Effect of K Addition and Acidification of Zeolite Support on the Performance of Zr:Mo/Hzsm-5 Modified Catalyst in Methane Aromatization
The conversion of methane into higher hydrocarbons and aromatics on potassium doped modified zeolite Zr:Mo catalysts under non oxidizing conditions have been studied in a fixed bed catalytic reactor system at 450 0 C and at atmospheric pressure. The potassium addition reduces the formation of carbon during the catalytic reaction. This also results in the stability of the catalyst system and increased aromatics production. This is due to electronically modified active sites and increase in Bronsted acidity.
Upgrading of light cycle oil by partial hydrogenation and selective ring opening over an iridium bifunctional catalyst
An iridium catalyst supported on USY zeolite has been evaluated for hydrotreating of light cycle oil (LCO) to reduce its aromaticity and improve its cetane index. The products were analyzed by GC and 13C NMR spectrometry to determine quantitatively the aromatic carbon content and the increase in cetane index. Addition of an appropriate amount of potassium was found to be an effective way of optimizing the acid properties of the catalyst; reducing the number of strongly acid sites reduced its cracking activity. The results confirm that 0.9% (w/w) Ir/USY zeolite catalyst doped with 0.75% (w/w) K was highly suitable for partial hydrogenation and ring opening of LCO to improve cetane quality, thus increasing the extent of its blending ratio with the diesel pool.
Reactions of propane over a bifunctional Pt/H-ZSM-5 catalyst
Abstract Propane can be converted to products with more than 3 carbon atoms by using a combination of platinum and H-ZSM-5. Zeolites with Pt incorporated in the zeolite pores lead to better results than physical mixtures of zeolite and supported Pt; the conversion is higher and almost no deactivation occurs. At least two steps can be distinguished: formation of propene over Pt and subsequent oligomerization over acid sites of the zeolite. Moreover a number of inevitable side reactions occur: Pt catalyzed hydrogenation and hydrogenolysis and acid catalyzed cracking. The main higher hydrocarbons formed are normal and iso butane. The high nC 4 /iC 4 ratio suggests that at reaction temperatures the propene oligomerization is controlled by the shape selective properties of the H-ZSM-5 zeolite.