Removal of sulfur compounds from transportation by adsorption

Abstract

As the conventional hydrodesulfurization process (HDS) is considered no longer practical or economical for the production of ultra low sulfur fuels, adsorption on solid adsorbent has gained increasing interest from researchers and refinery operators throughout the world. In this regard, the batch liquid adsorption of three thiophenic sulfur compounds, 3-methylthiophene (3MT), benzothiophene (BT) and dibenzothiophene (DBT), on NaX and NaY zeolites was the main focus of this study. Decane and isooctane were used as model transportation fuels, representing diesel and gasoline, respectively. The effects of temperature and fuel to adsorbent weight ratio on sulfur adsorption were also examined. In a comparison between the two zeolite adsorbents studied, NaX exhibited slightly better ability to adsorb 3MT and BT than did NaY. For DBT, the adsorption of this sulfur compound on both zeolites was shown to be quite similar. It was also observed that BT and DBT, having a benzo functional group in their structure, were better adsorbed on both zeolites than 3MT, especially at low concentration. The results also revealed that the adorption of all thiophenic compounds on both adsorbents decreased with increasing temperature. Moreover, increasing fuel to adsorbent weight ratio in the reactor resulted in an increase in the adsorption of thiophenic compounds.