Nebula

CHAPTER 5: Fuel Standard Feasibility IN: Final Regulatory Impact Analysis (2004) (www.epa.gov/nonroad-diesel/2004fr/420r04007f.pdf) is useful for its descriptions of the various desulfurization technologies available as of the time of the document. For example, here is its description of Akzo Nobel’s Nebula …

“In 2001 and 2003, Akzo Nobel announced two new catalysts. In 2001, Akzo announced the introduction of a highly active catalyst named Nebula, which offers a different way to use coatings for catalysts. A typical catalyst is composed of two parts: an active coating containing metals and a generally inactive substrate. For Nebula, Akzo Nobel concentrated the metal coatings and omitted the substrate. Because of the very high metals content, Nebula costs several times more than conventional catalysts. The higher activity of the Nebula catalyst leads to an increased tendency for coking, which must be countered by using a high hydrogen partial pressure, resulting in a higher hydrogen consumption. (The hydrogen consumption is higher because a higher percentage of the aromatics are saturated to nonaromatic compounds.) According to Akzo Nobel, a refiner may be able to meet the 15 ppm sulfur standard by simply replacing a part of or all of its existing catalyst with Nebula and providing significantly more hydrogen (which may possibly require the addition of a hydrogen plant). Nebula may significantly reduce the capital investment for meeting the 15 ppm sulfur standard. In 2003, Akzo announced that Nebula was modified somewhat to contain 15 - 20 percent less metals, but with the same activity as the original Nebula. The updated Nebula catalyst, now called Nebula 20, can better handle heavier feeds.18

“In 2003, Akzo Nobel announced a new catalyst named KF-760. The KF-760 catalyst is a CoMo catalyst designed for better denitrogenation of diesel fuel, in addition to the desulfurization being sought after. Where the nitrogen content is inhibiting the desulfurization of the diesel fuel, this catalyst can have 15 - 20 percent higher activity compared to their previous best, KF-757, with only a modest increase in hydrogen consumption. “