Resid Conversion factory

Resid conversion (FLEXICOKING™)  

FLEXICOKING™ technology is a commercially proven, cost-effective, continuous fluidized bed process that thermally converts heavy feeds to lighter products and flexigas. FLEXICOKING technology, as an integrated process, offers great flexibility when upgrading residuum, as it provides high-value liquid products as well as clean flexigas that can be used as refinery fuel or for power generation.

ExxonMobil and Axens have signed a licensing alliance agreement to allow Axens to provide ExxonMobil’s FLEXICOKING™ technology and integrated resid conversion solutions. This new alliance leverages collective expertise to meet customer needs by providing a resid conversion solution that maximizes liquid yields and minimizes pet-coke production.

Key benefits

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    • Simple integrated steam/air gasification and carbon steel construction
    • Reduced plot space requirement

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    • Continuous non-batch operation and closed coke handing system, resulting in low emissions

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    • Handles a wide variety of feeds

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How FLEXICOKING technology works  

The vacuum resid feed enters the scrubber for “direct-contact heat exchange” with the reactor overhead product vapors. The higher boiling-point hydrocarbons (~975°F+/525°C+) present in the reactor product vapors condense in the scrubber and return to the reactor, in mixture with the fresh feed. Lighter overhead product vapors in the scrubber go to conventional fractionation and light-ends recovery. The feed is thermally cracked in the reactor fluidized bed to a full range of gas and liquid products, and coke. Coke inventory is maintained by circulating the bed coke from the reactor to the heater via the cold coke transfer line.
Coking processing

In the heater, the coke is heated by the gasifier products and circulated back to the reactor via the hot coke transfer line to supply the heat that sustains the thermal cracking reaction. The excess coke in the heater is transferred to the gasifier, where it reacts with air and steam to produce flexigas. The gasifier products, consisting of flexigas and coke mixture, return to the heater to heat up the coke. The flexigas exits the heater overhead and goes to steam generation, to dry/wet particulate removal, and to desulfurization in the integrated FLEXSORB™ process. The clean flexigas is then ready for use as fuel in refinery boilers and furnaces and/or for steam and power generation.

Only a small amount of product (1% weight on Fresh Feed) is collected as fines from the flexigas and purged from the heater to extract feed metals.


Full range products slate  

FLEXICOKING technology produces a full range of products, from a C1+ reactor gas to C5/975°F (525°C) liquid products, the multi-purpose flexigas and a small stream of low-sulfur coke that is purged to extract feed metals.

FLEXICOKING technology services include:  

  • Initial consultations
  • Development of licensing proposal
  • Basic engineering package, including basic design specification and operating guide
  • Engineering support during FEED and EPC stages
  • Technology transfer, training and startup support
Coke gas make up 1

Featured resources

View highlighted news, events, technical papers and case studies below. To see our full collection of resources, browse our Library.
  • ExxonMobil Chemical Library icon

    Axens and ExxonMobil Sign Alliance Agreement to Provide FLEXICOKING™ Technology and Integrated Resid Conversion Solutions

    This new alliance leverages collective expertise to meet customer needs by providing a resid conversion solution that maximizes liquid yields and minimizes pet-coke production.

    Read more
  • ExxonMobil Chemical play button icon

    A Particle of Difference

    How ExxonMobil Catalysts and Technology Licensing solves shared challenges through expertise, specialty catalysts, technology licensing and collaboration.

    Watch the video
  • ExxonMobil Chemical Library icon

    ExxonMobil Catalysts and Technology Licensing – summary of technologies offered

    Learn about the cutting-edge, proprietary catalysts and advantaged process technologies that ExxonMobil provides for refining, gas and chemical needs.

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