(132g) Deep Desulfurization of Diesel by Adsorption Over Ni/Zsm-5

Deep desulfurization of diesel by adsorption over Ni/ZSM-5

Abstract

Desulfurization by adsorption (ADS) is based on the ability of a solid sorbent to selectively adsorb organosulfur compounds from refinery streams. Based on the mechanism of the sulfur compound interaction with the sorbent, ADS can be divided into two groups: ‘adsorptive desulfurization' and ‘reactive adsorption desulfurization'. Adsorptive desulfurization is based on physical adsorption of organosulfur compounds on the solid sorbent surface.

In the present work, attempts were made to develop a suitable zeolite based adsorbent for desulfurization of diesel. Hydrogen peroxide was used as an oxidizing agent. The analysis of sulphur compounds namely thiophene, benzothiophene, dibenzotheophene, mercaptan and sulfides was done using X-Ray Fluorescence (XRF). Preliminary experiments were carried out with zeolites having different silica to alumina ratio. Different amount of Ni was loaded onto ZSM-5 by ion exchange method. Adsorptive desulfurization study was made using a model diesel containing different form of sulfur compounds. Detailed runs were carried out with commercial diesel with a total sulfur content 350 ppm. The adsorption kinetics and equilibrium studies were carried out for understanding the mechanism of adsorption. More than 90% removal of sulfur was observed with 8%Ni/ZSM in presence of H2O2 based catalyst in the batch study. The adsorption capacity was 4.8 mg Sulfur/g adsorbent. The performance of Ni-ZSM was also investigated in a continuous operation. Effect of flow rate, bed height and oxidizing agent was investigated in column experiments.