Sorbents for Gasoline Desulfurization

Conventionally, deep desulfurization in a refinery is accomplished by a multi-stage process including hydrodesulfurization (HDS) over CoMo/Al2O3 and NiMo/Al2O3 catalysts and subsequent removal of the H2S. However, the HDS process is not well suited to produce ultra clean (essentially sulfur free) transportation fuels. At the severe reaction conditions required for deep desulfurization, the olefins and aromatics in the gasoline become saturated, decreasing the octane number and the value of the fuel. TDA Research, Inc. (TDA) proposes to develop a low-cost, high-capacity sorbent that directly removes the organic sulfur from gasoline blend stocks, producing a fuel that meets the new 30 ppm sulfur specification for gasoline. In Phase I, we developed a promising regenerable sorbent that showed good capacity and high sulfur removal efficiency. The sorbent also maintained its capacity over 40 adsorption/ regeneration cycles. In Phase II, we will first optimize the sorbent and scale-up its production. We will demonstrate the key aspects of our technology in a field test. Based on the performance results, we will conduct a preliminary design of the desulfurization system and estimate its size and cost. In addition, we will conduct an engineering assessment to evaluate its merits. To reduce the emissions of environmental pollutants, the U.S. Environmental Protection Agency (EPA) has announced new regulations that require refineries to reduce sulfur levels in the transportation fuels; the allowable sulfur in gasoline is being reduced from 330 to 30 ppmw in gasoline and the diesel specification is being reduced form 3,000 to 15 ppmw in diesel by 2006. TDA’s technology will supply U.S. refineries with a cost-effective sulfur removal technology that will help them to meet the EPA target, and the even lower target that will likely be implemented in the future.