(191g) Desulfurization of Fuels Using Activated Carbon Prepared from Asphaltenes

Sulfur compounds which exist in liquid hydrocarbons have harmful effects to the environment and to the human health. Especially for the heaviest of these compounds (thiophenes, benzothiophenes, naphthothiophenes), it is difficult to be removed using the most common current industrial desulfurization process (hydrodesulfurization). Adsorptive desulfurization has, therefore, emerged as a promising alternative, as it is less energy intensive and it can more efficiently achieve the deep desulfurization of commercial fuels.

Asphaltenes are the most complex and the most polar fraction of crude oil, consisting of fused aromatic rings with short aliphatic chains. According to ASTM D3279-97, they are defined as the fraction of crude oil and bitumen which is soluble in toluene and insoluble in n-heptane. These compounds are associated with problems in the transportation and in the processing of crude oil. However, they contain a large proportion of carbon, which makes them attractive for the production of activated carbon.

In this work, asphaltenes were extracted from bitumen and they were subjected to stabilization and carbonization. Moreover, their porosity was enhanced through chemical and physical activation. The asphaltene-based activated carbon was used for the adsorption of sulfur compounds (thiophene, benzothiophene) from liquid fuels. These results will be presented here, together with a characterization of the properties of the precursor asphaltenes, as well as of the activated carbon.