Reformer for Conversion of Diesel Fuel into CO and Hydrogen
DOE SBIR Phase II Contract DE-FG02-05ER84394
A major impediment to the commercialization of solid oxide fuel cell systems for the very large automotive market is the lack of efficient, low-cost, compact reformers for conversion of diesel fuel into synthesis gas. Cost, carbon deposition in the cooler zones of the reformer, and catalyst intolerance to sulfur are the major issues.
The reformer incorporates a novel modification of oxygen transport membrane material integrated with novel sulfur-tolerant reforming catalysts based upon proprietary oxygen transport ceramic materials. The system, using commercial grade diesel as a feedstock, prevents carbon build-up by transport of oxygen through self-cleaning reformer walls, operates stably, and is compact and inexpensive.
During Phase I, catalysts were designed for partial oxidation of diesel fuel into synthesis gas using oxides with high conductivity of both electrons and oxygen anions. Some 40 catalyst formulations were evaluated. Preferred self-cleaning catalysts showed stable reforming activity without carbon deposition for pump-grade D-2 diesel fuel with 200 ppm by mass sulfur over a two-month continuous test at the target temperature of 1000°C.
In Phase II, diesel fuel reforming catalysts with oxygen transport properties developed in Phase I will be incorporated into self-cleaning reformer walls. The self-cleaning reactor walls, along with beds of diesel fuel reforming catalysts, will be tested and optimized. A design for a commercial prototype diesel fuel reformer will be completed and a techno-economic analysis leading to commercialization in Phase III will be performed.
A sulfur-tolerant fuel reformer, with a cost of less than $90 per kW, with an overall efficiency of greater than 80% would enable wide-spread adoption of diesel-based solid oxide fuel cell systems. Such reformers would also allow conversion of very high sulfur military fuel, JP-8, and very high sulfur bottom-of-the-barrel petroleum reserves into synthesis gas. The synthesis gas from the latter could be used to run turbines or to produce alternative fuels including low-sulfur diesel, methanol and synthetic natural gas.
This diesel fuel reforming technology will reduce the cost of fuel cell systems for producing electricity in diesel-powered vehicles. This compact system can be fed all grades of sulfur-containing diesel as well as other liquid and gaseous fuels ranging from natural gas to bottom-of-the-barrel petroleum resid.