EPA/600/A-95/Q69
PILOT-SCALE INCINERATION OF BALLISTIC MISSILE
LIQUID PROPELLANT COMPONENTS
by
Larry R. Waterland and Shyam Venkatesh
Acurex Environmental Corporation
Incineration Research Facility
Jefferson, Arkansas 72079
Contract No. 68-C9-0038
Project Officer
Robert C. Thurnau
Waste Minimization, Destruction and Disposal Research Division
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268

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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA/600/A-95/069
2.
3. RECIP
4. TITLE AND SUBTITLE
PILOT-SCALE INCINERATION OF BALLISTIC MISSILE
LIQUID PROPELLANT COMPONENTS
5. REPORT DATE
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Lariy Waterland and Shyam Venkatesh
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Acurex Environmental Corporation
55S Qyde Avenue
Mountain View, CA 94039
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-C9-0038
12. SPONSORING AGENCY NAME AND ADDRESS
RISK REDUCTION ENGINEERING LABORATORY-CINCINNATI, OH
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
13. TYPE OF REPORT AND PERIOD COVERED
Research Paper -1994
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES Donald A. Oberackcr 513/569-7510
To be published in the Proceedings of the International Incinerator Conference
May 1995, Bellevue, Washington
16. ABSTRACT
The U.S. Department of Defense (DOD) recently concluded agreements with the Ukraine and the Russian Federation under which the DOD is
committed to providing both former Soviet Union (FSU) states with equipment and other aid for use in eliminating their strategic offensive arms in
accordance with schedules negotiated in the Strategic Arms Reduction Treaty. One specific need consists of process equipment to treat or destroy
pure ballistic missile liquid propellant components as well as vapor or purge media contaminated by these components. The propellant components
are unsymmetrical dimethythydrazine (UDMH) fuel and nitrogen tetroxide (^O^) oxidizer. Incineration is one possible treatment process. The
Defense Nuclear Agency is responsible for providing the treatment/destruction process equipment. Should incinerators be provided, one requirement
is that they meet the U.S. environmental regulatory requirements, as well as those of the respective FSU states. To supply data to demonstrate that
incineration is a safe and effective treatment process, a series of tests was conducted at the U.S. Environmental Protection Agency's Incineration
Research Facility.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b. ID ENTIF1ERS/OPEN ENDED TERMS
c. COSATI Field/Group
Hazardous Waste Incineration
Rocket Propellant Destruction
UDMH
n2o4
Incineration

18. DISTRIBUTION STATE
RELEASE TO PUBLIC
19. security class (This Report)
UNCLASSIFIED
21. NO. OF PAGES
22
20. security class (This Report)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE

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PILOT-SCALE INCINERATION OF BALLISTIC MISSILE LIQUID
COMPONENTS
Larry R. Waterland and Shyam Venkatesh
Acurex Environmental Corporation
Incineration Research Facility
Jefferson, Arkansas 72079
ABSTRACT
* The U.S. Department of Defense (DoD) recently concluded agreements with the Ukraine and the
Russian Federation under which the DoD is committed to providing both former Soviet Union
(FSU) states with equipment and other aid for use in eliminating their strategic offensive arms in
accordance with schedules negotiated in the Strategic Arms Reduction Treaty. One specific need
consists of process equipment to treat or destroy pure ballistic missile liquid propellant components
as well as vapor or purge media contaminated by these components. The propellant components
are unsymmetrical dimethylhydrazine (UDMH) fuel and nitrogen tetroxide (N204) oxidizer.
Incineration is one possible treatment process.; The Defense Nuclear Agency is responsible for
providing the treatment/destruction process* equipment. Should incinerators be provided, one
requirement is that they meet the U;S. environmental regulatory requirements, as well as those of
the respective FSU states. To supply data to demonstrate that incineration is a safe and effective
treatment process, a series of tests was conducted at the U.S. Environmental Protection Agency's
Incineration Research Facility.. r?.***"'r**. ¦¦
In the test program completed, the two propellant components were independently incinerated in
separate sets of triplicate tests. All tests were performed at a primacy combustion chamber exit gas
temperature of nominally 980°C (1,800°F) and a secondary combustion chamber (afterburner) exit
gas temperature of nominally 1,090°C (2,000°F). The test program results show that NOx levels
were in the range of 690 to 780 ppm at 7% 02 at the primary combustion chamber exit during
UDMH incineration; these were reduced to 410 to 500 ppm at 7% 02 at the secondary combustion
chamber exit, largely due to the dilution that accompanies the addition of the extra fuel and air
required to raise the secondary chamber's temperature. Scrubber exit levels were similar to those
at the secondary chamber exit, at 440 to 500 ppm at 7% 02. NOx levels were quite high for the
N204 tests, at 9,300 to 10,000 ppm (uncorrected) at the primary chamber exit; 8,400 to 8,800 ppm,
lowered again due to dilution, at the secondary chamber exit; and 5,900 to 7,100 ppm at the
scrubber exit. Approximately 30 to 50% of the flue gas NOx was N02, the lower fractions
corresponding to the scrubber exit location.
No UDMH was measured at any flue gas location for any UDMH test; UDMH destruction and
removal efficiencies (DREs) corresponding to the method detection limits (MDLs) were greater
than 99.9997%. No cyanide, dimethylamine, tetramethyltetrazene, or N-nitrosodimethylamine, all
postulated UDMH combustion byproducts, were measured at any flue gas sampling location for any
UDMH test. Flue gas formaldehyde levels ranged from 2 to 8 ^g/dscm at all three sampled
locations for the UDMH tests. Total dioxin and furan levels measured at the scrubber exit were
0.45 ng/dscm at 7% 02 for one UDMH test and 0.13 to 0.36 ng/dscm at 7% 02 over three N2G4
tests. In terms of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalents, the scrubber exit flue gas
levels were 0.02 ng/dscm for the UDMH test, and 0.01 to 0.02 ng/dscm for the three N204 tests.
INTRODUCTION
The U.S. Department of Defense (DoD) recently concluded agreements with the Ukraine and the
Russian Federation under which the DoD is committed to providing both former Soviet Union
(FSU) states with equipment and other aid for use in eliminating their strategic offensive arms
2
PROPELLANT

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3
(SOA) in accordance with schedules negotiated in the Strategic Arms Reduction Treaty (START),
The agreement with the Ukraine specifically includes supplying this FSU state with mobile and
transportable single-trailer incinerators for use in destroying either pure components or the vapor
or purge media contaminated by the two propellant components, unsymmetrical dimethylhydrazine
(UDMJH) and nitrogen tetroxide (N204), used in FSU land-based and submarine-launched ballistic
missiles. The agreement with the Russian Federation requires supplying liquid propellant
component treatment or destruction process equipment, while not specifically requiring the process
to be incineration. Nevertheless, incineration may be the process selected.
The Defense Nuclear Agency (DNA) is responsible for providing the treatment/destruction process
equipment. Should incinerators be provided, one requirement is that they meet both the U.S.
environmental regulatory requirements, as well as those of the respective FSU states. Thus, to
supply the data to demonstrate that purge media contaminated by either compound, or that pure
UDMH or N204 can be effectively destroyed by incineration while complying with the requisite
environmental regulations, DNA funded a series of incineration tests at the U.S. Environmental
Protection Agency's (EPA's) Incineration Research Facility (IRF), located in Jefferson, Arkansas.
The general objectives of the test program performed were to demonstrate the U.S. and FSU
environmental certifiability of the incineration of FSU ballistic missile fuel UDMH and ballistic
missile oxidizer N204. Environmental certifiability was to be established by showing that both
UDMH and N204 can be separately destroyed in an incinerator to levels which meet both U.S. and
FSU state environmental regulations, while resulting in emissions of incineration byproducts
considered acceptable under those regulations.
TEST PROGRAM
The test program was conducted in the IRF rotary kiln incineration system (RKS), Fig. 1 is a
process schematic of the RKS as it was configured for these tests. However, because very little flue
gas particulate was expected from the incineration of either component of the ballistic missile liquid
propellant, the baghouse system shown in Fig. 1 was bypassed.
PLACE FIG. 1 HERE
Environmental Regulations
As noted above, the objectives of the test program were to establish that UDMH and N204 can be
destroyed in an incineration system in a manner that meets U.S. and FSU state environmental
regulations. The applicable U.S. environmental regulations are the hazardous waste incinerator
performance standards established under the Resource Conservation and Recovery Act (RCRA).
The applicable provisions of these standards require that the incinerator achieve at least a 99.99%
destruction and removal efficiency (DRE) of the principal organic hazardous constituents (POHCs)
in the waste feed to the incinerator. For UDMH fuel, the POHC would be UDMH. N204 is not
an organic constituent, so no N204 DRE requirement would apply.
In addition to the DRE specification, hazardous waste incinerator permits currently being enforced
in the U.S. require that CO emissions be no greater than a 1-hour rolling average of 100 ppm,
corrected to 7% 02.
The Russian environmental regulations limit the emissions of UDMH and several potential UDMH
products of incomplete combustion (PICs) from the incineration of UDMH. These limits are
summarized in Table L Ukrainian regulations are essentially the same. The limits noted in the
table are occupational exposure limits in terms of maximum permissible concentrations in workplace
air.

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PLACE TABLE I HERE
The U.S. incinerator standard of 100 ppm CO, 1-hour rolling average at 7% 02, equates to an
emission concentration of 183 mg/dscm at 7% 02. Thus, only about a 10-fold dilution of stack
emissions into ambient air would be needed to meet the Russian workplace standard of 20 mg/m3.
Typical stack to maximum ambient concentration dilution factors are much larger, generally 100 to
several thousand.
The U.S. hazardous waste incinerator standards do not address NO, emissions. However, the new
source performance standard (NSPS) for large municipal waste incinerators (greater than
250 tons/day [227 Mg/day] capacity), established under the Federal Clean Air Act, is 180 ppm NO,
at 7% 02. This equates to 265 mg/Nm3 as N02 at 7% 02. About a 130-fold dilution of stack
emissions of 265 mg/Nm3 would satisfy the Russian workplace standard for N02. This is at the
lower bound of typical dilution factors, as noted above.
In summary, the specific test program objectives were:
•	To develop the data to evaluate whether UDMH and N204 can be incinerated in
compliance with the U.S. hazardous waste incinerator performance standards and recent
permitting guidance of:
-	99.99% UDMH DRE
—	CO emissions of less than 100 ppm 1-hour rolling average at 7% 02
•	To develop CO and NOx (NO plus N02) emission rate data from the incineration of
UDMH and N204 for comparison to the U.S. hazardous waste incinerator permit
guidance limits and the NSPS for large municipal waste incinerators
•	To develop UDMH PIC emission rate data from the incineration of UDMH for
comparison to the emission rate limits corresponding to the Russian occupational
exposure limits
Additional test program objectives were:
•	To develop polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran
(PCDD/PCDF) emission rate data from the incineration of UDMH and N204
•	To develop trace metal emission rate data from the incineration of N204 to verify
expectation that metal emissions are insignificant
Test Conditions
The test program consisted of nine incineration tests. Three tests (triplicate testing) were
performed under the same incineration system operating conditions feeding each component of the
missile propellant. Two sets of triplicate tests feeding UDMH (six total) were required to complete
all the flue gas sampling procedures planned for the UDMH feed tests, as noted below. Thus, nine
tests in total, six feeding UDMH and three feeding ^O*. were performed.
The six UDMH destruction tests were performed at a nominal kiln exit gas temperature of 980°C
(1,800°F). Only UDMH was fed to the kiln along with the required combustion air. UDMH was
fed via the liquid waste/fuel nozzle of the kiln's dual fuel burner. The UDMH was directly pumped
and metered from its nitrogen-blanketed storage container to the burner nozzle via a UDMH feed
system custom-fabricated at the IRF for these tests. Fig. 2 is a schematic of this feed system. The

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5
key feature of the system is the substitution of nitrogen as the atomization Quid for the RKS air-
atomized burners. This substitution provided an extra precaution against any UDMH explosion in
the burner feed system.
PLACE FIG. 2 HERE
The three N204 destruction tests were also performed at kiln exit gas temperature of 980°C
(1,800°F). Diesel fuel served as the material to be oxidized by N204 for its destruction. The diesel
fuel was fed to the kiln via the liquid nozzle of the kiln's dual fuel burner. The N204 oxidant was
added to the burner primary air supply via an N204 feed system, also custom-fabricated at the IRF
for the tests. Fig. 3 is a schematic of this system. The key feature of this system is the use of an
electrically heated evaporator to vaporize the N204 prior to its addition to the combustion air.
PLACE FIG. 3 HERE
For all nine tests, the RKS afterburner was fired with natural gas to maintain a nominal afterburner
exit gas temperature of 1,090°C (2,000°F).
Sampling and Analysis Procedures
The RKS sampling locations and the scope of the sampling effort are shown in the process
schematic given in Fig. 4. For ail tests, the sampling matrix defined to meet the test program
objectives listed above included:
PLACE FIG. 4 HERE
•	Obtaining a composite sample of the pre-test and post-test scrubber system liquor
•	Continuously measuring 02, CO, NOx, and TUHC concentrations in the kiln exit flue
gas; 02, C02, and NOx concentrations in the afterburner exit flue gas; 02, C02, and
NOx concentrations in the scrubber exit flue gas; and 02 and CO concentrations in the
stack gas
•	Sampling flue gas at the scrubber exit for PCDDs/PCDFs using Method 231
•	Sampling flue gas at the scrubber exit and the stack for particulate and HCl using
Method 52; the stack gas sample was needed to comply with the IRFs permit
requirements
Additional sampling procedures were performed for the UDMH incineration tests. These were:
•	Sampling flue gas at the kiln exit, afterburner exit, and scrubber exit for:
—	UDMH and dimethylamine using a variation of the National Institute for
Occupational Safety and Health (NIOSH) Method S1433
—	N-nitrosodimethylamine and 1, l,4,4-tetramethyl-2-tetrazene (tetramethyltetrazene)
using Method 00104
—	HCN using a modified California Air Resources Board (CARB) Method 4265
—	Formaldehyde using Method 00111
•	For the N204 tests, sampling the scrubber flue gas exit for trace metals using the EPA
multiple metals train1

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Measurements of NO,, UDMH, and UDMH PICs were specified at the three locations noted,
specifically to supply data to allow evaluating the need for a secondary combustion chamber
(afterburner) and/or a wet scrubber APCS in the units potentially supplied to the FSU states. The
number of sampling procedures specified for the UDMH tests could not be performed
simultaneously at the IRJF due to the unavailability of sampling ports in all the locations specified.
Thus, the UDMH sampling matrix was completed over two sets of tests. The procedures denoted
U1 in Fig. 4 were simultaneously completed over one set of three test days; the procedures denoted
U2 in the figure were completed during a second set of three test days.
TEST RESULTS
Table II summarizes the RKS operating conditions for the six UDMH tests performed. Table HI
presents an analogous summary for the N204 tests. As shown, incineration conditions for all nine
tests were quite close to the test target temperatures of 9806C (1,800°F) at the kiln exit and
1,090°C (2,000°F) at the afterburner exit. All six UDMH tests destroyed nominally 45 kg/hr
(100 lb/hr) of UDMH. Each of the three N204 tests destroyed nominally 64 kg/hr (140 lb/hr) of
N204 using nominally 32 kg/hr (70 lb/hr) of diesel fuel.
PLACE TABLES II AND III HERE
Table IV summarizes the CEM data for the UDMH tests. As shown in the table, both CO and
TUHC levels at the kiln exit were low, at <2 ppm and about 1 ppm, respectively. NO, levels at the
kiln exit ranged from 693 to 781 ppm at 7% 02, with a six-test average of 733 ppm. Afterburner
exit NO, levels lower, at 414 to 500 ppm at 7% 02, with a six-test average of 462 ppm at 7% 02.
However, these lower afterburner exit concentrations can be shown to result from flue gas dilution
by the C02 and N2 added to the flue gas resulting from the extra auxiliary fuel burned in the
afterburner to raise its gas temperature. Original hopes were that some true NO, reduction via
reburning mechanisms would occur in the afterburner. To increase the probability that this would
occur, the afterburner burner was fired as fuel rich as possible. Despite this, no true NO, reduction
in the afterburner was achieved. In fact, additional NO, was produced in the afterburner during
these tests. However, the additional dilution gas introduced in the afterburner more than
compensated for the extra NO, produced, so that NO, concentrations were decreased in the
afterburner exit gas.
PLACE TABLE IV HERE
NO, levels at the scrubber exit were comparable to those at the afterburner exit, ranging from 449
to 497 ppm at 7% 02, with a six-test average of 480 ppm at 7% 02. Because essentially all the NO,
measured for the UDMH tests was as NO (no difference in NO, monitor reading was observed
when going from an NO measurement to a total NO, measurement), this is as expected.
All NO, levels measured were substantially greater than the target level of 180 ppm at 1% 02.
About a 75% reduction in the kiln exit NO, levels measured would be needed to reach the 180 ppm
target. The corresponding reduction needed to reach the target from the afterburner and scrubber
exit levels measured is about 60%. Some low-NO, burner concepts may be capable of achieving
these reduction levels, but their applicability to UDMH combustion is uncertain given the safety
considerations UDMH combustion demands. Non-catalytic NO, reduction processes, such as
ammonia or urea injection, might also be effective, though 70% NO, reductions are about the limit
of effectiveness for these approaches.
Table V summarizes the CEM data from the three N204 destruction tests. Again, kiln exit CO
levels were low, at less than 2 ppm, for two of the three N204 tests. For some unknown reason the
average kiln exit CO level for the third test was substantially higher at 60 ppm. Kiln exit TUHC

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7
levels, at 15 to 16 ppm, were higher for the N204 tests than were measured for the UDMH tests,
although even these higher levels are common from industrial combustion sources.
PLACE TABLE V HERE
The NO, concentrations measured at all three flue gas locations for the N204 tests were extremely
high. Levels measured ranged from 18,000 to 20,600 ppm at 7% 02 at the kiln exit, with a three-
test average of 19,300 ppm; from 12,200 to 13,300 ppm at 7% 02 at the afterburner exit; and from
10,600 to 12,200 ppm at 1% 02 at the scrubber exit Again, the afterburner exit NO, levels were
apparently reduced from those measured at the kiln exit. However, as was the case for the UDMH
tests, and as discussed below, additional NO, was produced in the afterburner; the addition of
diluent C02 and N2 from the afterburner burner operation more than compensated for the
additional NO, produced, so that the afterburner exit NO, concentrations were reduced from kiln
exit concentrations.
The data in Table V further show that a significant fraction of the flue gas NO, measured at all
three locations was N02. Of course this would be expected given that N204 is the dimer of N02.
The data in Table V indicate that about 50% of the kiln exit NO, was N02 for two of the three
N204 tests; a lower fraction, about 40%, was measured for the third test. N02 fractions at the
afterburner exit were lower, at about 35%. This would be expected because the additional NO,
formed in the afterburner would be combustion-generated NO. Thus, the afterburner adds NO,
in the form of NO to the combustion gas; the NO, amount increases, but the N02 fraction
decreases. At the scrubber exit the N02 fractions were slightly lower still, at about 30%. This
would be expected if the scrubber system removed some of the more soluble N02. Apparently
some removal may have occurred as evidenced by the decrease in NO, concentrations, corrected
to 7% 02, from the afterburner exit to the scrubber exit for Test 3.
Unfortunately, a complete picture of flue gas NO, levels for the N204 tests cannot be discussed,
because for two of the three tests performed, one of the three NO, monitors in use malfunctioned,
as noted in Table V. Of course, in retrospect perhaps this might have been expected. The
extremely high flue gas NO, levels present in the tests presented a severe and challenging
environment to the monitors used, so that more frequent malfunction might be expected.
The very high NO, levels measured in the flue gas for these tests clearly suggests that N204
destruction was not complete. The N204 DREs achieved for these tests are summarized in
Table VI. The DREs given in the table are based on the measured flue gas N02 concentrations
only, thus giving "destruction credit" to any partial reduction of N02 to NO. The data in Table VI
show that the N204 (or NO2) DREs achieved were essentially 90% for all the tests as measured
at all three flue gas locations sampled.
PLACE TABLE VI HERE
The very high levels of NO, measured at all locations for the N204 destruction tests suggest that
meeting a 180 ppm at 7% 02 standard when destroying N204 cannot be achieved. Measured kiln
exit levels would require over 99% reduction to meet the 180 ppm level; measured afterburner exit
and scrubber exit levels would require greater than 98% reduction. The most effective NO, control
techniques are selective catalytic reduction approaches using ammonia. These processes offer no
better than 95% NO, reductions Further, they require ammonia addition as a reducing agent, an
aspect that would greatly complicate the operation of a transportable incinerator at a remote FSU
operation site.
Table VII summarizes the test data on the flue gas concentrations of other constituents of interest
measured in the first set of UDMH incineration tests. Data on flue gas concentrations of UDMH,

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8
dimethylamine, and formaldehyde are given in Table VII. As shown in the table, the concentrations
of UDMH and dimethylamine were less than method destruction limits (MDLs) at all three flue
gas locations sampled. Some formaldehyde was measured at the afterburner exit and scrubber exit
locations at levels between 9.4 and 8.0 jxg/dscm. A comparable level at 7.2 /ig/dscm was measured
for one test at the kiln exit.
PLACE TABLE VII HERE
The UDMH MDLs can be used to set a lower bound on the UDMH DREs achieved for the tests.
These are also shown in Table VII. As indicated, UDMH DREs achieved were greater than
99.9997% in all cases at all locations, well above the 99.99% level required under the current
hazardous waste incinerator performance standards.
Table VIII summarizes the flue gas concentrations of other constituents of interest measured during
the second set of UDMH incineration tests. Data on cyanide, N-nitrosodimethylamine, and
tetramethyltetrazene are given. As shown, none of the three constituents was found in the flue gas
at any sampled location for any test at the MDLs noted in the table.
PLACE TABLE VIH HERE
Table IX summarizes the PCDD/PCDF concentrations measured in the scrubber exit flue gas for
the one UDMH incineration test sampled and for the three N204 destruction tests. As shown, total
PCDD/PCDF concentrations for all four tests were comparable and quite low, in the 0.13 to
0.45 ng/dscm at 7% 02 range. These levels are far below the 1993 EPA guidance target of 30
ng/dscm at 7% 02. On a 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) toxicity equivalent
(TEQ) basis, measured concentrations were 0.01 to 0.02 ng/dscm at 7% 02. These levels would
similarly be far below the European target of 0.1 ng/Nm3 TEQ at 11% 02, dry.
PLACE TABLE IX HERE
Scrubber exit flue gas concentrations of antimony, arsenic, barium, beryllium, cadmium, chromium,
cobalt, lead, manganese, nickel, silver, thallium, tin, and vanadium were measured for the N204
destruction tests. None except lead was found in any test at the method detection limits given in
Table X. Lead was found in the flue gas for two tests at 17 and 31 /xg/dscm, respectively.
PLACE TABLE X HERE
CYANIDE METHOD VALIDATION
As noted above, one of the flue gas emission analytes of great interest for UDMH incineration was
total cyanide. The traditional method for collecting cyanide from a gas stream is absorption into
a basic absorption solution such as 0.1N NaOH. This is the basis for California Air Resources
Board (CARB) Method 426.5 However, if the gas stream contains C02, as does all combustion
process flue gas, some C02 will also be absorbed and, if equilibrium is reached, form a carbonate
buffer solution. The flue gas C02 levels measured at the afterburner exit for the UDMH tests were
in the 4 to 6% range. The pH of an initial 0.1N NaOH solution in equilibrium with a gas stream
containing these levels of C02 is about 8. The pK^ of HCN is 9.3, so HCN would be purged out
of an initial 0.1N NaOH impinger solution if equilibrium with the purging gas C02 concentration
is reached. Thus, it is possible that any cyanide in a flue gas stream containing 4 to 6% C02 would
not remain collected in an impinger initially containing 0.1N NaOH, because the collection solution
may become acidified by dissolving C02 to the point that any collected cyanide would revert to
HCN gas and be purged.

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9
Increasing the pH of the initial impinger solution by using 1.0N NaOH would help offset the
buffering capacity of dissolving C02, but the equilibrium pH of an initial 1.0N NaOH solution under
a 4 to 6% C02-containing gas is about 9, still below the pKj of HCN. Only by starting with an
impinger solution containing ION NaOH would there be certainty that, if equilibrium with the flue
gas C02 is reached, the final pH of the resulting solution remains sufficiently basic to retain
cyanide. The equilibrium pH of an initial ION NaOH solution under a 4 to 6% C02-containing gas
is about 10.
CARB Method 426 recommends substituting 0.1M NaHCOj for the 0.1N NaOH absorbing solution
"in the case of sources which produce significant levels of C02." However, the basis for this
recommendation cannot be understood in light of the above discussion. Other absorbing reagent
systems have been proposed for cyanide capture. For example, the former Texas Air Control Board
(TACB) specified 2% zinc acetate as the cyanide collection solution.6 A 2% zinc acetate solution
is initially basic; however, with C02 dissolution, this solution would also acidify.
Given the uncertainty over whether documented methods for measuring cyanide in gas stream
discharges would function as intended for gas streams containing 4 to 6% C02, it was decided to
conduct a method validation study. In the study, sampling trains as described in CARB Method 426
were set up to sample scrubber exit Que gas from the RKS fired with natural gas auxiliary fuel. The
six different reagent systems listed in Table XI were tested. Validation study results are also
summarized in Table XI. As indicated, only the ION NaOH impinger charging solution yielded
acceptable cyanide capture and retention. In contrast, the two charging solutions recommended in
CARB Method 426 produced no cyanide recovery. The TACB method and a modification to this
method recommended for use in gas streams containing H2S (the use of lead acetate as the initial
impinger solution) gave measurable, but poor, cyanide recoveries.
PLACE TABLE XI HERE
CONCLUSIONS
Test program results show that:
•	NOx levels were in the range of 690 to 780 ppm at 7% 02 at the primary combustion
chamber exit while incinerating UDMH; these were reduced to 410 to 500 ppm at 7%
02 at the secondary combustion chamber exit, due largely to the dilution that
accompanies the addition of the extra fuel and air required to raise the secondary
chamber's temperature. Scrubber exit levels were similar to afterburner exit levels, at
440 to 500 ppm at 7% 02.
•	NOx levels were quite high for the N204 tests, at 9,300 to 10,000 ppm (uncorrected) at
the primary chamber exit; 8,400 to 8,800 ppm, lowered again due to dilution, at the
secondary chamber exit; and 5,900 to 7,100 ppm at the scrubber exit. Approximately
30 to 50% of the flue gas NOx was N02, the lower fractions corresponding to the
scrubber exit location. The lower total NOx levels and the lower N02 fractions at the
scrubber exit location are likely due to some removal of N02 by the wet scrubber.
•	No UDMH was measured at any flue gas location for any UDMH test; UDMH DREs
corresponding to the MDLs were uniformly greater than 99.9997%.
•	No cyanide, dimethylamine, tetramethyltetrazene, or N-nitrosodimethylamine, all
postulated UDMH combustion byproducts, were measured at any flue gas sampling
location for any UDMH test. Corresponding MDLs were 30 /xg/dscm for cyanide; 300

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10
to 800 pg/dscm, depending on sampled location, for dimethylamine; 3 /jg/dscm for
tetramethyltetrazene; and 5 jtg/dscm for N-nitrosodimethylamine.
•	Flue gas formaldehyde levels ranged from 2 to 8 ^g/dscm at all three sampled locations
for the UDMH tests.
•	Total PCDD/PCDF levels measured at the scrubber exit were 0.45 ng/dscm at 1% 02
for the one UDMH test for which they were measured; levels measured for the three
N204 tests were 0.13 to 0.36 ng/dscm at 7% 02. In TEQ terms, the scrubber exit flue
gas levels were 0.02 ng/dscm for the UDMH test, and 0.01 to 0.02 ng/dscm at 1% 02
for the three N204 tests.
•	None of the 14 trace metals sought in the N204 tests were found in the scrubber exit
flue gas with the exception of low levels (17 to 30 /ig/dscm) of lead.
In addition, during method validation tests performed as part of this test program, it was found that
the routinely used sampling procedures for cyanide, particularly those documented by the TACB
and the CARB, failed to capture and retain cyanide from a gas stream that contains C02 levels of
4 to 6%, such as typical combustion source flue gas.
ACKNOWLEDGEMENTS
The test program described in this paper was performed under EPA Contract 68-C9-0038. Funding
for the test program was provided by DNA under two Interagency Cost Reimbursement Orders
(IACROs), IACRO 93-691, Work Unit 00005, and IACRO 94-7615. This paper has been subjected
to both EPA and DNA review, and has been approved for publication.
REFERENCES
1.	40 CFR Part 266, Appendix IX.
2.	40 CFR Part 60, Appendix A.
3.	P. M. ELLER, ed., "NIOSH Manual of Analytical Methods," Third Edition, February 1984, with
Supplements 1, 2, 3, and 4 (1985, 1987, 1989, 1990).
4.	"Test Methods for Evaluating Solid Waste: Physical/Chemical Methods," EPA SW-846, Third
Edition, Revision 1, (July 1992).
5.	"Stationary Source Test Methods, Volume HI, Methods for Determining Emissions of Toxic Air
Contaminants from Stationary Sources," CARB, Sacramento, California (Mar. 1988).
6.	"Texas Air Control Board Sampling Procedures Manual," TACB, Austin, Texas (Jan. 1983).
FIGURE CAPTIONS:
Fig. 1. Schematic of the IRF rotary kiln incineration system.
Fig. 2. UDMH feed system schematic.
Fig. 3. N204 feed system schematic.
Fig. 4. Test sampling locations.

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11
TABLE I
Russian Federation Environmental Regulations for UDMH Incineration
Maximum Permissible
Concentration in Workplace Air,
	Compound	mg/m3	
UDMH	0.1
Dimethylamine	1.0
N-Nitrosodimethylamine	0.001
Hydrogen cyanide (HCN)	0.3
l,l,4,4-Tetramethyl-2-tetrazene	3.0
Formaldehyde	03
CO	20
N02	2.0
TABLE II
Test Operating Conditions for UDMH Tests
Average Kiln Exit
Conditions
Average Afterburner
Exit Conditions
Test
No.
Test Date
uumn
Feed rate, kg/hr
(lb/hr)
Temperature,
*C (°F)
°2,
*
Temperature,
°C (°F)
op
%
1
(2/1/94)
47 (104)
994 (1,821)
12.6
1,107 (2,024)
9.1
2
(2/3/94)
47 (103)
992 (1,817)
11.9
1,097 (2,007)
9.2
3
(2/15/94)
44 (96)
981 (1,797)
11.4
1,097 (2,007)
9.5
4
(2/23/94)
41 (91)
981 (1,797)
11.1
1,097 (2,007)
8.7
5
(2/24/94)
42 (92)
982 (1,800)
11.4
1,097 (2,007)
93
6
(3/1/94)
44 (97)
977 (1,791)
11.1
1,097 (2,007)
9.4

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TABLE III
Test Operating Conditions for N204 Tests
Feedrate, kg/hr	Average Kiln	Average Afterburner
	(Ib/hr)		Exit Conditions	Exit Conditions
Diesel	Temperature, Op	Temperature, Op
Test N2Q4 Fuel	°C (°F)	%	°C (BF)	%
1	(3/24/94) 61 (135) 27 (60)	979(1,795) 13.8	1,097(2,007) 10.8
2	(3/30/94) 65 (142) 33 (72)	980 (1,796) 13.8	1,098 (2,008) 11.4
3	(4/5/94) 67(147) 33 (72)	985(1,805) 14.2	1,098(2,008) 11.7
TABLE IV
CEM Data for the UDMH Tests

Test 1
Test 2
Test 3
Test 4
TestS
Test 6
Parameter
(2/1/94)
(2/3/94)
(2/15/94)
(2/23/94)
(2/24/94)
(3/1/94)
Kiln exit






CO, ppm
<2
<2
<2
<2
<2
<2
TUHC, ppm as propane
1.5
13
1.1
13
1.0
13
NOx, ppm
456
453
490
520
489
490
NO,, ppm at 7% 02
781
702
738
761
724
693
Afterburner exit






NOx, ppm
427
403
383
442
418
353
NOx, ppm at 7% 02
497
414
463
478
500
421
Scrubber exit






NOx, ppm
314
305
314
349
335
301
NO„, ppm at 7% Oj
486
473
489
497
485
449

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TABLE V
CEM Data for the N204 Tests
Parameter
Test 1
(3/24/94)
Test 2
(3/30/94)
Test 3
(4/5/94)
Kiln exit



CO, ppm
<2
<2
60
TUHC, ppm as propane
15
16
15
NOx, ppm
NOx, ppm at 1% 02
9,720
18,020
9,860
19,170
10,010
20,610
NO, ppm
4,220
4,690
6,100
N02> ppm
5,050
5,170
3,910
N02/N0X, %
54
52
39
Afterburner exit



NOx, ppm
NOx, ppm at 7% 02
	a
8,390
12,230
8,800
13,250
NO, ppm
—
5,180
5,850
N02, ppm
—
3,110
2,950
N02/N0X, %
—
37
34
Scrubber exit



NOx, ppm
NOx, ppm at 7% 02
5,880
10,550
—
6,860
12,160
NO, ppm
4,190
—
4,800
N02, ppm
1,690
—
2,060
N02/N0X, %
29
—
30
*— = Malfunctioning monitor.

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TABLE VI
N204 DREs

Test 1
Test 2
Test 3
Parameter
(3/24/94)
(3/30/94)
(4/5/94)
N204 feedrate, kg/hr
61
65
67
Kiln exit



Flue gas Qowrate, dscm/hr
750
770
770
no2



Concentration, g/dscm as N02
9.7
9.9
7.5
Emission rate, kg/hr
7.2
7.6
5.7
DRE, %
88
88
91
Afterburner exit



Flue gas flowrate, dscm/hr
1,060
1,130
1,350
no2



Concentration, g/dscm as NOz
	a
6.0
5.6
Emission rate, kg/hr
—
6.7
7.6
DRE, %
—
90
89
Scrubber exit



Flue gas flowrate, dscm/hr
1,930
1,840
1,770
no2



Concentration, g/dscm as N02
3.2
—
3.9
Emission rate, kg/hr
63
—
7.0
DRE, %
90
—
90
¦— = Malfunctioning monitor.

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TABLE VII
Flue Gas Hazardous Constituent Concentrations for the UDMH Set 1 Tests
Parameter
Test 1
(2/1/94)
Test 2
(2/3/94)
Test 3
(2/15/94)
Kiln exit
Concentrations:
UDMH, fig/dscm
Dimethylamine, ptg/dscm
Formaldehyde, ^g/dscm
UDMH DRE, %
Afterburner exit
Concentrations;
UDMH, jig/dscm
Dimethylamine, pg/dscm
Formaldehyde, pg/dscm
UDMH DRE, %
Scrubber exit
Concentrations:
UDMH, jig/dscm
Dimethylamine, pg/dscm
Formaldehyde, ^g/dscm
Particulate, mg/dscm at 7% 02
UDMH DRE, %
<40
<440
12
<50
<460
6.8
<80
<770
6.5
4
<40
<380
<0.23
<50
<280
2.4
<70
<700
8.0
4
<40
<410
<1.1
>99.99991 >99.99993 < 99.99993
<40
<410
4.3
>99.99982 > 99.99988 >99.99983
<70
<710
8.0
30
> 99.99974 > 99.99976 > 99.99973
TABLE Vin
Flue Gas Hazardous Constituent Concentrations for the UDMH Set 2 Tests
Test 4	Test 5	Test 6
	Parameter	(2/23/94) (2/24/94)	(3/1/94)
Kiln exit concentrations
Cyanide, ^ig/dscm	<40	<30	<30
N-nitrosodimethylamine, fig/dscm <5	<5	<5
Tetramethyltetrazene, /ig/dscm	<3	<3	<3
Afterburner exit concentrations
Cyanide, jig/dscm	<30	<30	<30
N-nitrosodimethylamine, fig/dscm <5	<5	<5
Tetramethyltetrazene, pg/dscm	<3	<3	<3
Scrubber exit concentrations
Cyanide, ^tg/dscm	<30	<30	<30
N-nitrosodimethylamine, jig/dscm	<5	<5	<5
Tetramethyltetrazene, jig/dscm	<3	<3		<3	

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TABLE IX
Scrubber Exit Flue Gas PCDD/PCDF Concentrations
UDMH	N2Q4 Tests	
Test 2	Test 1 Test 2	Test 3
	Parameter	(2/3/94)	(3/24/94) (3/30/94)	(4/5/94)
Scrubber exit flue gas PCDD/PCDF
concentration, ng/dscm at 7% 02
Total 0.45	0.27 0.13	0.36
TEQ 0.02	0.02 0.01	0.01
TABLE X
Flue Gas Trace Metal Concentration Method Detection Limits

Detection Limit,

Detection Limit,
Metal
/ig/dscm
Metal
/ig/dscm
Sb
12
Pb
15
As
21
Mn
1.0
Ba
1.0
Ni
4.0
Be
0.1
Ag
3.0
Cd
1.0
n
15
Cr
3.0
Sn
89
Co
17
V
3.0

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TABLE XI
Cyanide Sampling Train Validation Results
Reagent
System
Reference
1st Absorbing
Solution
2nd Absorbing
Solution
CN
Recoveiy,
%
1
CARB 426,5 standard
procedure
0.1N NaOH
O.IN NaOH
<0.2
2
CARB 426,5 option for
high C02
0.1M NaHCOj
0.1M NaHCOj
<0.2
3
CARB 426,3 increase pH
1.0N NaOH
l.ON NaOH
<0.2
4
CARB 426,5 further
increase pH
ION NaOH
ION NaOH
106
5
TACB,6 standard
procedure
2% Zn(CH3COO)2
2% Zn(CH3COO)2
28
6
TACB,6 option for high
H2S
Saturated
Pb (CH3COO)2
2% Zn(CH3COO)2
14

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fig. 2. UDMH feed system schematic.

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20
Fig. 3. N204 feed system schematic.
Nnm ma
<
%
i

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21
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