PROCESSES FOR PRODUCING AROMATIC AND OLEFINIC COMPOUNDS
20220135497 · 2022-05-05
Assignee
Inventors
- Travis CONANT (Sugar Land, TX, US)
- Dustin FICKEL (Sugar Land, TX, US)
- Raul Velasco Pelaez (Sugar Land, TX, US)
- Joseph William SCHROER (Sugar Land, TX, US)
Cpc classification
C10G69/06
CHEMISTRY; METALLURGY
C10G69/00
CHEMISTRY; METALLURGY
C10G69/10
CHEMISTRY; METALLURGY
C07C4/025
CHEMISTRY; METALLURGY
C10G69/08
CHEMISTRY; METALLURGY
International classification
C07C4/02
CHEMISTRY; METALLURGY
Abstract
Disclosed are systems and processes to produce aromatic and olefinic compounds by aromatization and thermal cracking of hydrocarbons.
Claims
1. A process to produce aromatic and olefinic compounds, the process comprising: (a) contacting a C6 to C8 hydrocarbons feed stream with an aromatization catalyst under conditions suitable to aromatize at least a portion of the C6 to C8 hydrocarbons and produce a crude products stream comprising C6 to C8 aromatic hydrocarbons and unreacted C6 to C8 hydrocarbons; and (b) thermally cracking at least a portion of the unreacted C6 to C8 hydrocarbons to produce olefins, pyrolysis oil, pyrolysis gas, or a combination thereof, and/or recycling at least a portion of the unreacted C6 to C8 hydrocarbons to step (a) to increase production of C6 to C8 aromatic hydrocarbons; wherein the selectivity for C6 to C8 aromatic hydrocarbons produced from the step (a) C6 to C8 hydrocarbons feed stream is at least 90% and selectivity to methane produced in step (a) is less than 5%.
2. The process of claim 1, wherein the C6 to C8 hydrocarbons feed stream comprises 30 to 99 wt. % C6 hydrocarbons.
3. The process of claim 2, wherein the C6 to C8 hydrocarbons feed stream comprises 50 to 70 wt. % C6 hydrocarbons, 20 to 30% C7 hydrocarbons, and 5 to 15% C8 hydrocarbons.
4. The process of claim 1, wherein the process further comprises: (i) separating the crude product stream from step (a) into a C6 to C8 aromatic hydrocarbons product stream and an unreacted C6 to C8 hydrocarbons stream; and (ii) recovering C6 aromatic hydrocarbons, C7 aromatic hydrocarbons, and/or C8 aromatic hydrocarbons from the C6 to C8 aromatic hydrocarbons product stream.
5. The process of claim 4, further comprising recycling at least a portion of the unreacted C6 to C8 hydrocarbons stream to step (a).
6. The process of claim 4, further comprising cracking at least a portion of the unreacted C6 to C8 hydrocarbons stream to produce olefins, pyrolysis oil, pyrolysis gas or a combination thereof.
7. The process of claim 1, further comprising prior to step (a): separating a C4+ hydrocarbons stream into a C5− hydrocarbons stream, the C6 to C8 hydrocarbons feed stream of step (a), and a C9+ hydrocarbons stream; and providing the C5− hydrocarbons stream to step (b) and cracking the C5− hydrocarbons to produce additional pyrolysis oil, pyrolysis gas, olefins, or combinations thereof.
8. The process of claim 2, further comprising prior to step (a): separating a C4+ hydrocarbons stream into a C5− hydrocarbons stream, the C6 to C8 hydrocarbons feed stream of step (a), and a C9+ hydrocarbons stream; and providing the C5− hydrocarbons stream to step (b) and cracking the C5− hydrocarbons to produce additional pyrolysis oil, pyrolysis gas, olefins, or combinations thereof.
9. The process of claim 8, further comprising hydrocracking the C9+ hydrocarbons stream under conditions suitable to produce a crude hydrocarbon stream comprising additional C6 to C8 hydrocarbons, optional unreacted C9+ hydrocarbons, and optional C1 to C4 hydrocarbons.
10. The process of claim 9, further comprising separating the crude hydrocarbon stream into an additional C6 to C8 hydrocarbons product stream, an optional unreacted C9+ hydrocarbons stream, and an optional C1 to C4 hydrocarbons stream and providing the additional C6 to C8 hydrocarbons stream to step (a).
11. The process of claim 10, further comprising cracking at least a portion of the step (a) unreacted C6 to C8 hydrocarbons, the additional C6 to C8 hydrocarbons, the unreacted C9+ hydrocarbons, the C5− hydrocarbons, or any combination thereof.
12. The process of claim 10, wherein the crude product stream of step (a) further comprises gaseous C1 to C4 hydrocarbons and the process further comprises separating a C1 to C4 hydrocarbons stream from the crude product stream and optionally providing to a light gas aromatization unit, a thermal cracking unit, or a furnace the separated C1 to C4 hydrocarbons stream from the crude product stream of step (a) and/or the optional C1 to C4 hydrocarbons stream from the crude hydrocarbon stream from the hydrocracked C9+ hydrocarbons stream.
13. The process of claim 1, wherein the pyrolysis gas comprises C5 to C10 olefins, C5 to C10 paraffinic compounds and C5 to C10 aromatic compounds, and the process further comprises separating a C6 to C8 nonaromatic hydrocarbons stream from the pyrolysis gas and providing at least a portion of the C6 to C8 nonaromatic hydrocarbons stream to step (a) and contacting the C6 to C8 nonaromatic hydrocarbons with the aromatization catalyst to produce additional C6 to C8 aromatic hydrocarbons.
14. The process of claim 13, further comprising subjecting the pyrolysis gas to: (iii) hydrotreating; and (iv) fractionation to produce an additional C5− hydrocarbons stream, a third C6 to C8 hydrocarbons stream, and an additional C9+ hydrocarbons stream.
15. The process of claim 14, further comprising: (v) subjecting the third C6 to C8 hydrocarbons stream to an extraction process to produce an additional C6 to C8 aromatic hydrocarbons stream and a C6 to C8 nonaromatic hydrocarbons stream; and (vi) providing a portion of the C6 to C8 nonaromatic hydrocarbons stream to step (a) and producing additional aromatic hydrocarbons.
16. The process of claim 15, wherein at least one of steps (iii) to (vi) are processed in a step (a) aromatization unit.
17. The process of claim 1, wherein the C6 to C8 hydrocarbons feed stream is obtained from shale oil condensate, naphtha or both.
18. The process of claim 1, wherein the aromatization step (a) conditions comprise a temperature of 450 to 650° C., a pressure of 0.03 to 2.17 MPa, and/or a WHSV of 1 to 100 h.sup.−1, and/or the thermal cracking step (b) conditions comprise a temperature of 750 to 900° C., a pressure of 0.1 to 0.3 MPa, and/or a and residence times of 50 to 1000 milliseconds.
19. The process of claim 1, wherein the C6 to C8 hydrocarbons feed stream comprises linear C6 to C8 hydrocarbons.
20. The process of claim 3, further comprising prior to step (a): separating a C4+ hydrocarbons stream into a C5− hydrocarbons stream, the C6 to C8 hydrocarbons feed stream of step (a), and a C9+ hydrocarbons stream; and providing the C5− hydrocarbons stream to step (b) and cracking the C5− hydrocarbons to produce additional pyrolysis oil, pyrolysis gas, olefins, or combinations thereof.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Advantages of the present invention may become apparent to those skilled in the art with the benefit of the following detailed description and upon reference to the accompanying drawings.
[0029]
[0030]
[0031]
[0032] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings. The drawings may not be to scale.
DETAILED DESCRIPTION OF THE INVENTION
[0033] A discovery has been made that provides a solution to the current problems associated with low C6 aromatic hydrocarbons selectivity and high methane selectivity obtained by thermal cracking of a hydrocarbon mixture (e.g., shale oil condensate, naphtha and like). The solution is premised on using an aromatization unit in combination with a thermal cracking unit to produce C6 aromatic hydrocarbons, preferably, benzene, in selectivities of greater than 90%.
[0034] These and other non-limiting aspects of the present invention are discussed in further detail in the following paragraphs with reference to the figures.
[0035] Referring to
[0036] Referring to
[0037] Referring to
[0038] A hydrocarbons stream 214 can be fed to the separation unit 202. In the separation unit 202, the hydrocarbon stream 214 can be separated into a C5− hydrocarbons stream 218, a C6 to C8 hydrocarbons stream 216 and a C9+ hydrocarbons stream 220. The C5− hydrocarbons stream 218 can be fed to the thermal cracking unit 206. The C6 to C8 hydrocarbons stream can be fed to the C6+ aromatization unit 204. The C9+ hydrocarbons stream 220 can be fed to the hydrocracking unit 208.
[0039] In the C6+ aromatization unit 204, C6 to C8 hydrocarbons can be contacted with an aromatization catalyst under conditions suitable to aromatize at least a portion of the C6 to C8 hydrocarbons and produce a crude product stream that includes C6 to C8 aromatic hydrocarbons, unreacted C6 to C8 hydrocarbons, and C1 to C4 hydrocarbons. The crude product stream can be separated into a C6 to C8 aromatic hydrocarbons stream 222, an unreacted C6 to C8 hydrocarbons stream 224, and a C1 to C4 hydrocarbons stream 240. The unreacted C6 to C8 hydrocarbons stream 224 can be fed to the thermal cracking unit 206. In some aspects, a portion 226 of the unreacted C6 to C8 hydrocarbons stream 224 can be fed back to the C6+ aromatization unit 204 (not shown) and/or, as shown in
[0040] In the disproportionation unit 210, a C6 aromatic hydrocarbon stream 246, a C7 aromatic hydrocarbon stream 248, and a C8 aromatic hydrocarbon stream 250 can be produced from the C6 to C8 aromatic hydrocarbons stream 222. The disproportionation unit can include reactors/reaction systems for converting one aromatic to another aromatic. For example, trans-alkylation unit can be included to convert toluene into benzene and xylenes, isomerization units can be included to convert ortho- and/or meta-xylene into para-xylene. Hydrodealkylation units can be included to convert toluene, and/or xylenes, and/or ethylbenzene into benzene in the presence of hydrogen. Hydrodealkylation can be performed thermally or catalytically. The disproportionation unit can also include internal recycles and any various sequence for processing aromatics that is known in the art or that could be conceived to be implemented. The disproportionation unit can separate at least a portion of stream 222 and disproportionation unit internal streams into any other combination of product streams (not shown), for example, a purified benzene stream and a stream containing both toluene and C8 aromatic hydrocarbons.
[0041] In the hydrocracking unit 208, by hydrocracking of C9+ hydrocarbons under suitable condition a crude hydrocarbon stream comprising C6 to C8 hydrocarbons, optionally unreacted C9+ hydrocarbons, and optionally C1 to C4 hydrocarbons can be produced. The hydrogen generated in the aromatization units and/or thermal cracking units can be used as a hydrogen source in the hydrocracking unit 208. In some embodiments, the conditions are adjusted to produce mostly C1 to C4 hydrocarbons, which can then be used as fuel for other processing units (e.g., naphtha cracking furnace). The crude product stream can be separated into a C6 to C8 hydrocarbons stream 234, an optional unreacted C9+ hydrocarbons stream 236, if the crude hydrocarbon stream includes unreacted C9+ hydrocarbons, and an optional C1 to C4 hydrocarbons stream 238, if the crude hydrocarbon stream includes C1 to C4 hydrocarbons. The C6 to C8 hydrocarbons stream 234 can be fed to the aromatization unit 204 (not shown) and/or, as shown in
[0042] In the thermal cracking unit 206, by thermal cracking of C5− hydrocarbons, a portion of the unreacted C6 to C8 hydrocarbons, C9+ hydrocarbons or any combination thereof, under suitable condition, pyrolysis gas 228, pyrolysis oil 230, and olefins 232 can be produced.
[0043] The pyrolysis gas streams 128, 228 can include C5 to C10 olefins, C5 to C10 paraffins, and C6 to C10 aromatic compounds.
[0044] In some aspects, the hydrocarbons streams 114, 214 can include C4+ hydrocarbons. In some aspects the hydrocarbons streams 114, 214 are obtained from shale oil condensate, naphtha, or both. Separation of hydrocarbons in the separation unit 102, 202 can be obtained by any suitable methods known in the art e.g., distillation, fractionation, pressure swing adsorption, and the like. In some aspects, the C6 to C8 hydrocarbon stream 116, 216 can include at least any one of, equal to any one of, or between any two of 30%, 40%, 50%, 60%, 70%, 80%, 90% and 99% C6 hydrocarbons. In certain particular aspects, the C6 to C8 hydrocarbon stream 116, 216 can include at least any one of, equal to any one of, or between any two of 50%, 55%, 60%, 65%, and 70% C6 hydrocarbons, at least any one of, equal to any one of, or between any two of 20%, 25%, and 30% C7 hydrocarbons at least any one of, equal to any one of, or between any two of 5%, 10%, and 15% C8 hydrocarbons. In some aspects, the C6 to C8 hydrocarbon stream 116, 216 can include linear C6 to C8 hydrocarbons.
[0045] The aromatization reaction condition in the C6+ aromatization units 104, 204 and/or light gas aromatization unit 212 can include a temperature of at least any one of, equal to any one of, or between any two of 450° C., 500° C., 550° C., 600° C. and 650° C., a pressure of at least any one of, equal to any one of, or between any two of 0.03 MPa, 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa, 1 MPa, 1.2 MPa, 1.4 MPa, 1.6 MPa, 1.8 MPa, 2 MPa and 2.17 MPa, and/or a WHSV of at least any one of, equal to any one of, or between any two of 1 h.sup.−1, 10 h.sup.−1, 20 h.sup.−1, 30 h.sup.−1, 40 h.sup.−1, 50 h.sup.−1, 60 h.sup.−1, 70 h.sup.−1, 80 h.sup.−1, 90 h.sup.−1, and 100 h.sup.−1. The aromatization catalyst of the C6+ aromatization unit 104, 204, or the light gas aromatization unit can be any aromatization catalyst known in the art. In some aspects, the aromatization catalyst can also catalyze skeletal isomerization of hydrocarbons, for example, the aromatization catalyst can catalyze in-situ isomerization of iso-hexane to n-hexane and subsequent aromatization of n-hexane to benzene. In some aspects, the aromatization catalyst can include a non-acidic aluminum-silicon-germanium zeolite on which a noble metal has been dispersed. The noble metal can be platinum, palladium, iridium, rhodium and ruthenium. The zeolite can be ZSM-5, ZSM-8, ZSM-11, ZSM-12, ZSM-35, ZSM-38 or any combination thereof. In certain particular aspects, the aromatization catalyst can include highly dispersed platinum on a GeZSM-5 that has been treated with alkali metal(s). The aromatization catalyst can be an aromatization catalyst as described in U.S. Pat. No. 6,784,333 to Juttu et al., and U.S. Pat. No. 7,902,413 to Stevenson et al, which are incorporated herein by reference. For example, the catalyst can be represented as: M[(SiO.sub.2)(XO.sub.2).sub.x(YO.sub.2).sub.y]Z.sup.+.sub.y/n where M is a noble metal, such as platinum, palladium, rhodium, iridium, ruthenium or combinations thereof, X is a tetravalent element, Y is aluminum and, optionally, another trivalent element, Z is a cation or combination of cations with a valence of n, such as H.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, Ca.sup.2+, Mg.sup.2+, Sr.sup.2+ or Ba.sup.2+, and x varies from 0-0.15 and y is 0-0.125. According to the IUPAC recommendations, an example catalyst would be represented as: Cs.sup.+Pt[Si.sub.91Ge.sub.4Al.sub.1O.sub.192]-MFI or H.sup.+Pt[Si.sub.91Ge.sub.4Al.sub.1O.sub.192]-MFI. In some aspects, aromatization unit 104, 204 can include, an aromatization reactor, a hydrotreating reactor and a fractionator.
[0046] The thermal cracking reaction condition in the thermal cracking unit 106, 206 can include a temperature of at least of any one of, equal to any one of, or between any two of 750° C., 800° C., 850° C., and 900° C., a pressure of at least of any one of, equal to any one of, or between any two of 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, and 0.3 MPa, and/or residence times of at least any one, equal to any one, or between any two of 50 milliseconds, 100 milliseconds, 200 milliseconds, 300 milliseconds, 400 milliseconds, 500 milliseconds, 600 milliseconds, 700 milliseconds, 800 milliseconds, 900 milliseconds, and 1000 milliseconds.
[0047] In
EXAMPLES
[0048] The present invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes only, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters which can be changed or modified to yield essentially the same results.
Example 1
Producing Aromatic and Olefinic Compounds from Saudi Light Naphtha (A-180)
[0049] Example 1 describes calculations for producing aromatic and olefinic compounds by aromatization and thermal cracking of Saudi Light Naphtha (A-180) using SPYRO® (Technip Benelux BV). In the first calculation, experiment 1, naphtha was fed to a thermal cracker and was thermally cracked. In another calculation, experiment 2, naphtha was separated into a C5− hydrocarbons stream, C6-C8 hydrocarbons stream and a C9+ hydrocarbons stream. The C6-C8 hydrocarbons stream was fed into an aromatization unit and was aromatized. The C5− hydrocarbons stream, and the C9+ hydrocarbons stream was fed to a thermal cracker and was thermally cracked. Data presented in Table 1 shows yield and production differences between the two calculations. The weight percentage yield of the C6 to C8 aromatics increased from 12 to 24% between calculation 1 and calculation 2. Moreover, overall useful product yield (total yield of C2 hydrocarbons, C3 hydrocarbons, C4 hydrocarbons and benzene) was increased by 3% in calculation 2 compared to calculation 1.
TABLE-US-00001 TABLE 1 Difference in Calculation 1 Calculation 2 production Products (kta) (kta) (MMUSD) CO.sub.2 9.9 8.4 (1.5) Hydrogen 51.7 100.8 49.1 Methane 743.6 635.3 (108.2) Ethylene - polymer grade 1484.7 1199.8 (284.9) Propylene - polymer grade 712.0 603.3 (108.7) Butadiene 220.6 187.1 (33.5) MTBE 180.0 171.6 (8.4) Butene-1 55.3 45.5 (9.7) Benzene 315.7 842.4 526.7 Toluene 93.3 84.2 (9.1) C8 aromatics 18.7 17.1 1.6 C9 aromatics 1.2 1.1 (0.1) Full range pyrolysis oil 113.4 103.4 (10.0) Total 4000.0 4000.0 0.0
Example 2
Reformation of Separated Gas Stream
[0050] Example 2 describes calculations for producing aromatic and olefinic compounds from a C6 hydrocarbons stream. Parallel calculations were run. In one calculation, experiment 3, a C6 hydrocarbons steam, from Saudi Light Naphtha (A-180), was fed to a thermal cracking unit and was thermally cracked. In another calculation, experiment 4, a C6 hydrocarbons stream, from Saudi Light Naphtha (A-180), was fed to an aromatization unit and was aromatized. Table 2 shows the wt. % yield of the products obtained in the experiments 3 and 4. The weight percentage yield of useful products (total yield of C2 hydrocarbons, C3 hydrocarbons, C4 hydrocarbons and benzene) was increased from 78% to 90% between experiments 3 and 4. Methane wt. % yield was decreased from 17% to 1% between experiments 3 and 4.
TABLE-US-00002 TABLE 2 Experiment 3 Experiment 4 Products (Wt. %) (Wt. %) CO.sub.2 0.2 0.01 Hydrogen 1.3 9.01 Methane 17.1 0.88 Ethylene - polymer grade 49.1 1.51 Propylene - polymer grade 17.3 0.60 Butadiene 5.3 0.10 MTBE 0.5 0.24 Butene-1 1.6 0.03 Benzene 4.7 87.55 Toluene 1.2 0.03 C8 aromatics 0.2 0.01 C9 aromatics 0.0 0.00 Full range pyrolysis oil 1.5 0.03 Total 100.0 100.0
[0051] 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 can be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.