Abstract
Changes in global supply and demand for fuels versus chemicals has increased the incentive to better control how much of each is produced from crude oil. In addition, there is incentive to improve the efficiency of upgrading the crude, in particular the resid. Such highly aromatic resid, which used to end up in petroleum coke or asphalt, are being upgraded to more valued products. Delayed coking has become less desirable as compared to other carbon rejection processes, such as high severity fluid catalytic cracking (HSFCC). Hydrogen addition, via hydrocracking, avoids the production of petroleum coke, transforming resid into more useful products.
This talk will explore both carbon rejection (FCC), and hydrogen addition (hydrocracking) routes to upgrading crude oil to chemicals. For FCC,we will show how co-mixing a heat generating material (HGM) with an FCC catalyst reduces activity loss. The HGM can be a solid that generates heat from redox reactions, or a liquid co-feed, designed to generate olefins and heat, which balances the endothermic acid cracking of gas oil.
For hydrogen addition, we will describe two aspects of hydrocracking catalysts. First, we studied a multifunctional hydrocracking catalyst, comprising both homogeneous Mo and heterogeneous zeolite components. The homogeneous components are based on soluble Mo that transform into nanoparticle sulfides which hydrocrack large asphaltenics. The mesoporous zeolites will then more effectively hydrocrack the smaller products of the asphaltenes, in order to make chemicals/fuels. However, with time on stream, the nanoparticles tend to sinter and become less active. We will present results on the Mo nanoparticles at various conditions in the presence of zeolites. Since the nanoparticles and zeolite crystals are both in the same hydrocracking reactor, it is important to understand their interaction under reaction conditions via characterization of the used catalytic materials. Such catalyst characterization will shed light on the interaction and deactivation mechanisms of these catalyst species.
In the second part of hydrocracking catalyst development we will present data on the synthesis of nano-sized Beta zeolite crystals and the effect of zeolite crystal size and shape on hydrocracking activity. Details of the synthesis method for preparation of the nano-sized Beta will be presented in addition to activity studies using a highly aromatic LCO (Light Cycle Oil) feedstock for the hydrocracking reaction.