Integration of catalytic cracking process with crude conversion to chemicals process

Abstract

A method that integrates a catalytic cracking process with a crude oil conversion to chemicals process is disclosed. The method may include contacting, in a catalytic cracking reactor, a mixture of the hydrocarbon stream comprising primarily C.sub.5 and C.sub.6 hydrocarbons from crude oil processing and a C.sub.4 to C.sub.5 hydrocarbon stream produced in a steam cracking unit with a catalyst under reaction conditions sufficient to produce an effluent comprising olefins.

Claims

1. A method of producing olefins, the method comprising: processing crude oil to produce a plurality of streams that include a hydrocarbon stream comprising primarily C.sub.5 and C.sub.6 hydrocarbons; receiving, in a catalytic cracking reactor, the hydrocarbon stream comprising primarily C.sub.5 and C.sub.6 hydrocarbons; receiving, in the catalytic cracking reactor, a C.sub.4 to C.sub.5 hydrocarbon stream from a steam cracking unit; contacting, in the catalytic cracking reactor, a mixture of the hydrocarbon stream comprising primarily C.sub.5 and C.sub.6 hydrocarbons and the C.sub.4 to C.sub.5 hydrocarbon stream from the steam cracking unit with a catalyst under reaction conditions sufficient to produce an effluent comprising olefins; and separating the effluent to produce at least a first product stream comprising C.sub.2 to C.sub.4 olefins, a second product stream comprising C.sub.2 to C.sub.4 paraffins, and a third product stream comprising C.sub.5+-gasoline; wherein the reaction conditions include a reaction pressure in a range of 2.1 to 5.0 bars a residence time of reactants in the catalytic cracking reactor is in a range of 1 to 10 seconds, and a reaction temperature in a range of from 625 C. to 700 C.; wherein the separating of the effluent further comprises producing a dry gas stream, and wherein the dry gas stream comprises methane and hydrogen.

2. The method of claim 1 further comprising: receiving, in the catalytic cracking reactor, material comprising a coke precursor; and contacting, in the catalytic cracking reactor, a mixture comprising (1) the hydrocarbon stream comprising primarily C.sub.5 and C.sub.6 hydrocarbons, (2) the C.sub.4 to C.sub.5 hydrocarbon stream from the steam cracking unit, and (3) the material comprising the coke precursor with the catalyst under reaction conditions sufficient to produce coke and the effluent comprising olefins.

3. The method of claim 2, wherein the material comprising the coke precursor comprises fuel oil and/or diolefin from the steam cracking unit.

4. The method of any of claim 3, wherein the diolefin comprises butadiene.

5. The method of claim 1, wherein the catalytic cracking reactor is a fluidized bed reactor.

6. The method of claim 5, wherein the fluidized bed reactor includes a selection from the list consisting of: a riser, a downer, multiple risers, and multiple downers, and combinations thereof.

7. The method of claim 5, wherein a ratio of total hydrocarbon to catalyst in the fluidized bed reactor is 2 to 40 wt. %.

8. The method of claim 1, wherein the catalytic cracking reactor is a fixed bed reactor system.

9. The method of claim 8, wherein the fixed bed reactor system includes a selection from the list consisting of: a single fixed bed reactor, multiple reactors arranged in series, multiple reactors arranged in parallel, and combinations thereof.

10. The method of claim 1, wherein the reaction conditions include a reaction pressure in a range of 2.2 bars to 5 bars.

11. The method of claim 1, wherein the catalyst comprises a solid acid based zeolite catalyst selected from the list consisting of: one or more large pore zeolites, including zeolite Y and ultra-stable zeolite Y; and combinations thereof.

12. The method of claim 1, wherein a yield of the C.sub.2 to C.sub.4 olefins resulted from the contacting is in a range of 25 to 65 wt. %.

13. The method of claim 1, wherein a yield of the C.sub.2 to C.sub.4 olefins resulted from the contacting is in a range of 35 to 65 wt. %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 shows a system that integrates a catalytic cracking process with a crude oil conversion to chemicals process, according to embodiments of the invention; and

(3) FIG. 2 shows a method that integrates a catalytic cracking process with a crude oil conversion to chemicals process, according to embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) A method has been discovered that integrates a catalytic cracking process with a crude oil conversion to chemicals process. The catalytic cracking may produce light olefins, dry gases and other heavier components in a reactor (e.g., a fluidized bed reactor or a fixed bed reactor). The conversion of crude oil to chemicals process may involve the steam cracking of hydrocarbon feedstock to form olefins such as ethylene.

(5) Embodiments of the invention include a method of producing olefins such as C.sub.2 to C.sub.4 olefins. The method may include processing crude oil in a pretreatment and distillation unit to produce a plurality of streams that include a hydrocarbon stream including primarily C.sub.5 and C.sub.6 hydrocarbons. The hydrocarbon stream including primarily C.sub.5 and C.sub.6 hydrocarbons is called a light naphtha stream. The method may further include receiving, in a catalytic cracking reactor unit, the hydrocarbon stream including primarily C.sub.5 and C.sub.6 hydrocarbons. The catalytic cracking reactor unit may include one or more fixed bed reactors, moving bed reactors, fluidized bed reactors, or combinations thereof.

(6) The method may further include receiving, in the catalytic cracking reactor unit, a C.sub.4 to C.sub.5 hydrocarbon stream produced in a steam cracking unit and contacting, in the catalytic cracking reactor unit, a mixture of the hydrocarbon stream comprising primarily C.sub.5 and C.sub.6 hydrocarbons and the C.sub.4 to C.sub.5 hydrocarbon stream produced in the steam cracking unit (e.g., of a petrochemicals plant that produces ethylene) with a catalyst under reaction conditions sufficient to produce an effluent comprising olefins. The method may also include separating the effluent to produce at least a first product stream comprising light olefins (C.sub.2 to C.sub.4 olefins), a second product stream comprising C.sub.2 to C.sub.4 paraffins, and a third product stream comprising C.sub.5+-gasoline.

(7) FIG. 1 shows system 10, which integrates a catalytic cracking process with a crude oil conversion to chemicals process, according to embodiments of the invention. FIG. 2 shows method 20, which integrates a catalytic cracking process with a crude oil conversion to chemicals process, according to embodiments of the invention. Method 20 may be implemented using system 10.

(8) Referring to FIG. 1, crude oil 100 is fed to pretreatment and distillation unit 101, which can process crude oil 100 by separating it into several different fractions to produce a plurality of streams that can include a hydrocarbon stream that includes primarily C.sub.5 and C.sub.6 hydrocarbons (e.g., light naphtha stream 104), as shown in block 200 of method 20. The separation into different fractions can take place in a single distillation or multiple distillation units of pretreatment and distillation unit 101. Some of the distilled streams from crude oil 100 may be processed in a steam cracking process. Processing of crude oil 100 by pretreatment and distillation unit 101 can also produce heavy naphtha stream 105, kerosene stream 106, diesel stream 107, and ATM residue 103. Embodiments of the invention described herein show a process of converting light naphtha into light olefins and how this process can be integrated with a steam cracking process. Heavy naphtha, for example, can be reformed to produce benzene, toluene and xylenes which are basic building block chemicals for the petrochemical industries.

(9) FIG. 1 further shows light naphtha stream 104 being fed to catalytic cracking reactor 108. In this way, system 10 implements block 201 of method 20, which involves receiving, in catalytic cracking reactor 108, the hydrocarbon stream comprising primarily C.sub.5 and C.sub.6 hydrocarbons (light naphtha stream 104). Block 202 of method 20, when implemented using system 10, may involve receiving, in catalytic cracking reactor 108, C.sub.4 to C.sub.5 hydrocarbon stream 112, produced in a steam cracking unit of petrochemicals complex 109. The C.sub.4 to C.sub.5 hydrocarbon stream 112, in system 10, is for conversion into light olefins.

(10) Method 20, when implemented using system 10, may also include, at block 203, providing coke precursor 111 from the steam cracking unit of petrochemical complex 109 to catalytic cracking reactor 108. Providing coke precursor 111 in this way can enhance heat balance and increase the amount of coke produced in catalytic cracking reactor 108. Coke precursor 111 may include fuel oil, portion of C.sub.9+ pygas, and/or a diolefin such as a stream of butadiene from the steam cracking unit of petrochemical complex 109.

(11) According to embodiments of the invention, catalytic cracking reactor 108 is adapted to carry out block 204 of method 20, which involves contacting a mixture of light naphtha stream 104 (comprising primarily C.sub.5 and C.sub.6 hydrocarbons), C.sub.4 to C.sub.5 hydrocarbon stream 112, and coke precursor 111 (when provided) with a catalyst under reaction conditions sufficient to produce an effluent comprising olefins. Catalytic cracking reactor 108 can include one or more of fixed bed reactors, moving bed reactors, and fluidized bed reactors, or combinations thereof, for cracking light naphtha stream 104.

(12) Method 20, as implemented by system 10, may further include block 205, which involves separating the effluent to produce one or more of light olefins stream 114 (C.sub.2 to C.sub.4 olefins), C.sub.2 to C.sub.4 paraffins stream 110, C.sub.5+-gasoline stream 115, and dry gas stream 113. In embodiments of the invention, dry gas stream 113 includes methane and/or hydrogen. In embodiments of the invention, C.sub.2 to C.sub.4 paraffins stream 110 is sent to petrochemicals complex 109, where it is used to produce more olefins in the steam cracking furnace. The products separation and olefins recovery processes are known to those of ordinary skill in the art. The petrochemicals complex and catalytic cracking can share the same separation units.

(13) FIG. 2 shows that method 20 may further include, at block 206, recycling unconverted C.sub.5 to C.sub.7 from the catalytic cracking of light naphtha stream 104 back to catalytic cracking reactor 108. As shown in FIG. 1, recycled stream 116 may be a portion of C.sub.5+ gasoline stream 115.

(14) In embodiments of the invention, catalytic cracking reactor 108 is a fluidized bed reactor that is configured to include a selection from the list consisting of: a riser, a downer, multiple risers, and multiple downers, and combinations thereof. When the catalytic cracking reactor 108 is a fluidized bed reactor, in embodiments of the invention, the residence time in the fluidized bed reactor may be in a range of 1 to 10 second, and all ranges and values there between including values 1 seconds, 2 seconds, 3 seconds, 4 seconds, 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds, and 10 seconds. Further, in embodiments of the invention, when catalytic cracking reactor 108 is a fluidized bed reactor, a ratio of total hydrocarbon to catalyst in the fluidized bed reactor may be in a range of 2 to 40 wt. %, and all ranges and values there between including ranges 2 wt. % to 10 wt. %, 10 wt. % to 20 wt. %, 20 wt. % to 30 wt. %, 30 wt. % to 40 wt. % and values 3 wt. %, 4 wt. %, 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. %, 10 wt. %, 11 wt. %, 12 wt. %, 13 wt. %, 14 wt. %, 15 wt. %, 16 wt. %, 17 wt. %, 18 wt. %, 19 wt. %, 20 wt. %, 21 wt. %, 22 wt. %, 23 wt. %, 24 wt. %, 25 wt. %, 26 wt. %, 27 wt. %, 28 wt. %, 29 wt. %, 30 wt. %, 31 wt. %, 32 wt. %, 33 wt. %, 34 wt. %, 35 wt. %, 36 wt. %, 37 wt. %, 38 wt. %, 39 wt. %, and 40 wt. %.

(15) In embodiments of the invention, catalytic cracking reactor 108 is a fixed bed reactor system that is configured to include a selection from the list consisting of: a single fixed bed reactor, multiple reactors arranged in series, multiple reactors arranged in parallel, and combinations thereof. When catalytic cracking reactor 108 is a fluidized bed reactor, in embodiments of the invention, the reaction conditions include a weight hourly space velocity WHSV in a range of 3 to 40 hr.sup.1, and all ranges and values there between including values 3 hr.sup.1, 4 hr.sup.1, 5 hr.sup.1, 6 hr.sup.1, 7 hr.sup.1, 8 hr.sup.1, 9 hr.sup.1, 10 hr.sup.1, 11 hr.sup.1, 12 hr.sup.1, 13 hr.sup.1, 14 hr.sup.1, 15 hr.sup.1, 16 hr.sup.1, 17 hr.sup.1, 18 hr.sup.1, 19 hr.sup.1, and 20 hr.sup.1.

(16) In embodiments of the invention, for example, when catalytic cracking reactor 108 includes one or more of a fluidized bed reactor, a moving bed reactor, and a fixed bed reactor, the reaction conditions may include a reaction temperature in a range of 500 C. to 700 C., and all ranges and values there between including ranges 500 C. to 505 C., 505 C. to 510 C., 510 C. to 515 C., 515 C. to 520 C., 520 C. to 525 C., 525 C. to 530 C., 530 C. to 535 C., 535 C. to 540 C., 540 C. to 545 C., 545 C. to 550 C., 550 C. to 555 C., 555 C. to 560 C., 560 C. to 565 C., 565 C. to 570 C., 570 C. to 575 C., 575 C. to 580 C., 580 C. to 585 C., 585 C. to 590 C., 590 C. to 595 C., 595 C. to 600 C., 600 C. to 605 C., 605 C. to 610 C., 610 C. to 615 C., 615 C. to 620 C., 620 C. to 625 C., 625 C. to 630 C., 630 C. to 635 C., 635 C. to 640 C., 640 C. to 645 C., 645 C. to 650 C., 650 C. to 655 C., 655 C. to 660 C., 660 C. to 665 C., 665 C. to 670 C., 670 C. to 675 C., 675 C. to 680 C., 680 C. to 685 C., 685 C. to 690 C., 690 C. to 695 C., and 695 C. to 700 C. Further, those reaction conditions may include a pressure in a range of 0.5 bars to 5 bars, and all ranges and values there between including values 0.5 bars, 0.6 bars, 0.7 bars, 0.8 bars, 0.9 bars, 1.0 bars, 1.1 bars, 1.2 bars, 1.3 bars, 1.4 bars, 1.5 bars, 1.6 bars, 1.7 bars, 1.8 bars, 1.9 bars, 2.0 bars, 2.1 bars, 2.2 bars, 2.3 bars, 2.4 bars, 2.5 bars, 2.6 bars, 2.7 bars, 2.8 bars, 2.9 bars, 3.0 bars, 3.1 bars, 3.2 bars, 3.3 bars, 3.4 bars, 3.5 bars, 3.6 bars, 3.7 bars, 3.8 bars, 3.9 bars, 4.0 bars, 4.1 bars, 4.2 bars, 4.3 bars, 4.4 bars, 4.5 bars, 4.6 bars, 4.7 bars, 4.8 bars, 4.9 bars, and 5.0 bars.

(17) In embodiments of the invention, for example, when catalytic cracking reactor 108 includes one or more of a fluidized bed reactor, a moving bed reactor, and a fixed bed reactor, the catalyst used in catalytic cracking reactor 108 may include a solid acid based zeolite catalyst selected from the list consisting of: one or more medium pore zeolites, including ZSM-5 and modified ZSM-5; one or more large pore zeolites, including zeolite Y and ultra-stable zeolite Y; and combinations thereof.

(18) In embodiments of the invention, the yield of light olefins (C2 to C4) is in a range of 25 to 65 wt. %, preferably. The method of any of claims 1 to 18, wherein yield of light olefins (C2 to C4) is in a range of 35 to 65 wt. %.

(19) Although embodiments of the present invention have been described with reference to blocks of FIG. 2, it should be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated in FIG. 2. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that of FIG. 2.

EXAMPLES

(20) As part of the disclosure of the present invention, specific examples are included below. The examples are for illustrative purposes only and are not intended to limit the invention. Those of ordinary skill in the art will readily recognize parameters that can be changed or modified to yield essentially the same results.

(21) A light naphtha feed having the composition shown in Table 1 was used as noted in the description of relevant Examples below.

(22) TABLE-US-00001 TABLE 1 Light Naphtha Composition Feed (LSRN) N-C5 28.8 I-C5 11.8 Cycl-C5 1.9 N-C6 24.5 I-C6 26.9 Cycl-C6 4.6 Benzene 1.3 C7 0.3 sum 100

Example 1

Cracking with Fluidized Bed Pilot Plant

(23) In Example 1, a catalyst was used to catalytically crack the light naphtha shown in Table 1 using a fluidized bed pilot plant. Reactor temperature, steam/feed ratio and residence time for the cracking of the light naphtha in the fluidized bed pilot plant are shown in Table 2. The experiment of Example 1 is based on a single pass. It should be noted that recycling C.sub.5-gasoline to the reactor would increase the conversion and yields of light olefins shown in Table 2.

(24) TABLE-US-00002 TABLE 2 Light Naphtha Cracking Over Fluidized Reactors Reaction Conditions and Product Yields Temperature ( C.) 670 Steam/Feed (wt %) 25 Res. Time (sec) 5 C5-Gasoline, wt % 34.6 LCO + slurry + coke, wt % 1.1 Dry gases (C1-C3 paraffins + H2), wt % 23 light olefins, wt % 30 C4 (total), wt % 11.3 IC4=, wt % 3.7 C4=, wt % 5.5

Example 2

Composition of C4 Stream from Steam Cracking Unit

(25) In Example 2, the composition of the C.sub.4 stream from the steam cracking unit is provided. The C.sub.4 stream composition may depend on the feed to the catalytic cracker, process configuration, and downstream units. Table 3 shows the composition of C.sub.4 stream from steam cracking.

(26) TABLE-US-00003 TABLE 3 C.sub.4 composition from steam cracking Comp. Conc. Iso-Butene 3.4 N-Butane 16.6 Trans-2-Butene 16.1 1-Butene 33.6 Iso-Butene 24.1 Cis-2-Butene 6.2 Total 100.00

Example 3

Catalytic Cracking of C.SUB.4 .to C.SUB.6 .Olefinic Stream

(27) In Example 3, the catalytic cracking of C.sub.4 to C.sub.6 olefinic stream carried out between 450 to 600 C. over zeolite based catalyst was considered. A simulated product distribution of cracking light naphtha and olefinic feed is shown in Table 4. The catalytic cracking can be done in single riser or in dual risers. The C.sub.4 to C.sub.6 olefinic stream is recycled to extinction. From the simulation, the yield of light olefin is increased to roughly around 40 wt. %. It should be noted that the yield can increase further if C.sub.2 to C.sub.4 paraffin is fed to a steam cracking process.

(28) TABLE-US-00004 TABLE 4 Simulated product distribution from the proposed integration Comp. Final Conc. C1-C3 15.0 Light olefins 41.4 C4 3.9 CS-Gasoline 37.2 LCO + Coke + slurry 2.5 Total 100.0

(29) Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.