Moreover, HCO is more difficult to be cracked than the fresh feedstock.
Fresh feedstock contains a considerable amount of high-boiling-point heavy components with large molecular weight, which are easy to crack.
RIPP thus developed FCC technology named FCC-LTG in which light LCO cut is recycled with fresh feedstock to achieve high gasoline [14].
In order to separate these two mixtures, first a three-column extractive distillation sequence including a preconcentration column was applied to diluted fresh feedstock.
But the cycle oil has a narrower boiling range, thus it is easier to vaporize and diffuse to grab the active sites, and influence the adsorption and reaction of the fresh feedstock.
In present study, sweet potato vines were used to study the effects of moisture content on ICSE pretreatment by investigating the composition, inhibitors production, sugar yield, and thermal stability, for different feedstock including fresh feedstock, naturally dried feedstock, manually dried feedstock, and soaked dried feedstock.
The sugar yield of ICSE-pretreated fresh feedstock was improved by 2.5-folds and reached to 88.05%, which was like soaking the biomass for 60 h, suggesting that the use of fresh biomass would be the best way to run ICSE.
Research found that the conventional RFCC reactor has some shortcomings, such as the overlong reaction time, the low overall activity and selectivity of the catalyst, and the competitive adsorption and reaction between fresh feedstock and cycle oil [6]. 1. Overlong reaction time will lead to the overcracking of light oil (gasoline and diesel).
Since FCC operation can work with a tailored recycling ratio in which heavy cycle oil (HCO) can be re-cracked via a recycling line with fresh feedstock, FCC diesel (LCO) can also be included by extending the true boiling point (TBP).
