United States
                  Environmental Protection
                  Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
                  Research and Development
EPA/600/S8-88/069 July 1988
^EPA         Project Summary
                   Construction  and
                   Operation of a  10  CFM
                   Sampling System  with a 10:1
                   Dilution  Ratio  for  Measuring
                   Condensable  Emissions

                   William J. Steele, Ashley D. Williamson, and Joseph D. McCain
                     This  report  describes a trans-
                  portable sampling apparatus de-
                  signed  to sample incineration
                  sources at municipal and hazardous
                  waste disposal facilities,and  to
                  provide non-contaminated samples
                  of condensable  materials. The sam-
                  ple gas, at a flowrate of 10 cfm (283
                  Ipm), passes through  a modified
                  Source  Assessment Sampling Sys-
                  tem (SASS) cyclone  and is then
                  diluted  with clean air at 100 cfm
                  (2830 Ipm)  by a novel, perforated
                  cone assembly.  Rapid uniform dilu-
                  tion takes place through the vigorous
                  mixing of the sample and clean  air
                  streams in the dilution chamber. The
                  resultant gas,  cooled to approx-
                  imately  atmospheric conditions, is
                  passed'through a mixing section that
                  provides a  residence  time  of
                  approximately 3 sec. The  resulting
                  aerosol particles are collected on a
                  Teflon-coated  glass-fiber  filter.
                  These solids, along with  those col-
                  lected in the cyclone, are subse-
                  quently provided for chemical and
                  biological assay  analysis.

                  This Project Summary was developed
                  by EPA's Air and Energy Engineering
                  Research  Laboratory,  Research
                  Triangle  Park, NC, to announce key
                  findings of the research project that
                  is  fully documented in  a separate
                  report of the same title (see Project
                  Report ordering information at back).
 Introduction

    The primary design objective of this
 apparatus was to provide (for bioassay)
 non-contaminated samples of con-
 densable materials from stack discharges
 at municipal  incinerators and hazardous
 waste disposal facilities. Two opposing
 design constraints were: (1) to provide
 sufficient quantities of particulate matter
 within a reasonable  sampling time
 (i.e.,<1 day),  and  (2) to  provide  a
 portable instrument  that  could be
 operated at various sites.  For microbial
 mutagenicity  (Ames) assays, sufficient
 particulate  to obtain 10-100  mg of
 extractable organic material is desirable.
 This resulted in the design of a  10 cfm
 (283 Ipm) sampling system with  a 10:1
 dilution ratio.

 System Description
    The main flow paths within the dil-
 ution system  are: 1) dilution air, 2) sam-
 ple gas, 3) diluted gas, and 4) outlet gas.
 The dilution  air is extracted from the
 ambient atmosphere and  conditioned
 with a condenser system, High Efficiency
 Particulate  Air (HEPA) filter,  and  a
 charcoal bed. A heater raises the  dilution
 air temperature to 70°F (21 °C) when
 necessary. An in-line orifice is used to
 measure  the dilution air flowrate
 (nominally 100 cfm or 2830 Ipm).
    The sample gas is extracted from the
 stack through a  3/4-in.  (1.9 cm) ID
 glass-lined probe.  The  probe introduces

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the stack gas  to a  modified  Source
Assessment  Sampling  System  (SASS)
cyclone which has a D$Q of 1.8 ^m for a
10  cfm  flowrate  at about   room
temperature  (75°F or  24°C). The  probe
and cyclone are heated to  maintain  the
sample gas at  the  existing flue gas
temperature.
    The sample gas  is diluted by  the
dilution air at a  10:1 ratio in the dilution
cone.  The sample gas is  introduced at
the throat of the cone, and the dilution air
is forced through the  perforations on the
outer surface of the cone. The combined
gas (called diluted gas) enters  a dwell
chamber where a residence  time  of
approximately  3 sec allows  for  the
formation of condensable emissions. The
resulting  paniculate materials are then
collected  on a  Teflon-coated  glass-
fiber filter.
    An outlet transform below  the filter
directs the filtered gas to  the  exhaust
pump.  The  flow  of  the  outlet gas is
measured  by an orifice upstream  of the
pump.
    The  support  assembly  for  the
dilution  system  provides  a cradle   for
supporting the  dilution manifold  and  the
associated probe.  The  cradle  can   be
adjusted vertically to  position the  probe
at the selected sampling port. The critical
temperatures  and pressures  of  the
dilution  system  are  regulated  by  the
control and monitoring assembly.

System Assembly
    The  first step  in assembling  the
system is to  construct  the  dilution
manifold  inside  the  support structure.
Three  wooden  cradles  support  the
assembled  dilution  manifold;  heavy-
duty elastic cords hold the  transform on
the cradles.  Once   the  manifold  is
supported, the outlet transform  may  bo
         removed  and the filter  placed in the
         recessed  surface of the filter flange. The
         cyclone may  then  be attached to the
         face  of  the diluter.  The  rear of the
         cyclone   is supported   with  a clamp
         attached  to a front  rail  of the support
         structure.  A second clamp  supports one
         end of the probe; this clamp is attached
         to a side  rail for horizontal probe access
         or to a rail directly under the cyclone for
         vertical probe access.
            The   HEPA  filter  and charcoal  bed
         used to condition the dilution air should
         be replaced prior to each test.  During a
run,  the probe  and cyclone should be
kept as near to stack temperature as
feasible.  The  cyclone should  not be
heated above  375°F  (191°C) to  avoid
damaging the internal finish. Care should
be used during leak tests and sampling
to apply  and  release pressures and/or
vacuums gradually  to avoid rupturing the
sample filter. At the completion of a run,
the  sample filter  should be  handled
carefully (surgical gloves are suggested)
and sealed  in a glass or Teflon container
to prevent external contamination
            William J. Steele, Ashley  D.  Williamson, and  Joseph D. McCain  are  with
                  Southern Research Institute, Birmingham, AL 35255-5305.
            Sharon L No/en is the EPA Project Officer (see below).
            The complete report, entitled "Construction  and  Operation of a  10 CFM
                  Sampling System With a 10:1 Dilution Ratio for Measuring Condensable
                  Emissions," (Order  No.  PB  88-198 551/AS;  Cost: S12.95,  subject to
                  change) will be available only from:
                     National Technical Information Service
                     5285 Port Royal Road
                     Springfield, VA22161
                      Telephone: 703-487-4650
            The EPA Project Officer can be contacted at:
                     Air and Energy Engineering Research Laboratory
                     U.S. Environmental Protection Agency
                     Research  Triangle Park, NC 27711
 United States
 Environmental Protection
 Agency
Center for Environmental Research
Information
Cincinnati OH 45268
 Official Business
 Penalty for Private Use $300
 EPA/600/S8-88/069

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