William Richard Gilbert

Chapter 3 Exploring FCC flexibility to produce mid-distillates and petrochemicals

Abstract FCC was traditionally designed to convert heavy gas oil range feedstocks to high octane gasoline. Brazilian refineries have relied on FCC as the chief conversion process. However, peculiarities of the local petroleum industry have forced refiners to change the FCC process, first to adapt to increasingly heavier feedstocks derived from national crude oils, and subsequently to change the product slate to comply with market demand, requiring less motor gasoline, more diesel oil and light olefins for petrochemicals. This paper will focus on the second set of process adaptations, including operating variables and choice of refinery processes schemes for low aromatics FCC products within crude oil choice constraints.

Comparison of NIR and NMR spectra chemometrics for FCC feed online characterization

The FCC unit is one of the most profitable units in a refinery, and small improvements in product slate or throughput substantially increases to the refinery revenue. One of the ways of enhancing FCC unit profitability is using sophisticated control systems, based on process simulators that ensure that the unit is always run at optimum performance. The difficulty of this approach is that it is often hard to measure the properties of the FCC feedstock, one of the most important determining factors in the FCC process, with the necessary speed, for it to be of use in a control system. To overcome this problem, on-line analyzers using Chemometrics and either near-infrared (NIR) or nuclear magnetic resonance (NMR) spectroscopy are offered to refiners by different suppliers, and both techniques are claimed to be effective. In this work, FCC feedstocks from three Brazilian refineries were analyzed during the course of one year, and Chemometric models of feed properties were developed using both NIR and NMR and the accuracy of feed characterization by each of the two techniques for a control system application was then compared, with the help of an FCC process simulator.

Mathematical model of FCC catalyst deactivation

A model is proposed that explains both lab-scale and commercial unit FCC catalyst deactivation, taking vanadium mobility between particles into account. Equilibrium catalyst density fractionation is also simulated, helping in the interpretation of the commercial unit results.