Project Title: Pollutant Emissions Study for Biodiesel (B20)
DRI Faculty: Hampden Kuhns, Vic Etyemezian, and Oliver Chang
Dates: Nov. 2003 – Oct. 2004
Sponsor: Community Planning Association of Southwest Idaho
Collaborators: None
Total Cost: $111,000
Objectives/Methods: The project objectives were to evaluate the effects of B20 biodiesel fuel use on particulate and gas-phase emissions from school buses under normal operating conditions. Cross plume and in-plume measurements of bus exhaust were made on approximately 200 buses operating first on petroleum diesel, and later on B20. Gaseous emissions were measured using a commercial remote sensing instrument. Particulate matter emissions were determined using a combination of the gas remote sensor along with a light detection and ranging (Lidar) and transmissometer system.
Results/Conclusions: Relative to the petroleum diesel, use of B20 increased exhaust emissions of carbon monoxide, hydrocarbons, and especially particulate matter. There results are contrary to many previous studies of emissions effects of B20. One likely contributing factor is the low quality of the biodiesel fuel used in this study. Analysis of the fuel detected a relatively high concentration of free glycerine, and relatively low flash point – both indicating poor fuel quality. This fuel did not comply with the biodiesel standards as specified in ASTM D6751. These results emphasize the importance of fuel quality control to ensure that anticipated emissions benefits of biodiesel are achieved.
Publications: A case study of real-world tailpipe emissions for school buses using a 20% biodiesel blend
