Chemical Characterization of Aerosol Particles in a Heptane Flame

 

 

ABSTRACT

 

The National Research Council proposed recently that more extensive research on determining the chemical constituents within particulate matter (PM) is needed to better understand the health affects associated with airborne particles.  The Environmental Protection Agency currently regulates PM based on sizes, e.g., PM10 and PM2.5.  One reason for this is that the chemical makeup of PM is complex and not well known.  Health effects attributed to PM can be better understood if the chemical constituents are known.  The focus of the current study is to identify the chemical species present in carbonaceous PM that is formed at different stages within a heptane spray flame.

 

Particle samples were collected at four different locations, in the streamwise direction along the injector centerline.  The flame was generated from a swirl burner enclosed in a stainless steel combustion chamber.  Liquid heptane was supplied at about 2.1 kg h-1 to a 60 degree, full-cone fuel atomizer, and the surrounding combustion air, which is swirled to provide flame stability, was supplied at about 17.8 m3 h-1.  The fuel equivalence ratio was approximately 1.5.  A water-cooled, gas sampling probe was used to extract the particulate samples from the flame, which were collected onto a borosilicate glass fiber media.  A Soxhlet extraction apparatus was used to extract the chemical species from the aerosol particles on the filter.  The solutions were then concentrated by using a Kuderna-Danish apparatus.  Three different solvents were used to determine if preferential solvent extraction would be observed.  The three solvents used were methylene chloride, toluene, and a 1:1 volumetric mixture of acetone and hexane.  Species identification was determined by gas chromatography/mass spectrometry.

 

 

 

Submitted by:  Chad Y. Sheng

Mentor:  Cary Presser

Division:  Process Measurements (836)

Lab:  CSTL

Building:  Physics (221) Room B314

Mailstop:  8360

Tel:  301-975-2739

Fax: 301-869-5924

E/m:  chad.sheng@nist.gov

Sigma Xi member:  No

Category:  Chemistry