Synthesis and characterization of enlarged-pore zeolite beta catalyst for heavy fuel oil cracking

Abstract

The enlarged-pore zeolite beta (h-BEA) was synthesized under hydrothermal condition. The effects of different parameters were investigated e.g. silica source, type and ratio of template and crystallization temperature and time. The prepared samples were characterized by X-ray powder diffraction (XRD), nitrogen adsorption analysis, scanning electron microscopy (SEM), inductively couple plasma atomic emission spectroscopic (ICP-AES) and Al nuclear magic angle spin nuclear magnetic resonance (27Al MAS NMR) techniques. The analysis data indicated that the enlarged-pore zeolite beta could be prepared from calcined Si-HMS and crystallized at 135°C for 3 days. Its pore diameter was larger than comparative zeolite beta. The pore size was more increased when mixed tamplate between tetraethylammonium hydroxide and hexadexylamine was used but ZSM-12 was a coexisting phase. The latter phase was predominated with increasing the crystallization temperature and time. The synthesized enlarged-pore zeolite betas were tested for catalytic cracking of heavy fuel oil to produce light hydrocarbon fuel on various conditions. It was found that conversion of heavy fuel oil into products over the enlarged-pore zeolite beta was higher than of zeolite beta and thermal cracking. The optimal condition for cracking of heavy fuel oil in this research was 380°C for 40 min, 10wt% of catalyst to heavy fuel oil and N2 flow of 20 cm3/min. The major components of gas fraction from heavy fuel oil cracking were 1,3-butadiene and the hydrocarbon having boiling point higher than n-pentane (C5+). The distillate oil was mainly composed of hydrocarbon in the gasoline range and heavy oil was mainly in the kerosene range. The used catalyst could be regenerated easily by simple calcination and its activity still does not change significantly.