United States
                    Environmental Protection
                    Agency
National Risk Management
Research Laboratory
Research Triangle Park NC 27711
                    Research and Development
EPA/600/SR-96/007   March 1996
4>EPA        Project  Summary
                    Experimental  Investigation of
                    PIC  Formation  During  CFC
                    Incineration
                    G. Kryder and B. Springsteen
                     Experiments were conducted to as-
                    sess (1) the effect of residual copper
                    retained in an incineration facility on
                    polychlorinated dibenzo-p-dioxin and
                    dibenzofuran  (PCDD/PCDF) formation
                    during incineration of non-copper-con-
                    taining  chlorofluorocarbons (CFCs);
                    and (2) the formation of chlorinated and
                    aromatic products of incomplete com-
                    bustion (PICs), including PCDD/PCDFs,
                    during incineration of CFC recycling
                    residue and hydrochlorofluorocarbons
                    (HCFCs). High concentrations of PCDD/
                    PCDFs (23,800 ng/dscm at 7% O2) mea-
                    sured in a fiscal year (FY) 91 study
                    during incineration of dichlorodifluo-
                    romethane (CFC-12) in  the turbulent
                    flame reactor (TFR) could not  be re-
                    peated in the present study. Repetition
                    tests  conducted  in the same  facility
                    under similar operating conditions re-
                    sulted  in  PCDD/PCDF concentrations
                    of 118 ng/dscm  at 7%  O2. However,
                    results of the present study suggest
                    that residual copper retained in an in-
                    cineration facility possibly promotes the
                    formation  of  PCDD/PCDFs during in-
                    cineration  of  CFC-12 which does not
                    contain copper. Tests conducted in the
                    TFR facility resulted in measured PCDD/
                    PCDF concentrations of 386 - 454 ng/
                    dscm at 7% O2 during incineration of
                    CFC-12 which followed incineration of
                    copper-containing compounds.  These
                    results suggest that CFCs may best be
                    incinerated in incinerators that  do not
                    treat any copper-containing waste  prior
                    to CFC incineration, in order to elimi-
                    nate the possibility that residual  cop-
                    per retained in the incineration systems
                    could promote PCDD/PCDF formation
                    during subsequent CFC incineration. In
                    this study, 1,1-dichloro-1-fluoroethane
                    (HCFC-141b) and the oily residue  gen-
                    erated during CFC recycling processes
                    were thermally destroyed without sig-
nificant emissions of volatile organic
PICs and PCDD/PCDFs.
  This Project Summary was developed
by EPA's National Risk Management
Research 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
  A bench-scale study of the incineration
of CFCs, CFC-12 and trichlorofluorometh-
ane (CFC-11), was conducted in FY 91.
For tests performed in the  TRF, a water-
cooled furnace (rated at 20.5 kW) at rela-
tively low flame temperatures (790°C for
the primary flame and 980°C for the sec-
ondary flame), the  CFCs were shown to
be consistently destroyed at very high ef-
ficiency (greater than 99.999%); however,
significant levels of chlorinated and aro-
matic PICs were detected. The test facility
in which the FY 91  tests were conducted
was previously exposed to trace  metals
including copper during  incineration  of
metals-containing waste  prior to the CFC
incineration study. PCDD/PCDFs were
sampled for and detected  at high levels
during a single test condition in this study.
The formation of high levels of PCDD/
PCDFs could have  been the result of the
catalytic effect of residual  copper in the
test facility remaining after incineration of
the metals-containing waste. Of particular
concern, PCDD/PCDFs were sampled for
and detected at high levels in one test
condition.
  Subsequently,  additional CFC incinera-
tion tests were performed  in T-Thermal's
pilot-scale incinerator (rated at 290 kW) in
FY 92. These tests were conducted at a
high  flame temperature (1,090°C) with
water  injection  into the flame zone for
temperature control. PCDD/PCDFs were

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found at moderate levels in only one test
with a high input of a CFC (69% CFC-11
by weight  in fuel oil).  PCDD/PCDFs were
not found  in other tests with lower CFC
inputs. The avoidance of PCDD/PCDF for-
mation in  these tests is possibly due to
the higher temperature and/or water injec-
tion.  Also, the  pilot-scale incinerator is
equipped  with a water-quench  tank  di-
rectly downstream of the burner to pro-
vide rapid  flue gas quenching; flue gases
were quenched from 1,090 to 120°C in
about 0.5  sec. The high flue gas quench-
ing rate may have limited chemical reac-
tions that lead to the formation of PICs in
the flue gas.
  Follow-up bench-scale tests were con-
ducted in FY 92, using the controlled tem-
perature tower  (CTT) to determine the
effect of flame zone temperature on gas-
phase flame formation and destruction of
PICs during CFC-12 incineration.  The ef-
fect of water injection into the flame zone
was also studied. PCDD/PCDFs were not
detected at  a high  flame zone tempera-
ture (1,200°C), while moderate levels of
PCDD/PCDFs were  detected  at a lower
flame zone temperature (900°C). Low lev-
els of PCDD/PCDFs  were also detected
at the lower temperature with water injec-
tion into the flame zone. Flame zone wa-
ter injection may have a reducing effect
on PCDD/PCDF formation during CFC-12
incineration.
  The  effect of  metal  contamination of
CFCs on the incineration emissions was
studied  in FY 93. The CFCs evaluated
during all of the previous incineration tests
were  unused, reagent grade  products;
waste and recycled CFCs were not exam-
ined. CFC refrigerants are likely to have
had long-term contact with heat exchang-
ers made of copper-based alloys. The pos-
sibility exists that  some copper may
have been leached from copper alloy tub-
ing by acids which may be formed as the
result of a CFC's degradation. The cata-
lytic properties of copper in PCDD/PCDF
formation  are well documented.  Test  re-
sults indicated that incineration of waste
CFC-11  produced low levels of PCDD/
PCDFs. Significant levels of PCDD/PCDFs
were found when the waste CFC-11 which
was tested was spiked with 300 ppm cop-
per.

Purpose
  The purposes  of this work were (1) to
further evaluate  incineration as one of the
appropriate technologies for the safe dis-
posal of CFCs, including HCFCs and CFC
recycling residues;  and (2) to compare
current results with those from earlier work
in order to determine if the earlier high-
dioxin emission results are typical for CFC
incineration or a one-time event. The first
objective of this study was to assess the
effect of residual  copper retained in  an
incineration facility on PCDD/PCDF for-
mation during incineration of non-copper-
containing CFCs. Therefore, initial  work of
the present study  was a repetition of the
PCDD/PCDF  formation measured in  FY
91. This repetition test was performed in
the same  water-cooled furnace (TFR) at
relatively low flame temperatures in which
the FY 91 tests were  conducted.  In fact,
the bench-scale  test facility was  not in
use between  the FY 91  and the  present
tests  so  any residual copper  that was
present in FY 91 should have been  present
in  FY 94. Subsequent to the  repetition
test, two  additional tests were performed
with more copper injected into the TFR
prior to the CFC-12  incineration to evalu-
ate the effect of residual copper retained
in  the TFR on subsequent CFC incinera-
tion. At the beginning of the test, copper-
containing fuel was incinerated in the test
facility, followed  by incineration of non-
copper-containing  CFC-12 during which
the emissions of PCDD/PCDFs were mea-
sured.
  The second objective of this study was
to  measure the formation  of chlorinated
and aromatic PICs,  including  PCDD/
PCDFs, during incineration of a CFC  re-
cycling  residue  and a  representative
HCFC. The production  of CFCs  is se-
verely restricted under international agree-
ments  and federal  regulations.  HCFCs
have become more  popular as CFC sub-
stitute  refrigerants.  Incineration may  be
an  appropriate  disposal  technology  for
HCFCs. Therefore, in the second  part of
this  study, the formation of PICs  and
PCDD/PCDFs during incineration  of a
HCFC was investigated. In addition to sub-
stitution of HCFC for CFC, recycling of
CFCs is becoming more popular.  Signifi-
cant quantities of residues generated dur-
ing the recycling process require disposal.
Incineration of these residues may be an
appropriate disposal method.  However,
preliminary analysis of CFC recycling resi-
dues has shown that they may contain up
to  15 ppm copper, which  has been shown
to  have a catalytic effect  on the  formation
of  PCDD/PCDFs.  Therefore, in the last
part of this study, the formation of PICs
and  PCDD/PCDFs during  incineration of
a CFC recycling residue was investigated.

Procedure
  All experimental testing was conducted
at  a test  site in  Irvine,  California. Two
bench-scale combustion research facilities
were  utilized  in this study. The  experi-
mental tests to assess the effect of  re-
sidual copper retained in  an incineration
facility on PCDD/PCDF formation  during
incineration of  non-copper-containing
CFCs, including the repetition of the  FY
91 tests, were conducted in the TFR used
for the FY 91  study.  The  experimental
tests to measure the formation of chlori-
nated and aromatic PICs, including PCDD/
PCDFs,  during incineration of a  CFC  re-
cycling residue  and a HCFC were con-
ducted in the CTT used for the FY 92 and
FY 93 studies.
  The experimental tests in this study con-
sisted of three tasks shown in Table 1.
The  primary focus  of the  experimental
sampling  was the measurement of PCDD/
PCDF  formation  during  incineration  of
CFC,  HCFC, and a CFC recycling resi-
due.  During each test, flue  gas  samples
were collected  for analysis of semi-vola-
tile PCDD/PCDFs using EPA Method 23.
During incineration of a HCFC and a CFC
recycling  residue, flue  gas samples were
collected  and analyzed for volatile haloge-
nated and non-halogenated  organic PICs
using EPA SW-846 Method 0030 (volatile
organic sampling train). Also, the flue gas
was monitored for other combustion prod-
ucts (O2,  CO2, CO,  and NO) using a con-
tinuous emission monitor.
  Task 1 was a repetition test of the  FY
91 high PCDD/PCDF emission experimen-
tal results. The tests were conducted in
the TFR. The TFR facility was not used
for experimental  testing after completion
of the CFC incineration study in FY 91;
however,  the  refractory quarl in the pri-
mary combustion zone had been replaced.
For these tests, the TFR  was configured
similarly to the FY 91  configuration. The
primary combustion zone was maintained
at 760 -  870°C, and the  secondary was
maintained at 980 - 1,090°C. The Task 2
tests were  also  conducted  in the TFR
facility which was operated  in the same
configuration as in the Task  1 tests. Fuel
oil containing copper was fired in the facil-
ity, and an aqueous solution of copper
salt was injected into the  facility  to simu-
late  incineration  of copper-containing
wastes. Following this, CFC-12 (~ 9% by
volume in propane) was incinerated, and
the formation of PCDD/PCDFs in the flue
gas was measured at two sampling loca-
tions. Additional copper-containing fuel was
fired  in the facility,  and then  the CFC-12
incineration test was repeated. Task 3 was
designed to measure formation of chlori-
nated and aromatic PICs, including PCDD/
PCDFs,  during  incineration  of a  HCFC
and a CFC recycling residue.

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Results and Discussion
  Task  1 consisted  of  three  repetition
tests,  Tests 1 to 3 (see Table 1). PCDD/
PCDFs were  not detected  in Test 1, the
TFR system  blank,  indicating  no back-
ground contamination in the propane fuel,
sampling train, recovery agents, or result-
ing from the analytical procedure. Tests 2
and 3 were conducted under similar con-
ditions as the FY 91 test  in which high
levels of PCDD/PCDFs were detected. The
two tests were conducted on  consecutive
days under similar facility operating condi-
tions in order to measure the  repeatability
of the experiment. The high temperature
sample (Location 1 at the afterburner out-
let)  for Test 3 was not analyzed due to
loss of sample prior to laboratory  analy-
sis.  Low  levels of PCDD/PCDFs (5.4 ng/
dscm) were detected at the high tempera-
ture sampling location sample collected
during Test 2. The PCDD/PCDF concen-
trations measured at the downstream sam-
pling  location (Location  2) were  higher
(117.8 ng/dscm for Test 3). However, these
measured PCDD/PCDF concentrations
were much lower than the high levels mea-
sured in  FY 91 (23,830 ng/dscm).  Excel-
lent combustion conditions were achieved
for all test conditions. In all  cases, less
than 50 ppmv of CO, corrected to 7% O2,
was detected  in the combustion flue gas.
  Prior to Task 2,  the TFR  facility was
conditioned by incinerating  a  copper-con-
taining fuel and  by injecting a copper-
containing  aqueous  solution.  The
copper-containing fuel was fired in the TFR
primary combustor, and  the  copper-con-
taining solution was  injected  into the pri-
mary zone during natural gas  combustion.
During combustion of the copper-contain-
ing  fuel and injection of the  copper-con-
taining solution, the primary  combustion
zone  of  the TFR was fired  at approxi-
mately 30 kWand the afterburner was not
fired.
  For Task 2 (see Table 1), Tests 7 and 8
were CFC-12 incineration tests  after cop-
per had been added into the test facility.
Results show that higher levels  of PCDD/
PCDFs were  formed  under these  condi-
tions.  In Test 7, the PCDD/PCDF concen-
trations at the afterburner outlet (Location
1) and at the low-temperature sampling
location (Location 2)  were 118 and 454
ng/dscm,  respectively.  During  Test  8,
PCDD/PCDF  formation was not quite  as
high: results indicated 53.8 and 386 ng/
dscm for the afterburner outlet and down-
stream locations, respectively. The major
difference between Tests 7  and  8 was the
elapsed time between copper injection and
CFC-12 incineration which allowed residual
copper to be purged from the  TFR.  Test 7
commenced 3 hours of propane firing af-
ter injecting copper into the TFR, while for
Test 8, 54 hours of propane firing elapsed
following copper injection prior to CFC-12
incineration.
  For Task 3, Tests 4 to 6  were con-
ducted in the CTT (see Table 1). Test 4
was  a facility system blank in  which only
propane was fired in the facility. During
Tests, HCFC-141bwas incinerated in the
facility at a HCFC/propane concentration
of 7.4%. Finally, during Test 6, CFC recy-
cling residue was  incinerated  without any
auxiliary fuel. Excellent combustion condi-
tions were achieved for all test conditions,
including incineration  of CFC recycling resi-
due  with no auxiliary fuel. In all cases,
less than 35 ppmv of CO, corrected to 7%
O2, was detected  in  the combustion  flue
gas.
  Volatile PICs, determined from the EPA
SW  846 Method  0030 sampling  trains,
were measured for Tests 4 to 6. The con-
centrations of volatile organics in the flue
gas for all three tests were very low. Dur-
ing Test 4 (facility  system blank), no vola-
tile organic compounds were measured at
levels significantly higher  than the back-
ground levels measured in the field blank.
During Test 5 (HCFC-141b incineration),
chloroform  was measured at  an average
concentration of 14.5 |ig/dscm. The con-
centrations of acetone and methylene chlo-
ride  were  67.9  and  129  |ig/dscm,
respectively; however, the concentrations
of these compounds in the associated field
blank were nearly  the same.  During Test
6 (CFC recycling residue incineration), no
compounds were measured at significant
concentrations.  For the  analysis in  all
cases,  surrogate  recoveries were within
acceptable limits.
  Test 4 was a facility blank test to mea-
sure the  background contamination of
PCDD/PCDFs during propane combustion
in the CTT. A moderate concentration of
(~ 3  ng/dscm) PCDD/PCDF was detected
in the facility blank test, suggesting back-
ground  contamination  from the  propane
fuel,  sampling train,  reagents, or  analyti-
cal procedure. Duplicate analysis was per-
formed  to  confirm  these facility blank
results. The presence of background con-
tamination  in the  Test  4  measurements
suggests that the Test 5 and 6 results
may  also contain background  contamina-
tion.
  Two Method 23 sampling trains collected
samples simultaneously at the downstream
sampling location  during Test 5.  Results
of the analysis of  these samples indicate
PCDD/PCDF concentrations of 2  and 11
ng/dscm for the two samples. These con-
centrations are relatively low compared to
those from CFC incineration.
  CFC recycling residue was incinerated
in Test 6. Two  simultaneous Method 23
samples were collected at the downstream
sampling location. The concentrations of
PCDD/PCDFs during these tests were 52
and  61  ng/dscm.  These measured con-
centrations are similar to those observed
from incineration of pure CFCs in the pre-
vious study.
  Note that the flue gas temperature for
Tests 4 to 6  at the Method 23 sampling
location (Location 2)  was  approximately
225°C, which is within the  PCDD/PCDF
formation  "temperature window"  of about
200  to 450°C.  The residence time be-
tween the 1,450°C flame zone tempera-
ture  and  this  sampling  location was
approximately 6.2 sec,  more  than  suffi-
cient time for the de novo synthesis of
dioxins and furans. However, results from
the  present study indicate  that  incinera-
tion of HCFC and CFC recycling residue
generates very low levels of PCDD/PCDF
emissions during this temperature window.
The  lack of  a sufficient  level  of copper-
contaminant present in the HCFC and the
CFC recycling residue to promote PCDD/
PCDF formation may be the  reason for
the observed low PCDD/PCDF emissions.
Comparable  levels of PCDD/PCDF emis-
sions were also observed from  incinera-
tion of pure CFC-12 in the FY 92 study.

Conclusions And
Recommendations
  High concentrations of PCDD/PCDFs
(23,800 ng/dscm) measured in a FY 91
study during incineration of CFC-12 in the
TFR could not be  repeated  in the present
study.  Repetition tests  conducted  in the
same facility under similar operating con-
ditions resulted  in PCDD/PCDF concen-
trations of 118 ng/dscm at 7% O2.
  Residual copper retained in an incin-
eration facility can possibly promote the
emission of  PCDD/PCDFs  during incin-
eration of CFC-12 which does not contain
copper. Tests conducted in  the TFR facil-
ity resulted in measured PCDD/PCDF con-
centrations of 386 - 454 ng/dscm  at 7%
O2 during incineration of CFC-12  which
followed incineration of copper-containing
compounds. Previous studies have shown
evidence of  PCDD/PCDF formation dur-
ing  incineration  of chlorinated wastes in
the  presence  of trace copper in systems
with sufficient residence time in the PCDD/
PCDF temperature formation window. This
promotional effect of copper may limit the
types of waste materials which can be
incinerated prior to incineration of highly
chlorinated CFCs. The present results sug-

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gest that CFCs may best be incinerated in
incinerators that do not treat  any copper-
containing waste materials prior to CFC
incineration,  in order to eliminate the pos-
sibility  that  residual  copper  retained  in
the incineration systems could  promote
PCDD/PCDF formation during subsequent
CFC incineration.
  Incineration can be used to destroy 1,1-
dichloro-1-fluoroethane (HCFC-141 b) with-
out generating significant  quantities  of
volatile organic PICs and PCDD/PCDFs.
Incineration can also be used to destroy
the oily residue  (which  contains 3 ppm
copper) generated during CFC  recycling
without generating significant quantities of
volatile organic PICs or PCDD/PCDFs.
Table 1.   Test Matrix

Task 1


Task 2

Task3


Test
Number
1
2
3
7
8
4
5
6
Test
Facility
TFR
TFR
TFR
TFR
TFR
CTT
CTT
CTT
Test
Material
Facility Blank
CFC -12
CFC -12
Fuel oil doped with Cu
followed by CFC-12*
Fuel oil doped with Cu
followed by CFC-12*
Facility Blank
HCFC-141b
CFC Residue
PCDD/F
Sampling
Location 1
# Replicates
0
1
1
1
1
0
0
0
PCDD/F
Sampling
Location 2
# Replicates
2
1
1
1
1
2
2
2
CFC/PIC
Sampling
# Replicates
0
0
0
0
0
3
3
3
  Fuel oil doped with copper was fired in the test facility prior to testing. Immediately following, CFC-12 was incinerated in the facility. Manual sampling for
  PCDD/PCDF occurred during CFC-12 incineration.
  G. Kryderand B. Springsteen are with Energy and Environmental Research Corp.,
    Irvine, CA 92718.
  C.W. Lee is the EPA Project Officer (see  below).
  The complete report, entitled "Experimental Investigation of PIC Formation During
    CFC Incineration," (Order No. PB96-152186; Cost: $38.00, 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
          National Risk Management Research Laboratory
          U.S. Environmental Protection Agency
          Research Triangle Park,  NC 27711
United States
Environmental Protection Agency
National Risk Management
Research Laboratory (G-72)
Cincinnati, OH 45268
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