Partial oxidation reactions

Enhancing throughput and quality and reducing catalyst costs

Partial oxidation reactions – used in the manufacture of many basic chemical building blocks such as acrylic acid, propylene oxide and phthalic anhydride – are a fundamental operation within the chemical industry.

However the design and operation of such processes is challenging. The key design and operational issues – selectivity, catalyst pellet design, reactor geometry and cooling – are closely interrelated.

Model-Based Engineering (MBE) approach

Fortunately partial oxidation processes lend themselves well to Model-Based Engineering techniques. PSE has extensive experience in this area. We can model, provide models for, or help you to model a wide variety of reactors and reaction types.

This is embodied in high-fidelity process models such as PSE's Advanced Model Library for Fixed-Bed Catalytic Reaction (AML:FBCR) and advanced industry-proven methodologies for detailed modelling and optimisation of design and operation.

High-fidelity reactor models can be fully integrated with downstream separator sections and the entire plant optimised simultaneously using whole-plant optimisation techniques.


The application of PSE's Model-based Engineering approach typically results in the following benefits:

  • Enhanced selectivity. Improved internals design or operating conditions can enhance selectivity to the main reaction.
  • Improved cooling design. By improving cooling fluid flows radial temperature profiles can be made more uniform, resulting in a more uniform product.
  • Reduction in hot-spot formation. With improved internals design or catalyst loading it is possible to reduce the likelihood of or eliminate hotspots.
  • Extension of catalyst life. Reducing the likelihood of hotspots and improving temperature distribution can help extend the catalyst life significantly.
  • Optimal catalyst loading. Tubes can be loaded with optimal catalyst profiles to ensure uniform temperature distribution and reduction in hotspot formation.
  • Optimisation of operating conditions. Operating conditions can be regularly optimised using the model to maximize catalyst life while meeting production targets.
  • Accurate reaction characterisation. Model-Based Engineering techniques allow the accurate characterisation of reaction sets from only limited experimental data.
  • Detailed equipment design. PSE's hybrid modelling technology provides the quantitative accuracy to perform detailed reactor design with confidence.
  • Activity monitoring. Model-based techniques can be used to determine up-to-date catalyst activity based on oeprating data history.
  • Optimal catalyst design. Model-based innovation techniques are used to optimise the design of catalyst pellets based on operating performance.

Payback on such projects is typically of the order of 6 to 12 months, depending on whether capital expenditure is required or not.

Typical systems

The following systems are typical targets for Model-based Engineering:

Acrylic acid/Acrolein Dimethyl sulphide Fischer-Tropsch gas-to-liquids
Hydrocracking Maleic anhydride Methanol
p-diiodobenzene Phthalic anhydride Propylene oxide
Reforming Styrene monomer Terephthaldehyde
Vinyl Acetate Monomer
More Information
We were able to reduce time between R&D experiments and plant design significantly

   Multitubular reactor design optimization variables

Multitubular reactor design variables. Catalyst design decisions can also
be included