The present disclosure pertains to the technical field of catalysts. In particular, the present disclosure pertains to a catalyst for reducing SOx emission from a fluid catalytic cracking process and a method of preparation thereof.
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art. [0003] Fluid Catalytic Cracking (FCC) is one of the most common commercial practices used world-wide to produce gasoline, heating oil and diesel fuel by cracking heavier petroleum fractions to lighter, more valuable materials. Typically, in a FCC riser, vacuum gas oil containing higher proportion of Sulphur compounds gets cracked. Most of the Sulphur compounds in the feed get converted to FbS and a little portion stays in the liquid products. About 5% of the feed sulphur gets deposited in the catalyst as a part of coke. [0004] In the FCC regenerator the catalyst gets regenerated at a high temperature in presence of hot air. During this process, coke in the catalyst gets converted to carbon oxides, and the sulphur in the coke produces sulphur oxides which get released into the atmosphere. These sulphur oxides are a major concern for atmospheric pollutions and causes acid rains. Therefore, there has always been a need for refiners to reduce emissions of sulphur oxides, mostly SO2 and little SO3, from FCC regenerator in the flue gas. The major options for reducing SOx emissions from the FCCU include flue gas scrubbing (FGS), hydrodesulfurization (HDS) of the FCC feed and the use of a SOx reduction additives. FGS requires a high capital investment and the operating costs are high. In addition, discarding the spent treating compounds, such as lime, caustic soda, or other compounds can also be problematic. HDS of vacuum gas oil requires the highest capital investment but will also provide improved yields as well as lower SOx emissions. Therefore, the use of SOx reduction additives is often the preferred route taken by

refiners, as they require very little capital investment and are extremely effective in reducing SOx emissions.
[0005] Efficient trapping of SOx in presence of an additive mechanistically involves three steps. In the first step SO2 gets oxidized to SO3 in presence of an oxidant. In the second step, chemisorption of SO3 occurs onto the catalyst to form metal sulfate. Finally, in the third step the metal sulfate gets reduced to metal oxide in presence of cracked hydrogen. In an alternate pathway, the metal sulfate gets converted to metal sulfide which finally gets converted to H2S in presence of steam in the FCC stripper. The first and the second step take place in FCC regenerator at a temperature between 680°C to 730°C under oxidizing atmosphere. However, the third step occurs at the FCC riser at a temperature between 500°C to 530°C under reducing atmosphere. As all the three steps occur in one after another, inefficiency in any one of the three steps can limit SOx transfer additive performance. Thus, SOx transfer catalysts and/or additives need to contain catalytic ingredients to promote the efficient and rapid oxidation of S02.
[0006] Significant efforts have been put forward to find new catalysts for reducing SOx emission from a fluid catalytic cracking (FCC) process. However, none of the current approaches/reports seem to satisfy the existing needs. There is, therefore, a need in the art to develop a new and improved catalyst and method of preparation thereof that may overcome one or more drawbacks associated with the existing catalysts and their methods of preparation. The present invention satisfies the existing needs, as well as others, and generally overcomes the deficiencies found in the prior art.
[0007] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTS OF THE INVENTION
[0008] It is an object of the present disclosure to provide a new and improved
catalyst that may overcome one or more limitations associated with the
conventional catalyst.
[0009] It is an object of the present disclosure to provide a SOx reduction
catalyst for reducing SOx emission from a fluid catalytic cracking (FCC) process.
[0010] It is another object of the present disclosure to provide a SOx reduction
catalyst that is efficient and cost-effective.
[0011] It is another object of the present disclosure to provide a SOx reduction
catalyst that is easy to prepare.
[0012] It is another object of the present disclosure to provide a method of
preparation of a SOx reduction catalyst for fluid catalytic cracking (FCC) process.
SUMMARY
[0013] The present disclosure pertains to the technical field of catalyst. In particular, the present disclosure pertains to a catalyst for reducing SOx emission from a fluid catalytic cracking process and a method of preparation thereof. [0014] An aspect of the present disclosure relates to a catalyst for reducing SOx emission from a fluid catalytic cracking (FCC) process, the catalyst including: a sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof in an amount ranging from 1% to 50% by weight of the catalyst; an oxide of magnesium, calcium, barium or combinations thereof in an amount ranging from 10% to 70% by weight of the catalyst; at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof in an amount ranging from 5% to 50% by weight of the catalyst; and silica in an amount ranging from 0% to 50% by weight of the catalyst. In an embodiment, the salt of the at least one metal is selected from nitrate, acetate, acetate and chloride.
[0015] Another aspect of the present disclosure relates to a method for preparation of a SOx reduction catalyst for fluid catalytic cracking (FCC) process, the method including the steps of: (a) preparing an aqueous slurry comprising a

sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof, an acid, at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof, an oxide of magnesium, calcium, barium or combinations thereof, and optionally, silica; (b) subjecting the aqueous slurry to drying at a temperature ranging from 100°C to 140°C for a time period ranging from 8 hours to 16 hours to obtain the dried catalyst; and (c) effecting calcination of the dried catalyst at a temperature ranging from 400°C to 800°C for a time period ranging from 2 hours to 6 hours to obtain the SOx reducing catalyst.
[0016] In an embodiment, the step of preparing the aqueous slurry includes: (i) mixing the sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof, and the acid in water to obtain a sorbent mixture; (ii) adding said at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof to the sorbent mixture and stirring the mixture for a time period ranging from 1 minute to 100 minutes; and (iii) adding said oxide of magnesium, calcium, barium or combinations thereof, and optionally, silica to the mixture obtained in step (ii) and stirring the mixture for a time period ranging from 30 minute to 180 minutes to obtain the aqueous slurry. [0017] In an embodiment, the step of calcination includes: (i) exposing the dried catalyst to a temperature ranging from 400°C to 600°C for a time period ranging from 30 minutes to 240 minutes to obtain a partially calcined catalyst; and (ii) exposing the partially calcined catalyst to a temperature ranging from 600°C to 800°C for a time period ranging from 30 minutes to 240 minutes to obtain the SOx reducing catalyst.
[0018] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.
BRIEF DESCRIPTION OF DRAWINGS
[0019] FIG. 1 illustrates an exemplary graph showing SOx reduction activity of catalyst-4 composition prepared in accordance with an embodiment of the

present disclosure (comparing results thereof with a case when SOx reduction no catalyst was added).
DETAILED DESCRIPTION OF THE INVENTION
[0020] The following is a detailed description of embodiments of the present invention. The embodiments are in such detail as to clearly communicate the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
[0021] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0022] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability.
[0023] Unless the context requires otherwise, throughout the specification which follow, the word "comprise" and variations thereof, such as, "comprises" and "comprising" are to be construed in an open, inclusive sense that is as "including, but not limited to."
[0024] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in

various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0025] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
[0026] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term "about."Accordingly, in some embodiments, the numerical parameters set forth in the written description are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. [0027] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. [0028] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments. [0029] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate

the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention. [0030] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0031] The present disclosure pertains to the technical field of catalyst. In particular, the present disclosure pertains to a catalyst for reducing SOx emission from a fluid catalytic cracking process and a method of preparation thereof. [0032] An aspect of the present disclosure relates to a catalyst for reducing SOx emission from a fluid catalytic cracking (FCC) process, the catalyst including: a sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof in an amount ranging from 1% to 50% by weight of the catalyst; an oxide of magnesium, calcium, barium or combinations thereof in an amount ranging from 10% to 70% by weight of the catalyst; at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof in an amount ranging from 5% to 50% by weight of the catalyst; and silica in an amount ranging from 0% to 50% by weight of the catalyst. In an embodiment, the sorbent is pseudobohemite.
[0033] In an embodiment, the sorbent is present in an amount ranging from P/o to 40%) by weight of the catalyst. In an embodiment, the sorbent is present in an amount ranging from 10% to 40% by weight of the catalyst. In an embodiment, the sorbent is present in an amount ranging from 10% to 30% by weight of the catalyst.
[0034] In an embodiment, the oxide of magnesium, calcium, barium or combinations thereof is present in an amount ranging from 10% to 60% by weight

of the catalyst. In an embodiment, the oxide of magnesium, calcium, barium or combinations thereof is present in an amount ranging from 10% to 50% by weight of the catalyst. In an embodiment, the oxide of magnesium, calcium, barium or combinations thereof is present in an amount ranging from 20% to 50% by weight of the catalyst.
[0035] In an embodiment, silica is present in an amount ranging from 0% to 40%) by weight of the catalyst. In an embodiment, silica is present in an amount ranging from 5% to 40% by weight of the catalyst. In an embodiment, silica is present in an amount ranging from 5% to 30% by weight of the catalyst. [0036] In an embodiment, the at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof is present in an amount ranging from 5% to 50% by weight of the catalyst, preferably, in an amount ranging from 10% to 50% by weight of the catalyst, more preferably, in an amount ranging from 15% to 50% by weight of the catalyst, and most preferably, in an amount ranging from 25% to 50% by weight of the catalyst.
[0037] In an embodiment, the salt of the at least one metal is selected from nitrate, acetate, acetate and chloride.
[0038] Another aspect of the present disclosure relates to a method for preparation of a SOx reduction catalyst for fluid catalytic cracking (FCC) process, the method including the steps of: (a) preparing an aqueous slurry comprising a sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof, an acid, at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof, an oxide of magnesium, calcium, barium or combinations thereof, and optionally, silica; (b) subjecting the aqueous slurry to drying at a temperature ranging from 100°C to 140°C for a time period ranging from 8 hours to 16 hours to obtain the dried catalyst; and (c) effecting calcination of the dried catalyst at a temperature ranging from 400°C to 800°C for a time period ranging from 2 hours to 6 hours to obtain the SOx reducing catalyst.

[0039] In an embodiment, the step of preparing the aqueous slurry includes: (i) mixing the sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof, and the acid in water to obtain a sorbent mixture; (ii) adding said at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof to the sorbent mixture and stirring the mixture for a time period ranging from 1 minute to 100 minutes; and (iii) adding said oxide of magnesium, calcium, barium or combinations thereof, and optionally, silica to the mixture obtained in step (ii) and stirring the mixture for a time period ranging from 30 minute to 180 minutes to obtain the aqueous slurry. [0040] In an embodiment, the step of calcination includes: (i) exposing the dried catalyst to a temperature ranging from 400°C to 600°C for a time period ranging from 30 minutes to 240 minutes to obtain a partially calcined catalyst; and (ii) exposing the partially calcined catalyst to a temperature ranging from 600°C to 800°C for a time period ranging from 30 minutes to 240 minutes to obtain the SOx reducing catalyst.
[0041] In an embodiment, the sorbent is present in an amount ranging from 1% to 50% by weight of the catalyst. In an embodiment, the oxide of magnesium, calcium, barium or combinations thereof is present in an amount ranging from 10% to 70%) by weight of the catalyst. In an embodiment, the at least one metal is present in an amount ranging from 5% to 50% by weight of the catalyst. In an embodiment, the silica is present in an amount ranging from 0% to 50% by weight of the catalyst. EXAMPLES
METHOD FOR PREPARATION OF SOx REDUCING CATALYST [0042] EXAMPLE 1
To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7 g), copper nitrate (2.4 g) was added, and the mixture was stirred for 10 min. Then, Magnesium oxide (4.0 g) was added into the above mixture to form slurry and was stirred for another 2 hrs. It was then dried at 110°C for about 16 h. The dried material was further calcined at 500°C for 1 hr and at 700°C for 3 hrs.

[0043] EXAMPLE 2
To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7 g), chromium nitrate (4.0 g) was added and the mixture was stirred for 10 min. Then, Magnesium oxide (4.0 g) was added into the above mixture to form slurry and was stirred for another 2 hrs. It was then dried at 110°C for about 16 hrs. The dried material was further calcined at 500°C for 1 hr and at 700°C for 3 hrs. [0044] EXAMPLE 3
To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7g), silver nitrate (1.7 g) was added, and the mixture was stirred for 10 min. Then, Magnesium oxide (4.0 g) was added into the above mixture to form slurry and was stirred for another 2 hrs. It was then dried at 110°C for 16 hrs. The dried material was further calcined at 500°C for 1 hr and at 700°C for 3 hrs. [0045] EXAMPLE 4
To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7 g), cerium nitrate (4.34 g) was added, and the mixture was stirred for 10 min. Then, Magnesium oxide (4.0 g) was added into the above mixture to form slurry and the slurry was stirred for another 2 hrs. It was then dried at 110°C for 16 hrs. The dried material was calcined at 500°C for 1 hrs and at 700°C for 3 hrs. Composition of the catalyst realized thereby is shown in Table 1 below:
Table 1: Composition of catalyst 4

Ingredient Amount (in wt. %)
Pseudobohemite 18.2
cerium nitrate 40.0
Magnesium oxide 36.4
Acetic acid 5.4
[0046] EXAMPLE 5
[0047] To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7 g), copper nitrate (2.4 g) was added and the mixture was stirred for 10 min. Then, 30% colloidal silica was added followed by the addition of Magnesium oxide (4.0 g) to form slurry. The slurry was than stirred for 2 hrs, and then dried at 110°C for

16 hrs. The dried material was further calcined at 500°C for 1 h and at 700°C for 3
hrs.
[0048] EXAMPLE 6
[0049] To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7
g), cerium nitrate (4.34 g) was added and the mixture was stirred for 10 min.
Then, 30% colloidal silica was added followed by the addition of Magnesium
oxide (4.0 g) to form slurry. The slurry was stirred for 2 hrs, and then dried at
110°C for 16 hrs. The dried material was further calcined at 500°C for 1 h and at
700°C for 3 hrs.
[0050] EXAMPLE 7
[0051] To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7
g), copper nitrate (2.4 g) was added and the mixture was stirred for 10 min. Then,
30%) polysilicate was added followed by the addition of Magnesium oxide (4.0 g)
to form slurry. The slurry was stirred for 2 hr, and then dried at 110°C for 16 hrs.
The dried material was further calcined at 500°C for 1 h and at 700°C for 3 hrs.
[0052] EXAMPLE 8
[0053] To an aqueous mixture of pseudobohemite (2.0 g) and acetic acid (0.7
g), cerium nitrate (4.34 g) was added and the mixture was stirred for 10 min.
Then, 30% polysilicate was added followed by the addition of Magnesium oxide
(4.0 g) to form slurry. The slurry was stirred for 2 hrs, and then dried at 110°C for
16 hrs. The dried material was further calcined at 500°C for 1 hr and at 700°C for
3 hrs.
[0054] PERFORMANCE OF THE CATALYST
[0055] Activity analysis of catalyst formulations were carried out in a bench
scale fixed bed quartz reactor unit. Petroleum coke containing 7.5 wt% Sulphur
was used as SOx source. Each experiment was carried out with 100 mg of
petroleum coke and 1000 mg catalyst mixture. The catalyst mixture consisted of a
combination of 10%> SOx reduction catalyst (prepared in Examples 1-8 above) and
90%) FCC equilibrium catalyst. Petroleum coke was heated up to a temperature of
600 °C in presence of catalyst and S02 produced is analyzed with Yokogawa S02
analyzer. To determine the total amount of S02 generated, the concentration of

S02 is plotted against time (Figure 1). The area under the curve represents the total amount of S02 produced upon combustion of petroleum coke. FIG. 1 illustrates an exemplary graph showing SOx reduction activity of catalyst-4 composition prepared in accordance with an embodiment of the present disclosure (comparing results thereof with a case when no SOx reduction catalyst was added). Table 2 below provides the activity data of representative catalysts prepared in example 1 to 7 hereinabove.
Table 2: Activity of various catalyst compositions

Catalyst Catalyst Composition Catalyst wt% SOx Reduction
(%)
Cat-1 Example-1 10 71.8
Cat-2 Example-2 10 58.8
Cat-3 Example-3 10 76.0
Cat-4 Example-4 10 70.2
Cat-5 Example-5 10 47.0
Cat-6 Example-6 10 46.3
Cat-7 Example-7 10 49.4
Cat-8 Example-8 10 48.1
ADVANTAGES
[0056] The present disclosure provides a new and improved catalyst that may overcome one or more limitations associated with the conventional catalyst. [0057] The present disclosure provides a catalyst for reducing SOx emission. [0058] The present disclosure provides a catalyst for reducing SOx emission from a fluid catalytic cracking (FCC) process.
[0059] The present disclosure provides a catalyst that is efficient and cost-effective.
[0060] The present disclosure provides a catalyst that is easy to prepare. [0061] The present disclosure also provides a method of preparation of a SOx reduction catalyst for fluid catalytic cracking (FCC) process.

We Claim:

1. A catalyst for reducing SOx emission from a fluid catalytic cracking (FCC)
process, the catalyst comprising:
a sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof in an amount ranging from 1% to 50% by weight of the catalyst;
an oxide of magnesium, calcium, barium or combinations thereof in an amount ranging from 10% to 70% by weight of the catalyst;
at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof in an amount ranging from 5% to 50% by weight of the catalyst; and
silica in an amount ranging from 0% to 50% by weight of the catalyst.
2. The catalyst as claimed in claim 1, wherein the salt of said at least one metal is selected from nitrate, acetate, acetate and chloride.
3. A method for preparation of a SOx reduction catalyst for fluid catalytic cracking (FCC) process, the method comprising the steps of:

(a) preparing an aqueous slurry comprising a sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof, an acid, at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof, an oxide of magnesium, calcium, barium or combinations thereof, and optionally, silica;
(b) subjecting the aqueous slurry to drying at a temperature ranging from 100°C to 140°C for a time period ranging from 8 hours to 16 hours to obtain the dried catalyst; and
(c) effecting calcination of the dried catalyst at a temperature
ranging from 400°C to 800°C for a time period ranging from 2 hours to 6
hours to obtain the SOx reducing catalyst.
4. The process as claimed in claim 3, wherein the step of preparing the
aqueous slurry comprises:

(i) mixing the sorbent selected from alumina, bohemite, pseudobohemite and mixtures thereof, and the acid in water to obtain a sorbent mixture;
(ii) adding said at least one metal selected from Cerium, Copper, Silver, Chromium, Manganese, Zinc, Vanadium, Iron or salt thereof to the sorbent mixture and stirring the mixture for a time period ranging from 1 minute to 100 minutes; and
(iii) adding said oxide of magnesium, calcium, barium or combinations thereof, and optionally, silica to the mixture obtained in step (ii) and stirring the mixture for a time period ranging from 30 minute to 180 minutes to obtain the aqueous slurry. 5. The process as claimed in claim 3, wherein the step of calcination comprises:
(i) exposing the dried catalyst to a temperature ranging from 400°C to 600°C for a time period ranging from 30 minutes to 240 minutes to obtain a partially calcined catalyst; and
(ii) exposing the partially calcined catalyst to a temperature ranging from 600°C to 800°C for a time period ranging from 30 minutes to 240 minutes to obtain the SOx reducing catalyst.