United States
Environmental Protection
Agency
Atmospheric Sciences Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S3-84/094 Mar. 1986
&EPA Project Summary
Gaseous HCI and Chlorinated
Organic Compound
Emissions from Refuse Fired
Waste-to-Energy Systems
Arthur B. Nunn
Testing of the emissions of hydrogen
chloride (HCI), chlorinated dibenzo-p-
dioxins, dibenzofurans, chloroben-
zenes, chlorophenols, polychlorinated
biphenyls, and aldehydes was conduct-
ed on a water-wall, mass-fired munic-
ipal waste incinerator and a refuse-
derived fuel (RDF)-fired municipal
waste incinerator. The purpose of the
testing was to evaluate the measure-
ment methods used for sampling and to
determine what differences may exist in
the emission characteristics of the two
types of units and the effect that this
difference would have on the applica-
bility of the methods employed.
Testing of HCI emissions was per-
formed by absorption in four midget
impingers each containing 20 ml of 0.1
N NaOH. Sampling of chlorinated or-
ganic compound emissions was con-
ducted using a modified EPA Method 5
sampling train with a cartridge of XAD-
2 resin between the third and fourth
impingers. Analysis was performed
using high resolution gas chromatogra-
phy/mass spectroscopy.
HCI emissions from the mass-fired
incinerator (Site A) exceeded the HCI
emissions from the RDF-fired inciner-
ator (Site B) by approximately 45%.
Chlorinated organic compound emis-
sions from Site A exceeded those from
site B by factors ranging from 12 to
371. Emissions from both sources
exhibited a large variation from test to
test; however, isomeric distributions
were similar.
The majority of all organic compounds
were detected in the back half of the
Method 5 sampling train with the larg-
est overall percentage found in the
impinger contents. Chlorobenzenes
were the only compounds of which the
majority was detected in the XAD-2
resin trap.
This Project Summary was developed
by EPA's Atmospheric 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
Subsequent to reports in the late
1 970's that various incineration process-
es give rise to emissions of chlorinated
dibenzo-p-dioxms(CDDs) and chlorinated
dibenzofurans (CDFs), the United States
Environmental Protection Agency con-
ducted preliminary investigations of a
resource recovery incinerator, which
further indicated the presence of these
compounds. The results of this program,
which included data of a qualitative rather
than quantitative nature, indicated the
need for further investigation of the
sampling methods used and, as a result,
the present program was embarked upon
in early 1 981
The purpose of this program was to
evaluate measurement methods used for
sampling the emissions of CDDs, CDFs,
Chlorobenzenes, chlorophenols, polychlor-
inated biphenyls, and aldehydes from
water-wall, mass-fired and from refuse-
derived-fuel (RDF)-fired municipal waste
incinerators These compounds were of
-------
interest not only because of the potential
lexicological properties associated with
each, but also because several of these
groups of compounds, particularly chloro-
benzenes and chlorophenols, have been
implicated as precursors to the formation
of CDDs, CDFs, and PCBs in the combus-
tion process. The purpose of testing the
two different types of incinerators was to
determine what differences may exist in
the emission characteristics of these
types of units and hence the effect these
differences would have on the applicabil-
ity of the method Water-wall, mass-fired,
and RDF-fired incinerators were chosen
for the program because they are the two
most prevalent types of waste-to-energy
systems currently in operation or likely to
become operational m the near future.
One unit of each type was tested during
the program
In addition to the chlorinated organic
compounds, sampling and analysis was
conducted for HCI emissionsfrom the two
units. This was conducted to evaluate the
distribution in the gas stream of the
chlorides released from the refuse during
the combustion process and the applica-
bility of the manual method.
Site Descriptions
This program consisted of tests con-
ducted at two separate facilities. The first
facility, Site "A", is a mass-fired, water-
wall, refuse-burning incinerator-boiler
that is used to generate steam for various
purposes at a nearby research center
The unit burns 100% refuse with no
auxiliary fuel at a rate approximately
90,000 to 135,000 kg/day (100 to 150
tons/day). The unit is operated at or near
capacity at all times except when firing
excessively wet trash.
The second facility that was tested, Site
"B", is a Detroit Rotograte Stoker Boiler
that produces steam for plant heating
The unit is designed to burn coal, on
which it is usually fired The facility
operators are, however, investigating the
possibility of switching to refuse-derived
fuel as a fuel, and the boiler was fired on
100% RDF during testing. During testing,
Site "B" was fired at a rate of approxi-
mately 205Kg (225 tons) of RDF per day.
Experimental Method
Sampling Methods
Sampling for HCI concentrations in the
exhaust stream was conducted by pulling
a sample through a stainless steel probe,
through four midget impingers each
containing 20 ml of 0.1 N NaOH, through
a diaphragm pump, and finally through a
flow meter, flow control valve, and a dry
gas meter
The sample was drawn at a rate of
approximately 2 L/mm and sampling was
conducted for 30 mm, thus, a sample
volume of approximately 006m3 was
collected The impingers containing the
absorbing solution were submerged in an
ice bath during sampling. Following sam-
pling, the impinger contents were placed
in labeled sample jars where they were
maintained until analyzed on site
Organic compound sampling was con-
ducted using a modified EPA Method 5
sampling system This system consisted
of a heated glass-lined sample probe with
a stainless steel nozzle, a glassfiber filter
m a heated glass filter holder with a
stainless steel filter support; a Greenburg-
Smith impinger containing 100 ml dis-
tilled water followed by a modified
Greenburg-Smith impinger (dry for mist
knockout), both containing 5 cm of 3 to 6
mm diameter glass beads and immersed
in an ice bath, a resin cartridge containing
60 g of XAD-2 sorbent resin, and finally
an impinger containing 200 to 300 g of
silica gel Sample flow was measured and
controlled by a conventional EPA Method
5 meter box All glassware used in the
tests was annealed prior to being taken
into the field
Sampling was conducted isokmetically
during all tests Tests were conducted for
180 and 300 mm time periods with
sample volumes ranging from 2 5 to 6 8
m3.
Analytical Procedures
HCI analysis was performed by the
mercuric nitrate (HgfNOs^) method,
which involves titrating Cl~ with a stand-
ardized Hg(NOa)2 solution using a di-
phenylcarbazone indicator-acidifier rea-
gent This method is known to be subject
to interference and endpomt masking by
the presence of sulf ite (SOs2") and cationic
metals in the exhaust stream In order to
alleviate this problem, samples were
treated with 3% hydrogen penoxide to
eliminate the sulfite interference, and
they were passed through a Rexyn 1 01 -H
column (a registered trademark of Fisher
Scientific) to eliminate the cationic end-
point masking.
The procedures used to separate the
halocarbonsof interest from the matrices
in which they were collected involved
solvent extraction with the addition of
internal standards of [37CU]-2,3,7,8-
TCDD, [37CI7]-1,2,3,4,6,7,8-HPCDD,
[37CI8]-OCDD,[D6]-3,3',4,4'-tetrachlorobi-
phenyl, [13C6]-pentachlorophenyl, and
[13C6]-hexachlorobenzeneto each sample
Further sample preparation procedures
included acid, water, basic, and further
solvent extractions, macro-column elu-
tion, and mini-column liquid chromatog-
raphy If preliminary GC-MS screening
analysis of a sample indicated the pres-
ence of potential interfering compounds
or other sample matrix constituents that
eluted from the GC at very long times,
then additional sample clean up or frac-
tionation was required using high per-
formance liquid chromatography (HPLC)
The HPLC used for this purpose was a
Varian Model 5021 Microprocessor Con-
trolled HPLC equipped with a CDS-1 1 1 L
Data System Dual Dupont Zorbax ODS
Columns (25 cm x 0.6 cm I D.) were
employed Methanol was employed as
the mobile phase in the isocratic mode
The instrumentation utilizedto perform
the quantitative analyses for the chloro-
carbons of interest was comprised of a
gas chromatograph-mass spectrometer-
data system (GC-MS-DS) that included a
Perkm-Elmer Sigma III Gas Chromato-
graph coupled through a specially modi-
fied interface to a Kratos System This
analytical system falls m a class of
analysis referred to as "high resolution
gas chromatography/high resolution
mass spectroscopy" (HRGC/HRMS) The
gas chromatograph was equipped with a
split/splitless injector and a wall-coated
open-tubular fused-silica capillary col-
umn The interface mentioned above
included provision for both direct admis-
sion of the column effluent into the mass
spectrometer source as well as admission
of the column effluent via a single-stage,
all-glass jet separator The interface was
modified to minimize peak broadening
due to excessive dead volume and to
optimize the temperature throughout the
interface The mass spectrometer was
operated m the multiple ion monitoring
mode under the control of the computer-
based Kratos DS55SM data system.
Elaborate programs for the DS55SM data
system were developed that permitted
rapid, automated retunmg of the mass
spectrometer during analysis of a sample
extract and thus 20 to 30 separate ion
masses were sequentially monitored
during an analysis Each of the groups of
chlorocarbons of interest (CDDs, CDFs,
chlorobenzenes, chlorophenols, and
PCBs) were analyzed separately
Results
The testing conducted on the twc
systems revealed considerable differenc-
es in the emission characteristics of the
mass-fired, water-wall incinerator anc
-------
the RDF-fired incinerator with the emis-
sions from the mass-fired unit higher in
all cases A summary of the emissions
from each unit tested is presented in
Table 1
HCI emissions from the mass-fired
incinerator (Site A) exceeded the HCI
emissions from the RDF-fired incinerator
(Site B) by approximately 45% Chlori-
nated organic compound emissions from
Site A exceeded those from Site B,
however, by factors ranging from 1 2 to
371 The overall distribution of chlorides
in the gas streams, which is presented in
Table 2, shows that a higher percentage
of total chlorides was emitted as HCI from
Site B than from Site A thus indicating
that combustion was more efficient for
the RDF-fired incinerator. This difference
may be due to differing moisture contents
of the two types of fuel. The RDF was
stored in silos, and was never exposed to
moisture thus it was very dry when
combusted The fuel for Site A, on the
other hand, was often quite wet as it was
stored in open areas where it was exposed
to rainfall prior to delivery to theplant site
where it was stored m a covered pit.
Conclusions
1. The sampling and analytical meth-
odologies used for this project per-
formed well
2. Chlorinated organic compound
emissions were higher from the
mass-fired incinerator than from
the RDF-fired incinerator.
3. The majority of the CDDs emitted
from both units were heptachlori-
nated dibenzo-p-dioxins
4 Chlorophenols were detected in the
highest concentrations of all types
of chlorinated organic compounds
evaluated.
Table 1. Summary of Emissions Data
Compound
HCI
TeCDD
PsCDD
H£DD
HfCDD
OCDD
JeCDF
P£DF
H£DF
HPCDF
OCDF
DCLB
T,CIB
TeCIB
P5C/B
H£IB
T,CP
TeCP
PsCP
T,CB
TeCB
PSCB
HXCB
Aldehydes
Site A
Emission Rate*
(mg/h!
6?**
153
19 7
31 5
354
92
765
350
41 2
365
26
563
2280
3550
551 0
1650
2,444 0
1.127 0
5880
146
84
1 7
09
1660
Site B
Emission Rate*
(mg/h)
76**
0 1
0 1
02
1 5
08
1 3
05
09
32
04
03
58
80
399
21 6
1490
2150
3520
--
--
94
Average of all tests at each site
*HCI in kg/h
Table 2.
Chloride Distribution in Gas Stream
Percent of Total
Chlorides in Gas Stream (%)
Compounds
HCI
Chlorophenols
Chlorobenzenes
Chlorinated Dibenzo furans
Chlorinated Dibenzo-p-Dioxins
Polychlonnated Biphenyls
Site A
99 92237
0 05233
002136
0 00235
000140
000019
WOO
Site B
99 992178
0 007650
0 000079
0 000064
0 000029
0 000000
WOO
Arthur B. Nunn III is with Scott Environmental Technology, Inc , Plumsteadville,
PA 18949.
James L. Cheney is the EPA Project Officer (see below/.
The complete report, entitled "Gaseous HCI and Chlorinated Organic Compound
Emissions from Refuse Fired Waste-to-Energy Systems," (Order No PB 86-145
661 /AS, Cost- $11 95, 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:
Atmospheric Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 2777 1
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S3-84/094
OC00329 PS
U S ENVIR PROTECTION AGENCY
*?GION 5 LIBRARY
230 S DEARBORN STREET
CHICAGO IL 60604
------- |