Clean fuels and fuel processing have become an important focus area of energy and fuels research. Towards developing a more energy-efficient and environment-friendly process for producing ultra-clean fuels in the future, we are exploring a novel process concept at the Pennsylvania State University called selective adsorption for removing sulfur from fuels (PSU-SARS) at ambient conditions without using hydrogen. The idea is to explore sulfur-selective solid adsorbent based on direct sulfur-adsorbent interaction. A number of solid sorbent materials have been designed and demonstrated in the laboratory that show specific interaction with sulfur compounds in the presence of aromatics (and olefins). The selected modified aluminosilicates, modified carbon materials, metal and metal oxides can attract sulfur compounds in liquid fuels to the surface by selective chemisorption in the presence of large amounts of aromatic compounds that are common components in liquid fuels. As an example, the adsorption selectivity trend of the selected carbon materials for the various sulfur and aromatic compounds in diesel fuels increases in the order of naphthalene < 2-methylnaphthalene < DBT < 4-MDBT < 4,6-DMDBT. The selective adsorption can achieve deep desulfurization from fuels with >1000 ppm sulfur to ultra clean fuels with <1 or 5 or 30 ppm depending on the cleanup needs or fuel specifications. We are also exploring oxidative desulfurization using air, where catalytic air oxidation of the fuel can generate in-situ hydroperoxides from alkyl aromatic components which can then selectively oxidize the organic sulfur compounds to sulfones, followed by removal of the oxidized sulfur components by selective adsorption or other methods. More general background and results can be found in recent publications [Song et al., Catal Today, 2002, 2003, 2006; Appl Catal B: Env 2003; Ind. Eng. Chem. Res. 2003; Energy & Fuels, 2005; J Phys Chem B, 2006; J Phys Chem C, 2009].
All Science Journal Classification (ASJC) codes
- General Chemistry
- General Chemical Engineering