(113c) Maximizing Pyrolysis Oil Utilization in Existing Naphtha Crackers

This paper presents a universal case study from the perspective of a traditional naphtha cracker operator aiming to maximize pyrolysis oil intake without requiring physical alterations to existing infrastructure. To achieve this, the pyrolysis oil undergoes extensive characterization, followed by COILSIM1D furnace simulations, supported by an updated CRACKSIM kinetic network that has been specifically tuned to handle pyrolysis oils. The new kinetic model is essential, allowing us to assess the steam-cracking furnace’s ability to handle increasing proportions of pyrolysis oil. The large quantities of olefins, diolefins and cyclic compounds in pyrolysis and supercritically produced pyrolysis oils required substantial developments. The objective is to determine the maximum feasible blend ratio of pyrolysis oil and conventional feed.

Key considerations include the convection section’s capability to vaporize the feed fully, as well as optimizing cracking conditions to maximize ethylene and propylene yields. Attention is also given to potential impacts on transfer line exchanger (TLE) performance and furnace run length, considering the benefits of mass-balance certification. Finally, a site-wide optimization is conducted to determine the optimal distribution of feedstock across furnaces, recognizing that while pyrolysis oil availability is expected to increase, it is unlikely to meet the total capacity of an ethylene complex in the short to medium term.