Technology

Process Overview

The Chevron Phillips Chemical (CPChem) Full-Range Normal Alpha Olefins (NAO) Process represents the world's first commercial ethylene oligomerization technology, originally developed by Gulf Oil Chemical Company in the early 1960s and commercialized in 1965-1966 at Cedar Bayou, Texas. The technology produces a broad spectrum of even-numbered linear alpha olefins ranging from C₄ to C₃₀⁺ following a Schulz-Flory distribution typical of chain-growth polymerization, through statistical oligomerization using a triethylaluminum-based Ziegler catalyst system, which distinguishes this technology from:

• Stoichiometric Ziegler processes (multi-step, high aluminum consumption)
• Selective oligomerization (single carbon number products)
• On-purpose processes (specific olefin targets)

Historical Development

Gulf Oil Era (1960s-1985)

• Technology Development: Pioneered by Gulf Oil Chemical Company research team
• First Patent: US 3,584,071 (June 8, 1971) - "Telomerization of Ethylene"
• Commercial Startup: 1965-1966 at Cedar Bayou facility
• Global First: World's first commercial ethylene oligomerization process
• Original Catalyst: Ethylaluminum sesquichloride (Et₁.₅AlCl₁.₅) + TiCl₄

Chevron Era (1985-2000)

• 1985: Chevron acquired Gulf Oil including oligomerization technology
• Technology Evolution: Transition to triethylaluminum-based catalyst system
• Process Optimization: Continuous improvements in catalyst efficiency and product distribution

CPChem Era (2000-Present)

• 2000: Chevron Phillips Chemical formed as 50-50 joint venture
• Facility Expansions: Multiple capacity increases (2015: +100,000 MT/year) to 810,000 MT/year
• Technology Integration: Strategic feedstock for downstream PAO production

Technical Description

Catalyst System

• Primary Catalyst: Triethylaluminum (AlEt₃) in catalytic amounts
• Co-catalyst: Titanium tetrachloride (TiCl₄) - trace amounts
• Catalyst Type: Homogeneous Ziegler catalyst system
• Catalyst Consumption: Catalytic quantities (vs. stoichiometric Ethyl process)

Process Chemistry

The oligomerization proceeds via a chain-growth mechanism with ethylene insertion into aluminum-carbon bonds:

• Growth Step: Al(C₂H₅)₃ + nC₂H₄ → Al[(CH₂CH₂)ₙC₂H₅]₃
• Displacement Step: Al[(CH₂CH₂)ₙC₂H₅]₃ + 3C₂H₄ → Al(C₂H₅)₃ + 3[RCH=CH₂], where R represents alkyl chains of varying lengths (C₂-C₂₈⁺)

Operating Conditions

• Temperature: 175-290°C
• Pressure: 2,000-4,000 psi (138-276 bar)
• Reactor Type: Plug flow reactor configuration
• Operation Mode: Single-stage continuous process
• Residence Time: Several hours (estimated 2-6 hours)
• Per-pass Conversion: 55% of ethylene
• Unconverted ethylene: 45 mass units (recycled)
• Per-pass LAO yield: ~mass units (accounting for 2% process losses)

Process Configuration

Based on available information and the original Gulf Oil patent, the process includes:

• Reactor Feed: Triethylaluminum and excess ethylene fed to plug flow reactor
• Oligomerization: Chain-growth reaction under high temperature and pressure
• Catalyst Quench: TEA catalyst neutralized with caustic solution
• Ethylene Recovery: Unreacted ethylene flashed off and recycled
• Product Separation: Linear alpha olefins separated by multi-stage distillation

Figure 1 - Simplified CPChem Triethyaluminum-catalyzed ethylene oligomerization process flow diagram

Figure 2 - Details of the products separation section, chart generated by Perplexity AI in Markdown format.

Product Specifications

Typical Product Distribution (Weight %)

Carbon Number	Product	Weight %
C₄	1-Butene	14%
C₆-C₁₀	Mixed LAO	41%
C₁₂-C₁₄	Detergent Range	19%
C₁₆-C₁₈	Industrial Range	12%
C₂₀⁺	Waxes/Higher	14%

Product Quality

Alpha-Olefin Content:

• C₄-C₁₈: 90.5-98.3% (butene-1 highest purity)
• C₂₀-C₂₄: 88.3% alpha-olefin content
• C₂₄-C₃₀⁺: 33.0-48.0% alpha-olefin content

Impurities: Internal olefins, paraffins, and branched olefins

Commercial Implementation

Current Operations

CPChem Cedar Bayou Facility, Texas, USA:

• Capacity: Estimated 810,000 metric tons/year
• Historical Data: 703,000 MT/year (2010) + 100,000 MT expansion (2015)
• Integration: Part of integrated ethylene-LAO-PAO complex
• Ethylene Supply: On-site 1.5 million MT/year ethane cracker
• Strategic Role: Primary feedstock for downstream PAO production

Qatar Chemical Company II (Q-Chem II), Mesaieed Industrial City, Qatar:

• Capacity: 345,000 metric tons/year - Qatar's first full-range NAO unit
• Startup: 2010 commercial operations
• Investment: $2 billion project (Q-Chem II total)
• Technology: Licensed CPChem Full-Range NAO process
• Ethylene Supply: Via 135km pipeline from Ras Laffan Olefins Company (RLOC) cracker
• NAO separated in 11 fractions: C₄, C₆ (1-Hexene), C₈, C₁₀, C₁₂, C₁₄, C₁₆, C₁₈, C₂₀-C₂₄, C₂₄-C₂₈, C₃₀⁺ (wax grades)

Historical Licensed Operations

Mitsubishi Chemical Corporation (Japan):

• Location: Mizushima, Okayama Prefecture
• Status: Discontinued production May 2009
• License: Direct CPChem technology licensing

Chemopetrol SPOLANA (Czech Republic):

• Location: Neratovice chemical complex
• Operation: September 1992 - 2003
• Status: Plant closed 2003

Process Evolution and Improvements

Catalyst System Development

• Original Gulf System (1960s): 
  • Primary: Ethylaluminum sesquichloride (Et₁.₅AlCl₁.₅)
  • Co-catalyst: Titanium tetrachloride
  • Promoters: Diphenyl ether for enhanced C₁₀-C₁₂ production
     
• Current CPChem System:
  • Primary: Triethylaluminum (AlEt₃)
  • Advantages: Reduced chlorine content, improved catalyst efficiency
  • Environmental: Elimination of chlorinated aluminum compounds

Process Enhancements

• Temperature Optimization: Refined operating window for optimal distribution
• Catalyst Recovery: Improved caustic washing and catalyst destruction
• Product Separation: Enhanced fractionation for specific carbon cuts
• Energy Integration: Heat integration with ethylene production

Economic Performance

Capital Investment (2025 USD Basis) for a Grassroots Plant (500,000 MT/year):

• Battery Limits: $200-300 million
• Utilities & Offsites: $100-150 million
• Total Installed Cost: $300-450 million

Operating Economics, Cash Cost Breakdown:

• Ethylene Feedstock: 85-90%
• Utilities: 3-5%
• Catalyst & Chemicals: 2-4%
• Labor & Maintenance: 3-5%

Key Economic Drivers:

• Ethylene feedstock cost (primary driver)
• Product mix optimization for market demands
• Energy integration efficiency
• Catalyst consumption rates

Environmental Profile

Process Advantages

• Lower temperature than competitive processes
• Catalytic quantities of aluminum compounds
• High ethylene utilization through recycle
• Minimal liquid waste generation

Environmental Considerations

• Aluminum waste from catalyst destruction
• Caustic consumption for catalyst neutralization
• Hydrocarbon emissions from separation systems
• Energy requirements for high-pressure operation

Competitive Position

Technology Advantages

• First-mover advantage: 60 years of operational experience
• Proven reliability: Decades of continuous operation
• Full-range production: Complete C₄-C₃₀⁺ spectrum in single process
• Integration synergies: Optimized for downstream PAO production
• Technical maturity: Well-understood process with extensive optimization

Technology Limitations

• Statistical distribution: Limited control over specific carbon number enhancement
• High temperature/pressure: Energy-intensive operation
• Catalyst handling: Requires specialized safety and handling procedures
• Product separation: Complex fractionation system required
• Market positioning: Statistical distribution may not optimize for all applications

Strategic Importance

Integration Benefits

The LAO process provides critical strategic advantages for CPChem's integrated operations:

• Feedstock Security: Captive supply eliminates market exposure for downstream units
• Cost Optimization: Integrated production reduces logistics and inventory costs
• Quality Control: Direct control over feedstock specifications for PAO production
• Operational Flexibility: Ability to optimize LAO production for internal consumption

Market Position

• Global significance: Second-largest LAO producer worldwide (2010: 20.5% market share)
• Strategic asset: Enables competitive positioning in specialty chemical markets
• Technology leadership: Pioneer status in ethylene oligomerization industry

Technology Licensing

• Historical Status: Limited licensing to select partners (Mitsubishi, Chemopetrol)
• Current Policy: Technology retained for internal CPChem operations
• Future Outlook: No active third-party licensing programs

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References

1. McNulty, J.G. & Walsh, W.L. (1971) "Telomerization of Ethylene", US Patent 3,584,071, Gulf Research & Development Company
2. IHS Markit (2010) "Linear Alpha-Olefins", Chemical Economics Handbook, Process Economics Program
3. CPChem Company History (2020) Available at: https://www.cpchem.com/who-we-are/company-history
4. CPChem Normal Alpha Olefins FAQ (2025) Available at: https://www.cpchem.com/what-we-do/solutions/normal-alpha-olefins/faq
5. Chevron Phillips Chemical Company (2025) Cedar Bayou Facility Fact Sheet
6. Forestière, A., et al. (2009) "Oligomerization of Monoolefins by Homogeneous Catalysts", Oil & Gas Science and Technology
7. Belov, G.P. & Matkovsky, P.E. (2010) "Processes for the production of higher linear α-olefins", Petroleum Chemistry
8. Various CPChem Press Releases (2013-2025) on NAO capacity expansions and facility developments
9. Qatar Chemical Company II Ltd (2023) "Company Overview", Available at: https://www.qchem.com.qa/app_pages/Company/Overview.aspx
10. Ras Laffan Operating Company (2009) "Q-Chem II Project Overview", Available at: https://www.rloc.com.qa/App_Pages/Partners/Q-ChemII.aspx
11. Mesaieed Petrochemical Holding Company (2004) "Qatar Chemical Company II Ltd", Available at: https://www.mphc.com.qa/en/about-mphc/group-companies/qatar-chemical-company-ii-ltd-qchem-ii/
12. Qatar Chemical Company II (2019) "Alpha Olefin Waxes Safe Handling Guidelines", Product Stewardship Document
13. Chevron Phillips Chemical Company (2020) "Mesaieed, Qatar", Available at: https://www.cpchem.com/locations/middle-east/mesaieed-qatar
14. CIOViews (2020) "Phillips and Qatar join hands to create Petrochemicals complex", October 18, 2020
15. Made in Qatar (2024) "Qatar Chemical Company - Factory Profile", September 4, 2024