 wt%; clay in an amount of 31.5 wt%; alumina in an amount of 8 wt%; silica in an amount of 10 wt%; and a combination of niobium and tin, wherein niobium is present in an amount of 0.4 wt%, and tin is present in an amount of 0.1 wt%.
In accordance with still another exemplary embodiment of the present disclosure, the FCC additive comprises phosphorous modified zeolite, wherein zeolite is present in an amount of 40 wt% and phosphorous pentoxide is present in an amount of 10 wt%; clay in an amount of 31.5 wt%; alumina in an amount of 8 wt%; silica in an amount of 10 wt%; and a combination of tungsten and tin, wherein tungsten is present in an amount of 0.4 wt%, and tin is present in an amount of 0.1 wt%.
In another aspect, the present disclosure provides a process for preparing the FCC additive.
Initially, a precursor of phosphorous is mixed with water to obtain a solution, to which at least one zeolite is added and the slurry is stirred for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a zeolite slurry.
Separately, at least one precursor of alumina is mixed with water along with a pre-determined quantity of acetic acid and the slurry is stirred for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain an alumina slurry.
At least one precursor of clay is added to the alumina slurry, followed by addition of water, and stirring for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a first mixture.
At least one precursor of silica is then added to so obtained first mixture and stirred for a time period in the range of 0.5 to 2 hours, at a temperature in the range of 25 to 35 °C to obtain a second mixture.
In the next step, the zeolite slurry and the second mixture are mixed together to obtain a third mixture.
At least one precursor of a promoter metal is added to the third mixture, followed by stirring for a time period in the range of 1 to 5 hours, at a temperature range of 25 to 80 oC to obtain a fourth mixture.
The fourth mixture is then subjected to spray drying, followed by calcining to obtain the FCC additive.
The precursor of phosphorous is selected from the group consisting of di-ammonium hydrogen phosphate (DAHP), Dihydrogen ammonium phosphate (DHAP) and phosphoric acid. In accordance with an exemplary embodiment of the present disclosure, the source of phosphorous is di-ammonium hydrogen phosphate (DAHP).
Typically, the weight ratio of the zeolite to the precursor of phosphorous is in the range of 1: 1 to 1: 4.
In accordance with the present disclosure, the peptization of the alumina is carried out using mild acid such as acetic acid. Use of strong mineral acids for peptization of alumina destroys the natural structure of alumina framework. However, acetic acid does not affect the alumina framework. Typically, the weight ratio of alumina to acetic acid is in the range of 1: 0.1 to 1: 0.5.
The precursor of clay is selected from the group consisting of kaolin clay, holloysite, and bentonite. In accordance with an exemplary embodiment of the present disclosure, the clay is kaolin clay.
The precursor of alumina is selected from the group consisting of colloidal alumina, pseduoboehmite, bayrite, and gamma alumina. In accordance with an exemplary embodiment of the present disclosure, the alumina is pseduoboehmite.
The precursor of silica is selected from the group consisting of silica sol, colloidal silica, and tetraethyl orthosilicate. In accordance with an exemplary embodiment of the present disclosure, the silica is colloidal silica.
The precursor of the promoter metal is at least one salt of the metal selected from the group consisting of nitrate, sulfate, acetonitrile, alkoxide, chloride, acetylacetonate, and acetate.
The metal is at least one selected from the group consisting of copper, tin, niobium and tungsten.
In accordance with an exemplary embodiment of the present disclosure, the precursor of copper metal is copper (II) nitrate trihydrate.
In accordance with another exemplary embodiment of the present disclosure, the precursor of tin metal is stannous chloride.
In accordance with yet another exemplary embodiment of the present disclosure, the precursor of niobium metal is ammonium niobate (V) oxalate.
In accordance with still another exemplary embodiment of the present disclosure, the precursor of tungsten metal is ammonium meta-tungstate hydrate.
Typically, the step of spray drying is carried out at a temperature in the range of 100 to 500 °C. In accordance with the present disclosure, the inlet temperature of the spray drying is in the range of 300 to 400 °C and the outlet temperature is in the range of 150 to 200 °C.
Typically, the step of calcining is carried out at a temperature in the range of 500 to 600 °C. In accordance with an exemplary embodiment of the present disclosure, the step of calcining is carried out at 550 °C.
The FCC additive of the present disclosure is optimized by inclusion of a promoter metal to provide the cracked hydrocarbon with the enhanced propylene yield. The incorporation of active metals increases weak and medium acidity of the additive, which leads to enhanced propylene yield. Further, the incorporation of active metals reduces the content of poisonous metal oxides in the additive such as sodium oxide and ferrous oxide, by forming salts with these metals.
The FCC additive of the present disclosure is used in combination with the FCC catalyst, for cracking a hydrocarbon feed to produce cracked hydrocarbons with enhanced propylene yield.
The hydrocarbon feed can be at least one of C5-C12 hydrocarbons, C4-C6 paraffin, gas oil, vacuum gas oil, oil residue, slurry oil, heavy crude.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Experiment 1: Preparation of the FCC additive of the present disclosure
Initially, 187 grams of Di-ammonium hydrogen phosphate (DAHP) was added to 1750 ml of water and stirred for 30 minutes until it gets dissolved/clear solution. 438 grams of ZSM-5 was added to above solution and stirred the mixture for 2 hours to obtain a zeolite slurry.
100 grams of alumina source was added to 500 ml of water followed by addition of 25 grams of acetic acid. The mixture was stirred for 1 hour to obtain an alumina slurry.
315 grams of kaolin clay was added to the first mixture along with 750 ml of water, followed by stirring for 30 minutes to obtain a first mixture.
250 grams of silica was added to the first mixture and the mixture was stirred for 1 hour to obtain a second mixture.
The phosphate modified ZSM-5 slurry was mixed with the second mixture to obtain a third mixture.
A solution of 15.2 grams of Cu(NO3)2.3H2O in 150 ml of water and 1.9 grams of SnCl2.H2O was added to the third mixture, followed by stirring for a time period of 4 hours, by gradually increasing the temperature from 25 to 80 °C to obtain a fourth mixture.
The fourth mixture was subjected to spray drying at 200 °C, followed by calcining at 550 °C for time period of 5 hours to obtain the FCC additive of the present disclosure.
The composition of an FCC additives is summarized in Table 1.
Comparative Experiment 2: Preparation of the FCC additive
Same experimental procedure as disclosed in experiment 1 was followed, except addition of the precursor of the active metals. The composition of an FCC additives is summarized in Table 1.
Table 1: Composition of an FCC catalyst and FCC additives
Catalyst composition Reference Catalyst
(E-cat) Comparative example
(Without Cu and Sn metals) FCC Additive
of the present disclosure
SiO2 (wt%) 48.72 64.98 65.3
Al2O3 (wt%) 45.74 23.54 22.47
P2O5 (wt%) - 9.98 11.09
TiO2 (wt%) - 0.35 0.4
CuO (wt%) - - 0.5
SnO (wt%) - - 0.16
Na2O (wt%) - 0.17 0.15
Fe2O3 (wt%) - 0.18 0.12
From table 1, it is evident the incorporation of active metals reduces the content of poisonous compounds in the additive such as sodium oxide and ferrous oxide.
Further, from figure 1, it is observed that incorporation of active metals copper and tin increases weak and medium acidity of the additive.
Experiment 3: Performance assessment of the FCC additive
The FCC additives obtained in Experiment 1 and Experiment 2 were used in combination with the FCC catalyst (E-CAT) for catalytic cracking of VGO. The properties of VGO used, are summarized in Table 2.
Table 2: Composition and properties of VGO
Properties VGO
Density at 15°C (g/cc) 0.9171
Sulphur content (wt%) 1.969
CCR (wt%) 0.60
Pour point, °C 45
Kinematic viscosity @100 °C, cSt 7.742

ASTM-7169 Distillation, wt% (°C)
IBP 283
5 345
10 365
30 404
50 429
70 457
90 506
95 529

SARA wt%
saturates 57.1
aromatics 33.3
resin 9.4
asphaltenes 0.2

The composition of cracked VGO was analyzed and the results are summarized in Table 3.
Table 3: Results for cracking of VGO
Parameters ECAT
(FCC catalyst, without additive) (Comparative Experiment)
E-CAT (95%) + Reference Additive (5%)
(Without Cu and Sn metals)
(Experiment 2) (Comparative Experiment) E-CAT (95%) + FCC Additive
of the present disclosure (5%)
(Experiment 1)
Feed VGO VGO VGO
Cracking temperature (°C) 529 529 529
Catalyst to oil ratio 3.0 3.5 4.0 3.0 3.5 4.0 3.0 3.5 4.0
Yields
Conversion 57.52 62.94 67.25 57.18 62.78 67.50 58.21 62.63 67.10
Coke 3.44 3.64 4.39 3.45 4.48 4.58 3.51 4.51 4.54
Dry gas 2.65 2.90 3.46 2.63 3.32 3.49 2.97 3.21 3.54
LPG 10.76 13.82 16.09 13.01 16.41 20.15 13.87 16.38 20.54
Propylene 3.66 4.55 5.50 4.65 5.77 6.28 4.81 6.04 6.92
Butylenes 4.44 5.82 6.52 5.22 5.71 5.90 5.63 5.87 6.67
Gasoline (C5-221 °C) 40.68 42.58 43.31 38.09 38.57 39.28 37.86 38.54 38.48
LCO
(221-370 °C) 21.98 20.77 18.95 22.33 20.95 18.60 21.71 20.86 18.50
Unconverted
(370 °C +) 20.50 16.29 13.80 20.49 16.27 13.90 20.08 16.50 13.95
From Table 3, it is evident that the FCC additive of the present disclosure when used in combination with the FCC catalyst (E-cat) produce cracked VGO comprising light hydrocarbons with increased propylene yield, as compared to E-CAT or E-CAT in combination with reference additive. The cracking process, where only E-CAT is used, shows lower propylene as compared to the cracking process where E-CAT is used in combination with additive of the present disclosure.
Further, the FCC additive without combination of active metals copper and tin exhibit slightly increased propylene yield compared to the E-cat, however, the yield is still lower as compared to the FCC additive of the present disclosure comprising combination of active metals copper and tin.
Thus, from results it is evident that the FCC additives of the present disclosure effectively enhances the propylene yield.
TECHNICAL ADVANCEMENTS AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an FCC additive that:
- enable production of propylene with high yield.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure 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 disclosure and not as a limitation.