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US-12618016-B2 - Methods for producing aviation fuels

US12618016B2US 12618016 B2US12618016 B2US 12618016B2US-12618016-B2

Abstract

Processes for making aviation fuels include a step of forming a C 16− olefin stream by oligomerizing a mixture of decenes with a C 6− alpha-olefin or by subjecting the mixture of decenes and a C 8− alpha-olefin to metathesis. The C 16− olefin stream is then hydrogenated to form C 16− paraffins, and these C 16− paraffins can be used to form an aviation fuel. Particular C 11 -C 16 olefin compositions and paraffin compositions prepared by these processes also are described.

Inventors

  • Thomas J. Malinski
  • MICHAEL S. WEBSTER-GARDINER
  • Steven M. Bischof
  • James L. Hillier
  • Jeffery C. Gee
  • Spencer A. Kerns
  • Reza KHANKAL
  • Jared T. Fern

Assignees

  • CHEVRON PHILLIPS CHEMICAL COMPANY LP

Dates

Publication Date
20260505
Application Date
20240819

Claims (16)

  1. 1 . A process for making a C 16 -olefin stream, the process comprising: (a) contacting an ethylene feed with a first catalyst system comprising a first oligomerization catalyst to form an oligomerization product comprising at least one C 4 -C 8 alpha-olefin and a mixture of decenes; (b) separating the mixture of decenes from the oligomerization product; (c) contacting the mixture of decenes with at least one C 6− alpha-olefin in the presence of a second catalyst system comprising a second oligomerization catalyst to provide the C 16− olefin stream; (d) optionally, hydrogenating the C 16− olefin stream in the presence of a first hydrogenation catalyst to provide C 16− paraffins; and (e) optionally, blending the C 16− paraffins as a component to form an aviation fuel.
  2. 2 . The process of claim 1 , wherein the at least one C 6− alpha-olefin comprises propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, or a combination thereof.
  3. 3 . The process of claim 1 , wherein the mixture of decenes comprises 1-decene, 2-butyl-1-hexene, 3-propyl-1-heptene, 4-ethyl-1-octene, 5-methyl-1-nonene, 4-decene, 5-decene, or any combination thereof.
  4. 4 . The process of claim 3 , wherein the mixture of decenes comprises from 76 mol % to 95 mol % C 10 monoolefins.
  5. 5 . The process of claim 1 , wherein the oligomerization product comprises 1-butene, 1-hexene, 1-octene, dodecenes, tetradecenes, or any combination thereof.
  6. 6 . The process of claim 1 , wherein the oligomerization product comprises: at least 60 mol % 1-hexene, at least 60 mol % 1-octene, or at least 60 mol % 1-hexene and 1-octene combined; or from 70 wt. % to 99.8 wt. % hexene or from 70 wt. % to 99.8 wt. % octene, and at least 0.2 wt. % of the mixture of decenes.
  7. 7 . The process of claim 1 , wherein the first catalyst system, the second catalyst system, or both comprise independently a chromium-based catalyst, a metallocene-based catalyst, a Ziegler-Natta based catalyst, a metal-oxide supported Group 6-10 transition metal-based catalyst, or a combination thereof.
  8. 8 . The process of claim 7 , wherein the first catalyst system, the second catalyst system, or both further comprise a metal alkyl compound selected from an organoaluminum compound, an organoaluminoxane, an organoboron compound, an organozinc compound, an organomagnesium compound, an organolithium compound, or any combination thereof.
  9. 9 . The process of claim 1 , wherein the first catalyst system, the second catalyst system, or both comprise independently a chromium-based catalyst, and the chromium-based catalyst comprises (a) a chromium-containing compound, (b) a heteroatomic ligand, (c) a metal alkyl compound, and (d) optionally, a diluent.
  10. 10 . The process of claim 9 , wherein the heteroatomic ligand is selected from a pyrrole compound, a diphosphino aminyl compound, an N 2 -phosphinyl amidine compound, an N 2 -phosphinyl formamidine compound, or combinations thereof.
  11. 11 . The process of claim 10 , wherein the diluent is present and comprises a hydrocarbon, a halogenated hydrocarbon, or combinations thereof.
  12. 12 . The process of claim 1 , wherein the first catalyst system, the second catalyst system, or both independently comprise: (a) molybdenum oxide on alumina (MoO 3 /Al 2 O 3 ), tungsten oxide on silica (WO 3 /SiO 2 ), tungsten oxide on silica-alumina (WO 3 /SiO 2 /Al 2 O 3 ), rhenium oxide on alumina (Re 2 O 7 /Al 2 O 3 ), cobalt oxide and molybdenum oxide on alumina (CoO/MoO 3 /Al 2 O 3 ), rhenium oxide on alumina activated with tetramethyl tin (Re 2 O 7 /Al 2 O 3 /SnMe 4 ), or any combination thereof; or (b) tungstated zirconium, molybdenum zirconium, nickel and/or cobalt doped tungstated zirconium, nickel and/or cobalt doped molybdenum zirconium catalysts, a Group 3 to Group 12 metal-treated zeolite, or combinations thereof.
  13. 13 . The process of claim 1 , wherein the first hydrogenation catalyst comprises: (a) a heterogeneous catalyst selected from a Group 8-12 metal deposited on a carrier selected from carbon, silica, alumina, silica-alumina, a zeolite, or calcium carbonate; or (b) a homogeneous catalyst selected from (i) a Ziegler catalyst comprising an organic salt of a Group 6-10 metal and an organoaluminum compound, or (ii) a coordination compound of Ru, Rh, or Ir, or (iii) a Group 4 metal organometallic compound.
  14. 14 . The process of claim 1 , wherein the C 16− olefin stream comprises: (1) 2-methyl-4-butyl-3-octene, 2-methyl-5-propylnon-3-ene, 6-ethyl-2-methyldec-3-ene, and/or 2,7-dimethylundec-3-ene; (2) 5-butyl-3-methylnon-4-ene, 3-methyl-6-propyldec-4-ene, 7-ethyl-3-methylundec-4-ene, and/or 3,8-dimethyldodec-4-ene; (3) 2,2-dimethyl-4-butyl-3-octene, 2,2-dimethyl-5-propyl-3-nonene, 2,2-dimethyl-6-ethyl-3-decene, and/or 2,2,7-trimethyl-3-undecene; (4) 6-butyl-4-methyldec-5-ene, 4-methyl-7-propylundec-5-ene, 8-ethyl-4-methyldodec-5-ene, and/or 4,9-dimethyltridec-5-ene; or (5) 5-butyl-7-methylundec-5-ene, 5-methyl-8-propyldodec-6-ene, 9-ethyl-5-methyltridec-6-ene, and/or 5,10-dimethyltetradec-6-ene.
  15. 15 . The process of claim 1 , wherein: at least a portion of the ethylene feed is a bio-ethylene feed; and the aviation fuel is formed and is a sustainable aviation fuel.
  16. 16 . The process of claim 15 , wherein: (a) the sustainable aviation fuel is certified as compliant with the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) sustainability criteria in accordance with the International Sustainability and Carbon Certification (ISCC) CORSIA certification system; or (b) the sustainable aviation fuel is certified as a Lower Carbon Aviation Fuel (LCAF) in accordance with the International Sustainability and Carbon Certification (ISCC) LCAF certification system; wherein the certification is based upon the weight or fraction of the sustainable aviation fuel attributable to the biomass ethanol determined by mass balance and a free attribution method.

Description

REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part application of co-pending U.S. patent application Ser. No. 18/462,567, filed on Sep. 7, 2023, now U.S. Pat. No. 12,528,999, and a continuation-in-part application of co-pending U.S. patent application Ser. No. 18/462,558, also filed on Sep. 7, 2023, now U.S. Pat. No. 12,540,287, the disclosures of which are incorporated herein by reference in their entirety. FIELD OF THE INVENTION The present disclosure generally relates to methods for making aviation fuels, and more particularly, relates to such methods that include a step of reacting particular alpha-olefins with a mixture of decenes in the presence of an oligomerization catalyst or a metathesis catalyst. BACKGROUND OF THE INVENTION Although the jet fuel market is smaller than the gasoline and diesel fuel markets, it still constitutes some 25% of the total transportation fuel consumption and currently exceeds 26 billion gallons per year in the U.S. alone. Market growth in jet fuels is expected to approximately double over the next 20 years, while the gasoline markets are expected to decline over this time. Therefore, maintaining a robust jet fuel production and transportation infrastructure, and developing improved processes for producing jet and aviation fuels are becoming increasingly important. Accordingly, it is to these ends that the present invention is generally directed. Further, sustainable aviation fuels (SAF) may offer the needed resilience to meet these future needs in terms of feedstock availability, while addressing the need to reduce emissions. Not only can SAF provide a large reduction of greenhouse gas emissions with little or no changes to current engine technology, SAF may also provide a drop-in fuel solution. Drop-in fuels allow current aircraft to use a 50 percent blend of SAF and Jet A with no engine or other modifications. In addition, SAF production facilities may be located near the airports they service, which may also improve fuel transport issues for jet fuels. Therefore, many companies have set SAF use goals as a primary strategy to attain net-zero emissions. However, challenges to the large scale production and use of SAF remain. While SAF provide an environmentally sustainable technology, current technologies to produce SAF are not yet economically viable. For example, SAF may cost four to five times as much as conventional jet fuel, and currently makes up less than one percent of fuel available in the market. Therefore, there remains a need for processes for making sustainable aviation fuels which may improve the technology, and enhance the production economics, and which may provide additional benefits or efficiencies to address the rapidly growing need for jet fuel. SUMMARY OF THE INVENTION This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify required or essential features of the claimed subject matter. Nor is this summary intended to be used to limit the scope of the claimed subject matter. Aviation fuels and specifically jet fuels contain primarily saturated hydrocarbon compounds, including linear and branched alkanes (paraffins), and cycloalkanes (cycloparaffins or naphthenes), with smaller concentrations of aromatic compounds and olefins. The high hydrogen-to-carbon ratio of the paraffins provides a high heat release per unit weight and a relatively cleaner burn than other hydrocarbons, while cycloparaffins provide less heat release per unit of weight but increase the fuel's density. Paraffins and cycloparaffins also beneficially reduce the freezing point of the fuel. The composition of aviation fuels is based primarily on fuel specifications which provide the maximum performance for the specific aircraft for which the fuel is used, rather than a specification based on chemical composition. The ethylene oligomerization process described herein can be used to provide products in the kerosene jet fuel range (C8-C16) or wide-cut jet fuel range (C5-C15 or C4-C16). For example, JP-4 is a wide-cut fuel because it is produced from a broad distillation temperature range and contains a wide array of carbon chain-lengths, from 4 to 16 carbons long. The approximate composition of JP-4 is about 86 vol. % saturated hydrocarbons, about 13 vol. % (v/v) aromatic hydrocarbons, about 1 vol. % olefins, and JP-4 has a distillation range of about 60° C. to 270° C. The disclosed processes for making aviation fuels takes advantage of the selective, on-purpose production of a C4-C8 alpha-olefin from ethylene, in which the principal by-product is a mixture of C10 olefins, also referred to herein as a mixture of decenes. The mixture of decenes in this normal alpha-olefin (NAO) mixture can be further subjected to oligomerization or to metathesis with an alpha-olefin to form an aviation fuel comprising C16− paraffins and cycloparaffins. Mo