Christopher L. Aardahl

Automated gas burette system for evolved hydrogen measurements.

This paper reports a simple and efficient gas burette system that allows automated determination of evolved gas volume in real time using only temperature and pressure measurements. The system is reliable and has been used successfully to study the hydrogen release kinetics of ammonia borane thermolysis. The system is especially suitable for bench scale studies involving small batches and potentially rapid reaction kinetics.

Emission control research to enable fuel efficiency: Department of energy heavy vehicle technologies

The Office of Heavy Vehicle Technologies supports research to enable high-efficiency diesel engines to meet future emissions regulations, thus clearing the way for their use in light trucks as well as continuing as the most efficient powerplant for freight-haulers. Compliance with Tier 2 rules and expected heavy duty engine standards will require effective exhaust emission controls (after-treatment) for diesels in these applications. DOE laboratories are working with industry to improve emission control technologies in projects ranging from application of new diagnostics for elucidating key mechanisms, to development and tests of prototype devices. This paper provides an overview of these R and D efforts, with examples of key findings and developments.

Solid-state 27 Al Nuclear Magnetic Resonance Investigation of Plasma-facilitated NO x Reduction Catalysts

Aluminum coordination distribution for alumina catalysts supported on mesoporous silica was examined. It was shown that aluminum coordination correlates to activity of the catalysts for plasma-enhanced, selective catalytic reduction of NO, with propene. Catalysts were prepared by incorporating aluminum onto the surface of a mesoporous silica support via three different post-synthesis routes to produce varying aluminum coordination. Aluminum trichloride, sodium aluminate, and aluminum isopropoxide precursors were examined. High-resolution, solid state 2 7 Al nuclear magnetic resonance was used to determine aluminum coordination distributions for the resulting catalysts. Unsaturated aluminum sites (i.e., structural defects) correlated with increased activity at high temperatures while tetrahedrally-coordinated aluminum or BrOnsted acid sites correlated with activity at low temperatures.

Down Select Report of Chemical Hydrogen Storage Materials, Catalysts, and Spent Fuel Regeneration Processes

The DOE Hydrogen Storage Program is focused on identifying and developing viable hydrogen storage systems for onboard vehicular applications. The program funds exploratory research directed at identifying new materials and concepts for storage of hydrogen having high gravimetric and volumetric capacities that have the potential to meet long term technical targets for onboard storage. Approaches currently being examined are reversible metal hydride storage materials, reversible hydrogen sorption systems, and chemical hydrogen storage systems. The latter approach concerns materials that release hydrogen in endothermic or exothermic chemical bond-breaking processes. To regenerate the spent fuels arising from hydrogen release from such materials, chemical processes must be employed. These chemical regeneration processes are envisioned to occur offboard the vehicle.

Steady-State Engine Testing of γ-Alumina Catalysts Under Plasma Assist for NOx Control in Heavy-Duty Diesel Exhaust

A slipstream of exhaust from a Caterpillar 3126B engine was diverted into a plasma-catalytic NOx control system in the space velocity range of 7,000 to 100,000 hr-1. The stream was first fed through a non-thermal plasma that was formed in a coaxial cylinder dielectric barrier discharge reactor. Plasma treated gas was then passed over a catalyst bed held at constant temperature in the range of 573 to 773 K. Catalysts examined consisted of g-alumina, In/g-alumina, and Ag/g-alumina. Road and rated load conditions resulted in engine out NOx levels of 250 ? 600 ppm. The effects of hydrocarbon level, catalyst temperature, and space velocity are discussed where propene and in one case ultra-low sulfur diesel fuel (late cycle injection) were the reducing agents used for NOx reduction. Results showed NOx reduction in the range of 25 ? 97% depending on engine operating conditions and management of the catalyst and slipstream conditions.