Desulfurization of Gasoline and Diesel by Fly Ash‐Derived FAU Zeolite

Abstract

Sulfur in fossil fuels is a major environmental and public health concern worldwide due to emissions of sulfur oxides formed during combustion. This may require new developments or upgrades of existing refining technologies. Hence, further desulfurization of gasoline and diesel to combat hazardous emissions could be a significant step toward environmental protection. In this study, adsorptive desulfurization of gasoline and diesel was achieved using a low‐cost fly ash‐derived faujasite (FAU) zeolite as complementary to the conventional hydrodesulfurization method. Sulfur levels of fuel samples, brought to the laboratory from typical fuel stations, were detected by a turbidimetric method before and after desulfurization. FAU zeolite sorbent, prepared from coal fly ash, was contacted with the fuel samples at stopped flow, and the residual fuels were analyzed to determine the sorbent's desulfurization performance. The process was optimized to enhance the sorbent's performance by varying the reaction conditions such as temperature, fuel volume, and the sorbent chemical composition. The results indicated that, at ambient temperature and pressure, the zeolitic desulfurization could reduce the sulfur content approximately by 40 % of its initial concentration, from 61 to 37 ppm and 155 to 97 ppm, in gasoline and diesel, respectively. Therefore, fly ash zeolites offer a possible opportunity for further desulfurization of refining petroleum fuels which may lead to economic and environmental gains.