United States
                    Environmental Protection
                    Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 27711
                    Research and Development
EPA-600/S3-83-102 Dec. 1983
&ER&         Project  Summary
                    Formation  of  a  Detached
                    Plume  from  a  Cement  Plant
                    James L Cheney, William D. Conner, Roy L Bennett, Donald L Duke, Carole L
                    Walters, and Kenneth T. Knapp
                      A coordinated study of process, source
                    emissions, and plume sampling was
                    conducted at a coal-fired cement pro-
                    duction plant. Both source and plume
                    sampling consisted of particle and gas
                    measurement and characterization. Par-
                    ticulate sampling of both the source and
                    plume addressed particle size, amount,
                    and composition.  Particles were ana-
                    lyzed by scanning electron microscopy,
                    x-ray fluorescence spectroscopy, and
                    chemical means. Gas sampling of both
                    the source and plume involved conven-
                    tional source sampling methods as well
                    as procedures adapted to this specific
                    measurement program. Plume opacity
                    was measured by visual observation
                    and a LIDAR system.
                      Comparison of the results from the
                    plume  and source measurement indi-
                    cated the formation of the plume was
                    the result of the reaction of ammonia
                    and hydrochloric acid. The formation of
                    ammonium chloride occurred within
                    the same set of reaction parameters as
                    independent laboratory studies'had
                    previously indicated.
                      The results of electron microscopy
                    analysis for one of the plume samples
                    indicated an NH4CI particle size of < 0.4
                    fjm. When an estimation of the amount
                    of these sized particles was compared
                    to source particle sizing measurements,
                    a 50 to 100% increase in such inhalable
                    particulates was occurring within the
                    plume, at less than 18 stack diameters
                    from the exit.

                      This Project Summary was developed
                    by EPA's Environmental Sciences Re-
                    search  Laboratory, Research Triangle
                    Park, NC, to announce key findings of
                    the research project that is fully docu-
                    mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).

Introduction
  This report discusses an in-depth study
of a coal-fired cement production plant to
determine the nature of the formation of a
visible plume  from the gases emitted
from the stack. The plant has the capa-
bility of operating on either a regular
mode or a bypass mode. The visible plume
formed each time the plant operated in
the bypass mode. During  the regular
mode, the off gases from the coal-fired
kiln passed through the raw product
grinding mill and a recovery electrostatic
precipitator (ESP) prior to their exit to the
atmosphere. Duri ng the bypass mode, the
kiln gases were rerouted around the mill
and through a cooling tower, after which
they were passed through the ESP and
vented to the atmosphere. During both
operating modes, source measurements
indicated that the plant was well within
compliance for both opacity and panicu-
late grain loading.
  A 1-week (5-day) sampling program
was conducted at the Lehigh plant at
Leeds, Alabama, in May 1981. The sampl-
ing addressed both source emissions of
gases and particles and plume sampling.
Source emissions were sampled by con-
ventional extractive methods to determine
the concentrations of S02, NH3, HCI, and
NOx as well as particulate mass emission
rates, particle size, and particle composi-
tion. Gaseous HCI, NH3, S02, CO and C02
were also  measured with an optical
cross-stack procedure. The plume sampl-
ing was performed with tethered balloons
and various filters. The filters,  which
were connected to a pump box on the
ground, were analyzed for such gases as

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  HCI, NH3, S02, and the particles  were
  analyzed for SO4=, S03=, CI", NH3, by x-
  ray fluorescence spectroscopy, and scan-
  ning electron microscopy. Opacity meas-
  urements for the plume at and  near the
  location of the balloon sampling location
  were performed with both a LIDAR system
  and by visual observation.

  Results
    Inclement weather and plant operating
  problems severely limited the time during
  which sampling  of  the  bypass mode
  plume could be  performed. However,
  adequate data were established to con-
  clude how the particles were formed in
  the plume.
    These data included:
   1)   In-stack measurements indicated
      that particulate NH4+ and CI* emis-
       sions of 0.68 (expressed as NH3) and
       7.21 (expressed as HCI) Ib/hr were
       emitted and that ~ 85 percent of the
       NH3and ~ 50 percent of the HCI were
       emitted as gases. A second improved
       HCI reference method indicated — 80
       percent of the HCI was emitted as gas
       phase.
   2)  The  mass emission  rate of particu-
       lates from the stack was 7.7 and 15.4
       Ib/hr from two samples acquired. X-
       ray  fluorescence analyses of the
       particles indicated their main com-
       ponents as Ca, Si, K, Fe, S,  and Al. A
       Pilat impactor sample indicated that
       56 percent of the total particulate
       catch was on the backup filter where
       the particles were less than 0.4 /urn in
       size.
   3)   Gas and particle composition of the
       plume were determined with a three-
       stage filter designed to collect parti-
       cles and gaseous HCI, NH3 and SC<2.
       The  second filters following the front
       prefilter were chemically impreg-
       nated to absorb gaseous components
       passing through the particulate filter.
          Analyses of all three filters indicated
          a total catch of 1.86,1.13, and 12.5/u
          moles of HCI, NH3, and S02, respec-
          tively. The first of the three filters
          was assumed to collect particles
          only.  The  first filter collected 1.25,
          0.75, and 0.08 fj moles of HCI, NH3,
          and S0<~, respectively. This indicated
          that ~ 40% of the HCI and NH3 had
          reacted to form particles but that very
          little (~ 7 percent) of the S02 had
          been converted_or was contained as
          particulate S04=.
       4)  Scanning electron microscopy of two
          plume samples acquired during  the
          high  opacity situation indicated a
          particle size range of 0.2 to 0.6 yum
          for both  samples.  In one of  the
          samples a predominant number of
          particles  contained CI* and  were
          volatile in the electron beam. It was
          assumed that NH4CI was the basic
          particle component.  The  second
          sample contained a large number of
          particles with K and S. There were no
          significant particles containing CI" in
          this sample.  These particles were
          assumed to contain I^SCu.
       5)  Opacity measurements by the LIDAR
          system  and  by visual observation
    agreed  well and ranged from less
    than 5 percent near the stack exit to
    as high as 41 percent within 50 m of
    the exit.
Conclusions
  The change from an invisible  plume
just above the stack to a  highly opaque
plume ~ 50 m from the stack indicates
some kind of particle formation.
  The change in composition between in-
stack and  plume  samples  showed a
conversion  of gaseous NH3 and gaseous
HCI to particulate matter containing NH4+
and CI". That this particulate matter was
indeed NH4CI was supported by electron
microscopy. There was also some evi-
dence of S04= formation. The increase in
particulate matter in the plume within 50
m downwind of the stack exit resulted in
an estimated double amount of fine  or
inhalable particulate matter than  that
indicated by the source measurements.
  It was concluded from the data that the
visible plume formed during bypass mode
operation was the result of fine particle
formation, predominantly NH4CI, but with
some sulfite-sulfate salt formation, prob-
ably a result of water droplet chemistry.
          The EPA authors, James L. Cheney (also the EPA Project Officer, see below),
            William D. Connor. Roy L. Bennett, Donald L. Duke, Carole L. Walters, and
            Kenneth T. Knapp  are with Environmental Sciences Research Laboratory,
            Research Triangle Park, NC 27711.
          The complete report, entitled "Formation of a Detached Plume from a Cement
            Plant," (Order No. PB 84-120 187; Cost: $11.50. subject to change) will be
            available only from:
                 National Technical Information Service
                 5285 Port Royal Road
                 Springfield, VA 22161
                 Telephone: 703-487-4650
          The EPA Project  Officer can be contacted at:
                 Environmental Sciences Research Laboratory
                 U.S.  Environmental Protection Agency
                 Research Triangle Park, NC 27711
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