Analysis Capabilities
Diesel Particulate Filter Characterization and Modeling
The U.S. Environmental Protection Agency has ruled that heavy duty diesel particulate be reduced 90% by 2007. Such a ruling requires that aftertreatment devices be developed.
Diesel particulate filters developed to address the problem of diesel emissions provide technical hurdles that must be addressed, including plugging, thermal failure (such as cracking and melting), less-than-desirable performance (in trapping effectiveness and sulfate particulate production), and high cost.
a flow pattern in a filter.
Researchers at the Pacific Northwest National Laboratory are developing a sub-grid model of a diesel particulate filter, using the Lattice-Boltzmann technique, a simulation method for modeling continuum flow and transport in complex systems. Through this modeling, researchers are attempting to determine how the soot burn rate term can best be expressed and to identify the soot cake layer intrinsic properties.
The Lattice-Boltzmann technique is based on a statistical mechanics approach and is extensively used for simulating transport in porous materials.
Diesel Soot Filter Regeneration Phenomena
Researchers at the Pacific Northwest National Laboratory (PNNL) are helping to meet the U.S. Environmental Protection Agency's mandate of a 90% reduction of diesel particulate matter by 2007 and of nitrogen oxides (NOx) by 2010.
devices and examples.
To satisfy these standards, diesel engine manufacturers will have to utilize exhaust aftertreatment technology. No viable commercial technologies are currently available that can be universally applied to all on-highway heavy-duty diesel engines. To address these issues, PNNL researchers are investigating the development of NOx reduction catalysts and soot filtration devices for diesel engines.
Soot filter devices are expected to be the prime candidate for future diesel particulate control. Soot filter devices under development by PNNL have been found to capture all forms of particulate material and are deemed extremely effective. Through use of the filter devices, the captured material is burned off, or regenerated, to avoid high back pressure, and this regeneration is enhanced using a catalyst.
Likewise, NOx adsorber technology holds the promise for effective control of NOx emissions. Much like a particulate filter, adsorbers can effectively capture the NOx but must be periodically regenerated. This regeneration is a difficult process to manage and will require substantial research and development before it can be made to be practical.
