Effect of Unburned Methyl Esters on the NOx Conversion of Fe-Zeolite SCR Catalyst
Engine and flow reactor experiments were conducted to determine the impact of biodiesel relative to ultra-low-sulfur diesel (ULSD) on inhibition of the selective catalytic reduction (SCR) reaction over an Fe-zeolite catalyst. Fe-zeolite SCR catalysts have the ability to adsorb and store unburned hydrocarbons (HC) at temperatures below 300 C. These stored HCs inhibit or block NO{sub x}-ammonia reaction sites at low temperatures. Although biodiesel is not a hydrocarbon, similar effects are anticipated for unburned biodiesel and its organic combustion products. Flow reactor experiments indicate that in the absence of exposure to HC or B100, NO{sub x} conversion begins at between 100 and 200 C. When exposure to unburned fuel occurs at higher temperatures (250-400 C), the catalyst is able to adsorb a greater mass of biodiesel than of ULSD. Experiments show that when the catalyst is masked with ULSD, NO{sub x} conversion is inhibited until it is heated to 400 C. However, when masked with biodiesel, NO{sub x} conversion is observed to begin at temperatures as low as 200 C. Engine test results also show low-temperature recovery from HC storage. Engine tests indicate that, overall, the SCR system has a faster recovery from HC masking with biodiesel. This is at least partially due to a reduction in exhaust HCs, and thus total HC exposure with biodiesel.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy Vehicle Technologies Program
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1045710
- Journal Information:
- SAE International Journal of Fuels and Lubricants, Vol. 2, Issue 2
- Country of Publication:
- United States
- Language:
- English
Similar Records
CRADA Final Report for CRADA Number ORNL00-0605: Advanced Engine/Aftertreatment System R&D
Hydrocarbon Fouling of SCR during PCCI combustion