Process for the conversion of crude oil to petrochemicals

Abstract

An integrated process to convert crude oil into petrochemical products includes distilling crude oil to produce gases fraction, naphtha, kerosene, gasoil and resid; subjecting resid to resid upgrading to produce LPG, light-distillate and middle-distillate; subjecting at least a portion of one or more of the group consisting of middle-distillate produced by resid upgrading, kerosene and gasoil to middle-distillate hydrocracking to produce LPG, light-distillate and hydrowax; and subjecting at least a portion of one or more of the group consisting of light-distillate produced by resid upgrading, light-distillate produced by middle-distillate hydrocracking and hydrowax to steam cracking. A process installation for performing the process is also provided.

Claims

1. A process to convert crude oil into petrochemical products comprising crude oil distillation, hydrocracking and steam cracking, which process comprises the steps of: (a) subjecting the crude oil to crude oil distillation to produce gases fraction, naphtha, kerosene, gasoil and resid; (b) subjecting resid to resid upgrading to produce LPG, light-distillate and middle-distillate; (c) subjecting at least a portion of one or more of the group consisting of middle-distillate produced by resid upgrading, kerosene and gasoil to middle-distillate hydrocracking to produce LPG, light-distillate and hydrowax; and (d) subjecting at least a portion of one or more of the group consisting of light-distillate produced by resid upgrading, light-distillate produced by middle-distillate hydrocracking and hydrowax to steam cracking; wherein the resid upgrading is conducted in a resid upgrading unit selected from the group consisting of a resid FCC, a Flexicoker, a visbreaker and a catalytic hydrovisbreaker.

2. The process according to claim 1, wherein the resid upgrading unit is a resid FCC.

3. The process according to claim 2, wherein the middle-distillate hydrocracking further produces a heavy-distillate, wherein at least a portion of said heavy-distillate produced by middle-distillate hydrocracking is subjected to resid upgrading.

4. The process according to claim 1, wherein the middle-distillate hydrocracking further produces a heavy-distillate, wherein at least a portion of said heavy-distillate produced by middle-distillate hydrocracking is subjected to resid upgrading.

5. The process of claim 4, wherein the resid upgrading unit is a resid FCC.

6. The process of claim 4, wherein the resid upgrading unit is a Flexicoker.

7. The process of claim 4, wherein the resid upgrading unit is a visbreaker.

8. The process of claim 4, wherein the resid upgrading unit is a catalytic hydrovisbreaker.

9. The process of claim 1, wherein the resid upgrading unit is a Flexicoker.

10. The process of claim 1, wherein the resid upgrading unit is a visbreaker.

11. The process of claim 1, wherein the resid upgrading unit is a catalytic hydrovisbreaker.

12. The process of claim 1, wherein in step (c) only LPG and light-distillate are produced.

13. The process of claim 1, wherein at least a portion of the hydrowax is subjected to steam cracking.

14. A process to convert crude oil into petrochemical products comprising crude oil distillation, hydrocracking and steam cracking, which process consists of the steps of: (a) subjecting the crude oil to crude oil distillation to produce gases fraction, naphtha, kerosene, gasoil and resid; (b) subjecting resid to resid upgrading to produce LPG, light-distillate and middle-distillate; (c) subjecting at least a portion of middle-distillate produced by resid upgrading, at least a portion of kerosene and gasoil to middle-distillate hydrocracking to produce LPG, light-distillate and hydrowax; and (d) subjecting at least a portion of light-distillate produced by resid upgrading, light-distillate produced by middle-distillate hydrocracking and hydrowax to steam cracking, wherein the resid upgrading is conducted in a resid upgrading unit selected from the group consisting of a resid FCC, a Flexicoker, a visbreaker and a catalytic hydrovisbreaker.

15. A process to convert crude oil into petrochemical products comprising crude oil distillation, hydrocracking and steam cracking, which process consists of the steps of: (a) subjecting the crude oil to crude oil distillation to produce gases fraction, naphtha, kerosene, gasoil and resid; (b) subjecting resid to resid upgrading to produce LPG, light-distillate and middle-distillate; (c) subjecting at least a portion of the middle-distillate produced by resid upgrading to middle-distillate hydrocracking to produce products consisting of LPG and light-distillate; and (d) subjecting at least a portion of one or more of the group consisting of light-distillate produced by resid upgrading, light-distillate produced by middle-distillate hydrocracking and hydrowax to steam cracking, wherein the resid upgrading is resid hydrocracking, wherein the middle-distillate hydrocracking further produces a heavy-distillate, wherein at least a portion of said heavy-distillate produced by middle-distillate hydrocracking is subjected to resid upgrading; and wherein the resid upgrading is conducted in a resid upgrading unit selected from the group consisting of a resid FCC, a Flexicoker, a visbreaker and a catalytic hydrovisbreaker.

16. The process of claim 15, wherein the resid upgrading unit is a resid FCC.

17. The process of claim 16, wherein the resid upgrading unit is a Flexicoker.

18. The process of claim 16, wherein the resid upgrading unit is a visbreaker.

19. The process of claim 16, wherein the resid upgrading unit is a catalytic hydrovisbreaker.

Description

EXAMPLE 1 (COMPARATIVE)

(1) The experimental data as provided herein were obtained by flowsheet modelling in Aspen Plus. The steam cracking kinetics were taken into account rigorously (software for steam cracker product slate calculations). The following steam cracker furnace conditions were applied for Examples 1 and 2: ethane and propane furnaces: coil outlet temperature (COT)=845 C. and steam-to-oil-ratio=0.37, C4-furnaces and liquid furnaces: COT=820 C. and Steam-to-oil-ratio=0.37. For the gasoline hydrocracking, a reaction scheme has been used that is based on experimental data reported in literature. For middle-distillate hydrocracking followed by gasoline hydrocracking according to WO 2015/000848 A1. a reaction scheme has been used in which all multi aromatic compounds were converted into BTX and LPG and all naphthenic and paraffinic compounds were converted to LPG. The product slates from propane dehydrogenation and butane dehydrogenation were based on literature data. The resid hydrocracker was modelled based on data from literature.

(2) In Example 1, which is according to Example 3 of WO 2015/000848 A1, Arabian light crude oil is distilled in an atmospheric distillation unit to provide a gases fraction, a naphtha fraction, a kerosene/gasoil fraction and a resid fraction. First, the naphtha fraction is subjected to feed hydrocracking to yield BTX (product) and LPG (intermediate). The kerosene and gas oil fractions are subjected to middle-distillate hydrocracking which is operated under process conditions to maintain 1 aromatic ring. The effluent from this middle-distillate hydrocracking unit is further treated in the gasoline hydrocracker to yield BTX (product) and LPG (intermediate). The resid is upgraded in a resid hydrocracker to produce LPG, light-distillate and middle-distillate. The light-distillate produced by resid hydrocracking is fed to the feed hydrocracker to yield BTX (product) and LPG (intermediate). The middle-distillate produced by resid hydrocracking is subjected to middle-distillate hydrocracking that is operated under process conditions to maintain 1 aromatic ring. The effluent from the middle-distillate hydrocracker is further treated in the gasoline hydrocracker to yield BTX and LPG. The gases fraction and the LPG produced by the various units is separated into ethane-, propane- and butane fractions, wherein the propane and butane are dehydrogenated into propylene and butene (with ultimate selectivities of propane to propylene 90%, and n-butane to n-butene of 90% and i-butane to i-butene of 90%). The ethane is subjected to steam cracking. Furthermore, the heavy part of the steam cracker effluent (C9+ hydrocarbons) is recycled to the resid hydrocracker. The ultimate conversion in the resid hydrocracker is close to completion (the pitch of the resid hydrocracker is 2 wt % of the crude).

(3) The products that are derived from the crude oil are divided into petrochemicals (olefins and BTXE, which is an acronym for BTX+ethylbenzene) and other products (hydrogen, methane and heavy fractions comprising C9 resin feed, cracked distillate, carbon black oil and resid). The total amount sums up to 100% of the total crude, since the resid is also taken into account. From the product slate of the crude oil the carbon efficiency is determined as:
(Total Carbon Weight in petrochemicals)/(Total Carbon Weight in Crude).

(4) Table 1 as provided herein below displays the total product slate from the steam cracker (cracked products of lights, naphtha and LPG) and from the gasoline hydrocracker (BTX product) in wt % of the total crude. The product slate also contains the pitch of the resid hydrocracker (2 wt % of the crude).

EXAMPLE 2 (COMPARATIVE)

(5) Example 2, also according to WO 2015/000848 A1, is identical to Example 1 except that the gases fraction and the LPG produced by the various units is separated into ethane-, propane- and butane fractions which are steam cracked in dedicated steam cracker furnaces.

EXAMPLE 3

(6) Example 3 is identical to the Example 2 except that the naphtha fraction and the light-distillates are not subjected to gasoline hydrocracking but are directly fed to the steam cracker. The C4 raffinate (remaining crude C4 produced by the steam cracker after separation of the butadiene, 1-butene and isobutene) is hydrogenated and recycled to the steam cracker as well as the C5 and C6 raffinate. The results are provided in table 1 as provided herein below.

(7) TABLE-US-00001 TABLE 1 Example 1 Example 2 Example (comparative) (comparative) 3 Petrochemicals (wt-% of crude) Ethylene 20.6 42.1 42.5 Propylene 40.2 10.8 14.2 Butadiene 0.0 2.0 3.2 1-butene 7.8 1.0 1.0 Isobutene 2.0 1.0 1.0 Isoprene 0.0 0.0 0.2 CPTD 0.0 0.0 0.9 Benzene 3.9 4.9 6.0 Toluene 7.8 8.8 5.6 Xylene 4.9 4.9 2.7 Ethylbenzene 0.0 0.0 0.8 Other components (wt-% of crude) hydrogen 3.9 2.0 2.2 methane 4.9 18.6 17.9 Heavy 0.0 0.0 0.0 components Resid 2.0 2.0 2.0 hydrocracker pitch Carbon 93.2 80.6 83.7 efficiency