Patent Application
20250236798
The present disclosure generally relates to the petrochemical industry, and in particular to an integrated process or system for enhancing petrochemical feedstock.
In the conventional fluid catalytic cracking (FCC) process, the cracked product stream from the reactor section is separated in the main fractionation column into various cuts, which are overhead wet gas, cycle oil (light and/or heavy middle distillate) and clarified oil depending on the configuration. The overhead wet gas stream containing off-gases, LPG, gasoline, and water, is separated into condensed liquid and uncondensed vapors by cooling. The condensed liquid and uncondensed vapors are sent to a reflux drum, where the uncondensed vapors, which consist of off gases and liquefied petroleum gas (LPG), are separated from the mixture. A part of the liquid that is unstabilized gasoline is sent as reflux in the main fractionator, while the other part is routed to the primary absorber. Condensed water is separated via the boot of the reflux drum. Off-gases are further removed from uncondensed vapors via compression and cooling method. The dry gas thus obtained generally contains a substantial amount of C3+ components, which are further processed in a series of absorption columns, such as primary and secondary absorption columns. The gasoline and middle distillate cuts are used as the absorbing media in these columns for recovering valuable C3+ hydrocarbon components. Further, the gasoline and LPG mixture are then set to a C2 stripper to remove any traces of dissolved off-gases. Gasoline and LPG are thereafter separated in a depentanizer column. LPG is further separated in a depropanizer column, where it gets separated into C3 and C4 fractions from top and bottom, respectively. The bottom C4 stream is routed to the oligomerization reactor for production of the oligomer products. The oligomer products stream is partially or fully recycled to the FCC feed to increase the olefins production or HP separator to augment the gasoline production.
U.S. Pat. No. 6,049,017 discloses an improved method for the production of ethylene and propylene from a heavier olefin feedstock generated from steam crackers that contains mixed olefins, paraffins, and dienes having C4 to C12 hydrocarbons. The dienes were selectively hydrogenated into mono-olefins via conventional processes, and further generated mono-olefins were converted to respective ethers via conventional etherification process. The unconverted butylenes and heavier hydrocarbon streams with less iso-olefins were sent to the catalytic cracking process, which consists of a specially formulated non-zeolite based catalyst with a pore size less than 5 Angstroms, which is selected from the group of SAPO-34, SAPO-11, and SAPO-17 at temperature of 460-700° C., pressure of 140-700 kPa and 0.05-10 h−1 of space velocity to produce ethylene and propylene. The unconverted stream from the catalytic cracking unit was partially recycled to maximize the yield of ethylene and propylene, and the remaining part of the stream was routed to the conventional oligomerization process. According to this invention, the product streams from the catalytic cracking process, which consists of unconverted C4-C5, were separated through a fractionation column for further oligomerization.
In U.S. Pat. No. 7,374,662, propylene yield was maximized in fluid catalytic cracking via a mix feed stream that comprises at least 50% of the heavy main feedstock, typically vacuum distillate with a boiling point above 350° C. and a mixture of gasoline range products collected from the oligomerization reactor, which is in the downstream configuration with the FCC, typically consists of C4-C10 olefins for maximization of propylene yield. According to this invention, the steam cracked products were selectively hydrogenated, and the C4-C5 olefins were recovered using fractionation column and oligomerized. The product effluent, which consists of C7-C10 from the oligomerization reactor, was mixed with the vacuum distillate feedstock in different ratios and fed to the conventional catalytic cracking reactors. According to one of the examples given in the invention, when 22 wt % of oligomer products were used in the FCC feed stream mixed with vacuum distillate, propylene yield increased by 11.1%.
In U.S. Pat. No. 8,128,879, a method is provided to convert FCC olefins to heavier compounds. According to this invention, off-gases, typically C2, from the gasoline product stream obtained from the FCC fractionator column were removed in a two-stage absorber. Further, C3+ streams were routed to the fractionator column, where C3-C5 streams were separated from the top section and C5+ streams were separated from the bottom section. These C3-C5 streams were further fractioned in a separate column to recover C3 from the top of the fractionation column. A C4-C5 rich stream from the fractionator bottom was routed into the conventional oligomerization or alkylation unit for further processing.
In US Patent No. 2014/0170028A1, a method is given for recovering a C4/C5 stream by fractionation of the FCC product stream and then oligomerizing C4 components using a zeolite/solid phosphoric acid catalyst in a series of reactors with a pre-treating section. In this invention, the product stream from the FCC was first split in the primary fractionator, where the naphtha stream was separated out and sent to the primary and secondary absorber. Further, naphtha stream thus obtained was sent to the depentanizer column to remove C5+ components. The top stream from this column is sent to depropanizer to separate out C4/C5 components. These C4/C5 components are sent to the feed treating section to remove impurities and then fed to oligomerization reactors in series. The product from oligomerization reactors is separated in the fractionation column and recycled back to FCC feed.
In U.S. Pat. No. 9,567,267, a technique for the oligomerization of the cracked C4-C5 streams that is obtained from conventional FCC processes is provided. According to this invention, the product stream, which comprises C4-C5 streams, obtained from the FCC unit via conventional purification and separation techniques that involve absorbers and a series of splitter columns, was sent to the oligomerization section, which is in downstream configuration with the FCC. The feed streams for the oligomer reactor were first desulfurized, selectively hydrogenated, and treated to remove mercaptan sulfur, diolefins, and nitrile impurities, respectively. The product from the oligomerize section was first separated into a debutanizer column to remove unconverted C4. The bottom stream is further separated into the C5 and C5+ fractions. C5 components were thus separated and then recycled back to the oligomerization reactor inlet to maintain the liquid phase in the reactor and control exothermicity. The C5+ product stream is further separated in a splitter to separate the diesel range product.
In the existing FCC processes, the cracked product stream from the reactor is separated into different cuts, such as off gases, LPG, gasoline, cycle oil (or middle distillate), and slurry oil, in the main fractionator followed by gas concentration section. The off-gases obtained consist of valuable C3+ hydrocarbon components. The typical values of C3+ components in the off-gases stream lie in the range of 0-10 wt %. These valuable hydrocarbons in the off-gases stream are generally used as fuel gas in the refinery, which is a substantial loss in terms of the cost of these hydrocarbons. Thus, there is a need to provide a process or system that recovers C3+ components in the off-gases stream.
This summary is provided to introduce a selection of concepts in a simplified format that are further described in the detailed description of the invention.
In a first aspect of the present disclosure, there is provided a process for integrating oligomerization of C4 hydrocarbon components and fluid catalytic cracking (FCC) for enhancing the recovery of C3+ hydrocarbon components from FCC off-gases, the process comprising:
In another aspect of the present disclosure, there is provided a system for integrating oligomerization of C4 hydrocarbon components and fluid catalytic cracking (FCC) for enhancing the recovery of C3+ hydrocarbon components from FCC off gases, the system comprising:
These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present disclosure, the inventions of which can be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
Further, the skilled in the art will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale.
Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps of the process, features of the invention, referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.
Definitions: For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are collected here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person skilled in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.
The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of elements or steps but not the exclusion of any other element or step or group of elements or steps.
As used in this disclosure, C1-C12 hydrocarbon components refer to C1 to C4 gaseous hydrocarbons at standard temperature and pressure (STP) conditions including methane, ethane, ethylene, propane, propylene, isobutane, n-butane, isobutylene, butene-1, cis-2-butene, trans-2-butene, 1,3 butadiene; and C5 to C12 liquid hydrocarbons at STP condition of paraffinic, naphthenic, olefinic and aromatic nature having a final boiling point (FBP) of 210° C.
As used in this disclosure, C5+ to C12 hydrocarbon components refer to C5-C12 liquid hydrocarbons at STP condition of paraffinic, naphthenic, olefinic and aromatic nature having FBP of 210° C.
As used in this disclosure, C5-hydrocarbons components refer to methane, ethane, ethylene, propane, propylene, isobutane, n-butane, isobutylene, butene-1, cis-2-butene, trans-2-butene, and 1,3 butadiene.
As used in this disclosure, C3+ hydrocarbon components refer to C3-C4 gaseous hydrocarbons at STP conditions including propane, propylene, iso-butane, n-butane, isobutylene, butene-1, cis-2-butene, trans-2-butene, 1,3 butadiene; and C5-C12 liquid hydrocarbons at STP condition.
As used in this disclosure, C2 hydrocarbon components refer to ethane and ethylene.
As used in this disclosure, C3 hydrocarbon components refers to propane and propylene; and C4 hydrocarbon components refer to n-butane, iso-butane, isobutylene, butene-1, cis-2-butene, trans-2-butene, and 1,3 butadiene.
As used in this disclosure, Olefinic C4 hydrocarbon components refer to isobutylene, butene-1, cis-2-butene, trans-2-butene, and 1,3 butadiene.
As used in this disclosure, C8+ hydrocarbon components refer to 244 tri-methyl pentene-1, 244 tri-methyl pentene-2 and other isomers of C8 olefins, tri-isobutylene, and tetra-isobutylene.
As used in this disclosure, clarified oil refers to hydrocarbons having boiling point more than 370° C.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference. The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products and methods are clearly within the scope of the disclosure, as described herein.
The present disclosure provides a process and a system for enhancing the petrochemical feedstock. The process scheme integrates the conventional fluid catalytic cracking (FCC) and oligomerization processes. According to the present disclosure, the product stream from the oligomerization reactor is recycled to the secondary absorber for the absorption of the valuable C3+ components from the off-gases stream. The rich oligomer product with absorbed C3+ components from the secondary absorption column is either routed to the FCC feed section or HP separator. The off-gases stream from this secondary absorption column is further treated in the absorption column with total cycle oil obtained from the main fractionator as an absorbing medium.
Problem being addressed by the present disclosure. FCC process disclosed in the prior literature provides that the cracked product stream from the reactor is separated into different cuts such as off gases, liquefied petroleum gas (LPG), gasoline, cycle oil (or middle distillate), and clarified oil, in the main fractionator followed by gas concentration section. The off-gases obtained consist of valuable C3+ hydrocarbon components. The typical values of C3+ components in the off-gases stream lie in the range of 0-10 wt %. These valuable hydrocarbons in the off-gases stream are generally used as fuel gas in the refinery, which is a substantial loss in terms of the cost of these hydrocarbons. The present disclosure provides a way to recover C3+ components in the off gases stream.
In the present disclosure, the product stream from the oligomerization reactor is routed to an absorption column where it recovers valuable C3+ hydrocarbon components from the off-gases stream.
The inventive feature of the present disclosure is the use of the oligomer products for the recovery of valuable C3+ hydrocarbon streams. The oligomer product stream has better absorption capacity for C3+ hydrocarbon components in comparison to the gasoline. Due to this, the oligomer products are used as an absorbent medium in a separate absorption column to recover the valuable hydrocarbons from the off-gas stream. In another embodiment of the present disclosure, the oligomer product stream is mixed with stabilized gasoline for absorption of C3+ hydrocarbon components, which resulted in better recovery of C3+ hydrocarbon components from off-gases stream considering the constant liquid flow in the absorption column. Additionally in one of the embodiments of the present disclosure, the C3+ rich oligomer product stream is recycled back to FCC feed which upon cracking resulted in an incremental yield of propylene.
The scheme of the present disclosure provides the following technical advantages over the conventional process disclosed in the prior literature.
In a first aspect of the present disclosure, there is provided a process for integrating oligomerization of C4 hydrocarbon components and fluid catalytic cracking (FCC) for enhancing the recovery of C3+ hydrocarbon components from FCC off-gases, the process comprising:
In an embodiment of the present disclosure, wherein the intermediate stream (215) obtained from the main fractionator (102) comprising the middle distillate cut is routed to a stripper column (111) and contacted with steam to strip off lighter components and a heavier stream, wherein the lighter components are routed back to the main fractionator (102), and the heavier stream comprising stabilized cycle oil after cooling is partially routed to the second absorber column (104) via the first stream (219) and partially withdrawn as a product via a second stream (220).
In an embodiment of the present disclosure, wherein the lighter cut obtained from the main fractionator (102) comprises gases and C1-C12 hydrocarbon components, wherein the middle distillate cut obtained from the main fractionator (102) is a total cycle oil, and wherein the heavier hydrocarbon obtained from the main fractionator (102) is a clarified oil.
In an embodiment of the present disclosure, wherein the unstabilized gasoline of the liquid stream (246) comprises majorly C5+ to C12 hydrocarbon components and some C5-hydrocarbons components.
In an embodiment of the present disclosure, wherein the top off-gases stream (226) still comprises some C3+ hydrocarbon components.
In an embodiment of the present disclosure, wherein the top liquefied petroleum gas stream (234) comprises mainly C3 and C4 hydrocarbon components.
In an embodiment of the present disclosure, wherein the overhead stream (237) comprises mainly C3 hydrocarbon components, and the bottom stream (238) comprises mainly C4 hydrocarbon components.
In an embodiment of the present disclosure, wherein the bottom stream (238) comprises paraffinic and olefinic C4 hydrocarbons, and wherein the olefinic C4 hydrocarbon components of the bottom stream (238) is oligomerized in the oligomerization reactor (109).
In an embodiment of the present disclosure, wherein the process further comprising:
In an embodiment of the present disclosure, wherein the catalyst is supplied from a regenerator (101) of the fluid catalytic cracking unit, and the catalytic cracking is performed in a continuous fluidized bed reactor at a riser top temperature in a range of 530° C. to 600° C., a catalyst to oil ratio of 10:1 to 25:1, and a catalyst contact time in a range of 1-10 seconds.
In an embodiment of the present disclosure, wherein the fractionation is performed at a bottom pressure in a range of 1 to 5 bar, a top temperature in a range of 100° C. to 135° C., and a bottom temperature in a range of 300° C. to 400° C.
In an embodiment of the present disclosure, wherein the recovery in the primary absorber (103), the second absorber column (104), and the third absorber column (105) is performed at a top pressure in a range of 10 to 17 bar, a top temperature in a range of 30° C. to 60° C., and a liquid to gas actual volume ratio in a range of 0.05:1 to 0.25:1.
In an embodiment of the present disclosure, wherein the hydrocarbon feed stream (210) comprises vacuum gas oil, resid oil fraction, or a combination thereof.
In an embodiment of the present disclosure, wherein the cooling is carried out through a condenser.
In another aspect of the present disclosure, there is provided a system for integrating oligomerization of C4 hydrocarbon components and fluid catalytic cracking (FCC) for enhancing the recovery of C3+ hydrocarbon components from FCC off gases, the system comprising:
In an embodiment of the present disclosure, wherein the system further comprises:
In an embodiment of the present disclosure, wherein the system further comprises:
In an embodiment of the present disclosure, wherein the system further comprises:
In an embodiment of the present disclosure, wherein the main fractionator (102) is a distillation column, wherein the distillation column is employed with a plurality of trays, random packing, structured packing or a combination thereof, and wherein the distillation column is employed with one or more pump-arounds.
In an embodiment of the present disclosure, wherein the fluid catalytic cracking unit is located upstream of the main fractionator (102), wherein the primary absorber (103), the second absorber column (104), and the third absorber column (105) are located downstream of the main fractionator (104), and wherein the oligomerization reactor (109) is located upstream of the third absorber column (105).
In an embodiment of the present disclosure, wherein the lighter cut of the top stream (212) referred to as wet gas. It comprises water vapor; gases including carbon monoxide, carbon dioxide, nitrogen, oxygen, hydrogen sulfide and hydrogen; and C1-C12 hydrocarbons.
In an embodiment of the present disclosure, wherein vapor stream (222) refers to water vapor; gases like carbon monoxide, carbon dioxide, nitrogen, oxygen, hydrogen sulfide, and hydrogen; C1 to C4 gaseous hydrocarbons at STP conditions, and C5-C12 liquid hydrocarbons at STP conditions.
In an embodiment of the present disclosure, wherein the aqueous stream (242) comprises water and dissolved hydrogen sulfide.
In an embodiment of the present disclosure, wherein the unstabilized gasoline (246, 213, 214) comprises mainly C5-C12 liquid hydrocarbons along with gases like carbon monoxide, carbon dioxide, nitrogen, oxygen, hydrogen sulfide, and hydrogen; and C1 to C4 gaseous hydrocarbons.
In an embodiment of the present disclosure, wherein the off-gases stream (232) comprises gases including carbon monoxide, carbon dioxide, nitrogen, oxygen, hydrogen sulfide and hydrogen; and C1-C12 hydrocarbons.
In an embodiment of the present disclosure, wherein the lighter components refer to gases including carbon monoxide, carbon dioxide, nitrogen, oxygen, and hydrogen; and methane.
In an embodiment of the present disclosure, wherein the bottom stabilized gasoline stream (235) comprises C5-C12 liquid hydrocarbons with C4 hydrocarbon components in the range of 0-2 wt %.
In an embodiment of the present disclosure, wherein the stabilized cycle oil (from the stripper column) refers to hydrocarbons that have a boiling point in the range of 210° C. to 370° C.
In a first aspect of the present disclosure, a process scheme is proposed between FCC and oligomerization process as given in
The top stream from the main fractionator after cooling in a condenser separated into vapor (222) and liquid stream (246) in the reflux drum (112). An aqueous stream (242) is also removed after cooling from the boot of the reflux drum (112). The vapor stream (222) compressed in a compressor (113) followed by cooling in a condenser to condense the heavier hydrocarbons which are separated in a HP separator (114). The liquid stream (246) from the reflux drum is partially routed back to the main fractionators as the reflux stream (213). This liquid stream obtained after cooling contains soluble lighter C5-components. Another part of this stream (214) is often termed as unstabilized gasoline and sent to primary absorber (103). Primary absorber is an absorption column employing trays or packing with or without one or more intermediate pump-arounds. The off gases from the HP separator comprises C3+ hydrocarbon components. A part of the unstabilized gasoline (214) and stabilized gasoline stream (224) are used to absorb these components. The bottom liquid stream (225) from the primary absorber is fed to HP separator (114). The liquid stream (230) from the HP separator drum is then fed to C2 stripper (106) where H2S, C2 hydrocarbon components and other lighter components are stripped off. The heat of stripping is supplied through a reboiler. Steam or any other appropriate high temperature stream is used as heating medium. The bottom stream (233) from C2 stripper is then fed to the stabilizer column (107) to separate LPG and gasoline. A part of the bottom stream (235) from this column is taken as stabilized gasoline product (236) while a part of this stabilized gasoline stream (224) is recycled back to primary absorber. The stabilizer column is a distillation column with trays or structure packing or a combination thereof, and employs overhead condenser and bottom reboiler to maintain vapor-liquid flow. The overhead stream (234) referrers as LPG comprising predominantly C3 and C4 hydrocarbon components. This LPG stream is sent to a C3/C4 splitter column (108) which is a distillation column with trays or structure packing or a combination thereof, and employs overhead condenser and bottom reboiler to maintain vapor-liquid flow. The overhead stream (237) from this column comprises predominantly C3 hydrocarbon components while the bottom stream (238) from this column comprises predominantly C4 hydrocarbon components. This bottom stream (238) constitutes the feed for the oligomerization reactor (109). In the oligomerization reactor, C4 olefins present are converted into C8+ oligomers. The oligomerization reactor employs an oligomerization catalyst to convert C4 olefins to oligomer products, wherein the catalyst is a polymer based cation exchange resin. The oligomerization reactor is operated at 60-90° C. temperature, 10-16 bar pressure and liquid hour space velocity of 0.5-15 h−1. In an aspect, one or more oligomerization reactors may be employed to improve the conversion of C4 olefins into oligomer product. The reactor product (239) is fed to the product separation column (110) where unconverted C4 is recovered from the top stream (240) while the oligomers product is obtained from the bottom stream (241). A part of the unconverted C4 stream may be recycled back to the reactor inlet to control the exothermicity in the reactor.
The off gases stream from the top of primary absorber (226) is divided into two parts; the first part of the off gases stream (244) is fed to the second absorber column (104) while the second part of the off gases stream (243) is fed to the third absorber column. These second and third absorption columns are used to recover the C3+ hydrocarbon components present in the off gases stream (226). The off gases are divided in these columns such that the liquid to gas ratio based on actual volume is in the range of 0.05:1 to 0.25:1 in both of these columns. A part of the cooled TCO stream (219) and the cooled oligomerize product stream from the product separation column (110) are used as absorption medium in the second and third absorption columns, respectively. The liquid bottom stream (216) from the second absorption column is again fed to the main fractionator (102). The bottom liquid stream (228) from the third absorber column is routed to the feed of the FCC riser (100) or entered in the FCC riser (100) through a separate feed injector located at a different elevation from the conventional feed injector.
In another aspect of the present disclosure,
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible.
The disclosure will now be illustrated with working examples, which are intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice of the disclosed methods, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary. Person skilled in the art will be aware of the fact that the present examples will further subject to variations and modifications specifically described herein based on the technical requirement of the experiment and shall not be limiting what specifically mentioned.
In accordance with the disclosed embodiments provided in the detailed description, absorption experiments are performed within an autoclave utilizing a synthetic mixed gas stream designed to replicate the composition of typical commercial Fluid Catalytic Cracking (FCC) off-gases, as outlined in Table 1. The absorbing medium employed for comparative analysis of absorption capacities, specifically in terms of the recovery of valuable C3+ components from the off-gas stream, comprises a conventional commercial oligomer product stream and an FCC stabilized gasoline stream. The compositions of the commercial oligomer product and FCC stabilized gasoline stream are detailed in Table 2.
This example elucidates the absorption capacity of two distinct absorbing mediums in accordance with the present disclosure—namely, commercial oligomer products and FCC stabilized gasoline. The comparison is conducted utilizing the pressure decay method to assess the absorption rates of valuable C3+ hydrocarbon components within the off-gases. The experiments were executed within a 600 ml stainless steel autoclave reactor. Initially, 100 ml of the absorbing medium was introduced into the autoclave reactor and purged with an inert gas, such as nitrogen, to eliminate trapped air. Subsequently, a synthetic mixed gas stream, at a pressure slightly higher than atmospheric pressure, was introduced. The autoclave reactor was then maintained at 40° C. with constant stirring at 0.7 rev/min. Upon temperature stabilization, the synthetic mixed gas stream was added to the reactor until the system pressure reached 10 bar. The pressure decay over time, employing different absorbing mediums, was recorded until the pressure drop in the autoclave reactor ceased. The final pressure inside the reactor at this point was denoted as the equilibrium pressure.
This example further illustrates quantitatively the absorption capacity of two different absorbing mediums as per the present disclosure, i.e., commercial oligomer products and FCC stabilized gasoline, to compare the recovery of the valuable C3+ hydrocarbon components present in the off-gases by using these absorbing mediums in the absorption column. The experiments were performed similarly to the procedure mentioned in Example 1. The absorption of valuable C3+ hydrocarbon components started, and consequently, the autoclave pressure gradually dropped. As the absorption proceeds, the pressure dropped in the autoclave reduces with time. Once the pressure drop approached zero, it was inferred that the absorption experiment had reached completion. The residual gas mixture within the autoclave reactor was subjected to analysis using a gas chromatograph equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD), the recovery of valuable components by the absorbing medium was calculated, and the results are detailed in Table 3. The findings indicate an additional 23.7% recovery of C3+ hydrocarbon components from the synthetic mixed gas when utilizing commercial oligomer products, in comparison to FCC stabilized gasoline.
This example illustrates the advantage of co-processing of commercial oligomer product stream (3 wt % and 6 wt %) in the FCC riser along with the conventional feed in terms of increase in the yield of propylene. The experiments are conducted using a conventional FCC catalyst evaluated in the standard fixed bed Micro Activity Test (MAT) reactor described as per ASTM D-3907 with minor modifications indicated subsequently as a modified MAT test. 7 g of the catalyst is loaded in the reactor and placed in a furnace. The reactor is heated to 570° C. and purged with nitrogen for at least 30 min for the pre-conditioning. Feed is introduced into the reactor for a very short contact time of 70 s. The yield pattern obtained is given in Table 4. As evident from the results, there is an increase in the yield of propylene by 0.54 wt % and 0.91 wt % while co-processing 3 and 6 wt % oligomer product in conventional FCC feed.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in the constructions set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense. The invention has been described with reference to preferred and alternate embodiments. Modifications and alterations will become apparent to those skilled in the art upon reading and understanding the detailed discussion of the invention provided herein. This invention is intended to include all such modifications and alterations insofar as they come within the scope of the present invention. These and other modifications of the preferred embodiments as well as other embodiments of the invention will be obvious from the disclosure herein, whereby the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.
Finally, to the extent necessary to understand or complete the disclosure of the present invention, all publications, patents, and patent applications mentioned herein are expressly incorporated by reference therein to the same extent as though each were individually so incorporated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202421004157 | Jan 2024 | IN | national |
