• What technology and strategies can resolve the huge gaps between ethylene and propylene production in certain markets?



  • Hernando Salgado, BASF Refining Catalysts,

    One strategy to adapt to changing market conditions, such as seasonal changes in ethylene and propylene demand, is having flexible process technologies that can adapt their product slate to the changing demand of both products. One of these process technologies is the always resilient work-horse of the refining industry (and becoming increasingly important to the petrochemical industry) – the fluid catalytic cracking (FCC) process. The FCC process is characterised by its inherent flexibility to manipulate severity, and therefore, it can have the flexibility to shift between types of light olefins produced.

    This is particularly true for FCC units specially designed to maximise light olefins – these can operate at very high severity (with reactor outlet temperatures higher than 540°C/1,000°F) and are equipped with special hardware, such as an additional riser to crack naphtha recycles or other light streams, and/or special riser terminations to maximise these secondary cracking reactions. Also, some units are designed to crack naphtha streams exclusively instead of conventional vacuum gasoil (VGO) or resid stock. These specialised FCC designs combined with the appropriate FCC catalyst and additive systems are very effective in maximising a variety of light olefins products.

    The presence of this kind of process unit in a refining or petrochemical complex can provide huge flexibility to play between propylene and ethylene production by changing operating conditions, particularly severity. In addition, the selection of a proper catalyst, such as BASF MPS, MPS-R, Fourte, Fourtune or Fourtitude, in combination with an olefins additive to crack naphtha range material, such as ZIP, will contribute to enhanced flexibility in the FCC unit, allowing adjustment to shifting demand for propylene and ethylene.