DESC:FIELD
The present disclosure relates to a fluid catalytic cracking (FCC) catalyst additive composition and its process of preparation.
BACKGROUND
Fluid Catalytic Cracking (FCC) is a process which employs specialized catalysts known as FCC catalysts to facilitate the catalytic cracking of heavy hydrocarbon feedstock, such as vacuum gas oil, to lighter products, such as naphtha and other distillate range fractions.
One of the significant objectives of carrying out the afore-stated cracking process is to convert the left-over heavy fraction obtained during the derivatization of crude oil into low molecular weight beneficial chemicals such as propylene, light cycle oil, liquefied petroleum gas, gasoline, olefinic gases and the like. After isolation, these products are recycled in the industry; which not only makes the industrial processes economical but also satisfies the ever increasing demand of the afore-stated chemicals.
However, it is often found that the yield of some of the chemicals is more desirable over the others in the product mix, purely to satisfy the industrial demands. Similarly sometimes, the content of undesired products in the isolated products is high. To improve this condition, various approaches have been explored.
One of the approaches is modifying the catalyst. Conventionally, zeolites are used as FCC catalysts. Zeolites that are used in the FCC units are typically crystalline alumino-silicates which have a uniform crystal structure characterized by a large number of regular microlevel cavities interconnected by a large number of smaller channels. These catalysts act as molecular sieves resulting in selective absorption of molecules having sizes below a defined value and rejection of molecules of larger sizes. However, in spite of making modifications in the catalyst, it has been found that a sastisfactory yield of the desirable products is not achieved.
Hence, there is felt need for developing a catalyst system that is capable of achieving optimum benefits of the FCC process.
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 fluid catalytic cracking (FCC) catalyst additive composition.
Another object of the present disclosure is to provide a FCC catalyst additive composition having a wide spectrum of industrial applicability.
Another object of the present disclosure is to provide a process for the preparation of the FCC catalyst additive composition.
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 fluid catalytic cracking (FCC) catalyst additive composition comprising at least one zeolite in an amount ranging from 30 to 50% of the total weight of the composition; at least one Group V element in an amount ranging from 0.1 to 5 % of the total weight of the zeolite; at least one promoter in an amount ranging from 1 to 3 % of the total weight of the zeolite and optionally, at least one excipient in an amount ranging from 50 to 70% of the total weight of the composition. Typically, the Group V element is phosphorus. Similarly, the promoter is at least one element selected from the group consisting of magnesium, calcium, strontium, barium, copper, iron, nickel, zinc, gallium, indium, thallium and the lanthanide series.
The present disclosure further provides a process for the preparation of the FCC catalyst additive comprising admixing at least one pre-dried zeolite with at least one promoter precursor and at least one Group V element precursor to obtain a slurry; agitating said slurry for a time period ranging from 2 to 4 hours to form a thick slurry; heating said thick slurry at a temperature ranging from 50 to 100 oC under vacuum to obtain a dried mass; calcining said dried mass at a temperature ranging from 500 oC to 750 oC at a time period ranging from 4 to 6 hours to obtain a calcined mass; grinding said calcined mass to obtain a ground mass and processing said ground mass to obtain the FCC catalyst additive composition.
DETAILED DESCRIPTION
In accordance with one aspect, the present disclosure provides an FCC catalyst additive composition consisting of at least one zeolite, at least one Group V element, at least one promoter and optionally at least one excipient.
The zeolite, which is the center of the catalytic activity, is included in the composition in an amount ranging from 30 to 50% of the total weight of the composition. Typically, the zeolite is at least one selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-48, ZSM-57, SAPO-5, SAPO-11, SAPO-17, SAPO-18, SAPO-34, SAPO-44, MCM-22, an intergrowth of ZSM-11, zeolite Y and Beta. In one embodiment, the zeolite is ZSM-5 with silica to alumina (SiO2/A2O3) molar ratio of 23.
Typically, the Group V element is phosphorus and is included in the composition in an amount ranging from 0.1 to 5 % of the total weight of the zeolite. The afore-stated range has been obtained on the basis of optimization data. The Group V elements are included in the composition to boost the catalytic activity. Furthermore, inclusion of the Group V element in the composition in the afore-stated quantity aids in effecting passivation of the highly active acid sites which in turn results in lower crackability, lesser production of dry gas and increase in the liquid yield.
The promoter, like the Group V element, enhances the catalytic activity and performance of the zeolite. The promoter included in the composition of the present disclosure is at least one element selected from the group consisting of magnesium, calcium, strontium, barium, copper, iron, nickel, zinc, gallium, indium, thallium and the lanthanide series and is included in the composition in an amount ranging from 1 to 3 % of the total weight of the zeolite. The promoter, when included in the afore-stated range, modifies the acidity of the active sites and provides stability. In one embodiment, the promoter is at least one selected from the group consisting of magnesium, calcium, strontium and barium. In another embodiment, the promoter is a combination of zinc and gallium.
The composition, optionally, includes at least one excipient in an amount ranging from 50 to 70% of the total weight of the composition. Typically, the excipient is at least one selected from the group consisting of binder, filler and matrix. In one embodiment, the binder is pseudoboehmite. Pseudoboehmite functions both as a binder and as matrix. In one embodiment, the filler is alpha alumina.
In accordance with another aspect, the present disclosure provides a process for the preparation of the FCC catalyst additive composition. Initially, at least one zeolite, in a pre-determined amount, is admixed with a pre-determined amount of at least one Group V element precursor and a pre-determined amount of at least one promoter precursor to obtain slurry.
Typically, the zeolite is pre-dried.
The Group V element precursor is selected from the group consisting of phosphoric acid, phosphates, phosphorous acid, phosphites, pyrophosphoric acid, pyrophosphate, polymeric phosphoric acid, polyphosphates, metaphosphoric acid and metaphosphates.
The promoter precursor is selected from the group consisting of a chloride of the promoter, a fluoride of the promoter, a bromide of the promoter, an oxalate of the promoter, sulfate of the promoter, acetate of the promoter, a carbonate of the promoter and an oxide of the promoter. In one embodiment, the promoter precursor is a nitrate of the promoter. Typically, the promoter precursor is admixed in pre-determined quantity of water before it is admixed with the Group V element and the zeolite.
In one embodiment, at least one excipient is also admixed to form the slurry. The addition of the excipient is accompanied by stirring for a time period ranging from 2 to 4 hours and is optionally followed by admixing aqueous nitric acid having concentration ranging from 40 to 60 % to adjust the pH.
The resulting slurry is agitated for a time period ranging from 2 to 4 hours at an agitation speed of 1 to 250 rpm to form a thick slurry. The thick slurry is heated at a temperature ranging from 50 to 100 oC under vacuum to obtain a dried mass. The dried mass is calcined at a temperature ranging from 500 oC to 750 oC at a time period ranging from 4 to 6 hours to obtain a calcined mass. The calcined mass is ground to obtain a ground mass and the ground mass is further processed to obtain the FCC catalyst additive composition. Typically, the step of processing is at least one selected from the group that includes but is not limited to pelletizing, pastilling, extruding, granulating and spray drying. Therefore, the resulting composition is in at least one form selected from the group that includes but is not limited to extrudates, pellets, pastilles, beads, flakes, granules and powder. In one embodiment, the composition is in the form of a spray dried powder.
The afore-stated ingredients are admixed in pre-determined quantities so as to have the eventual composition comprise at least one zeolite in an amount ranging from 30 to 50% of the total weight of the composition; at least one Group V element in an amount ranging from 0.1 to 5 % of the total weight of the zeolite; at least one promoter in an amount ranging from 1 to 3 % of the total weight of the zeolite and optionally, at least one excipient in an amount ranging from 50 to 70% of the total weight of the composition.
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. These laboratory scale experiments can be scaled up to industrial/commercial scale:
Preparation of the catalyst additive composition without excipients:
Example 1:
5 g of dried ZSM-5 was admixed with 0.05 g of magnesium nitrate in 10 g deionized water and 0.05 g of orthophosphoric acid to form a slurry. The slurry was agitated at room temperature for 3 hours. The resulting thick slurry was heated in a rotary evaporator maintained at 75 oC under vacuum to obtain a dried mass. The resulting dried mass was calcined at 550 oC for 5 hours, after which it was ground into fine powder, pressed into pellets and sieved to obtain particles having particle sizes ranging from 600 µm to 800 µm.
Examples 2 – 10:
As in Example 1, catalyst additives were prepared containing different promoters such as calcium, strontium, barium, nickel, iron, copper, lanthanum and cerium.

Example Zeolite Group V element (1% of the total weight of the zeolite) Promoter
1 ZSM-5 P Mg (1% of the total weight of the zeolite)
2 Ca (1% of the total weight of the zeolite)
3 Sr (1% of the total weight of the zeolite)
4 Ba (1% of the total weight of the zeolite)
5 Ni (1% of the total weight of the zeolite)
6 Fe (1% of the total weight of the zeolite)
7 Cu (1% of the total weight of the zeolite)
8 La (5% of the total weight of the zeolite)
9 Ce (1% of the total weight of the zeolite)
10 ZSM-5 P Zn (1% of the total weight of the zeolite); and
Ga (2% of the total weight of the zeolite)
Preparation of the catalyst additive composition with excipients:
Example 11:
1.5 g of pre-dried ZSM-5 was admixed with 0.015 g of calcium nitrate in 10 ml water and 0.015 g of orthophosphoric acid and stirred for 3 hours, after which 3.5 g of a combination of pseudoboehmite and alpha alumina was admixed, accompanied by further stirring for 3 hours to form a thick slurry. 50% aqueous nitric acid was added to this slurry during stirring. The thick slurry was evaporated in a rotary evaporator maintained at 75 oC under vacuum. The resulting dried mass was calcined at 650 oC for 4 hours, after which it was ground into fine powder and extruded to form the catalyst additive composition in the form of extrudates.
As in Example 11, extrudates were also prepared using strontium nitrate as the precursor.
Example Zeolite Group V element (1% of the total weight of the zeolite) Promoter
11 H-ZSM-5 (SiO2/Al2O3 molar ratio of 23) P Ca (1% of the total weight of the zeolite)
12 Sr (1% of the total weight of the zeolite)
13* 0.5% Zr, 0.5 % Mo, 0.5% Ni, 0.5% Co, 1% Zn and 1% Ga (% is with respect to the total weight of the zeolite)
14* 1% Ni and 1% Ca (% is with respect to the total weight of the zeolite)
*the metal nitrates were dissolved in water independently and then admixed together to form a promoter pool; the resulting additive composition is in the form of granules of average size 700 microns and contains 40% zeolite and 60% pseudoboehmite
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the 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 will 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.
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The catalyst additive of the present disclosure described herein above has several technical advantages including but not limited to the realization of:
? The catalyst additive of the present disclosure has a wide spectrum of applications in various fields such as polymer, metallurgy and petrochemicals.
,CLAIMS:The catalyst additive of the present disclosure described herein above has several technical advantages including but not limited to the realization of:
? The catalyst additive of the present disclosure has a wide spectrum of applications in various fields such as polymer, metallurgy and petrochemicals.

WE CLAIM:
1. A fluid catalytic cracking (FCC) catalyst additive composition comprising:
i. at least one zeolite in an amount ranging from 30 to 50% of the total weight of the composition;
ii. at least one Group V metal in an amount ranging from 0.1 to 5 % of the total weight of the zeolite;
iii. at least one promoter in an amount ranging from 1 to 2 % of the total weight of the zeolite; and
iv. optionally, at least one excipient in an amount ranging from 50 to 70% of the total weight of the composition.
2. The composition as claimed in claim 1, wherein said zeolite is at least one selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-48, ZSM-57, SAPO-5, SAPO-11, SAPO-17, SAPO-18, SAPO-34, SAPO-44, MCM-22, intergrowth of ZSM-11, zeolite Y and Beta.
3. The composition as claimed in claim 1, wherein said zeolite is ZSM-5 with silica to alumina (SiO2/A2O3) molar ratio of 23.
4. The composition as claimed in claim 1, wherein said Group V metal is phosphorus.
5. The composition as claimed in claim 1, wherein said promoter is at least one element selected from the group consisting of magnesium, calcium, strontium, barium, copper, iron, nickel, zinc, gallium, indium, thallium, zirconium, molybdenum, cobalt and the lanthanide series.
6. The composition as claimed in claim 1, wherein said promoter is at least one selected from the group consisting of magnesium, calcium, strontium and barium.
7. The composition as claimed in claim 1, wherein said promoter is a combination of zinc and gallium.
8. The composition as claimed in claim 1, wherein said excipient is at least one selected from the group consisting of binder, filler and matrix.
9. The composition as claimed in claim 8, wherein said binder is pseudoboehmite.
10. The composition as claimed in claim 8, wherein said filler is alpha alumina.
11. The composition as claimed in claim 1, being in the form of shaped articles selected from the group consisting of extrudates, pellets, pastilles, beads, flakes and granules.
12. The composition as claimed in claim 1, being in the form of spray dried powder.
13. A process for the preparation of a fluid catalytic cracking (FCC) catalyst additive composition comprising at least one zeolite in an amount ranging from 30 to 50% of the total weight of the composition; at least one Group V metal in an amount ranging from 0.1 to 5 % of the total weight of the zeolite; at least one promoter in an amount ranging from 1 to 2 % of the total weight of the zeolite; and optionally, at least one excipient in an amount ranging from 50 to 70% of the total weight of the composition; said process comprising the following steps:
i. admixing at least one pre-dried zeolite with at least one promoter precursor and at least one Group V metal precursor to obtain a slurry;
ii. agitating said slurry for a time period ranging from 2 to 4 hours at an agitator speed of 1 to 250 rpm to form a thick slurry;
iii. heating said thick slurry at a temperature ranging from 50 to 100 oC under vacuum to obtain a dried mass;
iv. calcining said dried mass at a temperature ranging from 500 oC to 750 oC for a time period ranging from 4 to 6 hours to obtain a calcined mass;
v. grinding said calcined mass to obtain a ground mass; and
vi. processing said ground mass to obtain the fluid catalytic cracking (FCC) catalyst additive composition.
14. The process as claimed in claim 13, wherein said promoter precursor is a nitrate of at least one element selected from the group consisting of magnesium, calcium, strontium, barium, copper, iron, nickel, zinc, gallium, indium, thallium and the lanthanide series.
15. The process as claimed in claim 13, wherein said promoter precursor is admixed in pre-determined quantity of water before the step of admixing.
16. The process as claimed in claim 13, wherein said Group V metal precursor is selected from the group consisting of phosphoric acid, phosphates, phosphorous acid, phosphites, pyrophosphoric acid, pyrophosphate, polymeric phosphoric acid, polyphosphates, metaphosphoric acid and metaphosphates.
17. The process as claimed in claim 13, wherein said step of admixing further comprises admixing at least one excipient in an amount ranging from 50 to 70% of the total weight of the composition accompanied by stirring for a time period ranging from 2 to 4 hours, followed by admixing at least one buffer.
18. The process as claimed in claim 17, wherein said buffer is aqueous nitric acid having concentration ranging from 40 to 60 %.
19. The process as claimed in claim 13, wherein said step of processing is at least one selected from the group consisting of pelletizing, pastilling, extruding, granulating and spray drying.