Technology

Key Takeaway

Aramco High-Severity FCC (HS-FCC™) is a down-flow, ultra–short‐contact‐time catalytic cracking process owned by Saudi Aramco Technologies Company and licensed exclusively by Axens and Technip Energies. Since its first full‐scale commercialization at S-Oil’s Ulsan refinery (76,000 bpd) in 2019, HS-FCC™ has become a cornerstone technology for maximizing propylene production from heavy feeds while integrating seamlessly into crude-to-chemicals schemes.

Technology History

• 1992–1996: Concept Development
  King Fahd University and JX Nippon (today ENEOS Corporation) initiated down-flow cracking research, formulating a low‐acid‐density Ultrastable Y zeolite (USY) catalyst to suppress hydrogen transfer and boost light-olefins selectivity^[1].

• 1996–2001: Pilot Testing
  A 0.1 bpd pilot at KFUPM confirmed feasibility of severe conditions (580–620 °C, C/O 25–30, 0.5–1 s) and Tempest™ separation^[2].

• 2001–2004: Demonstration Unit
  A 30 bpd unit at Ras Tanura Refinery validated scale-up, catalyst performance, and separator design^[2].

• 2007–2014: Semi-Commercial Operation
  A 3,000 bpd HS-FCC™ unit at ENEOS Mizushima Refinery, Japan, confirmed propylene yields ~17–19 wt% on various feeds; gasoline octane ≥ 98.1^[2].

• 2015–2019: First Commercial Deployment
  S-Oil Ulsan refinery commissioned the world’s first commercial HS-FCC™ unit (76,000 bpd) in late 2018–2019, integrated into a residue upgrading complex producing polypropylene and propylene oxide downstream^[3][4][5].

Technology Summary & Chemistry

• Process Type: Down-flow fluid catalytic cracking
• Ownership: Saudi Aramco Technologies Company
• Licensors: Axens Solutions & TechnipFMC
• Feeds: VGO, deasphalted oil, atmospheric residue, vacuum residue (CCR up to 4 wt%)
• Catalyst: Rare-earth USY zeolite base, low acid site density, compatible with ZSM-5 additive
• Operating Severity:
  • Temperature: 580–620 °C
  • Catalyst/Oil ratio: 25–30 (wt/wt)
  • Contact time: 0.5–1.0 s
• Key Chemistry:
  • Primary cracking on acid sites to light olefins (C₂–C₄)
  • Short contact time minimizes hydrogen transfer and coke
  • Rare-earth zeolite maximizes primary olefin formation; ZSM-5 additive further upgrades gasoline olefins to propylene

Detailed Technology Description

Reactor & Separation System

• Down-Flow Reactors (DFR): Plug-flow design with impact-type feed injectors
• Tempest™ Separator: High-velocity disengagement to strip hydrocarbons in < 1 s
• Structured Stripper Packing: Ensures < 1 wt% hydrocarbon entrainment
• Regenerator: Single-stage full combustion; optional catalyst cooler

Figure 1 - HS-FCC™ reactor/regenerator system main features^[7]

Design & Operating Parameters

Design and operarating parameters are described in the following table:

Mass Balance & Efficiency

Mass balance and technology efficiency is determined on the basis of hydrotreated VGO feedstock in wt% in the following table:

• Conversion: 83–94 wt% (higher with lighter feeds)
• Propylene selectivity: up to 25 wt% vs. 10–11 wt% in conventional high-propylene FCC^[6]

Economic Performance

• CAPEX:
  • New build: +10–15% over conventional FCC for DFR internals & Tempest™ separator
  • Retrofit: 30–50% of new-unit cost using existing regenerator & cyclones
     
• OPEX:
  • Catalyst consumption +5–10% due to higher circulation
  • Moderate additional cooling steam/power for regenerator temperature control
     
• Profit Impact:
  • Incremental propylene revenue (~ $300/tonne) yields ~$3–5 million/year per 50,000 bpd HS-FCC™ capacity
  • Enhanced margins in crude-to-chemicals integration further boost returns^[2]

Commercial Experience & Deployment

Technology deployments are summarized in the following table:

References

1. Shimizu et al., History of HS-FCC Technology Development, Petroleum Society Japan, 2020.
2. A. Maller, Technip Stone & Webster, Technip Stone & Webster Process Technology Offering in Refining High Severity Fluidized Catalytic Cracking (HS-FCC™): From concept to commercialization, REFCOMM Galveston, 2016.
3. Axens Press Release, Axens to supply technologies for S-OlL’s residue upgrading capacity expansion project, 2015.
4. Technip press release, Technip to provide proprietary equipment for S-Oil’s refinery in South Korea, 2016.
5. Xu et al., Using machine learning to elucidate the kinetics of cracking reactions in a down‐flow reactor system, CPFD Software, 2021.
6. Parthasarathi & Alabduljabbar, HS-FCC High-severity fluidized catalytic cracking: a newcomer to the FCC family, Springer, 2014.
7. Technology handbook, Technip Energies, 2023.