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US-12624300-B2 - Cyclization and fluid catalytic cracking systems and methods for upgrading naphtha

US12624300B2US 12624300 B2US12624300 B2US 12624300B2US-12624300-B2

Abstract

A process for upgrading a naphtha feed includes separating the naphtha feed into at least a light naphtha fraction, contacting the light naphtha fraction with hydrogen in the presence of at least one cyclization catalyst, and contacting the cyclization effluent with at least one cracking catalyst. Contacting the light naphtha fraction with hydrogen in the presence of at least one cyclization catalyst may produce a cyclization effluent comprising a greater concentration of naphthenes compared to the light naphtha fraction. Contacting the cyclization effluent with at least one cracking catalyst under conditions sufficient crack at least a portion of the cyclization effluent may produce a fluid catalytic cracking effluent comprising light olefins, gasoline blending components, or both. A system for upgrading a naphtha feed includes a naphtha separation unit, a cyclization unit disposed downstream of the naphtha separation unit, and a fluid catalytic cracking unit disposed downstream of the cyclization unit.

Inventors

  • Omer Refa Koseoglu

Assignees

  • SAUDI ARABIAN OIL COMPANY

Dates

Publication Date
20260512
Application Date
20240320

Claims (16)

  1. 1 . A process for separating and upgrading a naphtha feed, the process comprising: passing the naphtha feed to a naphtha separation unit that separates the naphtha feed into at least a light naphtha fraction and a heavy naphtha fraction; passing the light naphtha fraction to a cyclization unit that contacts the light naphtha fraction with hydrogen in the presence of at least one cyclization catalyst to produce a cyclization effluent comprising a greater concentration of naphthenes compared to the light naphtha fraction, wherein the at least one cyclization catalyst comprises ultra-stable Y-type (USY) zeolite; passing the cyclization effluent to a fluid catalytic cracking unit that contacts the cyclization effluent with at least one cracking catalyst under conditions sufficient to crack at least a portion of the cyclization effluent to produce a fluid catalytic cracking effluent comprising light olefins, gasoline blending components, or both; passing the heavy naphtha fraction to a naphtha reforming unit that contacts the heavy naphtha fraction with at least one reforming catalyst to undergo one or more reactions under conditions sufficient to produce a reformate effluent, wherein the at least one reforming catalyst consists of: a precious metal selected from the group consisting of platinum, palladium, and combinations thereof; and a catalyst support selected from the group consisting of alumina, silica, titania, and combinations thereof.
  2. 2 . The process of claim 1 , wherein a supplemental fluid catalytic cracking feed is combined with the cyclization effluent.
  3. 3 . The process of claim 2 , wherein the supplemental fluid catalytic cracking feed comprises vacuum gas oil, demetallized oil, atmospheric residue, or combinations of these.
  4. 4 . The process of claim 1 , wherein the at least one cyclization catalyst comprises from 0.01 weight percent to 40 weight percent iron, cobalt, nickel, rhodium, palladium, silver, iridium, platinum, gold, molybdenum, tungsten, or combinations thereof.
  5. 5 . The process of claim 1 , wherein the light naphtha fraction is contacted with hydrogen in the presence of the at least one cyclization catalyst at a molar ratio of hydrogen to light naphtha fraction of from 1 to 10.
  6. 6 . The process of claim 1 , wherein the light naphtha fraction is contacted with hydrogen in the presence of the at least one cyclization catalyst at a pressure of from 10 bar to 40 bar.
  7. 7 . The process of claim 1 , wherein the light naphtha fraction is contacted with hydrogen in the presence of the at least one cyclization catalyst at a temperature of from 350 degrees Celsius to 550 degrees Celsius.
  8. 8 . The process of claim 1 , further comprising combining a portion of the fluid catalytic cracking effluent and the reformate effluent to produce gasoline.
  9. 9 . The process of claim 8 , wherein the gasoline comprises an octane number greater than 100.
  10. 10 . The process of claim 1 , wherein the cyclization effluent comprises greater than 30 wt. % naphthenes based on the total weight of the cyclization effluent.
  11. 11 . The process of claim 1 , wherein the USY zeolite comprises a crystal lattice constant from 2.430 nanometers to 2.450 nanometers and a specific surface area from 600 square meters per gram to 900 square meters per gram.
  12. 12 . The process of claim 1 , wherein the at least one cyclization catalyst comprises from 1 weight percent to 80 weight percent framework-substituted ultra-stable Y-type zeolite based on the total weight of the at least one cyclization catalyst and an active phase metal selected from the group consisting of, iron, cobalt, nickel, rhodium, palladium, silver, iridium, platinum, gold, molybdenum, tungsten and combinations thereof, supported on the framework-substituted ultra-stable Y-type zeolite.
  13. 13 . The process of claim 12 , wherein the at least one cyclization catalyst comprises from 0.01 weight percent to 40 weight percent of the active phase metal.
  14. 14 . The process of claim 1 , further comprising passing a portion of the fluid catalytic cracking effluent, at least a portion of the reformate effluent, or both to an aromatic recovery complex to produce benzene, toluene, xylene, or combinations of these.
  15. 15 . The process of claim 1 , further comprising contacting the naphtha feed with hydrogen in the presence of a desulfurization catalyst in a desulfurization unit prior to separating the naphtha feed into the light naphtha fraction and the heavy naphtha fraction, wherein the contacting causes at least a portion of sulfur components to be removed from the naphtha feed to produce a desulfurized naphtha feed.
  16. 16 . The process of claim 1 , wherein the desulfurized naphtha feed comprises less than or equal to 0.5 parts per million by weight of sulfur compounds and less than or equal to 0.5 parts per million by of weight nitrogen compounds based on the total weight of the desulfurized naphtha feed.

Description

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation application of U.S. patent application Ser. No. 17/150,012, filed Jan. 15, 2021, the entire contents of which are hereby incorporated by reference in the present disclosure. BACKGROUND Field The present disclosure generally relates to processes and systems for upgrading hydrocarbons, more specifically, systems and processes for upgrading naphtha to greater value chemical products and intermediates. Technical Background Hydrocarbon feeds, such as naphtha, can be converted to chemical products and intermediates such as olefins and aromatic compounds, which are basic intermediates for a large portion of the petrochemical industry. The worldwide increasing demand for light olefins and aromatic compounds remains a major challenge for many integrated refineries. In particular, the production of some valuable light olefins, such as ethylene, propene, and butenes, has attracted increased attention as pure olefin streams are considered the building blocks for polymer synthesis. Additionally, aromatic compounds such as benzene, toluene, ethylbenzene, and xylenes can be valuable intermediates for synthesizing polymers and other organic compounds as well as for fuel additives. Further the processing of naphtha streams, such as light naphtha, may be desirable, as light naphtha possess a low octane number and its use in gasoline production is limited. SUMMARY Light naphtha, which is generally described as a C5-C6 hydrocarbon, may be produced by routine refinery processes or gas plants. Light naphtha possesses a low octane number. Typically, the octane number of light naphtha may range from 40 to 60. Over time, light naphtha has become relatively limited for use as a blending stock for gasoline production due to this low octane number. Light naphtha may be isomerized to increase its octane number and be used in gasoline blending despite its vapor pressure limitations. Light naphtha may also be commonly used as a feed for a stream cracker for light olefin production. However, the transformation of light naphtha into desirable gasoline-blending components or desirable chemicals is an ongoing challenge. The fluid catalytic cracking (FCC) unit is one of the primary hydrocarbon conversion units in the modern petroleum refinery. The FCC unit may predominantly produce gasoline in a conventional FCC unit, or produce propylene in a high severity FCC unit. In high severity FCC units, the hydrocarbons may be converted to gasoline over a cracking catalyst, which can also be converted to olefins over a cracking catalyst additive. In FCC processes, hydrocarbons are catalytically cracked with an acidic catalyst maintained in a fluidized state. One of the main products from such processes has typically been gasoline. The gasoline and other hydrocarbon products may be further cracked to light olefins, such as ethylene, propylene, butenes, or combinations of these, during the FCC process. Despite the many advances in FCC processes, upgrading light naphtha in an FCC process is limited due to the paraffins in the light naphtha are not being reactive in the FCC process. The industry is constantly seeking improved systems and methods for upgrading hydrocarbons, including light naphtha, to produce greater value products and intermediates. Accordingly, there is an ongoing need for systems and methods of upgrading hydrocarbons, such as light naphtha, to increase the efficiency of the upgrading process and improve yields of desired products, such as gasoline-blending components and light olefins. As FCC processes are typically used to produce gasoline and gasoline-blending components, there has been a desire to process light naphtha in FCC units to use light naphtha for gasoline blending. The present disclosure is directed to systems and methods for upgrading naphtha feeds to produce greater value products and intermediates, such as gasoline-blending components, light olefins, or both, by cyclizing and cracking light naphtha. Cyclizing the light naphtha may convert a portion of paraffins in the light naphtha to naphthenes, which are more reactive in FCC process compared to the non-reactive paraffins. According to one or more aspects of the present disclosure, a process for separating and upgrading a naphtha feed may include passing the naphtha feed to a naphtha separation unit that separates the naphtha feed into at least a light naphtha fraction and a heavy naphtha fraction. The process may further include passing the light naphtha fraction to a cyclization unit. The cyclization unit may contact the light naphtha fraction with hydrogen in the presence of at least one cyclization catalyst to produce a cyclization effluent. The cyclization effluent may comprise a greater concentration of naphthenes compared to the light naphtha fraction. The process may further include passing the cyclization effluent to a fluid catalytic cracking (FCC) unit. The FCC unit may contact the cycl