Stabilized Nano-ZnO for Diesel Desulfurization for Fuel Cell Applications

The SBIR Phase II will demonstrate scale-up, manufacturability and performance benefits of stabilized nano-ZnO adsorbents in bench scale testing of diesel desulfurization for fuel cell applications. Logistic fuels are a desirable fuel choice for military based fuel cell applications. However, distillate fuels must be processed to a fuel useable by the fuel cell. Diesel fuels have high sulfur levels (0.5 – 1.0 wt%), and sulfur deactivates catalysts used for hydrogen generation as well as fuel cell electrode catalysts. It is also a toxic emission into the environment. Sulfur is removed from diesel fuels using hydrodesulfurization followed by adsorption. ZnO based adsorbents from commercial sources provide low capacity for sulfur removal, resulting in large bed size and cost. Novel stabilized nano-ZnO desulfurizer adsorbents have shown significant increase in desulfurization capacity. Phase I results demonstrated performance benefits with nano ZnO adsorbents for diesel desulfurization. Nano ZnO had 4 times higher capacity than commercial ZnO with excellent regenerability. The desulfurizer bed size can be reduced by more than 15 times or maintenance time can be extended significantly. The Phase II study will focus on nano ZnO synthesis scale-up, manufacturability and performance demonstration in bench scale power plant design with marine diesel fuel.