Recently, Japan and the European Union have been experiencing declining petroleum demand owing to global initiatives aimed at reducing environmental impact by curtailing CO₂ emissions. Consequently, alternative products and operational conditions should be developed to utilize the fluid catalytic cracking (FCC) unit. Using simulation software (Aspen Hysys), this study modeled a typical FCC unit and compared the simulation results with operational data to ensure reproducibility. Two new process models were developed to investigate two scenarios: (i) the slurry discharged from the FCC unit is utilized as a feedstock for the FCC process and (ii) the slurry and fraction obtained from the downstream absorber of the FCC unit are introduced into a delayed coker unit to facilitate carbon fixation. Within an optimum riser outlet temperature (ROT) of 520–530 °C, the yields of gasoline and liquefied petroleum gas increased up to 4%. For profit performance, although ROT of 535–545 °C yielded peak efficiency, the CO₂ emissions increased by 70%. Thus, a ROT of 530–540 °C, coupled with a delayed coker unit, can maximize profitability. Furthermore, a correlation graph illustrated the relationship between CO₂ emissions and profit for selecting optimal FCC operational conditions.

The Snake River in the northwestern United States was once home to abundant populations of Chinook salmon. However, the building of hydropower dams has led to a dramatic drop in their numbers and puzzling changes in their migratory behaviour. Dr Charles Coutant and other biologists in the region embarked on a mission to uncover exactly how these dams are interfering with the crucial downstream journey of young Chinook salmon. His creative approach, drawing on knowledge from many different fields, has revealed a hidden culprit that may be throwing these fish off course.