Claims:WE CLAIM
1. A dual functional catalyst additive for optimizing increase in propylene yield and decrease in olefin yield, said dual functional catalyst additive represented by a formula
(SrO)A(MnO)B(TiO)C(FeO)D(M1O)E(P2O5)F(SiO2)K(Al2O3)(100-X-K)
wherein, M1O is metal oxide of a metal selected from the groups IIIA, IVA, VIB, and lanthanides,
wherein, A+B+C+D+E+F = X,
A is strontium oxide content in the range of 1 wt% to 3 wt%,
B is manganese oxide content in the range of 0.5 wt% to 3 wt%,
C is titanium oxide content in the range of 0 to 2 wt%
D is ferrous oxide content in the range of 0 to 1 wt%, and C+D =1 wt%,
E is M1O content in the range of 0 to 3 wt%,
F is P2O5 content in the range of 3 wt% to 15 wt%, and
K is SiO2 (silica) content in the range of 20 to 75 wt%.
2. The dual functional catalyst additive for optimizing increase in propylene yield and decrease in olefin yield, said dual functional catalyst additive represented by a formula
(SrO)A(MnO)B(TiO)C(FeO)D(M1O)E(P2O5)F(SiO2)K(Al2O3)(100-X-K)
wherein, M1O is metal oxide of a metal selected from the groups IIIA, IVA, VIB, and lanthanides,
wherein, A+B+C+D+E+F = X,
A is strontium oxide content in the range of 1 wt% to 3 wt%,
B is manganese oxide content in the range of 0.5 wt% to 3 wt%,
C is titanium oxide content in the range of 0 to 1 wt%
D is ferrous oxide content in the range of 0 to 1 wt%, and C+D =1 wt%,
E is M1O content in the range of 0 to 2 wt%,
F is P2O5 content in the range of 6 wt% to 12 wt%, and
K is SiO2 (silica) content in the range of 58 to 65 wt%.
3. The catalyst additive as claimed in claim 1, said catalyst additive is
(SrO)1(MnO)0.5(TiO)1(FeO)0.5(P2O5)9(SiO2)65(Al2O3)23.
4. The catalyst additive as claimed in claim 1, said catalyst additive is
(SrO)2(MnO)2(TiO)1(LaO)2(CeO)1(P2O5)12(SiO2)60(Al2O3)20.
5. The catalyst additive as claimed in claim 1, said catalyst additive is
(SrO)3(MnO)3(FeO)1(MoO)0.5(GaO)0.5(P2O5)6(SiO2)58(Al2O3)28.

, Description:FIELD
The present disclosure relates to the field of the FCC catalyst additives.
DEFINITIONS
As used in the present disclosure, the following words and phrases are generally intended to have the meaning as set forth below, except to the extent that the context in which they are 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, and Calcium and the like.
Dual functional: The characteristic of the material, which is helpful in simultaneously achieving two different results.
Wet impregnation: Wet impregnation is a commonly used technique for the synthesis of heterogeneous catalysts. In this method, the active metal precursor is dissolved in an aqueous or organic solution. The metal-containing solution is then added to a catalyst support to obtain slurry. The slurry can be dried and calcined to drive off the volatile components, thereby resulting in the deposition of the metal on the catalyst support surface.
Pour point: Pour point of a liquid is the temperature at which it becomes semi solid and loses its flow characteristics.
Conradson carbon residue (CCR): CCR is a laboratory test used to provide an indication of the coke-forming tendencies of oil. Quantitatively, the test measures the amount of carbonaceous residue remaining after the oil's evaporation and pyrolysis.
Kinematic Viscosity: Kinematic viscosity is a quantity representing the dynamic viscosity of a fluid per unit density and is measured in centistokes (cSt).
Attrition Resistance: An attrition resistance is a measure of the resistance of a granular material to wear and is measured in wt%.
BACKGROUND
Demand for light hydrocarbons is increasing exponentially. Therefore, the use of the fluid catalytic cracking (FCC) units is important 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 cracked hydrocarbons comprising light hydrocarbons. Cracking of heavy hydrocarbons in the presence of E-CAT produces propylene in low yields, typically, less than 6 wt%, and high amounts of olefins, typically 45 wt% to 55 wt%.
The higher content of olefins in the cracked naphtha and in the cracked naphtha derived products is responsible for fouling of the downstream processing units, automobile engines, petroleum product storages and transportation containers. The higher content of olefins in the gasoline derived from naphtha does not meet the environmental regulations. If the content of total olefins in the cracked naphtha and in the products derived from cracked naphtha is brought down, the fouling in the process units can be controlled and the cracked naphtha can be absorbed in the gasoline stream leading to increased refinery margins.
Conventionally, the FCC catalyst additives are specifically used either for increasing the propylene yield or for reducing the total olefin content. However, for practical purposes both results are necessary and therefore, the FCC catalyst additives need to be optimized for combination of both results.
There is, therefore, felt a need for the development of additives to simultaneously increase the propylene yield and reduce the content of total olefins in the cracked naphtha.
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 a dual functional FCC catalyst additive.
Another object of the present disclosure is to provide a dual functional FCC catalyst additive, which when used in combination with an FCC catalyst, is capable of providing the cracked naphtha with reduced total olefin content and enhanced propylene yield.
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 provides a dual functional FCC catalyst additive for optimizing increase in propylene yield and decrease in olefin yield. The dual functional FCC catalyst additive can be represented by a formula
(SrO)A(MnO)B(TiO)C(FeO)D(M1O)E(P2O5)F(SiO2)K(Al2O3)(100-X-K)
wherein, M1O is metal oxide of a metal selected from the groups IIIA, IVA, VIB, and lanthanides,
wherein, A+B+C+D+E+F = X,
A is strontium oxide content in the range of 1 wt% to 3 wt% of the total weight of the dual functional FCC catalyst additive.
B is manganese oxide content in the range of 0.5 wt% to 3 wt% of the total weight of the dual functional FCC catalyst additive.
C is titanium oxide content in the range of 0 to 2 wt% of the total weight of the dual functional FCC catalyst additive, preferably 0 wt% to 1 wt%.
D is ferrous oxide content in the range of 0 to 1 wt% of the total weight of the dual functional FCC catalyst additive, and C+D =1 wt%,
E is M1O content in the range of 0 to 3 wt% of the total weight of the dual functional FCC catalyst additive, preferably 0 wt% to 2 wt%.
F is P2O5 content in the range of 3 wt% to 15 wt% of the total weight of the dual functional FCC catalyst additive, preferably 6 wt% to 12 wt%.
K is SiO2 (silica) content in the range of 20 to 75 wt% of the total weight of the dual functional FCC catalyst additive, preferably 58 to 65 wt%.
In accordance with one embodiment of the present disclosure, the dual functional FCC catalyst additive is
(SrO)1(MnO)0.5(TiO)1(FeO)0.5(P2O5)9(SiO2)65(Al2O3)23.
In accordance with another embodiment of the present disclosure, the dual functional FCC catalyst additive is
(SrO)2(MnO)2(TiO)1(LaO)2(CeO)1(P2O5)12(SiO2)60(Al2O3)20.
In accordance with one embodiment of the present disclosure, the dual functional FCC catalyst additive is
(SrO)3(MnO)3(FeO)1(MoO)0.5(GaO)0.5(P2O5)6(SiO2)58(Al2O3)28.
DETAILED DESCRIPTION
Conventionally, crude oil is upgraded into lighter fractions by using the FCC process. Propylene and LPG are among the fractions obtained by cracking of crude oil. There is a continuous increase in the demand of propylene and LPG due to their wide range of applications. The higher olefin content of the cracked naphtha fraction creates fouling problems in automobile engines, storage and transportation vessel and does not meet the environmental gasoline regulations (BS IV, V and VI). Therefore, there is a need for an FCC catalyst/additive, which will enhance refinery margins by increasing the yields of propylene and producing cracked naphtha with reduced total olefin content.
The present disclosure envisages a dual functional FCC catalyst additive, which when used in combination with an FCC catalyst for cracking heavy hydrocarbon feed, is capable of providing enhanced propylene yield and cracked naphtha with reduced olefins content.
The present disclosure provides a dual functional FCC catalyst additive represented by the formula
(SrO)A(MnO)B(TiO)C(FeO)D(M1O)E(P2O5)F(SiO2)K(Al2O3)(100-X-K)
wherein, A+B+C+D+E+F = X.
M1O is at least one metal oxide of at least one metal selected from the groups IIIA, IVA, VIB, and lanthanides.
In accordance with one embodiment of the present disclosure, M1O is a mixture of LaO and CeO.
In accordance with another embodiment of the present disclosure, M1O is a mixture of MoO and GaO.
The strontium oxide content, represented by A is in the range of 1 wt% to 3 wt% of the total weight of the dual functional FCC catalyst additive.
The manganese oxide content, represented by B is in the range of 0.5 wt% to 3 wt% of the total weight of the dual functional FCC catalyst additive.
The titanium oxide content, represented by C is in the range of 0 to 2 wt% of the total weight of the dual functional FCC catalyst additive, preferably 0 to 1 wt% .
The ferrous oxide content, represented by D is in the range of 0 to 1 wt% of the total weight of the dual functional FCC catalyst additive, and C+D = 1.
The dual functional catalyst of the present disclosure essentially comprises strontium oxide, manganese oxide, phosphorus pentoxide, silica, alumina and at least one of titanium oxide and ferrous oxide. The M1O content, represented by E is in the range of 0 to 3 wt% of the total weight of the dual functional FCC catalyst additive, preferably 0 wt% to 2 wt%.
The P2O5 content, represented by F is in the range of 3 wt% to 15 wt%n of the total weight of the dual functional FCC catalyst additive, preferably 6 wt% to 12 wt% and
the SiO2 (silica) content, represented by K is in the range of 20 to 75 wt% of the total weight of the dual functional FCC catalyst additive, preferably 58 to 65 wt%.
In accordance with the present disclosure, silica (SiO2) and alumina (Al2O3) act as support material.
Typically, the metal oxides are impregnated on the silica and alumina support.
Typically, the total metal oxide content of the dual functional FCC catalyst additive of the present disclosure is in the range of 3 wt% to 25 wt% of the additive, whereas, the support content is in the range of 75 wt% to 97 wt% of the additive.
The FCC catalyst additive comprising strontium oxide, manganese oxide and phosphorous pentoxide impregnated on support material comprising silica and alumina, when used in combination with FCC catalyst for cracking of heavy hydrocarbons, results in cracked hydrocarbons showing enhanced propylene yield. However the total olefin content of the cracked hydrocarbons is still high and there is slight reduction in the total olefin content.
The FCC catalyst additive comprising strontium oxide, manganese oxide, phosphorous pentoxide and at least one of titanium oxide and ferrous oxide impregnated on support material, when used in combination with FCC catalyst for cracking of heavy hydrocarbons, results in cracked hydrocarbons showing enhanced propylene yield, as well as reduction in total olefin content.
Thus, it is observed that the FCC catalyst additive comprising support impregnated with strontium oxide, manganese oxide, phosphorous pentoxide and at least one of titanium oxide and ferrous oxide along with at least one other metal oxide is also capable of performing the dual function of improving the propylene yield as well as reduction in total olefin content simultaneously.
The dual functional FCC catalyst additive of the present disclosure is optimized by inclusion of at least one metal oxide of at least one metal selected from the group consisting of group IIIA, VI B and lanthanides to provide the cracked hydrocarbon with enhanced propylene yield and reduced olefin content in the fluid catalytic cracking of the heavy hydrocarbons.
In accordance with an exemplary embodiment of the present disclosure, the dual functional FCC catalyst additive is
(SrO)1(MnO)0.5(TiO)1(FeO)0.5(P2O5)9(SiO2)65(Al2O3)23.
In accordance with another exemplary embodiment of the present disclosure, the dual functional FCC catalyst additive is
(SrO)2(MnO)2(TiO)1(LaO)2(CeO)1(P2O5)12(SiO2)60(Al2O3)20.
In accordance with still another exemplary embodiment of the present disclosure, the dual functional FCC catalyst additive is
(SrO)3(MnO)3(FeO)1(MoO)0.5(GaO)0.5(P2O5)6(SiO2)58(Al2O3)28.
The dual functional FCC catalyst additive of the present disclosure can be prepared using any one method selected from the group consisting of wet impregnation, dry impregnation, pore volume impregnation, spray impregnation, combustion impregnation, solid-solid deposition and the like.
Typically, silica can be obtained from at least one silica source selected from the group consisting of tetraethylorthosilicate, precipitated silica, fumed silica, colloidal silica, sodium silicate and silicon alkoxides.
Typically, silica can be obtained by basic hydrolysis or acidic hydrolysis of the silica source to obtain a gel, which on drying and calcining results in formation of silica.
Typically, alumina can be obtained from at least one alumina source selected from the group consisting of aluminum alkoxide, aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum carbonate, aluminum bicarbonate, aluminum acetate, aluminum acetylacetonate, aluminum acetonitrile, pseudoboehmite, bayerite and gibbsite.
Typically, the alumina can be obtained by basic hydrolysis or acidic hydrolysis of alumina source.
The dual functional FCC catalyst additive of the present disclosure is prepared by impregnating metal oxides on the support comprising silica and alumina. The sources for the metal oxides are respective metal salts. Typically, the metal salts can be at least one selected from the group consisting of nitrate, sulfate, nitrile, alkoxide, chloride, acetylacetonate, acetate and organometallic compounds.
Typically, the metal salts are independently dissolved in at least one fluid medium to obtain respective metal salt solutions. The metal salt solutions are mixed with the predetermined amounts of silica and alumina to obtain a mixture. The so obtained mixture is dried and calcined to obtain the dual functional FCC catalyst additive.
Typically, the fluid medium can be at least one selected from the group consisting of water, methanol, ethanol, propanol, isopropyl alcohol and butanol.
In accordance with the embodiments of the present disclosure, the mixture can be dried at a temperature in the range of 150 °C to 250 °C.
In accordance with one embodiment of the present disclosure, the mixture is dried using a spray drier and the spray dried material has an average particle size in the range of 60 to 100 µm.
In accordance with the embodiments of the present disclosure, the surface area of the dual functional FCC catalyst additive is in the range of 120 to 200 m2/g. In one embodiment of the present disclosure, the surface area of the dual functional FCC catalyst additive is 158 m2/g.
In accordance with the embodiments of the present disclosure, the attrition resistance of the dual functional FCC catalyst additive is in the range of 0 to 3 wt%. In accordance with the present disclosure, the attrition resistance is measured using ASTM D5757.
In accordance with the embodiments of the present disclosure, the step of calcination can be carried out at a temperature in the range of 450 °C to 850 °C for a time period in the range of 3 hours to 9 hours.
The dual functional FCC catalyst 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 and reduced total olefin content.
Typically, 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 present disclosure is further described in the light of the following laboratory experiments, which are set forth for illustration purpose only, and not to be construed as 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.
EXPERIMENTS
Experiment set 1:
The dual functional FCC catalyst additives were prepared using the wet impregnation method. The composition of the catalyst additives are given in Table 1.
Table 1: Composition of the dual functional catalyst additives
Additive/ Component Reference Additive Additive 1 Additive 2 Additive 3
SrO (wt%) 1 1 2 3
MnO (wt%) 1 0.5 2 3
TiO (wt%) 0 1 1 0
FeO (wt%) 0 0.5 0 1
LaO 0 0 2 0
CeO 0 0 1 0
MoO 0 0 0 0.5
GaO (wt%) 0 0 0 0.5
P2O5 (wt%) 10 9 12 6
SiO2 (wt%) 65 65 60 58
Al2O3 (wt%) 23 23 20 28

Experiment set 2: FCC cracking of VGO
The dual functional catalyst additives of experiment set 1 were used in combination with the conventional FCC catalyst (E-cat) for cracking of vacuum gas oil (VGO) to obtain the cracked VGO.
VGO used in cracking process of the present disclosure comprises 57.1 % of saturated hydrocarbons, 33.3% of aromatics, 9.4 % of resin and 0.2 % of asphaltenes. 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) 0.915
Sulphur content (wt%) 2.0
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

The composition of the cracked VGO is summarized in Table 3.

Table 3: Results of FCC cracking of naphtha
ECAT Reference Additive Additive 1 Additive 2 Additive 3
Conversion (%) 70 70 70 70 70
Ethylene 0.73 1.53 2.01 1.87 1.78
Propylene 7.54 9.44 9.97 10.21 9.86
LPG 21.49 27.47 27.66 28.19 27.74
Gasoline (C5-216) 41.65 37.95 36.19 36.13 37.29
Total olefins 29.14 18.54 17.75 15.72 17.65
Reduction in olefins (%) 0 36.38 39.09 46.05 39.43
Increase in propylene (%) 0 25.18 32.24 35.46 30.82

E-cat and additive 1 were used for comparative purpose.
From Table 3, it is observed that the propylene yields for Additives 2, 3 and 4 were higher as compared to E-cat and reference additive. Reference additive, when used for FCC cracking of VGO, 36.38 % of olefin reduction was observed and 25.18 % increase in the propylene yield was observed, as compared to E-cat. However, when additional metal oxides such as ferrous oxide, titanium oxide or other metal oxides were the part of the additive compositions (Additive 1, Additive 2 and Additive 3), a significant increase in propylene yield and reduction in olefin yield was observed.
Thus, it can be established that the dual functional catalyst additives of the present disclosure perform dual function of increasing the propylene yield and decreasing the olefin content of the cracked product.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a dual functional FCC catalyst additive that:
- enable production of propylene with high yield; and
- reduces the total olefin content of the cracked products.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
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 invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment 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.