Preparation of Perovskite-Based Catalysts and Fuel Injection System for Diesel Reforming

Autothermal reforming processes of hydrocarbon liquids such as diesel fuels are spotlighted as methods to produce hydrogen for Fuel cell. However, the use of higher hydrocarbons as feedstocks for hydrogen production causes some problems which increase the catalyst deactivation by the carbon deposition. Coking can be inhibited by increasing the water dissociation on the catalyst surface. This results in catastrophic failure of whole system. Performance degradation of diesel autothermal reforming (ATR) leads to increase of undesirable hydrocarbons at reformed gases and subsequently decrease the performance. And it is hard to feed diesel fuel homogeneously because of high evaporation point. Non-homogeneous injection of fuel cause poor performance and fail of system.

In this study, perovskites (ABO3)-based catalysts were investigated as alternatives to substitute the noble metal catalyst for the autothermal reforming (ATR) of diesel fuels. The investigated perovskite structure was based on LaCrO3. And some metals were added at the A-site to enhance oxygen ion mobility, transition metals were doped on the B-site to enhance the reformation.

And we compare peroveskite based only catalysts and physically mixed provskite & noble catalyst(Pt-CGO). Pt-CGO catalyst is novel metal catalyst and it was used widely in the industrial fields. But high cost of novel metal is critical weak point. If the amount of noble catalyst were reduced without the degradation of performance, it can be significant. Substituted Lanthanum chromium perovskites were made by aqueous combustion synthesis, which can produce high surface area conveniently. For LaCrO3, lanthanum nitrate and chromium nitrate were dissolved in water and Ruthenium nitrate solution was added to the solution. Glycine as a fuel was added in the 1:1 molar ratio to the sum of La and Cr. The solution was slowly boiled in a quartz beaker and heated to cause the combustion. The produced oxides were calcined in air at 1250^oC for 4hrs.

The physically mixed catalyst were made by milling 24hr in 1:1 wt ratio of LaCrRu & Pt-CGO.

Furthermore, for the homogeneous fuel supply, we made ultrasonic injection system for reforming. The ultrasonic injector made form of fuel to fine particle, so it is possible to get homogeneous mixing condition. We compared durability of evaporation system and ultrasonic system for fuel injection.