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BEA and MOR as additives for light olefins production

Paper ID Volume ID Publish Year Pages File Format Full-Text
43983 45998 2007 7 PDF Available
Title
BEA and MOR as additives for light olefins production
Abstract

The use of MFI-based additives in the fluid catalytic cracking (FCC) process in order to increase both – the production of light olefins and gasoline octane number – has been commercially proven. It is well known that impregnation by phosphorus increases the stability of aluminum atoms of H-MFI zeolite framework, resulting in higher yields of desired products. This paper discusses the possibility of combining either beta (BEA) or mordenite (MOR) zeolites – before and after treatment – with phosphoric acid (P/Al ratio of 1) with the conventional MFI-based additive. Zeolite samples were characterized by nitrogen adsorption, X-ray diffraction (XRD) and 27Al and 31P solid state NMR before and after hydrothermal treatment. Such treatment was responsible for decreases in zeolite surface area, crystallinity and also in the number of framework tetrahedral aluminum species of all samples. After impregnation with phosphoric acid and hydrothermal treatment, besides other species, both H-MOR/P/St and H-BEA/P/St presented resonance signals at 38 and −30 ppm at the 27Al and 31P MAS NMR spectra, respectively, which can be attributed to tetrahedral aluminum and phosphorus in AlPO's-like crystalline structures. After being mixed with an equilibrium FCC catalyst, the laboratory performance of the different additives was investigated using a gasoil feedstock and a fixed-bed micro activity test unit. Similarly to what was previously reported for H-MFI/P/St, the phosphoric acid treatment improved the performance of H-MOR/P/St and H-BEA/P/St zeolites with an expressive increase in lighter products yields in detriment of naphtha. The results suggest that, besides classical tetrahedral aluminum in the framework (Altet-f), other aluminum species also take part in the improvement of the zeolites performance.

Graphical abstractBeta (BEA) or mordenite (MOR) zeolites were combined with conventional MFI-based additive. After H3PO4 impregnation and hydrothermal treatment, both zeolites presented tetrahedral aluminum and phosphorus in AlPOs-like crystalline structures. Laboratory performance of samples treated with phosphorus showed an expressive increase in lighter products yields in detriment of naphtha. Besides tetrahedral aluminum in framework other aluminum species are also important for performance. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
MFI; BEA; MOR; NMR; Phosphorus; Additive
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 319, 1 March 2007, Pages 137–143
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us