Claims:WE CLAIM
1. A process for reducing dry gas and coke, said process comprising the following steps:
i) mixing hydrocarbon feed with a heated FCC catalyst in the bottom portion of a riser to obtain a first mixture;
ii) cracking hydrocarbons in said first mixture, by heating said first mixture to a temperature in the range of 500 oC to 750 oC, within said riser, to obtain a spent catalyst and a second mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas and coke; and
iii) passing said second mixture to a post-riser section, said post-riser section being in fluid communication with said riser, and contacting said second mixture with an inorganic catalyst at a temperature in the range of 450 ?C to 580 ?C, wherein said inorganic catalyst is at least one inorganic salt selected from the group consisting of FeSO4, MgSO4 and CuSO4, and is introduced at a predetermined location selected from said post-riser section and a conduit connecting said post-riser section and a fractionator, to obtain a third mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas and coke;
wherein the combined yield of light crude oil (LCO), liquified petroleum gas (LPG), and cracked run naphtha (CRN), in said third mixture is greater by 1 to 5% than their combined yield in the second mixture; and the combined yield of dry gas and coke in said third mixture is lower by 1 to 5% than their combined yield in the second mixture.
2. The process as claimed in claim 1, wherein the ratio of said FCC catalyst to said hydrocarbon is in the range of 4:1 to 20:1.
3. The process as claimed in claim 1, wherein said hydrocarbons comprise at least one liquid hydrocarbon selected from the group consisting of vacuum gas oil, vacuum residue, atmospheric residue, heavy fuel oil, recycled HCO, and recycled slurry.
4. The process as claimed in claim 1, wherein said FCC catalyst is at least one selected from the group consisting of fresh FCC catalyst and regenerated FCC catalyst.
5. The process as claimed in claim 1, or 2, or 4, wherein said FCC catalyst is at least one selected from ZSM-5, USY, and bottoms upgrading additive.
6. The process as claimed in claim 1, wherein said first mixture is lifted in an operative upward direction in said riser by a lift gas, wherein said lift gas is at least one selected from the group consisting of steam, hydrogen, nitrogen, krypton, argon, natural gas, and dry gas produced in the FCC process.
7. The process as claimed in claim 1, wherein said cracked products further comprise at least one product selected from the group consisting of propylene, and light cycle oil (LCO).
8. The process as claimed in claim 1, wherein said inorganic catalyst is in an amount in the range of 100 ppm to 10,000 ppm of said hydrocarbon.
9. The process as claimed in claim 1, wherein said inorganic catalyst is injected as an aqueous solution having a concentration in the range of 40 wt% to 60 wt%.
10. The process as claimed in claim 1, wherein said predetrmined injection point in the post-riser section is determined by the temperature of the post-riser section and the nature of the product gases formed; wherein said location is at least one selected from the group consisting of a stripper, a cyclone inlet zone, and reactor outlet line.
11. An apparatus for a catalytic cracking of hydrocarbons, said apparatus comprising:
a) a riser (8) having:
an operative bottom end (8a) and an operative top end (8b),
- a lift gas inlet (10) and a catalyst inlet (11) configured in proximity of said operative bottom end (8a);
- one or more hydrocarbon inlets (9) configured between said operative top end (8b) and said operative bottom end (8a) of said riser (8);
b) a post-riser (30):
o in fluid communication with
? said riser (8) and housing said operative top end (8b) and a portion of said riser proximate to said operative top end (8b) defining a stripper section (7);
? a fractionator (13), said fractionator being configured to fractionate one or more products from said post-riser (30);
? a first outlet (6) for facilitating removal of said one or more products from said post-riser (30);
? at least one inorganic catalyst inlet (22) configured on at least one position selected from the group consisting of said first outlet (6), a top portion of said post-riser (23) and a middle portion of said post-riser (24); and
? a second outlet (12) for facilitating removal of spent catalyst from bottom portion of said post-riser;
? one or more cyclone separators (3) operatively disposed in proximity of a top end of said post-riser therein;
c) a regenerator (2) for regenerating said spent catalyst received from said second outlet (12); wherein said regenerated catalyst from said regenerator is introduced into said riser (8) through the catalyst inlet (11).
, Description:FIELD
The present disclosure relates to a process and an apparatus for reducing dry gas and coke in FCC process.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Coke: The term “Coke” refers to coke or petroleum coke, which is a byproduct of the fluid catalytic cracking in the oil refining.
Fluid Catalytic Cracking (FCC): The term “fluid catalytic cracking” refers to the process used in petroleum refineries to convert the high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils to more valuable gasoline, olefinic gases and other products.
FCC catalyst: The term “FCC catalyst” refers to catalytic material used in a fluidized bed catalytic process to convert a petroleum fraction into a primarily gasoline fraction.
Dry gas: The term “Dry gas” refers to natural gas consisting primarily of methane, and some condensable heavier hydrocarbon compounds such as propane and butane.
Natural gas: The term “Natural gas” refers to colourless highly flammable gaseous hydrocarbon consisting primarily of methane and ethane that occurs in association with crude oil.
Vacuum Gas Oil (VGO): is part of the petroleum hydrocarbon heavy distillate family. Vacuum Gas Oil also known as cat feed, which is feedstock for fluid catalytic crackers used to make gasoline, gasoil and many other by-products.
Clarified Slurry Oil (CSO): The term “Clarified Slurry Oil” refers to the heavy aromatic oil produced as a byproduct in an FCC unit, which end up in the bottoms of the fractionator.
Clarified Oil (CLO): The term “Clarified Oil” also known as Decant Oil, refers to a complex combination of hydrocarbons obtained from a catalytic cracking unit, which boils primarily above 650 F. It consists predominantly of hydrocarbons having carbon numbers predominantly in the range of C1 through C6. Clarified Oil can be recycled with FCC feed to an extent to product more lighters i.e LPG and
Gasoline.
Light Cycle Oil (LCO): The term “light cycle oil” refers to an unwanted liquid residue produced during catalytic cracking of heavy hydrocarbon fractions from earlier stages of refining.
Upgrading hydrocarbon (cracked products): The term “upgrading hydrocarbon (cracked products)” refers to reducing impurities such as coke and dry gas components from a hydrocarbon (cracked products) containing impurities.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
In refining and petrochemical industry, “fluid catalytic cracking” (FCC) is used to convert the high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils to more valuable gasoline, olefinic gases and other products. FCC process employs a highly active catalyst particles, which are dispersed in hydrocarbon vapours that are undergoing reaction (i.e. cracking) to provide valuable products such as liquefied petroleum gas (LPG) and gasoline. However, an FCC process involves highly active catalyst, short reactions times (i.e. 0.1 to 10 seconds), high temperature reactions, and complicated structures and compositions of the feedstock and products. As a result, along with catalytic cracking, various other reactions such as thermal cracking, hydrogen transfer, isomerization occur in an FCC reactor. Thermal cracking and overcracking of desired products leads to formation of low value products such as coke, clarified oil (CLO), and dry gas, which are mostly undesired byproducts of crude oil. These by-products result in low yields of LPG and gasoline, and high yields of dry gas and coke.
Therefore, development of a new FCC process for reducing the yields of low value products and increasing the yields of high value products in the area of refining and petrochemicals is of commercial interest.
Therefore, there is felt a need to provide an FCC process that mitigates the drawbacks mentioned herein above.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide a process for post-riser catalytic cracking.
Still another object of the present disclosure is to provide an apparatus for post-riser catalytic cracking.
Yet another object of the present disclosure is to provide increased yields of gasoline and LPG.
Yet another object of the present disclosure is to provide reduced yields of coke and dry gas.
Yet another object of the present disclosure is to inhibit the thermal cracking in the post-riser.
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
In a first aspect, the present disclosure provides a process for reducing dry gas and coke in FCC process. The process comprises mixing the hydrocarbon feed with a heated FCC catalyst in the bottom portion of a riser to obtain a first mixture. Hydrocarbons in the first mixture are cracked by heating the first mixture to a temperature in the range of 500 oC to 750 oC, within the riser, to obtain a spent catalyst and a second mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas and coke. The second mixture is passed to a post-riser section, which is in fluid communication with the riser, and the second mixture is contacted with an inorganic catalyst at a temperature in the range of 450?C to 580 ?C, wherein the inorganic catalyst is at least one inorganic salt selected from the group consisting of FeSO4, MgSO4 and CuSO4, and which is introduced at a predetermined location selected from the post-riser section and a conduit connecting the post-riser section and a fractionator, to obtain third mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas and coke. The combined yield of light crude oil (LCO), liquified petroleum gas (LPG), and cracked run naphtha (CRN), in the third mixture is greater by 1 to 5% in comparison with their combined yield in the second mixture, and the combined yield of dry gas and coke in the third mixture is lower by 1 to 5% in comparison with their combined yield in the second mixture.
In the step of contacting, the inorganic catalyst is at least one inorganic salt selected from the group consisting of FeSO4, MgSO4, and CuSO4.
In the step of contacting, the third mixture comprises high yields of high value gasoline range molecules and reduced yields of clarified oil, coke and/or dry gas.
The weight ratio of the FCC catalyst to Hydrocarbon feed is in the range of 4:1 to 20:1.
The hydrocarbon feed comprises at least one liquid hydrocarbon selected from the group consisting of vacuum gas oil, vacuum residue, atmospheric residue, heavy fuel oil, recycled HCO, and recycled slurry.
The FCC catalyst is at least one selected from the group consisting of ZSM-5, USY, and bottoms upgrading catalyst
The first mixture is lifted in an operative upward direction in the riser by a lift gas, wherein the lift gas is at least one selected from the group consisting of steam, hydrogen, nitrogen, krypton, argon, natural gas, and dry gas produced in the FCC process.
The cracked products further comprise at least one product selected from the group consisting of ethylene, propylene, LPG, Gasoline and light cycle oil (LCO).
The inorganic catalyst is in an amount in the range of 100 ppm to 10,000 ppm of the hydrocarbon feed.
The inorganic salt is injected as an aqueous solution having a concentration in the range of 40 wt% to 60 wt%.
The predetrmined injection point in the post-riser section is determined by the temperature of the post-riser section and the nature of the product gases formed; wherein the location is at least one selected from the group consisting of a stripper, a cyclone inlet zone, and reactor outlet line.
In the present disclosure, the step of passing further comprises a step of separating the spent FCC catalyst from the cracked products, followed by transferring the separated spent FCC catalyst to a regenerator, wherein the FCC catalyst is regenerated at a temperature in the range of 650 °C to 750 °C, and the regenrated catalyst recycled for dispersing into the atomized hydrocarbon. The the spent catalyst can be separated from the cracked products before or after contacting the cracked products with the inorganic catalyst.
In a second aspect, the present disclosure provides an apparatus for a catalytic cracking of hydrocarbon feed. The apparatus comprises a riser (8), having an operative bottom end (8a) and an operative top end (8b), a lift gas inlet (10) and a catalyst inlet (11) are configured in proximity of the operative bottom end (8a), and one or more hydrocarbon feed inlets (9) configured between the operative top end (8b) and the operative bottom end (8a) of the riser (8). Further, the apparatus comprises a post-riser (30), which is in in fluid communication with the riser (8) and houses the operative top end (8b) and a portion of the riser proximate to the operative top end (8b) defining a stripper section (7). The post-riser is also in fluid communication with a fractionator (13), the fractionator being configured to fractionate one or more products from the post-riser (30). The post-riser has, a first outlet (6) for facilitating removal of one or more products from the post-riser (30), at least one inorganic catalyst inlet configured on at least one position selected from the group consisting of the first outlet (6), a top portion of the post-riser (30) and a middle portion of the riser (24), and a second outlet (12) for facilitating removal of spent catalyst from bottom portion of the post-riser, and one or more cyclone separators (3) operatively disposed in proximity of a top end of the post-riser (23) therein. Furthermore, the apparatus comprises a regenerator (2) for regenerating the spent catalyst received from the second outlet (12), wherein the regenerated catalyst from the regenerator (2) is introduced into the riser (8) through the catalyst inlet (11).

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 an apparatus for catalytic cracking of hydrocarbons, wherein the inorganic catalyst is injected in the post-riser section of an FCC unit;
Figure 2 (Prior Art): illustrates an apparatus for catalytic cracking of hydrocarbons, wherein the inorganic catalyst is injected at a location inside the riser of the FCC unit.

Reference numbers Elements
100 An apparatus for catalytic cracking of hydrocarbons, wherein the inorganic catalyst is injected in the post-riser section of an FCC unit
200 An apparatus for catalytic cracking of hydrocarbons, wherein the inorganic catalyst is injected at a location inside the riser of the FCC unit
1 Reactor
2 Regenerator
3 Cyclone Separator
4 Cyclones
5 Outlet for Flue Gases
6 First Outlet (for removing separated mixture of cracked products)
7 Stripper section for stripping off any hydrocarbons from the spent catalyst
8 Riser
8a Operative bottom end of the Riser
8b Operative top end of the Riser
9 Hydrocarbon feed Inlet or Injection Nozzle for receiving and atomizing the hydrocarbon
10 Lift Gas Inlet for receiving lift gas
11 FCC Catalyst Inlet for receiving and dispersing an FCC catalyst into the hydrocarbon feed
12 Second Outlet for transferring the spent catalyst into a regenerator
13 Fractionator for distillation of the upgraded cracked products
14 Catalyst tank for storing aqueous solution of the inorganic catalyst
15 Catalyst pump for pumping the inorganic catalyst solution
16 Transfer line for Inorganic Catalyst
17 Riser Outlet for transferring the mixture of cracked products and the spent catalyst into a post-riser section or reactor
18 Stripping stream
19 Inlet for Air
20 Transfer line for transferring the separated mixture of upgraded cracked products to a fractionator
21 Cyclone Inlet
22 Inorganic Catalyst Inlet
23 top end of the post-riser
24 middle portion of the riser
30 post-riser section

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.
When an element is referred to as being "mounted on," “engaged to,” "connected to," or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
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.
Terms such as “inner,” “outer,” "beneath," "below," "lower," "above," "upper," and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
An FCC process involves highly active catalyst, short reactions times (i.e. 0.1 to 10 seconds), high temperature reactions, and complicated structures and compositions of the feedstock and products. As a result, along with catalytic cracking, various other reactions such as thermal cracking, hydrogen transfer, and isomerization occur in an FCC reactor. Thermal cracking and overcracking of desired products leads to formation of low value products such as coke, clarified oil (CLO) and drygas, which are mostly undesired byproducts of crude oil refining. These by-products result in low yields of LPG and gasoline, and high yields of dry gas and coke.
The present disclosure envisages a process and an apparatus for reducing dry gas and coke in FCC process.
In a first aspect of the present disclosure, the present disclosure provides an apparatus for reducing dry gas and coke in FCC process. Figure-1 illustrates an apparatus (100) for catalytic cracking in post-riser section of an FCC unit, in accordance with the present disclosure. The apparatus comprises a riser (8), having an operative bottom end (8a) and an operative top end (8b), wherein a lift gas inlet (10) and a catalyst inlet (11) are configured in proximity of the operative bottom end (8a), and one or more hydrocarbon inlets (9) configured between the operative top end (8b) and the operative bottom end (8a) of the riser (8). Further, the apparatus comprises a post-riser (30), which is in fluid communication with the riser (8) and houses the operative top end (8b) and a portion of the riser proximate to the operative top end (8b) defining a stripper section (7). The post-riser (30) is also in fluid communication with a fractionator (13), the fractionator being configured to fractionate one or more products from the post-riser (30). The post-riser has, a first outlet (6) for facilitating removal of one or more products from thed post-riser (30), at least one inorganic catalyst inlet configured on at least one position selected from the group consisting of the first outlet (6), a top portion of the post-riser (23) and a middle portion of the riser (24), and a second outlet (12) for facilitating removal of spent catalyst from bottom portion of the post-riser, and one or more cyclone separators (3) operatively disposed in proximity of a top end of the post-riser (23) therein. Furthermore, the apparatus comprises a regenerator (2) for regenerating the spent catalyst received from the second outlet (12), wherein the regenerated catalyst from the regenerator (2) is introduced into the riser (8) through the catalyst inlet (11).

The process of the present disclosure will now be described with respect to the above apparatus.
In a second aspect, there is provided a process for reducing dry gas and coke in FCC process. The process comprises mixing the hydrocarbon feed with a heated FCC catalyst in the bottom portion of a riser to obtain a first mixture. Hydrocarbons in the first mixture are cracked by heating the first mixture to a temperature in the range of 500 oC to 750 oC, within the riser, to obtain a spent catalyst and a second mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas, and coke. The second mixture is passed to a post-riser section, which is in fluid communication with the riser, and the second mixture is contacted with an inorganic catalyst at a temperature in the range of 450 ?C to 580 ?C, wherein the inorganic catalyst is at least one inorganic salt selected from the group consisting of FeSO4, MgSO4 and CuSO4, and which is introduced at a predetermined location selected from the post-riser section and a conduit connecting the post-riser section and a fractionator, to obtain a third mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas, and coke. The combined yield of light crude oil (LCO), liquified petroleum gas (LPG), and cracked run naphtha (CRN), in the third mixture is greater by 1 to 5% in comparison with their combined yield in the second mixture obtained, and the combined yield of dry gas and coke in the third mixture is lower by 1 to 5% in comparison with their combined yield in second mixture.
In the present disclosure, in an operative configuration, the hydrocarbon inlets (9), which are in the form of nozzles, receive and atomize the hydrocarbon in the riser (8). The catalyst inlet (11) receives and disperses a heated FCC catalyst into the riser. The lift gas inlet (10) receives lift gases to transport the dispersed FCC catalyst in an upwardly direction towards the receiving point of the hydrocarbon for contacting the atomized hydrocarbon with the heated catalyst to form a first mixture. The hydrocarbon in the first mixture is cracked to form a spent FCC catalyst and a second mixture comprising comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas, and coke. The suspension of the spent catalyst and the second mixture in the riser is transferred through the riser outlet (17) into the post riser section of the FCC unit.
In the present disclosure, the weight ratio of the FCC catalyst to the hydrocarbon is in the range of 4:1 to 20:1.
In the present disclosure, the hydrocarbon feed is at least one liquid hydrocarbon selected from the group consisting of vacuum gas oil, vacuum residue, atmospheric residue, heavy fuel oil, recycled HCO, and recycled slurry.
In one embodiment, the hydrocarbon feed is Vacuum Gas Oil (VGO).
In the present disclosure, the temperature of heated FCC catalyst is in the range of 650 to 750 °C.
In one embodiment, the temperature of heated FCC catalyst is 700 °C.
In one embodiment, the FCC catalyst is regenerated FCC catalyst.
In the present disclosure, the FCC catalyst is at least one selected from from the group consisting of ZSM-5, USY, and bottoms upgrading catalyst.
In one embodiment, the FCC catalyst is USY.
The lift gas is at least one selected from the group consisting of steam, hydrogen, nitrogen, krypton, argon, natural gas, and dry gas produced in the FCC process.
In one embodiment, the lift gas is steam.
In the riser, the atomized hydrocarbon in the first mixture is cracked by contacting with FCC catalyst, at a temperature in the range of 500 oC to 750 oC, into high value gasolene range products, and the FCC catalyst is spent due to the deposition of coke to provide a suspension of spent FCC catalyst and a second mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas, and coke. The suspension of the spent catalyst and the second mixture exits the riser (8) through the the riser outlet (17) and enters a post riser section of the FCC unit.
In one embodiment, the hydrocarbons in the first mixture are cracked at a temperature of 530 oC.
In the present disclosure, the spent catalyst and the second mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas, and coke is passed from the riser to a post-riser section, which is in fluid communication with the riser.
In the post riser section of the FCC unit, the suspension of the spent catalyst and the second mixture is first received in the stripper section (7), which separates the spent FCC catalyst from the second mixture by stripping off second mixture from the spent catalyst with a stripping stream (18) to provide a separated spent FCC catalyst and separated second mixture. In next step in the post riser section, the separated second mixture is transferred into the cyclone separator (3), which retrieves any residual spent catalyst from the second mixture and transfers the residual spent catalyst to the stripper (7).
In the present disclosure, in the post riser section of the FCC unit, the second mixture is contacted with an inorganic catalyst by injecting the inorganic catalyst into the post-riser section of the FCC unit, at a predetermined point, at a temperature in the range of 450 to 580 °C , to obtain third mixture comprising light crude oil (LCO), liquified petroleum gas (LPG), cracked run naphtha (CRN), dry gas, and coke. The combined yield of light crude oil (LCO), liquified petroleum gas (LPG), and cracked run naphtha (CRN).
The predetrmined injection point in the post-riser section is determined by the temperature of the post-riser section and the nature of the product gases formed.
The location of the predetrmined injection point in the post-riser section is at least one selected from the group consisting of a stripper (7), a cyclone inlet zone (21), and a reactor outlet (6).
The catalyst injection system comprises a catalyst tank (14) for storing aqueous solution of the catalyst, a catalyst pump (15) for pumping the catalyst solution and a conduit for delivering the catalyst to the designated catalyst injection point.
The catalyst tank (14) stores the aqueous solution of the catalyst, which is pumped using a catalyst pump (15) though a conduit for delivering the catalyst to the designated catalyst injection point in the post-riser section, at a rate in the range of 100 to 10000 ppm, at a pressure in the range of 1 to 10 bar.g, at a temperature in the range of 450 to 580 °C
In one embodiment, the predetermined catalyst injection point for delivering the inorganic catalyst is stripper (7).
In the step of contacting, the second mixture is contacted with an inorganic catalyst in an amount in the range of 100 ppm to 10,000 ppm of the hydrocarbon feed introduced in the riser.
In one embodiment, the second mixture is contacted with 1000 ppm of an inorganic catalyst with respect to the hydrocarbon feed introduced in the riser.
In the step of contacting, the second mixture is contacted with an inorganic catalyst at a temperature in the range of 450 ?C to 580 ?C.
The inorganic catalyst is at least one inorganic salt selected from the group consisting of FeSO4, MgSO4 and CuSO4.
In one embodiment, the inorganic catalyst is MgSO4.
In the step of contacting, the inorganic catalyst is injected in the post-riser section, as an aqueous solution having a concentration in the range of 40 wt% to 60 wt%.
In one embodiment, in the step of contacting, the inorganic catalyst is an aqueous solution having 50 wt% concentration.
In the present disclosure, the spent catalyst from the second mixture can be separated from the second mixture, before or after contacting the second mixture with an inorganic catalyst.
The step of passing the second mixture to a post-riser section, further comprises a step of separating the spent FCC catalyst from the second mixture to obtain separated spent catalyst and separated second mixture, and the separated second mixture is contacted with the inorganic catalyst at 530 °C, in the post-riser section to obtain a third mixture.
In one embodiment of the present disclosure, the spent FCC catalyst is separated from the second mixture to obtain separated spent catalyst and separated second mixture and the separated second mixture is contacted with the inorganic catalyst at 530 °C, in the stripper section of the post-riser to obtain a third mixture.
In the step of contacting, the third mixture comprises higher yields of high value gasoline range molecules comprising light crude oil (LCO), liquified petroleum gas (LPG), and cracked run naphtha (CRN).
The process of catalytic cracking of the present disclosure, the third mixture comprises reduced yields of dry gas and coke.
The step of contacting, further comprises a step of separating the spent FCC catalyst from the second mixture, followed by transferring the separated spent FCC catalyst to a regenerator, wherein the FCC catalyst is regenerated at a temperature in the range of 650 °C to 750 °C, and the regenerated catalyst is recycled for mixing with the hydrocarbon feed; wherein the spent catalyst can be separated from the cracked products before or after contacting the cracked products with the inorganic catalyst.
The separated spent catalyst containing un-strippable coke from the stripper is transferred through second outlet (12) to the regenerator (2), which regenerates the FCC catalyst by heating the separated spent FCC catalyst to burn the coke using air (19), and recycle the regenerated FCC catalyst back to the riser (8), though the catalyst inlet (11).
In the post-riser section, the first outlet (6) facilitates removal of the third mixture into the fractionator (13), which fractionates one or more cracked products from the post-riser to separate into purified products.
The third mixture is fractionated by distillation to obtain fractions of purified products.
Therefore, the catalyst composition of the present disclosure provides benefits of long service life, thereby avoiding the frequent catalyst replacement and generation of huge solid waste. Further, the spent catalyst composition can be easily regenerated and efficiently used for converting bottoms into useful gasoline like products.
The present disclosure provides an inorganic catalyst comprising an inorganic salt for converting a high-molecular weight hydrocarbon bottom fraction into gasoline and for minimizing undesired low value products such as coke, clarified oil (CLO), and dry gas.
The inorganic catalyst of the present disclosure is effectively used in an FCC process, for selectively increasing the yields of high value molecules such as LPG and gasoline by catalytically cracking the low value by-products such as clarified oil (CLO), and for suppressing the thermal cracking of the high value products (LPG and gasoline) in the post riser section/zone, thereby reducing the yields of low value products such as coke, and dry gas.
The better performance of the catalyst composition is due to injection of the catalyst of the present disclosure at a predetermined point of injection in the post-riser section of the FCC unit. The designated point of injection is selected based on the temperature, and the product gases formed in the FCC process.
On the other hand, injection of the catalyst just above the hydrocarbon inlet zone in the riser section of the FCC unit increases the thermal crackbility of the hydrocarbon, thereby increasing the yields of low value products such as dry gases and coke.
Thus, injection of the catalyst just above the hydrocarbon inlet zone in the riser section of the FCC unit reduces the crackbility of the hydrocarbon, thereby decreasing the yields of high value gasoline range molecules such as LPG and gasoline.
The predetermined catalyst injection point for delivering the inorganic catalyst is selected from the group consisting of stripper (7), cyclone inlet zone (21), and reactor outlet (6).
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 and the results obtained can be extrapolated to industrial scale.

Experimental details
Comparative Experment 1:– Conventional FCC reaction without addition of the inorganic catalyst
Catalytic cracking of vacuum gas oil (VGO) feed was carried out at atmospheric pressure, at 530 °C in a fluidized bed reactor, at a feed rate of 2.5 g/min, without addition of the inorganic catalyst of the present disclosure in the post-riser section/zone.
The experimental results at 69% conversion levels are summarized in Table-1.
Comparative Experiment 2: Conentional FCC reaction comprising injection of the catalyst (inorganic salt) in the riser (just above hydrocarbon feed inlet)
Catalytic cracking of vacuum gas oil (VGO) feed was carried out at atmospheric pressure, at 530 °C in a fluidized bed reactor, at a feed rate of 2.5 g/min. MgSO4 (50 wt% aqu. soln.) was injected at the rate of 1000 ppm of the VGO feed, just above the VGO feed inlet in the riser section/zone.
The experimental results at 69% conversion levels are summarized in Table-1.
Experiment 3: FCC process comprising injection of the catalyst (inorganic salt) in the post-riser section of the FCC unit, in accordance with the present disclosure
Catalytic cracking of vacuum gas oil (VGO) feed was carried out at atmospheric pressure, at 530 °C in a fluidized bed reactor with feed rate of 2.5 g/min, MgSO4 (50 wt% aqu. soln.) was injected at the rate of 1000 ppm of the VGO feed, in the top zone in the post riser section/zone.
The experimental results at 69% conversion levels are summarized in Table-1.
Table-1: Experimental results of conventional FCC reaction and FCC reaction with post riser catalytic cracking having same conversion level
Attribute Units Comparative Experiment 1 Comparative Experiment 2
(1000 ppm catalyst injection just above the feed inlet) Experiment 3
(1000 ppm catalyst injection at reactor top zone)
Temperature °C 530 530 530
Pressure Bar.g Atm Atm Atm
Yield Pattern
Gas wt% 2.08 2.20 1.87
LPG wt% 11.71 11.58 11.78
CRN wt% 49.28 49.12 49.52
LCO wt% 17.20 16.80 19.18
CLO wt% 13.80 14.20 11.82
COKE wt% 5.93 6.10 5.83
Total wt% 100.00 100.00 100.00
Conversion wt% 69.00 69.00 69.00

It is clearly seen from Table-1, that the injection of the liquid inorganic catalyst in the post riser section of the FCC unit of the present disclosure in Example 3 of the present disclosure, improves the yield of gasoline, LPG, and CRN while minimizing the amount of coke and Dry gas, in comparison with the conventional FCC reaction in comparative Example-1, which provide lower yield of gasoline while providing increased amounts of coke and dry gas.
It is clearly seen from Table-1, that the injection of the liquid catalyst in the post riser section of the FCC unit of the present disclosure in Example 3 of the present disclosure, improves the yield of gasoline, LPG, and CRN while minimizing the amount of coke and Dry gas, in comparison with FCC catalytic cracking carried out by injection of the liquid catalyst in the riser section of the FCC unit of the present disclosure in Example 2 of the present disclosure, which reduces the crackability of the hydrocarbon and provides lower yield of gasoline while providing increased amounts of coke and dry gas.
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.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of:
- a process that improves the yield of gasoline, and LPG;
- a process for lowering the yields of coke and bottoms such as clarified oil (CLO); and
- a process for suppressing thermal craking in the post riser.
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 a 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.