May 13 1998
Stamford, CT-based Clean Diesel Technologies Inc. announced that test results of its platinum/cerium bimetallic diesel fuel additive at Delft Technical University, Netherlands, will be presented at the 22nd CIMAC Congress on May 19 in Copenhagen.
Researchers at Delft and CDT have identified a novel approach which uses extremely low levels of a bimetallic platinum/cerium fuel additive and a lightly catalyzed soot filter to reduce the oxidation temperature of soot by over 200 degrees Celsius to temperatures as low as 310°C. Temperatures in excess of 540°C are normally required to oxidize soot collected in diesel particulate filters. This was accomplished at metal treatment rates as low as 5 ppm. Based on comparison of the Platinum Plus bimetallic additive against several other trap regeneration systems, the report concluded in part that:
"A combination of a Corning Cordierite monolithic filter, Corning EX80 or EX47, and a Platinum/Cerium fuel additive results in stable operation for soot collection and continuous regeneration from temperatures of 583 K (310°C) and higher. This is superior in performance to any system known yet." and "The metal concentrations needed for sustained operations can be as low as 0.5 ppm of Platinum and 5 ppm of Cerium."
CDT noted that even lower levels of additive are likely to be used in practice, but these lower levels were not evaluated in the program at Delft.
"The work at Delft gives us a fundamental understanding of the catalytic synergy between platinum and cerium and helps explain the excellent success we have had with this system in full scale engine tests and field demonstrations," stated James M. Valentine, chief operating officer of CDT.
Diesel soot filters are a proven technology for removing soot emissions from existing and new vehicles, but they will quickly plug with soot unless a method to efficiently oxidize the soot is applied. While burners and electrical heaters have been used to raise temperatures in the filter, engineers generally agree that a "passive" means is more economical using either a catalyzed filter or a metal combustion catalyst added to the fuel. In either approach, the catalyst lowers the oxidation temperature of soot collected in the filter and "passively" regenerates the filter.
Catalyzed filters, however, suffer from high initial cost, poor long-term durability and a tendency to form unwanted sulfate by-products due to the high level of catalyst applied initially to the filter surface. As an alternative to catalyzed soot filters, fuel additives such as iron, cerium and copper have been used to catalytically activate the soot, but due to their low catalytic activity must be used at levels of 50-125 ppm of metal in the fuel. This high level of metal can lead to engine wear and build up of metallic ash residue in the filter.
Previous testing has also shown that the additive alone can reduce gaseous and particulate emissions from diesel engines by 15-30% and that its use with aftertreatment devices such as oxidizers and filters can give increasingly higher levels of reduction from both existing and new engines, in the range of 70-95%. Thus the additive can serve as a base in marketing a clean diesel fuel for low cost emission reduction now and will assist advanced control technologies as they are deployed.
The additive is easily blended with the bulk fuel supply or dispensed through on-board dosing and metering systems already developed by engine manufacturers. Cost is expected to be in range of $0.02-$0.05 per gallon of fuel treated once production volumes increase.
Clean Diesel Technologies is a development-stage company with patent-protected products that reduce emission from diesel engines while simultaneously improving fuel economy and power. R&D efforts and products are grouped into two categories: Platinum Fuel Catalysts and NOx Reduction Systems. Platinum Plus is a registered trademark of Clean Diesel Technologies Inc.
Contact: Clean Diesel Technologies Inc., James M. Valentine, 203/327-7050