Patent Application
20230227738
The present invention relates to a process of converting crude oil to produce petrochemical feedstocks such as light olefins and aromatics. More particularly, the present invention relates to a processing scheme involving integrating Desalter unit, Atmospheric and vacuum column, high severity FCC process, Naphtha cracking process, residue slurry hydrocracking process, Delayed coking process, Selective mild hydrocracking aromatic production unit, Dehydrogenation units, Aromatic/olefin recovery section, gasifier unit along with syngas to olefins conversion section.
U.S. Pat. Nos. 7,550,642B2 and 8,658,022B2 describes olefin production process utilizing whole crude oil/condensate as feedstock using thermal cracking process. Here the feed is sent to a vaporization step other than distillation, thereby producing a vaporous output and a liquid bottoms fraction and the vaporous output is fed to cracking furnace in presence of steam. In the later patent, liquid bottom fraction is sent to a hydro processing unit for further conversion.
U.S. Pat. No. 9,290,705B2 describes a process in which crude oil feedstock having total metals (Ni+V)<5 ppm and CCR <5 wt % is fractionated into a low boiling fraction & a high boiling fraction. The low boiling fraction is catalytically cracked in a first downflow reaction zone & high boiling fraction is catalytically cracked in a second downflow reaction zone of fluid catalytic cracking unit, having a common catalyst regeneration system.
U.S. Pat. No. 9,550,707B2 describes an integrated process involving atmospheric and vacuum distillation units, catalytic cracking unit, coker unit and reforming unit. Here the crude oil is routed to ADU & VDU for separation to gas fraction, liquid fraction, vacuum gas oil fraction and a vacuum residuum fraction. Vacuum gas oil fraction is routed to catalytic cracking unit and vacuum residue to coker unit. Liquid fraction from VDU, catalytic cracker & delayed coker and C3 paraffins, C4 paraffins are routed to steam cracker.
U.S. Pat. No. 10,259,758B2 describes a process installation to convert crude oil into petrochemical products comprising of a CDU, where it is separated into gases fraction, resid, kerosene and gasoil. The resid fraction is send to resid upgradation unit and the gas oil is routed to fluid catalytic cracking unit. The distillate from resid unit along with kerosene and gasoil stream is send to aromatic ring opening unit and LPG produced in the integrated process is send to olefin synthesis unit for production of lighter olefins.
US2013/0292299 describes an integrated ebullated bed and hydrotreater for whole crude oil upgrading. The crude oil is first flashed into lighter components which are sent for hydrotreating in a fixed bed hydrotreater unit. The heavy atmospheric residue is hydrotreated in an ebullated bed hydrotreater reactor. Distillates from the hydrotreater and unconverted residue from ebullated bed reactions are combined to form a synthetic crude oil stream.
WO2014/062465 describes a process for high severity catalytic cracking of crude oil. The crude oil is separated into high boiling fraction and low boiling fraction and are separately processed in two downer type of reactors. The deactivated catalyst from both vessels are regenerated in a common regenerator vessel.
US 2015/0321975 provides a process for producing aromatics from a hydrocarbon source in the presence of supercritical water. Supercritical water is used as an alternate to catalysts, which are not stable at these conditions. The dominant source of BTX aromatics are heavy aromatic compounds with single aromatic core with alkyl side chains.
US2013/0197284 describes an integrated hydrotreating, solvent deasphalting and steam pyrolysis process for complete conversion of crude oil. Here, crude oil after pretreatment is sent to hydrotreater and thereafter processed in solvent deasphalting unit. Deasphalter unit products are thermally converted in a steam Pyrolysis process.
US2016/0122668 describes an integrated slurry hydroprocessing and steam Pyrolysis process for production of olefins and aromatic petrochemical feedstocks from crude oil feedstock. Crude oil is hydro processed to produce effluent rich in hydrogen content and the said effluent is then routed to steam Pyrolysis unit to cause thermal cracking reactions. Mixed product stream is separated, and the olefins and aromatic products are recovered.
WO2013/112967 describes an integrated solvent deasphalting, hydrotreating and pyrolysis processes for direct processing of crude oil to produce olefins, petrochemical feedstocks and aromatics. Here, crude oil after pretreatment is sent to the solvent deasphalting unit and the deasphalted oil is routed to the hydrotreater unit. The hydrotreated material is then sent to a Pyrolysis unit for cracking into lighter products. Olefins and aromatic products are recovered from the mixed product stream.
US2019/0256786A1 relates to a process and system for complete conversion of crude oils by integrating delayed coking process, high severity catalytic cracking process and naphtha cracking processes along with olefin recovery section, aromatic recovery section and gasifier section to maximize the crude oil conversion to valuable products like light olefins, aromatics, and chemicals. The resid upgradation of heavy cut i.e., 370+ cut is through DCU and only LCO stream is utilized using selective mild hydrocracking process.
Conventionally, the Light Cycle Oil (LCO) product from the catalytic cracking unit as well as the Light Coker Gasoil (LCGO) from Delayed Coker Unit are normally send for producing Diesel product whereas in the present invention, a novel ‘selective mild hydrocracking aromatic production unit’ is employed which selectively cracks the polyaromatics to produce aromatic molecules like xylene while producing a small fraction of diesel. Also, the present process effectively distributes the LCGO stream to cracking process which produces light olefins along with aromatics as well as to selective mild hydrocracking process for aromatic production. The present process also provides a route for further conversion of LCO range streams produced from Catalytic Naphtha cracker unit to aromatics by making use of selective mild hydrocracking process. The present process achieves high conversion of naphtha streams including that produced from residue slurry hydrocracking process, selective mild hydrocracking process and also the paraffinic raffinate from aromatic recovery unit. The present process also enables to achieve higher conversions along with product qualities produced from high severity fluid catalytic cracking process by feeding the Hydrotreated streams from crude as well as residue slurry hydrocracking processes and Delayed Coker. The present process has high conversion of crude oil to light olefins and aromatics and maximizes extraction of value-added products from heavy residue through resid slurry hydrocracking, Delayed coking, Gasification and Syngas to Olefin conversion, with an option to withdraw coke from Delayed Coker unit as high value product.
In an aspect of the present invention, provides an improved process for converting crude oil to high value petrochemicals products, the process comprising:
In another embodiment of the present invention, the desalted crude oil is fractionated via unit selected from atmospheric distillation unit, vacuum distillation unit or a combination thereof. In another embodiment of the present invention, the Primary fractionation section comprises of an Atmospheric distillation unit operating at a pressure in the range of 1-2 Kg/cm2(g) and top temperature in the range of 150 to 250° C. preferably in the range of 190 to 210° C.; and a Vacuum distillation unit operates at pressure in the range of 0.01 to 0.05 Kg/cm2(g).
In another embodiment of the present invention, the processing of Light Coker Gas Oil from first resid upgradation unit, light cycle from Catalytic Naphtha cracker unit and Light Cycle Oil from using Selective Mild Hydrocracking increases the yield of aromatics and light olefins.
In another embodiment of the present invention, the mass ratio at which the LCGO stream from second Resid upgradation unit is split, is selected from the range of 10:90 to 90:10 for routing to SMHC and Catalytic Naphtha Cracker Units.
In an embodiment of the present invention, the upper light cut with boiling point below 350° C. from primary fractionation section is optionally routed to Thermal Naphtha cracker unit via Naphtha hydrotreater unit to remove Sulfur and Nitrogen impurities; and the upper light cut with boiling point below 350° C. from primary fractionation section comprises Straight Run Naphtha, Kerosene, Light Gas Oil, Heavy Gas Oil and middle cut comprises of Vacuum diesel and Vacuum Gas Oil (VGO) and Lower heavy cut comprises Vacuum Residue (VR), respectively.
In an embodiment of the present invention, high value coke has sulphur in range of 1-3 wt % and sponge structure for use as graphite grade coke.
In an embodiment of the present invention, a part of the high value coke is withdrawn as a product depending upon requirement and the remaining coke is optionally sent to the Gasification section.
In another embodiment of the present invention discloses that the first Resid Upgradation Unit is a Residue Hydrocracking Unit which uses oil soluble liquid catalyst comprising a Ni (1-5 wt %) and Mo (95-99 wt %).
In another embodiment of the present invention, the Naphtha Hydrotreater Unit is operated at temperature in the range of 300-360° C. and at a pressure in range of 10-20 bar.
In another embodiment of the present invention, the selective mild hydrocracking unit has two reactors for hydrotreating and selective mild hydrocracking respectively.
In another embodiment of the present invention, the Second Resid upgradation unit is a Delayed Coker Unit, and the Coke Drums are operated at temperature in the range of 470 to 520° C., preferably between 480° C. to 500° C. and desired operating pressure ranging from 0.5 to 5 Kg/cm2 (g) preferably between 0.6 to 3 Kg/cm2 (g) and residence time in the range of 10 to 32 hours.
In another embodiment of the present invention, the High severity FCC unit operates at a high reactor outlet temperature of 550 to 650° C., preferably between 580 to 620° C., Reactor pressure in the range of 0.7 to 2.5 Kg/cm2 (g), preferably in the range of 0.8 to 1.5 Kg/cm2 (g) and the catalyst to oil ratio in the range of 10 to 25, preferably in the range of 15 to 20; and the Catalytic Naphtha Cracker Unit operates at a reactor outlet temperature of 580 to 670° C., preferably between 590 to 630° C., reactor pressure in the range of 0.7 to 2.5 Kg/cm2 (g), preferably in the range of 0.8 to 1.5 Kg/cm2 (g) and the catalyst to oil ratio in the range of 15 to 30, preferably in the range of 15 to 25.
In another embodiment of the present invention, the first Resid upgradation unit is a Residue Slurry Hydrocracker Unit which operate at a pressure in the range of 45 to 80 Kg/cm2 (g), preferably in the range of 50 to 70 Kg/cm2 (g) and temperature in the range of 360 to 450 C, preferably in the range of 390 to 420° C.
In another embodiment of the present invention, the coke Gasifier operates with 1st stage as a Low temperature fluidized gasifier and 2nd stage as high temp entrained Gasifier with the temperature of both stages in the range of 750 to 825° C. and 1400 to 1500° C. respectively and residence time in the range of 50 to 100 and 2 to 5 seconds.
In another aspect of the present invention, a system to implement process for converting crude oil to high value petrochemicals products, the system comprising:
In another embodiment of the present invention, the system is optionally provided with a Naphtha Hydrotreater unit for receiving fully or a part of the upper cut and other naphtha streams for removing the impurities such as Sulfur and Nitrogen and an optional Steam cracker unit to receive treated naphtha stream to generate lighter olefins, pyrolyzed gasoline, and ethylene tar (Pyrolytic Fuel oil) by thermal cracking.
It is a primary objective of the invention to provide a process and system for improving the selectivity for production of light olefins and aromatics.
It is another objective of the invention to achieve higher conversions along with product qualities produced from high severity fluid catalytic cracking process by feeding the Hydrotreated streams from crude as well as residue slurry hydrocracking processes and Delayed Coker
It is yet another objective of the invention to effectively distribute the LCGO stream to cracking process which produces light olefins along with aromatics as well as to selective mild hydrocracking process for aromatic production
It is further objective of the present invention to provide a process for maximizing extraction of value-added products from heavy residue through resid slurry hydrocracking, Delayed coking, Gasification and Syngas to Olefin conversion.
It is another objective of the invention to high conversion of naphtha streams including that produced from residue slurry hydrocracking process, selective mild hydrocracking process and also the paraffinic raffinate from aromatic recovery unit
It is further objective of the present invention to minimize/reduce the diesel production from crude oil.
Further objective of the invention is to produces gas oils with low sulfur, nitrogen content to increase catalyst life and reduces operating cost.
It is yet another objective of the present invention to provide for an option to produce high value coke from Delayed Coker Unit
While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the scope of the invention as defined by the appended claims.
The following description is of exemplary embodiments only and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention.
Feedstock
The liquid hydrocarbon feedstock that can be used in the process is crude oil or crude oil blends and/or crude oil fractions thereof and/or synthetic crude oils and/or oil sand bitumens and/or oils derived from same having Conradson Carbon Residue (CCR) content less than 15 wt % and in particular ranging from 1 to 15 wt %. The feed blend may also comprise of waste plastic pyrolysis oil and/or biomass pyrolysis oil as part of the blend within a limit of up to 50 wt %.
Process Conditions
In the process of present invention, atmospheric distillation unit operates at pressure in the range of 1-2 Kg/cm2(g) and top temperature in the range of 150 to 250° C. preferably in the range of 190 to 210° C. while vacuum distillation unit operates at pressure in the range of 0.01 to 0.05 Kg/cm2(g). These process conditions are to be fine-tuned to enable separation of lighter boiling (<200° C.) naphtha range compounds from the crude.
Coke drums in the delayed coking section of the process may be operated at a higher severity with desired operating temperature ranging from 470 to 520° C., preferably between 480° C. to 500° C. and desired operating pressure ranging from 0.5 to 5 Kg/cm2 (g) preferably between 0.6 to 3 Kg/cm2 (g). The residence time provided in coke drums is kept in the range of 10 to 32 hours.
High severity FCC unit is operated at a high reactor outlet temperature of 550 to 650° C., preferably between 580 to 620° C. Reactor pressure shall vary in the range of 0.7 to 2.5 Kg/cm2 (g), preferably in the range of 0.8 to 1.5 Kg/cm2 (g). The catalyst to oil ratio is selected from the range of 10 to 25, preferably in the range of 15 to 20.
The catalytic naphtha cracker unit as mentioned in the present invention is a circulating fluidized bed unit for continuous catalyst regeneration and operates at a reactor outlet temperature of 580 to 670° C., preferably between 590 to 630° C. Reactor pressure shall vary in the range of 0.7 to 2.5 Kg/cm2 (g), preferably in the range of 0.8 to 1.5 Kg/cm2 (g). The catalyst to oil ratio is selected from the range of 15 to 30, preferably in the range of 15 to 25.
Thermal Naphtha cracking unit is operated in presence of steam in the ratio of 0.4 to 1 with feedstock and carried at a higher reactor temperature of 800 to 900° C. at a residence time in the range of 0.1 to 0.5 seconds.
Naphtha hydrotreater unit for obtaining hydrotreated naphtha, feed for Thermal naphtha cracker is operated at temperature in the range of 300-360° C. at a pressure of 10-20 bar in presence of hydrogen.
Selective Mild Hydrocracking Aromatic production unit involves hydrotreating and selective mild hydrocracking steps being carried out in two reactors. The reactors operate at a pressure in the range of 45 to 80 Bar, preferably in the range of 50 to 70 bars and temperature in the range of 360 to 450° C., preferably in the range of 390 to 420° C. in presence of hydrogen.
The residue slurry hydrocracker unit is operated in the temperature range of 250-550° C. and pressure in the range of 40-250 bar in presence of hydrogen.
Gasifier unit for conversion of coke into syngas is operated at and Syngas to Methanol & Methanol to olefins is operated with 1St stage as a Low temperature fluidized gasifier and 2′ stage as high temp entrained gasifier. The temperature of both stages in the range of 750-825° C. and 1400-1500° C. respectively and residence time in the range of 50-100 and 2-5 sec respectively.
Catalyst
In the process scheme of present invention, no catalysts are employed in Atmospheric/vacuum distillation units, delayed coker units and thermal naphtha cracker units. High severity FCC unit employs a circulating fluidized bed reactor configuration and a catalyst mixture containing ‘large pore bottoms selective active material’ of pore size more than 50 Å, Y/REY/USY/RE-USY zeolites of medium pore size of 7 to 11 Å and shape selective pentasil zeolite components. The catalytic naphtha cracker unit also employs a circulating fluidized bed reactor configuration and uses a catalyst composition, with predominantly shape selective pentasil zeolite. Naphtha Hydrotreater uses CoMo/NiMo Catalyst while Residue Hydrocracking unit employs oil soluble liquid catalyst comprises a Ni (1-5 wt %) and Mo (95-99 wt %) organometallic compound in a suitable solvent such as toluene. Selective Mild Hydrocracking Aromatic production unit employs a bifunctional catalyst based on Nickel and Molybdenum.
Process and System Flow Scheme
In the process and system of present invention as depicted in
In another feature of the present invention as depicted in
In another feature of the present invention as depicted in
In another preferred feature of the present invention as depicted in
Two crude blends from an Indian refinery and the properties were analyzed and provided in Table-1.
In a preferred feature of the present invention, crude oils with properties provided in Table-1 were subjected to multiple steps of processing as per the process scheme described above in
Comparison of process as disclosed in the present invention with the process known in the art, particularly, with US2019/0256786A1.
In one feature of the present invention, the Resid is processed in resid slurry hydrocracker, to produces gas oils with low sulfur, nitrogen content and is beneficial for FCC catalyst in terms of increased catalyst life and reduced operating cost as compared to process of US2019/0256786A1 where resid is processed in DCU.
Value extraction from Pitch containing saturates with low sulfur, nitrogen, metals, less production of unwanted product, making the present process more profitable.
The process scheme of present invention produces higher quality coke meeting anode grade specifications compared to scheme of US2019/0256786A1 where coke is of fuel grade quality.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202221003413 | Jan 2022 | IN | national |
