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Advanced Method for Measurement of the Solid Carbonaceous (Soot) Component of Mobile Source Particulate Matter
This page updated March 1, 2010
Chair’s Air Pollution Seminar |
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Thursday, April 1,
2010
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Advanced Method for
Measurement
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William D. Bachalo,
Ph.D.
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This presentation
will provide an overview of the laser induced incandescence (LII)
instrument and demonstrate its suitability for measuring fine
particulates (soot) associated with emissions from combustion systems
including diesel, gas turbine (jet engines) and direct injected
gasoline engines. In the LII method, soot particles are rapidly heated
to high temperatures by a laser and the resulting incandescence signal
is measured and analyzed to estimate the soot primary particle size and
the soot volume fraction. The LII method has an exceptionally high
dynamic range of over one million to one. The measurements are made in
real time with high sensitivity and resolution and the instrument
requires minimal maintenance. However, the biggest advantage of the
method is that it can measure soot directly in exhausts without
requiring expensive dilution tunnels or other treatment. Under the ICAT funded program, the measurement sensitivity of the LII was enhanced to allow ambient soot particulate concentration measurements. The LII technology was also further developed into a useful portable instrument that now provides immediate time-resolved measurements of particulate emissions for a broad range of applications including diesel and gas turbine engine development, evaluation of particulate control systems, and compliance verification to particulate emissions regulations. During this effort, a NIST traceable calibration method was developed and refined to improve the reliability and to better define the instrument response to soot. At the same time, optical systems were developed to produce a more compact instrument which was thoroughly tested for operational integrity under typical industrial environments. Software was developed that included algorithms to fully automate the instrument set up functions and to automatically track the soot concentrations over a range of one million to one. The earlier LII 200 version was evaluated and tested at our industrial partners sites. As a result of these tests, several improvements were defined and implemented. From these results, a next generation LII 300 instrument evolved which is much more compact, has greater sensitivity and is easier to operate. Comparisons were made to gravimetric measurements, the current EPA standard method, to demonstrate that the LII instrument is able to produce results are in acceptable agreement with the established EPA method. Measurement comparisons made with gravimetric results at our industrial partners’ sites and after several round of instrument testing and refinement, showed excellent agreement. Results of tests acquired at our industrial partner sites will be presented and reviewed. A brief description of the on-road measurement capability of the instrument will be presented.
William D. Bachalo,
Ph.D., is
President and CEO of Artium Technologies Inc., Sunnyvale, California.
Dr. Bachalo was founder and president of Aerometrics
Inc. (1981 to 1995) where he invented and led the development of the
phase Doppler interferometry technique for measuring the size and
velocity of spray droplets which is now the worldwide standard for this
purpose. Dr. Bachalo worked as vice president in
charge of scientific affairs at Islet Technology, Inc. (1996 to
2005) developing encapsulation and transplantation the islets
of Langerhans in an effort to cure juvenile diabetes. Dr.
Bachalo cofounded Artium Technologies in 1998 with the goal of
developing the laser induced incandescence method into a commercially
viable instrument for measuring particulate emissions from combustion
systems. Dr. Bachalo is led development of
next-generation phase Doppler interferometer instruments for measuring
clouds related to meteorological and aircraft icing phenomena.
Dr. Bachalo has received several international awards
including the international Tanasawa Award twice for his work in
atomization and sprays and instrumentation development. Dr.
Bachalo has co-authored over 150 technical papers.
For information
on this Series please contact: For
a complete listing of the ARB Chairman's Series and the related
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