New staining method enables imaging of function of individual FCC catalyst particles; tool for optimizing and designing cracking catalysts for petroleum refining
Netherlands Organization for Scientific Research (NWO) researcher Bert Weckhuysen and his team from Utrecht University, in collaboration with the company Albemarle Catalysts, have developed a staining method allowing confocal fluorescence microscopy to probe within single fluid catalytic cracking (FCC) catalyst particles, visualize the structure, and assess catalytic activity. As a result of being able to image how well catalyst particles function, better catalysts can be developed.
This will, among other things, enable the oil industry to continue producing qualitatively good fuels from the dwindling reserves of crude oil that are often of a poor quality, NWO said. The research was published in journal Nature Chemistry.
Fluid catalytic cracking (FCC) is the major conversion process used in oil refineries to produce valuable hydrocarbons from crude oil fractions. Because the demand for oil-based products is ever increasing, research has been ongoing to improve the performance of FCC catalyst particles, which are complex mixtures of zeolite and binder materials. Unfortunately, there is limited insight into the distribution and activity of individual zeolitic domains at different life stages.
Here we introduce a staining method to visualize the structure of zeolite particulates and other FCC components. Brønsted acidity maps have been constructed at the single particle level from fluorescence microscopy images. By applying a statistical methodology to a series of catalysts deactivated via industrial protocols, a correlation is established between Brønsted acidity and cracking activity. The generally applicable method has clear potential for catalyst diagnostics, as it determines intra- and interparticle Brønsted acidity distributions for industrial FCC materials.—Buurmans et al.
The catalysts used by oil refineries are smart, minuscule grains full of pores and ‘acid sites’. The oil particles, long hydrocarbon chains, creep into the pores and are chopped into shorter chains at the acid sites—i.e., cracking. These shorter hydrocarbon chains can then be combusted as gasoline or diesel in a car engine.
Everyone had always thought that each cracking catalyst sphere had about the same activity and that active sites were spread equally over the grain. Yet the reality is very different. Under a fluorescence microscope we made a 3D map of the active sites in such spheres. We can detect those sites using thiophene. As soon as such a molecule is in the vicinity of the acid sites it emits green fluorescing light.—Bert Weckhuysen
Knowledge about these active acidic sites can be used to select the most effective catalysts. Furthermore, using this technique it can be seen when the particles become less active and therefore need replacing.
The research into the effectiveness of catalysts took place within the framework of the public-private partnership platform ACTS, NWO’s platform for public-private research in the field of sustainable chemical technology. Albemarle Catalysts in Amsterdam sponsored part of the research and together with the researchers from Utrecht University investigated two different production methods for cracking catalysts.
In 2012, four new Technology Areas for Sustainable Chemistry (TASCs) will start as a successor to ACTS. These will focus on research and innovation in sustainable chemistry with a strong focus on applying innovative technological developments.
Inge L. C. Buurmans, Javier Ruiz-Martínez, William V. Knowles, David van der Beek, Jaap A. Bergwerff, Eelco T. C. Vogt & Bert M. Weckhuysen (2011) Catalytic activity in individual cracking catalyst particles imaged throughout different life stages by selective staining. Nature Chemistry. DOI: 10.1038/nchem.1148