EPA-R2-72-051
September 1972 Environmental Protection Technology
Development of the Aqueous
Processes for Removing NOX
From Flue Gases
Office of Research and Monitoring
U.S. Environmental Protection Agency
Washington, D.C. 20460
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EPA-R2-72-051
DEVELOPMENT OF AQUEOUS PROCESSES
FOR REMOVING N0 FROM FLUE GASES
By
Gilford A. Chappell
Esso Research and Engineering Company
Government Research Laboratory
Linden, New Jersey 07036
Contract No. 68-02-0220
Program Element No: 1A2014
Project Officer: Stanley J. Bunas
Control Systems Division
National Environmental Research Center
Research Triangle Park, North Carolina 27711
Prepared for
OFFICE OF RESEARCH AND MONITORING
'U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
September 1972
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EPA REVIEW NOTICE
This report has been reviewed by the Environmental
Protection Agency and approved for publication.
Approval does not signify that the contents necessarily
reflect the views and policies of the Agency, nor does
mention of trade names or commercial products constitute
endorsement or recommendation for use.
11
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ABSTRACT
This report summarizes the findings of the laboratory program
for "Development of Aqueous Processes for Removing NOX from Flue Gases"
(EPA Contract 68-02-0220) . A screening study was conducted to evaluate
the capability of aqueous solutions to scrub NOX from the flue gases
emitted by stationary power plants fired with fossil fuels.
The key findings of this program are as follows:
• The addition of N0£ to flue gas to improve NOX (mostly NO) absorption
does not appear promising. While the presence of N(>2 does improve the
absorption of NO, the magnitude of the increase is insufficient to
support a viable process.
• Sulfite solutions and slurries are efficient N02-S02 absorbents.
Soluble sulfites (Na2SO-j) are better NO absorbers than insoluble
slurries (CaSOg) because of the higher level of sulfite ion in solution,
• Calcium, magnesium, and zinc hydroxide slurries are effective N02~S02
absorbers. The sulfite formed when S02 is absorbed is necessary for
efficient N02 scrubbing.
• Limestone (CaC03) is also a good N02-S02 absorbent for the same rea-
sons as for Ca(OH)2*
• NOo scrubbing is enhanced by removing oxygen from the flue gas or by
adding an anti-oxidant such as hydroquinone to the scrubbing solution.
• Sulfide solutions are excellent N02 and S02 absorbers but do generate
a small amount of NO.
• Part of the absorbed SO 2 is oxidized to sulfate.
Combined NOX-SOX scrubbing seems feasible using any of several
hydroxide or carbonate systems provided NOX (NO) can be efficiently oxidized
to N02 upstream from the scrubbing unit.
ACKNOWLEDGEMENTS
This work was conducted by the Government Research Laboratory
of the Esso Research and Engineering Company for the Environmental Protection
Agency under EPA Contract 68-02-0220. Dr. Gilford A. Chappell, the Principal
Investigator for the work reported herein, is a member of the Air Conservation
Section managed by Mr. Alvin Skopp.
The advice and assistance of Dr. Victor Engleman and Dr. Henry Shaw
is gratefully acknowledged.
The invaluable assistance of Mr. William Moss in the laboratory
during the entire project is sincerely appreciated.
Mr. Stanley J. Bunas was the EPA Technical Project Officer during
the program.
iii
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iv
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TABLE OF CONTENTS
ABSTRACT
1. INTRODUCTION 1
2. LABORATORY STUDIES 4
2.1 Apparatus 4
2.1.1 Flue Gas Blending System 4
2.1.2 Flue Gas Scrubbers 4
2.2 Analysis 8
2.2.1 Gas Analysis 8
2.2.2 Solution Analysis 9
2.3 Experimental Results 10
2.3.1 Absorption of NOX from Flue
Gases Containing No S02 1°
2.3.1.1 NOX Absorption by Water 10
2.3.1.2 NOX Absorption by Metal
Hydroxides and Slurries 11
2.3.1.3 NOX Absorption by Ammonia
and 2-Aminoethanol Solutions 14
2.3.1.4 NOX Absorption by Acidic Solutions 15
2.3.1.5 NOX Absorption by Salt Solutions 16
2.3.1.6 Sulfate Formation in Sulfite Scrubbers. . . 17
2.3.2 Scrubbing Flue Gas Containing N02 and S02 20
2.3.2.1 N02-S02 Absorption by Sulfites 20
2.3.2.2 N02-S02 Absorption by Hydroxides
and Carbonates 22
2.3.3 Miscellaneous Scrubbing Experiments 24
3. CONCLUSIONS AND RECOMMENDATIONS 28
3.1 Conclusions 28
3.2 Recommendations for Future Work 29
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APPENDICES
Appendix A Energy Requirements for Regeneration
of Spent Sorbent 30
A.I Electrochemical Reduction of
Sulfate to Sulfite 30
A. 2 Thermal Regeneration of MgO from MgSO^ 30
A. 3 Thermal Regeneration of MgO from MgS03 31
Appendix B Experimental Results - Flue Gas Scrubbing 32
B. 1 Emission Data and Run Sheets 35
vi
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1. INTRODUCTION
The oxides of nitrogen, NO and N02 are essential components in
the formation of photochemical smog in addition to being pollutants in
their own right. Large fossil fuel fired boilers, such as those found
in electric power generating plants, are major sources of these oxides.
In such boilers, the nitrogen oxides are formed by the reaction of molecular
nitrogen and oxygen in the high temperature combustion zone of the furnace.
The immediate product of this reaction is the thermodynamically favored NO.
As the combustion gases cool, part of the NO, typically less than 10%,
oxidizes to N02. The two oxides are generally considered together as NOX.
If the fuels contain organically bound nitrogen, as do coal and oil, part
of this nitrogen is also converted to NO during combustion. The composition
of different flue gases is shown in Table 1.
TABLE 1
TYPICAL COMPOSITIONS OF FLUE GASES
Volume % Combustion Of
Component
0>2
H20
S02
NO
x
Participates
grams/ft3
Coal 011(b>
76.2
14.2
6.0
3.3
0.2
0.5(e)
77.0
12.0
8.0
3.0
0.15
0.01
Gas
72.3
9.1
16.8
1.8
)
(a) Calculated for burning with 20% excess air a typical
high volatile bituminous coal of the following com-
position = carbon -70.1%, oxygen -6.6%, hydrogen -4.9%,
nitrogen -1.4%, sulfur -3.0%, ash -12.7%, and H20 -1.3%.
(b) Calculated a typical residual fuel oil of the following
composition = 86.5% carbon, 10.3% hydrogen, 2.5% sulfur,
0.7% nitrogen with 20% excess air.
(c) Calculated for burning natural gas with 10% excess air.
(d) This is an average value. Actual values range from
0.01% to 0.15%.
(e) Assumes 90% participates removal.
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- 2 -
In Volume II of the report, "Systems Study of Nitrogen Oxide
Control Methods for Stationary Sources" (1-1) , Esso Research and Engineering
Company assessed the various NOX control techniques. One promising pro-
cedure was aqueous alkaline scrubbing of the flue gas to which N0£ had
been added. Nitric oxide, the chief NOY constituent, does not itself com-
A
bine with water or basic solutions. Absorption requires that some of the
NO be oxidized to N0£. A mixture of NO and N0£ reacts to form a small
amount of N20_.
NO + N02
Sherwood and Pigford (1-2) found the rate of absorption of NO + N02 by a
46% NaOH solution to be approximately proportional to the first power of
the N203 concentration, indicating it to be the reacting specie. Mi rev
et al. (1-3) found that the completeness of the reaction between an NaOH
solution and NO /NO 2 mixtures reached a maximum at a 1:1 molar ratio of the
oxides .
The N£03 hydrolyzes rapidly in basic solutions to form nitrous
acid and nitrite salts.
N2°3 + H2° ^ 2HN°2 > 2N02 + 2H2°
Based on the promise of aqueous alkaline scrubbing, a flue
gas scrubbing apparatus was constructed and used to screen
a large number of potential scrubbing solutions. The original NOX levels
were 350 ppm each of NO and N02 with no S02 present. The S02 was eliminated
to simplify the scrubbing chemistry since S02 would also be absorbed by the
alkaline scrubbers.
The poor results of the early work led to a second phase directed
toward N02 absorption by aqueous solutions, notably sulfites. This effort
presumed the prior oxidation of NO to N02 by a suitable technique such as
ozone addition or catalysis. In these latter scrubbing studies, S02 was
usually present in the flue gas and was found to be beneficial for N02
absorption. The results from the second phase are quite promising and
indicate the possibility of simultaneous N02/S02 scrubbing.
The objectives of our program were to:
1. Screen various aqueous sorbents for NOX scrubbing potential
using a flue gas containing equimolar NO and N02 but no
2. Otpimize NOX absorption in promising systems by varying
experimental parameters.
3. Explore effect of SO. on NO scrubbing.
^ X
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REFERENCES
1-1 Bartok, W., Crawford, A.R., Cunningham, A.R., Hall, H.J., Manny, E.H.,
and Skopp, A., "Systems Study of Nitrogen Oxide Control Methods for
Stationary Sources", Esso Research and Engineering Company, Final
Report GR-2-NOS-69, Contract No. PH 22-68-55 (PB 192 789), November
1969.
1-2 Sherwood, T.K., and Pigford, R.L., "Absorption and Extraction",
Chem. Eng. Series, McGraw-Hill, 1952.
1-3 Mirev, D., Balarev, Khr., Boyadzhiev, L., and Lambiev, D., "Absorption
of Nitrogen Oxides by Vibrating Layers of NaOH Solutions", Compt. Rend.
Acad. Bulgare Sci., 14 : 250-62, 1961.
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2. LABORATORY STUDIES
This section of the report describes the laboratory apparatus
used to screen the various aqueous solutions and slurries for NOX scrub-
bing potential. The experimental results are contained in the latter part
of this section.
2.1 Apparatus
The basic scrubbing apparatus consisted of a flue gas blending
system and the gas scrubbers. The blending system was capable of producing
a wide variety of flue gas compositions by mixing the pure components in
different proportions. The flue gas passed through heated lines to the
scrubbers where the NOX and S02 were absorbed. The effluent gases were
carried by heated lines to the gas analyzers for the determination of the
residual NO, N02, and S02. The different components of the total scrubbing
system are described in greater detail below.
2.1.1 Flue Gas Blending System
The blending system was designed to produce a heated flue gas
from the various components contained in cylinders. The flue gas con-
taminants S02» N02» and NO were each contained in a separate high pressure
gas cylinder at 5 mole % (50,000 ppm) with nitrogen making up the balance.
Other cylinders contained pure oxygen, pure C02 and pure nitrogen. Each
gas was delivered through 0.25 inch O.D. stainless steel tubing to a
calibrated rotameter for flow measurement prior to mixing. Wet steam,
which was available in the laboratory, was dried by passing through
heated aluminum coils. The dry, hot steam also passed through a calibrated
rotameter before mixing with the other components. Figure 2-1 shows
a schematic of the gas blending system. The order of mixing was important
for minimizing gas phase reactions between N02 and S02-
N02 + S02 > NO + SO
After passing through their respective rotameters, N£, C02, 02, and S02
fed into a common line which passed through the heated steam box where
steam was added to the mixture. At this point the dewpoint of the gas
was about 115°F and the lines were maintained at approximately 200°F.
After blending with NO and N02, the entire mixture passed through a
heated rotameter to determine the total flow rate. The synthetic flue
gas was delivered through heated lines to the gas scrubbers. The com-
position of a typical blend was 350 ppm NO, 350 ppm N02, 2400 ppm S02,
3 mole % Oo, 12 mole % 2» 10 roole % steam, and N2 as the balance. The
flue gas blending system functioned satisfactorily.
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FIGURE 2-1
GAS BLENDING SYSTEM
To
Scrub
4 9
House Steam Input
O
O
O
O
o
CN
(^.Electric Steam Box
• All lines downstream of the
steambox were heated.
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- 6 -
A recurring annoyance, however, was the destruction of the
viton '0' rings in the rotameters by N(>2. This corrosive gas should not
contact anything organic for long time periods except possibly teflon.
The degradation products from the viton tended to foul the rotameters,
which necessitated periodic cleaning. Fortunately, this did not occur
often.
The heated steel lines initially underwent a conditioning
process bv the flue eas. The composition of gas exiting from the
system varied for 10-20 minutes before stabilizing. If the system
was not used for several days, the lines required reconditioning.
No gas phase reactions were observed. Nitric oxide (NO) was not
oxidized to NC>2 in the lines and N0£ did not react with S02 at these low
concentrations.
2.1.2 Flue Gas Scrubbers
The gas scrubber was a two-liter round-bottom glass flask con-
taining one liter of scrubbing solution or slurry. A teflon-coated
magnetic stirring bar agitated the solution. The scrubber temperature
was maintained by an electric heating mantle which was controlled by a
thermocouple immersed in the solution. The thermocouple was clad with
stainless steel. The temperatures of the scrubbing solution, the heated
lines, and the steam box were continuously recorded by a 24 point
temperature recorder.
The hot flue gas was introduced into the absorbing solution
through a porous glass frit located approximately four inches below the
surface.
The temperature of the scrubber was maintained at approximately
125°F for most runs. This is the approximate adiabatic humidification
temperature of an actual flue gas.
Figure 2-2 contains a schematic of the scrubber portion of the
system. Three scrubbing units were available and could be run in series
or parallel. This flexibility allowed one significant advantage in that
we could quickly start a second run after finishing the first by simply
turning several valves and directing the flue gas to bypass the first
scrubber and to enter the second. Thus, the second scrubber could be set
up and heated to the operating temperature while the first scrubber was
running.
The gas exiting from the scrubber was carried by heated lines
to the gas analyzers which measured the NO, N02, and 802 levels.
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FIGURE 2-2
to "C
pot "B" jumper vent
mixture
from
pot "a"
SCRUBER
Note: • all lines are stainless steel,
• all lines heated,
• all connections either
ground glass or swagelok
thermocouple
2 liter flask
heating mantle
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2.2 Analysis
2.2.1 Gas Analysis
The heated line carrying the scrubber effluent entered a junction
from which three lines exited. These lines transferred the hot gas to the
analyzers for measurements of the NO, NC>2 , and S02 levels.
The S02 and N02 were analyzed independently by two DuPont 400
spectrophotometers. These were double-beam instruments containing analyzer
cells maintained at 212° F. The flue gas passed through the cells
continuously. The two analyzers were totally separate except that they
shared the same light source; the two gas cells were oriented at 90° to
each other. Each analyzer contained a set of filters to isolate the
pertinent spectral line. Each unit also had a calibration filter which
was equivalent to a fixed ppm level of gas at a fixed temperature and
total pressure. The filter was normally outside the light path but could
be positioned in the beam to check the response of the instrument. The
signals from the N02 and S02 analyzers were recorded continuously by
strip chart recorders. The two DuPont instruments were rugged and reliable
and no difficulties were encountered.
The NO analysis involved considerable problems. Initially, a
Whitaker "NOX Box" measured total NOX (NO + N02) and was insensitive to
water vapor. However, the flue gas had to be cooled below its dewpoint
before analysis in order to keep water droplets from forming inside the
instrument. Unfortunately, the water trap removed part of the NOX from
a flue gas containing equal parts NO and N02. This occurred by the
hydrolysis of ^03 within the trap to yield nitrous acid and nitrate ion.
The N£0 forms in the vapor phase from NO and N02.
N0(g)+N°2(g) ^=^ N2°3(g)
N2°3(g) + H20(1) ^ ^ 2HN02 (ln solution>
Eventually, the trap would equilibrate with the gas stream and NOX
fluctuations would cease. This problem caused a significant lag in the
response of the instrument to changes in the NOX levels. If the primary
NOX constituent is NO, this problem does not occur.
Following the initial attempts with the Whitaker NOX Analyzer,
a Beckman NDIR (Non-Dispersive Infra-Red) was used for NO measurements
because of its better signal stability and because it read NO directly,
not total NOX. However, all of the water had to be removed from the gas
because the instrument read the moisture as NO.
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In order to eliminate the NO-NC^-I^O interaction in the water trap, the
NC»2 had to be removed before the trap. After trying several approaches,
a saturated solution of sodium sulfite at room temperature was finally
adopted for use as the N02 absorber because of its capacity to remove
all traces of N02- Part of the NO was also removed by the Na2S03 trap,
but the fraction of the NO absorbed depended on the amount of N02 in the
gas stream. The sulfite trap was calibrated with known gas mixtures so
that the NO level before the sulfite trap could be calculated from the
NDIR reading, the N02 reading, and the calibration chart. In the final
arrangement for NO analysis, the flue gas passed through the Na2S03 solu-
tion, then entered a cold trap chilled with dry ice and methanol. The dry
gas was warmed to room temperature before entering the NDIR. The cold trap
was packed with glass beads to increase surface area and to reduce the
dead volume.
The sulfite trap also removed all S02 from the gas stream.
Had this not occurred, the S02 would have condensed in the water trap.
The final configuration of the gas analysis section proved to be
reliable and stable and was used for the majority of the experiments.
2.2.2 Solution Analysis
As the nitrogen oxides are absorbed by the alkaline scrubbing
solution, nitrite and nitrate ions are produced.
N2°3(g) + H2°(1) - ^ 2HN02(aq)
OH"
2N02(g) + H20 (1) - >
HNO + OH~ - > HO + N03"
At first, an Orion Specific Ion Electrode was used for nitrate ion measure
ments. The nitrite level was determined by oxidizing the N02~ to NO 3"
with hydrogen peroxide followed by a total nitrate measurement; the
initial nitrate reading was then subtracted from the total nitrate. While
this procedure worked well with dilute solutions, it proved somewhat
cumbersome. With concentrated salt solutions, interference becomes a
problem so a spectrophotometric procedure developed by Wetters and
Uglum (2-1) was used.
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Simultaneous determinations of nitrite and nitrate were achieved
by measuring the light absorption of the sample at two different wavelengths
in the ultraviolet region. Nitrite absorbs at 355 nm and 302 nm with molar
absorptivities of 23.3 and 9.12 respectively, whereas nitrate absorbs only
at 302 nm with a molar absorptivity of 7.24. The absorbance due to nitrate
in a sample can be calculated by dividing the nitrite absorbance at 355 nm
by 2.5 and subtracting the quotient from the total absorbance at 302 nm.
We used cells with a path length of four centimeters to measure nitrate
and nitrite levels down to 1 x 10~4 molar. The procedure was rapid and
reliable. However, at high pH, 002 produces carbonate ion which interferes
with the spectrophotometric measurement. Also, nitrite ion converts to
nitrous acid at a pH less than 5 and this species interferes with the
determination. Most measurements were made in a pH range of 7.5 to 9.5.
Sulfate ion also formed in the scrubber and derived from the
oxidation of sulfite ion by oxygen and NOX. In some experiments, the
sulfite was added to the scrubber as a salt (e.g., Na2S03) , whereas in
other runs the species was produced by the absorption S02 from the flue
gas by the scrubbing solution. Once formed, the sulfate level was
determined by the standard gravimetric procedure which involved 'acidifica-
tion with HC1 followed by boiling and then precipitation with BaCl2
solution. This is one of the most accurate of analytical procedures.
2.3 Experimental Results
The first part of the program used a flue gas containing equal
parts NO and N02 but no S02• The absence of S02 simplified data interpreta-
tion. In addition, the NOjj scrubber in an actual system might be located
downstream from the S02 level in the gas entering the NOx unit.
The second part of the program was concerned with NOX and S02
absorption by solutions and slurries. In particular, N02 scrubbing by
sulfites was investigated. In these experiments the flue gas contained
S02.
The details of each run are recorded in Appendix B.
2.3.1 Absorption of NOX From
SO? Free Flue Gas
2.3.1.1 NOy Absorption by Water
The first series of runs used water to scrub a flue gas con-
taining 3% oxygen, 8-10% steam, 12% C0£, approximately 350 ppm each of
NO and N02, and nitrogen as the balance. The flow rate was 3200 cc/min
at room temperature (75°F) and pressure. Table 2 contains some of the
results.
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TABLE 2
NOX SCRUBBING WITH WATER
Input (ppm) % Absorption* Solution Run Time
Exp. f NO N02 NO N02 Temp. (°F) (min)
11-10-71 400 390 -5** 18 125 220
11-16-71 175 400 -9** 23 123 220
11-17-71 360 380 1 23 129 250
11-18-71 305 350 -6** 20 126 240
* % of the input concentration being absorbed at the end of the run.
** Negative absorption signifies net % generation.
Nitric oxide was absorbed during the early part of the runs, but as the
level of nitrous and nitric acid increased, NO was generated by the
hydrolysis of N02.
+ H20 - > NO + 2HN03
During experiment #11-10-71, an average of 45 ppm of NOx was absorbed for
215 minutes. The total dissolved NOX should have been, 0.9 x 10~3 molar.
Solution analysis yielded 0.9 x 10~3 molar nitrate and 0.2 x 10~3 molar
nitrite which totaled 1.1 x 10~3 molar. This constitutes a reasonably
good NOX mass balance. In addition, the agreement in scrubbing efficiency
among the runs listed in Table 2 shows good experimental reproducibility.
2.3.1.2 NOX Absorption by Metal Hydroxide
Solutions and Slurries _
The hydroxides of sodium, calcium, magnesium, and zinc were
investigated for their scrubbing potentials. Both slurries and solutions
were used and gave somewhat different results. Table 3 contains a summary
of the data which may be found in its entirety in the Appendix. The total
gas flow rate was 3200 cc/min in all experiments. The two NaOH runs listed
with the Ca and Mg runs used solutions with the same initial pH as the
saturated solution of the corresponding metal hydroxide. The scrubbing
efficiency varied somewhat during a run so the values in Table 3 are
approximate.
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TABLE 3
NO.,. SCRUBBING WITH METAL HYDROXIDES
Exp. #
11-19-71
12-5-71
1-19-72
1-27-72
2-8-72
12-20-71
12-7-71
2-9-72
12-13-71
12-17-71
2-9-72
12-15-71
Absorbent
5N NaOH
5N NaOH
50 Wt. % NaOH
14.8 molal (45 Wt %) NaOH
Ca(OH)2 Slurry**
Ca(OH)2 Sat. Soln.
NaOH
Mg(OH)2 Slurry
Mg(OH)2 Sat. Soln.
NaOH
ZnO Slurry
ZnO Sat. Soln.
Initial
pH
14
14
14
14
11.5
11.5
11,5
8.9
8.9
8.9
7.5
7.5
Input
NO
350
274
345
333
353
390
311
330
377
404
353
400
(ppm)
N02
400
320
330
360
365
380
360
350
360
370
370
400
% Absorption
NO
20
35
28
47*
20
8
10
6
7
6
7
8
N02
18
34
23
28
21
29
29
23
22
24
16
29
Solution
Temp. (°F)
126
112
120
80
124
121
120
125
122
120
121
119
Run Time
(min)
\ »*»^** /
180
60
30
80
130
300
i
"0 M
60
80
90
130
90
* This value decreased to 28% as the solution temperature increased to 140°F.
** The porous glass frit plugged with CaC03 early in the run and had to be replaced with an open tube.
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- 13 -
In most of the runs, the N02 absorption was only slightly improved
over pure water; however, the NO absorption was significantly better in
several experiments. A qualitative temperature effect was observed in the
first four NaOH runs listed in the Table. As the temperature of the
scrubbing solution decreased, the scrubbing efficiency increased.
The data from the saturated solutions of Mg(OH>2 and Ca(OH)2
agree with the data from the corresponding NaOH solutions which implies
a pH effect. Thus, the Ca(OH>2 system was more alkaline than the Mg(OH)2
system and absorbed more NO . Increasing the pH to 14 (5N NaOH) from 11.5
did not improve the absorption efficiency at the same temperature which
indicates that the influence of pH is not simple. The ZnO [Zn(OH>2]
slurry absorbed only 16% of the N02 whereas the solution absorbed 29%.
This seems unusual and no explanation is proposed.
The NOX mass balance between solution and gas phase was
determined at the end of several runs. In general the balance is
satisfactory as shown in Table 4. The one exception is exp. #12-17-71
where the solution analysis is much greater than the gas analysis. This is
probably due to dissolved carbonate from the C02 in the flue gas.
TABLE 4
N0y MATERIAL BALANCE
Exp.
Absorbent
Time NOX Absorption (ppm) Solution Anal
12-17-71 NaOH (pH = 8.9)
12-20-71 Ca(OH)2 sol'n
12-13-71 Mg(OH)2 sol'n
12-15-71 ZnO sol'n
70
300
80
90
AND
30
32
25
25
Total Dissolved NOX
Calculated From
Gas Anal .
1.1*
5.9
1.2
1.6
Sol'n Anal
1.6*
5.0
0.9
1.7
* Concentration unit is millimoles per liter.
Although the overall balance is reasonable, the ratio of nitrite to nitrate
in solution is significantly higher than expected, assuming that only simple
hydrolysis occurs.
3N0
NO + 2HN03 (source of nitrate)
2HN02 (source of nitrite)
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- 1.4 -
The data in Tables 3 and 4 indicate that the hydroxide scrubbers
are not good NOX absorbers in the absence of SC»2 and N0£ recycle is not
attractive under these conditions.
2.3.1.3 NOX Absorption by Ammonia and
2-Aminoethanol Solutions
The best NO removal observed occurred with a 28 Wt. %
scrubbing solution which removed 74% of the NO and 80% of the N02
Table 5 contains these results in addition to scrubbing data from a
similar system, 2-aminoethanol.
TABLE 5
NOX SCRUBBING WITH AMINES
Input (ppm) % Absorption Solution Run Time
Exp // Absorbent NO N02 NO N02 Temp. (°F) (min)
1-26-72 NH4OH (28 Wt %) 330 355 74 80 70 40
2-3-72 2AE* 340 320 40 91 128 95
2-4-72 50% 2AE** 340 330 48 88 127 120
2-4-72 25% 2AE 347 350 48 86 127 110
3^-8-72 25% 2AE 360 360 47 89 126 480
* 2AE is 2-aminoethanol.
** 50% by volume 2AE and 50% water.
The vapor pressure of NH3 above the NH^OH scrubber dicated
operation at room temperature. A water scrubber (one liter of H20 at
70°F) was placed downstream from the NltyOH scrubber to trap NH3 vapors
for continued scrubbing. Thus, the data in the table result from two
scrubbers in series. When the water scrubber was by-passed, the % absorp-
tion changed to 54% for NO and 58% for the N02- A flask containing dilute
I^SO^ was placed downstream from water scrubber to protect the analyzers
from ammonia vapor. The l^SO^ trap was saturated with NOX before putting
the NH^OH scrubber on line. The interdependence of NO-N02 absorption was
shown by varying the input levels of each specie. Halving the N02 input
dropped the NO absorption from 74% to 49%. On the other hand, reducing the
NO input to zero dropped the N02 absorption from 80% to 51%. The problems
associated with the high NH3 vapor pressure led to considering a higher
boiling amine, 2-aminoethanol, for scrubbing.
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- 15 -
The vapor pressure of 2-aminoethanol (2AE) is much lower than that
of 28 Wt. % NItyOH. The pure araine has a vapor pressure of 7 Torr at 150°F
whereas the NH3 partial pressure over the ammonia solution is 570 Torr at
70°F. The use of 2AE in the scrubber did not eliminate the need for a
dilute H2SC>4 trap. The small amount of amine vapor emanating from the NOX
absorber had to be removed before the gas stream entered the analyzers.
The mist which formed above the scrubbing fluid when N02 was present in
the flue gas, was removed from the effluent by the l^SO^ trap. Before
recording data, this trap was saturated with NOX. As Table 5 shows, the
2AE solutions were excellent NOX scrubbers but did not remove as much NO
as did the ammonia solution. The 2AE was observed to heat up when C02 was
present in the flue gas indicating that C02 is reacting with the solution.
This is to be expected since this type of compound is used commercially for
scrubbing C02 from gas streams. The color of the 2AE solutions changed
from colorless to orange as the runs progressed. An attempt to determine
the exact nature of the reaction proved inconclusive. A variety of
products may result when a primary amine reacts with N203 (NO + N02).
These include molecular nitrogen (N2), alkyl ammonium nitrites and
nitrates, and alkyl nitrites and nitrates. Secondary amines form dialkyl-
ammonium nitrites and dialkyl N-nitroso compounds which are colored. These
reactions are essentially irreversible.
2.3.1.4 NOx Absorption by Acidic Solutions
In order to compare the NOX absorption potential of acidic
solutions with alkaline baths several runs were made with sulfuric acid
and glacial acetic acid. The results were not particularly impressive
as indicated by Table 6.
TABLE 6
NOx ABSORPTION BY ACIDS
Input (ppm) % Absorption Solution Run Time
Exp. # Absorbent NO N02 NO NO? Temp. (°F) (min)
12-3-71 H2S04 (79 Wt. %) 350 350 1. 14. 202 120
4-25-72 H2S04 (30 Wt. %) 350 300 0 20. 120 110
1-19-72 Glacial Acetic Acid 335 370 0 80 120 20
-------
- 16 -
Approximately 18 ppm of S02 was generated during run # 4-25-72. The S02
analyzer was not turned on during run // 12-3-71 so SC>2 may also have been
produced in that experiment. Sulfuric acid is a poor NOX absorber whereas
acetic acid removes most of the N02 but no NO.
2.3.1.5 NOX Absorption by Salt Solutions
A number of aqueous salt solutions have been screened for NOX
scrubbing potential and some of these appear very promising. Table 7
summarizes the experimental data.
TABLE 7
NOX ABSORPTION BY SALT SOLUTIONS
% Absorption Solution Run Time
N02 Temp. (°F) (min)
100 112 150
100 129 25
100 70-85 140
100 122 60
100 125 90
25 119 100
49 123 80
39 123 160
100 122 60
100 127 60
26 126 90
100 124 40
60 125 40
* 4.1m (NH4)2S03 means 4.1 molal (NH4>2S03.
** Copius amounts of S02 were generated during solution preparation and during
scrubbing run. The pH at the start of the run was 2.4.
Exp. #
12-5-71
12-21-71
12-21-71
1-3-72
1-10-72
1-17-72
1-18-72
1-24-72
1-28-72
2-15-72
2-10-72
3-3-72
3-7-72
Absorbent
4.1m (NH4)2 S03*
5N NaOH Sat'd with Na2S03
same as above
Sat'd Na2S03
f3.6tn NH4HS03*A
1.9m NH4HS04 J
6M NaOAc
8.4m NH4C1
8.4m NH40Ac
2.3m Na2S03
2.5m Na2S03
1.0m Ammonium Citrate
1.0m Na2S03
CaS03 Slurry
Input
NO
328
357
380
375
360
340
330
362
355
358
358
355
390
(ppm)
N02
350
355
330
350
330
360
350
360
500
350
350
400
380
% i
NO
23
12
27
21
24
18
27
31
18
16
25
15
33
-------
- 17 -
Not included in the table is scrubbing run # 1-26-72 which
involved passing flue gas through.a 2.3 molal solution of Na2S. Despite
some experimental difficulties, the results show 100% absorption of N02
and minor absorption of NO from a flue gas containing approximately 350
ppm of each.
The data in Table 7 has one, very clear, message; sulfite ion
is an excellent N02 absorbent but a poor NO absorbent. The agreement
between several Na2S03 runs again demonstrates the stability and
reproducibility of our procedures. Runs # 1-3-72, 1-28-72, and 2-15-72
all show 100% absorption of N02 and 21%, 18%, and 16% reduction of NO,
respectively. Also, run # 1-10-72 shows that low pH and high sulfate
levels do not inhibit the absorption of N02 by sulfite or bisulfite solu-
tions. The absorption of NO by the (NH4)2S03 solution (run # 12-5-71)
dropped to zero when N02 was eliminated from the flue gas. In addition,
a NOX material balance was made for the (NH4)2S03 run and after 140 minutes
on line, the gas analysis indicated a loss of 7.5 millimoles of NOX (6.3
N02 and 1.2 NO) whereas the solution analysis showed 5.8 millimoles of
dissolved NOX (5.2 N03~ and 0.6 N02~). A similar balance determined at
the end of run // 1-28-72 (2.3m Na2S03) showed a loss of 4.4 millimoles of
NOX (3.9 N02 and 0.5 NO) from the flue gas and 2.4 millimoles of NOjj
(2.0 N03~ and 0.4 N02~) dissolved in the scrubber. The reason for the
imbalance is unclear. Another balance was measured at the end of run
# 2-15-72. In this case, the gas analysis indicated a loss of 3.2
millimoles of NOX (2.7 N02 and 0.5 NO) while solution analysis gave 5.3
millimoles of dissolved NOX (4.2 N03~ and 1.1 N02~).
2.3.1.6 Sulfate Formation in Sulfite Scrubbers
When flue gas containing oxidants such as NOX and 02 is bubbled
through a sulfite containing scrubber, some sulfate is .formed which con-
stitutes a problem if solution regeneration is comtemplated. In order
to ascertain the magnitude of the problem, several runs were made with
saturated sodium sulfite solutions. The flue gas did not contain S02
but did have 350 ppm each of NO and N02, 3% 02, 8% H20, 12% C02, and the
balance was nitrogen. Runs were made with and without 02 and NO. In
addition, hydroquinone (HQ) was used in some scrubbers to reduce oxidation.
Table 8 contains the results.
-------
- 18 -
TABLE 8
SULFATE FORMATION IN SATURATED Na2SCh SCRUBBERS
Flue Gas >•
Scrubber >
Initial S04= (wt . %)
Final SO*" (wt. %)
Complete
no HQ
1.28
1.51
Complete
with HQ
0.33
0.61*
Without NOX
with HQ
0.22
0.23
Without 02
with HQ
0.31
0.37
Without 02
no HQ
0.46
0.58
Without NOX
no HQ
0.10
0.40
(60 min on line)
A.. 0.23 0.28 0.01 0.06 0.12 0.30
oU
millimoles S04= 29. 36. 1.3 7.6 15. 39.
formed
* Run lasted for 70 minutes.
The scrubbing solution consisted of one liter of liquid whose
specific gravity was 1.22. All of the N02 was absorbed plus 60 ppm of the
NO with gave a total NOx absorption of 410 ppm. The solutions absorbed
3.2 millimoles of NOX per hour while being exposed to 234 millimoles of
oxygen per hour. The presence of hydroquinone did reduce sulfate formation
except in the case of the "complete" flue gas; however, these two runs may
be suspect due to the unusually high initial and final sulfate levels.
The data suggest that oxygen is involved in the oxidation of sulfite to
sulfate.
The effect of initial pH upon the sulfate formation was
investigated in 1.0 molal ^2803 scrubbers. The flue gas did not contain
S02 but did have 380 ppm N02 and 370 ppm NO. All of the N02 and 60 ppm
of the NO were absorbed by the solutions. The initial pH was raised by
adding a small amount of concentrated NaOH and was lowered with hydrochloric
acids. The pH changed rapidly upon introducing flue gas into the solution.
These runs lasted for 50 minutes and Table 9 contains the results.
TABLE 9
EFFECT OF pH ON SULFATE FORMATION
J.IIJ.LJ.CIJ. pa '^ /./ j.u -L^._»
wt. :
wt. ;
Wt. !
I S04=
I 804°
I so4=
(t
(t
(t
= o)
= 25
= 50
min)
min)
0
0
0
0
.51
.74(7.
.97(7.
.46
6)
6)
0
0
0
0
.73
.86(7.
.97(8.
.24
9)
0)
0.33
0.64(8.0)
0.90(8.1)
0.57
-------
- 19 -
The numbers in parentheses are the pH's at the end of the
specified time. No trend is apparent, but as before, more sulfate is
formed than NOX absorbed.
In other runs, an aqueous slurry containing 8 grams of CaS03
per liter was used to scrub NOX and to generate sulfate data. Several
different initial pH's were employed with the results shown in Table 10.
TABLE 10
NOX SCRUBBING BY CaSOq
Initial pH Input NO Input N02 Input S02 A NO (ppm) A NQ2 (ppm) A S02 (ppm)
7.2 380 ppm 380 0 132 250
8.0 390 370 0 132 220
12 390 370 0 125-KL87+125 370+150
7.6 0 340 500 — 220 500+440
The first three runs, which did not involve SC>2, lasted for 50 minutes each.
The best NOX absorption occurred in the most basic slurry. The pH was
raised to 12 by the addition of a small amount of concentrated NaOH solution.
In this run, the NO absorption increased linearly with time over a 40 minute
period. After 40 minutes, the ANO was 187 ppm. Between 40 and 50 minutes
on line, the absorption dropped back to 125 ppm NO. Similarly, the N02
absorption was complete for the first 40 minutes; however, during the last
ten minutes on line the absorption rapidly dropped to 150 ppm. The last run
shown in the table lasted for two hours. During the first 70 minutes, the
S02 absorption gradually dropped from 500 ppm to 440 ppm. This trend
continued until the end of the two hours when the absorption of S02
rapidly decreased to almost zero. This is probably due to saturation and
the decline in pH.
The sulfate formation occurring in the CaS03 experiments is
shown in Table 11.
-------
- 20 -
TABLE 11
SULFATE FORMATION IN CaSCh SLURRIES
Initial pH
7.2
8.0
12
Wt. % S04 (t = o)
Wt. % S0^= (t = 25 min)
Wt. % S04= (t = 50 min)
A50
0.29
0.33
0.36
0.07
0.18
0.23
0.31
0.13
0.16
0.45
7.6 (S02 in Flue Gas)
0.16
0.51*
0.35
* Run lasted 70 minutes.
The higher pH's dropped rapidly with the introduction of flue gas so that
no runs were made at constant acidity throughout the experiment. The
trend in these data is to greater sulfate formation at the higher pH.
The presence of S02 also increased the formation of sulfate.
2.3.2 Scrubbing Flue Gas
Containing N02 and S02
The data of section 2.3.1.1 to 2.3.1.6 indicated that the
addition of N0£ to flue gas did not significantly improve NO absorption
whereas N02 absorption by sulfite solutions appeared feasible assuming
the NO could be oxidized to N0£ upstream from the scrubber. In order to
explore N02-S02 absorption, several solutions and slurries were screened
for scrubbing potential.
2.3.2.1 N02- SO? Absorption by Sulfites
Sulfur dioxide readily dissolves in alkaline solutions but not
in acids. The sulfite solutions are more or less basic depending on the
solubility of the salt. The hydrolysis of the soluble sulfite ion
raises the pH.
HSO., + OH
Flue gas contains approximately 12 volume % (X>2 which is also soluble
in alkaline solutions, but because of the relative acid strengths of 1
and H2C03, there is a range of pH where S02 is quite soluble whereas C02
is only slightly so. This range, which is around pH 7, would be optimum
for scrubbing N02-S02. The absorption of N02 by sulfites is not sensitive
to pH.
-------
- 21 -
Several sulfite scrubbers were screened for simultaneous N02-
S02 scrubbing. Table 12 contains a summary of the results.
TABLE 12
N02-SO? ABSORPTION BY SULFITES
Input (ppm) % Absorption Solution p_H Run Time
_Exp. It Absorbent N02_ S02 N09 S02 Temp. (°F) Initial Final (min)
3-13-72 CaS03 Slurry (8 g/1) 330 500 60 92 125 7.6 5.0 70
3-30-72 MgS03 (5 g/1) 690 2610 100+45 100 126 9.4 3.7 40
4-3-72 CaS03 Slurry (25 g/1) 860 1890 100 100 126 9.1 7.2 75
i-24-72(2TI
\0.
;»5»H4H«>3_1 700 2370 94 83 122 5>9 5>9 145
500 100
6-22-72 (NH4)2S03 Mixture* + 2860 + 97 128 6.3 6.3 70
(450 NO) (22% NO)
* Mixture consisted of 11.2 Wt. % NfyHSO^ 14.6 Wt. % (NH4)2S03, 16.6 Wt. %
and 57.6 Wt. % H20. The specific gravity was 1.24.
The S02 removal was good in all the runs but the N02 absorption
varied with the amount soluble sulfite present. After going on line, the
pH of the CaS03 slurry in run # 3-13-72 dropped to 5.3 within 30 minutes.
This run was continued for 290 minutes and at 115 minutes the slurry became
saturated with S02. When S02 broke through, its value exceeded the input
level for about an hour, then gradually decreased to slightly less than the
input value. Apparently, some of the sulfite or bisulfate evolved S02 for
a short while. With a greater solids loading in the slurry as in run
# 4-3-72, the absorption of N02 and S02 was improved.
The sulfite in the MgS03 experiment may have been rapidly
depleted by the 02 in the flue gas. This would account for the continuous
decrease in N02 absorption during the run. The original sulfite level was
0.08 molar (MgS03 is quite soluble).
-------
- 22 -
The last two runs listed in Table 12 again indicate that the
presence of sulfate does not inhibit N02 absorption as long as sufficient
sulfite ion is available. Run # 6-22-72 also included NO in the flue gas
which reaffirmed the earlier conclusion that sulfites are not attractive
NO absorbents.
2.3.2.2 N02-S02 Absorption by
Hydroxides and Carbonates
Several metal hydroxide slurries were screened for N02-S02
scrubbing potential. In addition, a limestone (CaCC>3) slurry was investigated.
Since magnesia, lime and limestone scrubbing systems are presently under
consideration for S02 scrubbing, the results on the combined scrubbing
are significant. A summary of results is contained in Table 13.
The results show these slurries to be less efficient for N02
scrubbing than the sulfite slurries and solutions. However, they exhibit
excellent absorption of S02- The presence of S02 is vital for N02 absorp-
tion as indicated by the two runs numbered 3-17-72. Only 19% of the N02
was absorbed in the absence of S02 wherease 50% was scrubbed out in its
presence Thus, the sulfite formed during S02 scrubbing becomes the
absorbent for N0«.
A NOX material balance was measured at the end of run #3-22-72, which
employed a Mg(OH)2 slurry. Gas analysis indicated 6.9 millimoles of N02 re-
moved. Solution analysis showed 6.1 millimoles of N03~ and 2.0 millimoles of
produced. Nitrate ion is the main product of N02 absorption from flue gas.
All of the slurries demonstrated roughly equal scrubbing efficiency
on the full flue gas. When oxygen was eliminated from the gas stream, the
scrubbing efficiency improved markedly. For example, during run # 4-10-72
the 02 was removed from the stream with the result that the N02 absorption
increased from 63% to 90%. With the oxygen, flow turned on, the N02 absorp-
tion dropped back to 69%. Similar effects were observed with the other
slurries. The presence of hydroquinone , an anti-oxidant , diminished the
negative influence of oxygen upon N02 absorption. Run // 4-18-72 provides
an example. A flue gas containing 670 ppm N02 and 2400 ppm S02 but no 02
was. bubbled into an Mg(OH>2 slurry. All of the NC»2 and S02 was absorbed.
When 3% oxygen was added to the flue gas, the N02 absorption dropped to
57% while the S02 continued to be totally removed. The addition of 1.0
gram of HQ to the slurry instantly caused the N02 absorption to increase to
93% in the presence of oxygen. The HQ was still effective 200 minutes
later, when the run was terminated. Similar effects were observed with
other slurries but were not as dramatic. An endurance run (#5-5-72) was made
with a slurry containing 15g of Mg(OH)2 and 1.0 gram of HQ. The flue
gas contained 675 ppm N02, 2280 ppm S02 and 3% 02 in addition to the normal
constituents. The S02 absorption was complete for the full 390 minutes of
the run. The N02 absorption was about 100% during the first 200 minutes
of the run but gradually decreased to 82% at the end of the experiment.
The slurry slowly turned yellow as the run progressed. The HQ is acting
as an oxidation inhibitor but undergoes slow degradation, perhaps due to
reaction with N02.
-------
TABLE 13
N02-S02 ABSORPTION
Exp. #
3-17-72
3-17-72
4-10-72
4-7-72
3-22-72
4-7-72
4-10-72
4-14-72
4-14-72
Absorbent
Ca(OH)2 slurry (10 g/1)
(continuation of 3-17-72)
Ca(OH)2 slurry (15 g/1)
Ca(OH)2 slurry (18 g/1)
Mg(OH)2 slurry 7.4 (g/1)
Mg(OH)2 slurry 14 (g/1)
ZnO slurry (10 g/1)
CaC03 slurry (10 g/1)
CaC03 slurry (4 g/1)
Input (ppm)
N02 S02
740
730
700
680
830
680
700
650
650
0
800
2490
2460
2460
2610
2490
2280
2280
BY HYDROXIDES AND CARBONATES
7* Absorption
N02 S02
19
50
63
56
58
56
63
46
46
81
100
100
100
100
100
100
100
Solution
Temp. (°F)
132
132
126
125
126
126
126
128
128
PH
Initial
11.2
6.6
11.2
11.2
8.7
9.3
9.3
7.5
7.2
Final
6.6
6.0
6.4
6.5
7.8
7.9
6.3
6.2
6.3
Run Time
(min)
50
70
80
40
110
100
to
40 "
100
60
-------
- 24 -
Several experiments were conducted in order to determine sulfate
formation during Mg(OH)2 scrubbing. These results are compared with
similar CaS03 scrubbing data in Table 14.
TABLE 14
SULFATE FORMATION IN MR (OH) 2 SLURRIES
bMg(OH)2 CMg(OH)2
Wt. % S04= ( t = o min) 0.005 0.019 0.0079 0.16
Wt. % S04= (t = 100 min) 0.181 0.230 0.202 0.51*
0.176 0.211 0.194 0.35*
millimoles of S04= formed 18.6 22.2 20.5 37
millimoles of N02 absorbed 5.2 4.9 8.7 2
millimoles of S02 absorbed 31 30 31 4.5
* 70 minutes on line.
a Contained 15g Mg(OH)2 per liter; S02 absorption was 2400 ppm;
absorption was 400 ppm out of 700 ppm input.
b Same as above except that the S02 absorption was 2300 ppm; N02
absorption was 380 out of 640 ppm input.
c Same as in footnote 'a' except that the N02 absorption was 670 ppm
out of 670 ppm input and the flue gas contained no oxygen.
d Contained 8g CaS03 per liter; S02 absorption was 500 ppm and the N02
absorption was 220 ppm out of 340 ppm.
Of the several absorbents, the CaS03 formed the most sulfate. Absorbent
rc' which scrubbed an 02-free flue gas, formed as much sulfate as the
other Mg(OH)2 slurries did in the presence of 3% oxygen. However 'c1
absorbed almost twice as much N02 so that the number of sulfates formed
per unit N02 absorbed is lower than the other two. The data show that
2/3 of the S02 absorbed by the magnesia absorbents is converted to sulfate,
2.3.3 Miscellaneous Scrubbing Experiments
This section contains a variety of scrubbing experiments that
did not fit into the discussions above. Table 15 presents the results.
-------
- 25 -
TABLE 15
Exp. // Absorbent
2-2-72 Hydroquinone (1. g/1)
3-24-72 FeCl3-6H20 (5. g/1)
3-24-72 3% H202
3-24-72 KMn04 (4 g/1)
4-13-72 1.88m Na2S
5-15-72 2.1m Na2S
5-3-72 3.8m Urea
5-3-72 3.8m Urea
5-3-72 3.8m Urea
N0x-S02 SCRUBBING
Input
NO
0
490
490
475
0
0
480
490
325
N02
360
0
0
0
650
370
0
0
400
ppm
S02
0
0
0
0
2250
0
0
2150
2160
% Absorption
NO
(gen)a
2
4
63
(gen)c
(gen)d
3.1
0
7.7
N02
47
—
, .b
(gen)
100
100
—
—
37
S02
—
—
95
—
70
70
Solution
Temp. (°F)
124
122
85
80
131
125
122
122
122
Run Time
(min)
70
100
40
30
80
60
10
20
15
5-2-72
5-9-72
0.47m Urea
in 40% HN03
1000 g of 10% Urea
sol'n + 360ml 6N H2S04
475
520
42
(gen)
135
125
75
30
a Absorption of 170 ppm N02 generated 180 ppm NO.
b Generated approximately 30 ppm N02.
c Generated 35 ppm NO.
d Generated 23 ppm NO.
e Absorbed 200 ppm NO and generated 360 ppm N02. If NO reacted with HN03 to produce
N02 [NO + 2HN03 -* 3N02 + H20], 600 ppm N02 should have been generated. We have other
data, however, to indicate that urea in HN03 absorbs approximately 45% of input N02
with negligible production of NO. This indicates that we should expel roughly 325 ppm
N02-into the effluent. This is reasonably close to what we observed.
A solution of HQ was observed to reduce N02 to NO almost
quantitatively. The only scrubber that was found capable of successfully
absorbing NO alone contained 4 grams of potassium permanganate. The
solution gradually changed color from deep purple to deep brown. This
appears to be due to the formation of lower oxides of manganese. A slurry
of Mn02 was found to have no effect upon NO absorption. The same was
true for a sodium arsenate solution (Na2HAs04).
-------
- 26 -
Sodium sulfide solutions were excellent N0£ absorbents but
generated a small amount of NO. The sulfide appears to become oxidized
to sulfur which forms polysulfide ion in the presence of excess sulfide.
A small amount of spent absorbent was acidified with HC1 which destroyed
the polysulfide ion and produced a milky precipitate of colloidal sulfur.
When S02 was absorbed by Na2S solutions, some I^S was generated. An
attempt was made to analyze the spent solution for nitrate and nitrite
levels but spectral interference by species in solution precluded this
approach.
Several experiments were conducted with urea under a variety
of conditions, however, none showed any promise.
-------
- 27 -
REFERENCES
2-1 Wetters, J.H., and Uglum, K.L., Anal. Chem., 42: 335-340, 1970,
-------
- 28 -
3. CONCLUSIONS AND RECOMMENDATIONS
3.1 Conclusions
A comprehensive screening program was instituted in order to
evaluate the capability of various aqueous systems to scrub NOX from the
flue gases emitted by stationary power plants fired with fossil fuels.
The conclusions of this study are listed as follows:
(1) NO and N02 present in the flue gas but no S02
(a) Slurries and solutions of calcium, magnesium, and zinc
hydroxide are very inefficient.
(b) Strong acid (H2SO^) and strong base (NaOH) are poor NOX
absorbents-
(c) Concentrated amines (ammonia and 2-aminoethanol) are efficient
NOX absorbents but they have excessive vapor pressures (28 wt '/
NH/OH) and may form exotic products such as alkyl nitrites and
nitrates, and nitro and nitroso compounds which are difficult
to regenerate and could not be introduced safely into the
environment .
(d) Potassium premanganate solutions are excellent absorbents of
NO even in the absence of N02« However, regeneration of the
spent solution appears to be a formidable obstacle.
(e) Sulfite solutions and slurries are excellent N0£ but poor NO
absorbents. The soluble sulfites are more effective N02
absorbents than the insoluble slurries because of the higher
sulfite levels attained in solution.
(f) In general, NOo recycle and addition to flue gas to achieve
equimolar NO/N02 is not attractive. While the presence of
N02 does increase the absorption of NO, the magnitude of the
increase is insufficient for developing a viable process.
(2) N02 and SO,, present in the flue gas but no
NO
(a) Calcium, magnesium and zinc hydroxides are effective N02 and
S02 absorbents . The sulfite formed when S02 is absorbed is
vital to N02 scrubbing.
(b) Limestone is an effective N02/S02 absorber.
(c) Sulfite solutions and slurries are efficient N02~S02 absorbers.
(d) N0» scrubbing is enhanced by removing oxygen from the flue gas
or by adding an anti-oxidant such as hydroquinone to the scrubb^
-------
- 29 -
(e) A portion of the absorbed SO,., is oxidized to sulfate.
(f) Sulfide solutions are excellent NO- and SO,, absorbers but do
generate a small amount of NO.
(g) Combined NOX - SO scrubbing is possible using any of several
hydroxide or carbonate systems provided NO can be oxidized to
N0£ upstream from the scrubber.
(h) Separate NO- absorption is feasible using the sulfite solution
or slurry produced in the S0_ scrubber.
Several scrubbing systems appear promising with a high degree of
flexibility available in their application. However, this hypothesis must
be supported by further research aimed at obtaining scale-up information in
addition to spent-solution regeneration data.
3.2 Recommendations for Future Work
Our results clearly indicate the technical feasibility of modifying
any of several aqueous alkaline flue gas desulfurization systems, now being
developed, to incorporate NOX emissions control. These include aqueous
ammonia, limestone, magnesium hydroxide, and sodium hydroxide based systems.
Pilot plant studies are now needed, however, to develop the engineering
data essential for process scale-up. Below are listed critical factors
which need to be defined under process conditions.
• The rates of N02 absorption by different alkaline solutions and
slurries need measuring under pilot plant conditions. The
influence of system parameters, such as temperature and flow
rates, upon the N0_ absorption rates must be determined.
• The effect of scrubber design upon the gas absorption must
be defined.
• The requirements for anti-oxidants must be assessed.
• The product distribution for the absorbed N0x (i.e., NO^- vs
NO^-) must be measured.
• The study of spent-solution regeneration will require a com-
prehensive effort in order to define sorbent make-up require-
ments and the power, fuel and other utility needs.
• The oxidation of NOX to N02 upstream from the scrubber is
vital to the project. Thus, studies should be instituted to
optimize this reaction under flue gas conditions using
catalysts or ozone.
The final goal would be to successfully cquple the NOX oxidation,
scrubbing, and solution regeneration techniques into an integrated process
which cleans flue gas and simultaneously minimizes the effect of scrubbing
products upon the environment.
-------
- 30 -
APPENDIX A
This appendix contains idealized thermodynamic calculations
for the energy required to regenerate certain species found in spent
sorbents .
A.I Electrochemical Reduction of Sulfate to Sulfite
Sulfate is formed during flue gas scrubbing via oxidation of
sulfite by the NOy or 02 present. In order to regenerate sulfite, which
is useful for N02 absorption, from sulfate, the following electrochemical
calculations are informative.
E°
298
40H~ - > 02 + 2H 0 + 4e- -0.40 volts
SOA= + "2° + 2e~ - * 20H" + S03= ~0>94 volts
When these half-cells are summed, we obtain
2SO ~ - * 0 + 2SO ~ -1.33 volts
Since the electrical work required, assuming no overvoltage, is equal to
the Gibbs free energy of the reaction, we have
A G = nFE = 61. kcal per mole of SO,
= 0.071 kwh per mole of SO,
4
If we consider 10 SCF of flue gas from which 400 ppm NO are
scrubbed, we calculate that 32.3 kwh are needed to regenerate the sulfite
Assuming that one SO^" is formed per NOx absorbed. This number represents
an idealized regeneration which may be scaled up or down depending on the
amount of NOX absorbed and the number of sulfates formed per NOX absorbed.
A. 2 Thermal Regeneration of MgO from MgSO,
Since sulfate is formed in NOX-S02 scrubbers using magnesia as the
absorbent, it is of interest to calculate the theoretical energy requirements
for the thermal regeneration of MgO from MgSO, •
MgS04(s) — ^-» MgO(s) + S03(g)
-306 kcal -144 kcal -95 kcal
AH = 67 kcal/mole
If water of hydration is included in the calculation, then an additional
reaction must be considered.
-------
- 31 -
MgS04-6H20(s) —=-> MgS04(s) + 6
-737 kcal -306 kcal -348 kcal
AH' =83 kcal/mole
The total theoretical energy required is 67 kcal per mol of anhydrous
MgS04 and 150 kcal/mole of the hexahydrate. This translates into 0.078
(0.175) kwh per mole of sulfate formed. The numbers in parentheses refer
to the hexahydrate. If we scrub 10^ SCF of flue gas from which 400 ppm
NOV are absorbed and assume the one mole of sulfate is formed per mole of
A
NOX absorbed, we require 35.8 (80.4) kwh for regeneration. If we scrub
10o SCF of flue gas and remove 700 ppm NOX and form 10 moles of sulfate per
mole of NOx absorbed then 626 (1400) kwh are needed for regeneration.
A.3 Thermal Regeneration of MgO from MgSCL
Magnesium sulfite is produced by the absorption of S02 by Mg(OH)2
slurries. Magnesium oxide may be thermally regenerated from the sulfite.
MgS03(s) —*-*> MgO(s) + S02(g)
-241 kcal -144 kcal -71 kcal
AH = 26 kcal/mole
MgS03'6H20(s) > MgS03(s) + 61^0^)
-673 kcal -241 kcal -348 kcal
Regeneration requires 26 (110) kcal per mole of sulfite formed. The numbers
in parentheses refer to the hydrate. This is 0.030 (0.130), kwh per mole
of sulfite. If 3000 ppm S02 are scrubbed from 10^ SCF of flue gas the
theoretical energy required for regeneration of MgO is 103.5 (448) kwh.
-------
- 32 -
APPENDIX B
Herein are contained the experimental results depicted in graphical
form. This style of presentation was chosen because it reflects the form
in which the data was originally recorded. The continuous line presentation
also communicates data trends to the reader more effectively than does the
tabular format. The leters 'BP1 signify that the flue gas by-passed the
scrubber.
Following each graph is a data sheet which gives the flue gas
composition, solution composition, and temperature, pH, etc. At the
bottom of each data sheet is a notation which indicates the sequence of
traps which treated that portion of the scrubber effluent going into the
NO analyzer. For example,
NO: Na2S03 > Dry Ice > NDIR
signifies that part of the scrubbed gas bubbled through a saturated solution
of Na2S03 (to remove residual N02) , then passed through a dry ice cold trap
(to remove water vapor) and finally entered the Beckman Non-Dispersive
Infra-Red (NDIR) nitric oxide analyzer. Some NO was absorbed by the
various traps employed but all were calibrated with known gas compositions
before going on line.
The following listing is an index to the data contained in this
appendix.
INDEX TO SCRUBBING EXPERIMENTS
Input
Run # NO N02 S02 Absorbent Composition Page
11-9-71 X X water
11-10-71 X X water
11-12-71 X X water
11-16-71 X X water
11-17-71 X X water
11-18-71 X X water
11-19-71 XX 5N NaOH
11-22-71 XX 83 wt.% H2S04
12-3-71 XX 79 wt.7» H2SOA
12-5-71a XX 5N NaOH
12-5-71b X X 4.1m(NH4)2S03
12-7-71 X X NaOH(pH=11.5)
12-13-71 X X Mg(OH)2 solution (pH=8.9)
12-15-71 X X Zn(OH)2 solution (pH=»7.5)
12-17-71 X X NaOH(pH=8.9)
12-20-71 X X Ca(OH)2 solution (pH=11.5)
12-21-71 X X sat'd Na2S03 in 5N NaOH
1-3-72 X X sat'd Na2S03
1-10-72 X X NHAHS03 + NH4HS04
1-17-72 XX 6m NaOAc
-------
- 33 -
INDEX TO SCRUBBING EXPERIMENTS (Cont'd)
Input
Run # NO N02 S02 Absorbent Composition Page
1-18-72 X X 8.4m NH4C1
1-19-72 XX 28 wt.7o NH40H
1-19-72 X X Glacial acetic acid
1-19-72 XX 50 wt.% NaOH
1-24-72 XX 8.4m N^OAc
1-25-72 XX 7.m NH40Ac
1-26-72 XX 28 wt.% NH40H
1-27-72 X X 14.8m NaOH
1-28-72 XX 2.3m Na2S03
1-31-72 X X 2.3m Na2S03 + hydroquinone (HQ)
2-1-72 X X Varying Na2S03 + NH4S03
2-2-72 X X Hydroquinone (HQ)
2-3-72 X X 2-aminoethanol (2AE)
2-4-72 XX 2AE + HoO (1:1)
2-4-72 XX 2AE + H20 (1:3)
2-8-72 X X Ca(OH)2 slurry
2-9-72 X X ZnO slurry
2-9-72 X X Mg(OH)2 slurry
2-10-72 X X 1.0m ammonium citrate
2-15-72 XX 2.5m Na2S03 + HQ
2-18-72 XX 2.5m Na2SC>3
3-3-72 XX 1.0m Na2S03 (vary pH)
3-7-72 X X CaS03 slurry (vary pH)
3-8-72 x X 2-aminoethanol
3-10-72 x X S02-N02 interaction in lines
3-13-72 x X CaS03 slurry
3-15-72 x X CaO + CaS03 slurry
3-16-72 x X Ca(OH)2 slurry
3-17-72 x X Ca(OH)2 slurry
3-22-72 x X Mg'(OH)2 slurry
3-24-72 X FeCla, H202, KMnO,
3-30-72 x X MgS03
4-5-72 X X CaS03 slurry
4-7-72 X X Mg(OH)2 slurry
4-7-72 X X Ca(OH)2 slurry
4-10-72 X X Ca(OH)2 slurry
4-10-72 X X ZnO slurry
4-11-72 X X Ca(OH)2 pre-doped with S02
4-13-72 X X 1.88m Na2S
4-14-72 X X CaC03 slurry
4-17-72 X X H20 + CaCl2, MgSOA
4-18-72 X X Mg(OH)2 slurry + HQ
4-24-72 X X 2m NfyHSOs + 0.5m (NH4)2SO-
4-25-72 X X 2m NltyHSOs + 0.5m (NHA)2
4-25-72 XX 30 wt.% H2S04
4-26-72 X X Mg(OH)2 slurry + HQ
4-27-72 x X Mg(OH)2 slurry + HQ
-------
- 34 -
INDEX TO SCRUBBING EXPERIMENTS (Cont'd)
Input
Run # NO N02 S02 Absorbent Composition Pa;
4-28-72 X X CaC03 slurry + HQ
5-1-72 X X Ca(OH)2 slurry + HQ
5-2-72 X Urea in HN03
5-2-72 X X Urea in HN03
5-2-72 X Urea in HN03
5-3-72 X Urea in H20
5-3-72 X X Urea in H20
5-3-72 X X Urea in H20
5-3-72 XXX Urea in H20
5-4-72 XXX Mg(OH)2 slurry
5-5-72 X X Mg(OH)2 slurry + HQ (endurance test)
5-9-72 X Urea in H2S04
5-9-72 X X Urea in H2S04
5-9-72 X Urea in H2S04
5-9-72 X X Urea in H2S04
5-9-72 XXX Urea in H2S04
5-15-72 X 2.1m Na2S
6-22-72 XXX (NH4)2S03, NH4HS03 mixture
-------
- 35 -
B.I EMISSION DATA AND RUN SHEETS
-------
11-9-71
ppm
x 100
CM CM
3 O O
5 a CO
D 5 10 -
1
1 ' ' "
, i . -
1
848-
1
1 '
717-
536-
1
5 5 -
j 2, 4 -
1
} 3 -
! 1 2 -
1 -^
I i
BP
_
0
^ -
^ -»***
.. •»*""
1 1 1
10 20 30
1
BP
*- ~^
-,
2
H
01
U
|— .^
O
....
1
40
0)
•H
-------
- 37 -
NOX SCRUBBING DATA SHEET
DATE: 11-9-71 SCRUB: H2°
OBJECT: Test water trap
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Final pH —
0,
Pot Temp. 130 °F
H00
NO
10
312
7
/o
, PPm
Initial
CO,,
f. ™
NO,,
pH
12
350
•
%
ppm
2
ppm
COMMENT:
(1) Wet ice trap converts *£_ 8% of the N02 to NO
(2) The dryerite converts *s 11% of the
NO: (wet ice, or dry ice, or Dryerite)+NDIR
-------
11-10-71
ppm
x 100
CM esi
3 O O
5 Z w
LO 5 10 _
1 .
1 ' -
: •-
1
} 48 —
1
i '-
i
) 36-
i 1 5
1
^ 24-
i -
> 3
> 12-
L 1 —
lii
BP
. w
*^
• ••
^i^
t
^ -.- — •""""
•^ *~
-14%
) 20 40 60 80
t
5P
**
.-
••^
i -15%
1 1 1 1
100 120
BP
*"*
^•M
-16?
1 1 1
140 160
BP
t*
•••
+5.0%
-18% f
1 1 1 1 1
180 200
BP
^->
— • -VS
I
o.
QE
1
i^— —
I.TJ.
-------
- 39 -
NOX SCRUBBING DATA SHEET
DATE: 11-10-71
SCRUB: H2°
OBJECT: Absorb NOX from flue gas
CONDITIONS:
Pot Temp.
H2°
NO
1500
Scrub volume @ 1666 ml
3100
125
10
400
_ppm
Total Gas Flow @ 3266 cm per minute
Initial pH — Final pH —
C00
12 7,
N0r
350
_ppm
so2
_ppm
COMMENT:
(1) After a slight initial absorption of NO, the water appears to
hydrolyze the N02 and create some NO (^20 ppm out of 390 ppm
N02 or 57o of the N02) . N02 adsorption is relatively constant
14 —» 187o
3N0
NO + 2HNO,
If only hydrolysis occurred,^5% NO generation would correspond
to 15% N02 adsorption.
(2) Solution sample taken at 215 minutes was analyzed by the nitrate
ion electrode. Solution was 0.9 x 10~3 molar nitrite.
NO: Wet Ice Trap
»Whit.
-------
11-12-71
H.O
ppm
x 100
CM (
O 0 0
a ss en
10 5 1
II
.
9 9
1
| 1
8 4 £
1 "
1 1
7 1 7
636
1 '
5 ' 5
i :
424
II
i
3 1 3
2 1 2
1
1 1
1
On n
u u
i
•vj
0 _
•
^^
—
-
_
.
_
-
-
-
-
-
BP
._. -
(
^ ._.— —
^. •*• ™~
^^ ^*
f
t
/
7
f
-20%
1 I 1 1 1 1 1 1
J 20 40 60 80
1
BP
•f m
— -
•~~v.
«<^
X
X
X
Pi
n
a
55
c
•H
O
4-1
CO
f18
1 1 1 1
105 125
+10%^
t
1 1
145 ie
1
BP
*"-*•
c
o
o
PQ
H
M
.
14-1
O
g
_ _
1
|
WHIT
iffijlts
Lot;
T
)5 1(
i
_ U-?J ^.f J3
i i i
i5 185 2(
*- BP
,2
)5
Time ±n Minutes
-------
- 41 -
NOX SCRUBBING DATA SHEET
DATE: 11-12-71 SCRUB: H20 (from 11-10-71)
OBJECT: To compare the NDIR with the Whittaker "NOX BOX"
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 126 °p Initial pH — Final pH —
H20 _ 10 % C02 12
NO varies ppm NQ2 _ 35° _ ppm S02 _ — ppm
COMMENT :
(1) Already had 230 minutes (from 11-10-71) at zero time on chart.
NO: Wet Ice "> NDIR
-------
11-16-71
ppm 1
x 100 1
CN CN
3 O O
5 B CO
10 5 10 -
» i H
848 —
1 ' -
7,7-
1 1 -
636 —
i • •
•:[•
424-
1 • -
3 ' 3 -
! i -
212 —
1 1 -
1,1-
1 ' '
I I \
BP
b—
1
1
\ i i
Q 20
V
BP
«- •>
^•^••1
— —
\
1 I 1 I
45 65
BP
•» *"^^
^m «^ ^B ^
1 1
85
1
AN02 @ 2l 22'5%
ANO @ ^ 9.1%
85 105 125 145 165
I
BP
1 1 I 1
190 210
BP
TUjna in. \ti-nu.te.s
-------
- 43 -
NOX SCRUBBING DATA SHEET
DATE: 11-16-71
SCRUB:
. H20
OBJECT: Absorb NOX and gain experience with system
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 123 °p Initial pH Final pH
H20 10 % C02 12 % 0,
NO
180
ppm
NO,
370
_ppm
"I
S0n
COMMENT:
The scrub generated NO after 10 min. The NO generated (^17 ppm)
is 9.1% of the NO and 4.2% of the N02 .
The reaction is:
3N0
NO + 2HN0
.'. 12. 67* of the N09 adsorption is due to conversion
NO: Wet Ice Trap
NDIR
-------
11-17-71
H,
ppm
x 100
CM CM
O O O
55 a w
10 5 10
I i •
I ill
8 4 8 -
i
636-
5 | 5 -
I ' I
424-
BP
r—
-6.5%
1
Down
in
Flow
3-
I i I
212-
'
1 I 1 -
I ! I
Q Q 0
lii
-18%
i
20
40
60
BP
-3.4%
-21%
80
100 120
BP
Water Meter
Frozefa Open
140
i i i i i i
160 180 200 220
BP
BP
-1.4%
-------
- 45 -
NOX SCRUBBING DATA SHEET
DATE: U-17-71
SCRUB:
. H20
OBJECT: Absorb NOX and gain experience
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 129 °F Initial PH _ Final PH -
H20 _ 10 % C0 W ° 0-
NO _ 348 ppm
2
N09
37°
PP™
J2
SO,
COMMENT:
(1) The water meter was inconsistent and was sticking throughout
the run.
(2) The NO was initially absorbed to & 6-1/2%. This decreased
to 1.4%. The N00 changed from 18% to 23%.
NO: Wet Ice Trap
NDIR
-------
11-18-71
ppm
x 100
IN
O O O
S5 53 Cfl
10 5 1(
i
1
9 i <
i i 1
8 4
I
7 '
/ 1
1 1
6_ .
3 <
1 i
5 1 .
1 '
4 2 '
i
i t
3 '
1 '
2 1
1 ,
1 1
0 0 (
U
IN
) -
m
J -
-
5 _
_
7 -
•
5-
5 -
1
••
1 -
i
L -
) -
*
V
BP
->
™^^ ™
•«•••••••
1
-9 . l%
r~
-18%
i
0
V
BP
(- -»
— -
20
\
•P —•—•""""" "" ""
-19%
1 1 1 1 1 1
20 40 60
V
BP
<- >
_•>—•>
80
\
^- — — — -"""""
-21%
^^^^•••^^••^^••••••V^B
I 1 1 1 1
80 100 120 1
BP
*- ->
. « «•
^^^|BH|H
40 1
l
+6.5%
as a % of
N02, +5.6%
-20%
1 1 1 1 1 1 I 1 1 I
40 160 180 200 220 2'
\
BP
•»-
^•^^
I^^H
+0
1
-------
- 47 -
NOX SCRUBBING DATA SHEET
DATE:
11-18-71
SCRUB:
OBJECT:
Absorb NOX and gain experience
CONDITIONS:
Pot Temp,
Scrub volume @ 1000 ml
126 „„
NO
10
360
_ppm
Initial pH
CO,
Total Gas Flow
12
NO,
330
ppm
3200 cm per minute
Final pH ""
°2
S0r
%
COMMENT:
(1) In the beginning of the run, NO was absorbed to - 9.1%. The
system saturated with NO @ - 80 min. ( 0%) and was producing
6.5% (5.6% as a frac. of N02> at the end of the run.
(2) The initial A N02 was 18%, the final 20%. Of the final A,
16.8% is accounted by 2N02 + H2Q => NO + 2HN03
NO: Wet ice trap -> NDIR
-------
11-19-71
5N NaOH
ppm
x 100
CS CM
O O O
53 53 W5
10 5 10 ~
II'-
gig-
1 1 1 -
8 4 8 ~
1 , ' -
7 | 7 -
Ml-
636-
1 1 • -
5 1 5 -
Ml-
2 4
1 i ' •
31 *5
1 3
Ml-
212-
1 ' -
i1 ! r -
i • *
* i
1 1 1
BP
• ^m ^v •
0
1
-18.5;
-17.55
I
20
1
BP
"
20
-19.4%
-17.5%
40 60
BP
f~ ~~5
^
60
1
-20.6%
T £. t*y
— -10. OA
80 100 12
BP
e — i
^ ^H-^» M
0 12
1
NO drop
is 18.4%
of N02
-22.6%
-19. 7%
1 1 1 1 1
0 140 160 18
1
BP
t
0
Time in Minutes
-------
- 49 -
NOX SCRUBBING DATA SHEET
DATE. 11-19-71 SCRUB. 5N NaOH
NOX Absorption
OBJECT:
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp.
126 °F Initial pH "" Final pH
H20 10 7. C02 12 7. 02 3 7.
NO 338 ppm N02 4QO ppm S02 ppm
COMMENT:
(1) The NO drop is nearly the same as the N02 which indicates that
absorption Is by ^Oj formation.
NO: Wet ice -> NDIR
-------
11-22-71
83 wt %
ppm
x 100
CS CM
O O O
55 55 w
10 5 10 -
1 1 • -
9 1 9 -
I ' 1 -
848-
1 t ' -
7 1 7 ~
1 1 1 -
636-
I 1 ' •
i
5 | 5 ~
III-
I •
424 —
*T «• "
1 1
3 1 3 -
M|-
212 —
1 • -
1
1 . 1 —
III ^
Q 0 0 -
Hi
BP
Off Scale
4
/
•
/
-53%^
I i i
Q 10 20 30
I
NO
@
2000
ppm
BP
20
t
1
18
i
i
16
1
^
14
1
12
i
i
10
—1
1
1
T~l
\J
1
I
6
i
f-
4
1
2
i
1
1
1
i
*H
O
1" CM
O
&
+ T or%
*v 120
i
L.
**fe?*
0
s »—
1
40 5
BP
•*- "^
M-l
O
g
cd
OJ
4J ^~~~>«
«W CO
14-1
o
pm ~0
ST?
"i
•
1
•
H
1 1 f mist in
• LLcell
0 5(
1
^ i
O
_
o
z
*<
+260 ppm
-220 pp" - — — —
i ill i
) 60 70 80 90 K
1
-230 J
t
V^-..+250_
i
)0 110 1
BP
r»
O
u
Cu
m
<4-l
cd
> cs,
^/*z
-------
DATE: 11-22-71
- 51 -
NOX SCRUBBING DATA SHEET
SCRUB: 83wt% H?SOA
OBJECT:
NOX Absorption
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 275 °F Initial pH — _ Final pH —
10 7, C02 _ 12 _ % 02 _ 3 %
N00 _ 390 ppm SO, _ ppm
H20
NO
325
pptn
COMMENT:
(1) The first attempt to run ended in failure. The thermocouple
dissolved causing all sorts of errors. The system was rerun
12-3-71 with temp, control in an aux. oil bath and a glass
thermometer in the t^SO/.
(2) The H2S04 was contaminated with Fe-Ni-Cr from the SS304 of
the thermocouple.
(3) Mist apparently forming in Dupont Cell; cell temperature 65°C.
(4) Data suspect due to (3).
NO: Wet ice -> NDIR
-------
12-3-71
79%
ppm
x 100
£V| 0^
o o o
25 K OT
10 5 10 -
919-
1 ' -
8 4 8 -
1 , ' •
717 —
i | v —
i ' -
636-
1 , ' -
5 1 5 -
1 "
424-
3 ' 3 —
1 '
212 —
1 , ' -
111-
i-i
BP
-1
"^
^"•^^^
I I
o 10 20 :
\
BP
* "*
^•MB
•MM*
>o :
t
"
X) 40 50 60 70 80 90 100 110 1
1 Time in Minutes
BP
1-
...
I^BK^
-
20
1
Ui
KJ
-------
- 53 -
NOX SCRUBBING DATA SHEET
DATE:
OBJECT:
12-3-71
SCRUB: 79wt%
Absorb NOX
CONDITIONS:
Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp.
H00
NO
202 °F
10 %
325
ppm
COMMENT:
Initial pH
CO,
12
Final pH
0
NO,
330
_ppm
2
SO,
_ppm
(1) N02 absorption was small, £"22%, .the same as for water.
(2) NO was essentially unchanged with a max absorption of = 2.5%.
(3) First 30 min N0_ meter unstable.
NO: Dry ice -> NDIR
-------
12-5-71
5N NaOH
ppm
x 100
IS CM
O O O
99 a co
10 5 10 —
1 ' -
1
9 | 9 -
Ml-
848 —
1 ' -
1
717-
. ' i -
636-
1 1 ' -
515-
i ' 1
1 1 -
424 —
1 , -
i
313-
Ml-
212 —
1 i
1 ! ! -
Ml-
\\\
BP
^ mi^^^ m
- ^ 35% -
-"""""
- ^34%
1 I 1
0 10 20 30
V
BP
._.
i
\
\
\
U^_-41%
-35%
1 1 1
40 50 60
BP
— — — — — v
-i
T-i.-nve.
-------
- 55 -
NOX SCRUBBING DATA SHEET
DATE: 12~5-71 SCRUB: 5N NaOH
OBJECT- Sodium Hydroxide comparison to (NH,)2SO_
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 112 °F Initial pH Final pH ~~
H20 10 % C02 ^ % 02 I %
320
NO 274 ppm NO- ppm S02 ppm
COMMENT:
(1) NO & N02 scrubbing was in the 35% area with the NO increasing
to about 41%.
(2) The N02 pullout was 120 ppm out of 340 & the NO 130 ppm out
of 320.
NO: Dry Ice -> NDIR
-------
12-5-71
4.1 Molal (NH4)2S03
ppm
x 100
CM
O O CM
25 Z O
0 5 10 _
1
1 * -
1
1 1 .
1
i 4 8 -
, «
|
1 \ 7 ~
1 1 -
136 —
i
1
1 5 -
1 1 -
+ 24-
1 3
3,3-
' 1
212 —
! * -
' 1
1 1
! 1
BP
-*
1
\
\
\
l.__^£2£_— — -
-100%
BP
—
^ f~~* """"
-—•""""
-100%
p
cd
M
H
HI
O
M
4J
01
0
w
o
4-1
•H
to
__
|i_.
•-
^
a
z
0)
4-1
C
o
4-1
4-1 C
O 0
CM CM
0 0
V—
i i
.J L.
-15%
-100%
BP
t-
,
S
i
0 20 40 60 60 80 100 120 130 150
1 II II
Time in Minutes
-------
- 57 -
NOX SCRUBBING DATA SHEET
DATE: 12~5-71 SCRUB: 4'1 Molal (NH4)2S03
OBJECT: Absorb NOX
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
112
Pot Temp. °F Initial pH — Final pH —
HO 10 7 CO 12 7 0 3 7
0 '•""'O fo ^>n la
328 350 ——
NO ppm N02 ppm S02 ppm
COMMENT:
(1) N02 scrubbing is 100%.
(2) NO absorption starts @ 2.3% & drops 15% over _ 2 hrs.
(3) With N02 turned off, no NO is absorbed.
(4) After 140 minutes on line solution analysis by UV showed 5.2
millimoles of NO-j" and 0.6 millimoles of N02~.
NO: Dry ice trap -> NDIR
-------
12-7-71
11.5 pH NaOH
ppm
x 100
cs co
O O O
2 2 CO
1
1
10 5 10 _
1 I ' '
9 j 9 -
II-
848-
1 . ' -
7 1 7 -
I ' l -
636 —
1 1 ' -
5 1 5 _
1 ' 1 -
424-
1 .
1 ( ' '
313-
1 ' 1
1 1 -
212-
1 , ' -
i i i _
lii
BP
01
i— i
0)
c
) 10 2(
BP
«-*
Sample
^•H
3 2
1
1 1 1
0 30 40 50 6C
1
X
-------
DATE:
12-7-71
- 59 -
NOX SCRUBBING DATA SHEET
SCRUB: NaOH @ 11.5 (3.16 X 10~3 molar)
same as sat'd Ca(OH)2
OBJECT: Compare hydroxide scrubbing at same pH
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 120____°F Initial pH 11*5 Final pH 6.3
7. 0. 3 7.
10 7,
NO
311
ppm
CO,
NO,
COMMENT:
(1) A NO « -10%
A N02 - -79%
12
360
ppm
S0r
_ppm
NO; Wet ice trap -> NDIR
-------
12-13-71
Mg(OH).
ppm
C
r-i
O
§
1
-22%
1
0 10
1
Sampl
BP
/ >
_t
-24%
20 3
Sample
BP
v «.
— — —
Q 3
t
-4.9%
0 40 * 50 6
Tt-4 — A 4-^ >JE-ln4.
Sample
BP
f •%
f
0 6
\
4- A. A
-6%
-26%
0 70 8
I
Sample
BP
.
^
o
c
1
0
I
-------
- 61 -
°ATE: 12-13-71
NOX SCRUBBING DATA SHEET
SCRUB: Sat'd soln. with slight excess of
Mg (OH ) _
OBJECT: NOX Absorption
°NDITIONS : Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
p°t Temp. 122 °F Initial pH 8.9 _ Final pH 7-5
_ _ 10
N°
H2°
C°MMENT :
C0
12
36°
ppm
(1) NO pullout was - 5%
(2) N02 pullout was - 25%
(3) Scrub, turned from cloudy to clear after 10 minutes.
(A) After 80 minutes on line, solution analysis (spectrophotometric)
gave zero nitrate and 0.9 x 10~3 M nitrate.
NO: Sat'd Na2S03 in HOAc -> dry ice -> NDIR
-------
12-15-71
Zn(OH),
ppm
x 100
es CN
O O O
a a en
10 5 10
9 i 9 „
i ' i
848
I
I
3
I
'
i
7
I I
636
I I
424
3 —
I -
212
I '
I ' 1
Q 0 Q
\\\
1
^*B
1
-H
]-
\
BP
.A
^T
— —
I
I
1 i—
a 10
l
BP
-------
- 63 -
NOX SCRUBBING DATA SHEET
DATE: 12-15-71 SCRUB- Sat'd soln- °f Zn(OH>2
OBJECT: Absorb NOX
3
Scrub volume @ 1000 ml Total Gas Flow (3 3200 cm per minute
Pot Temp. 119 °F Initial pH 7.5 Final pH 6'9
H n 10 „,
C02 12 7o 02
NO 397 ... 400
NU ppm N00 ppm
COMMENT:
(1) A NO - 8.3%
A N02 * 29%
(2) After 90 minutes on line, spectrophotometric solution analysis
gave 0.3 x 10~3 M nitrate and 1.4 x 10~3 nitrite.
NO: HOAc • NaS0 -> dry ice ->NDIR
-------
12-17-71
8.9 pH NaOH
ppm
x 100
tN CM
000
10 5 10 —
919 —
l ' 1 -
848
, ' -
717-
i ' 1 -
636-
1 ' -
5 ! 5 _
1 ' 1 -
424
1 ' -
3 I 3
1 ' 1 -
2 1 2 _
1 ' -
i ! i _
i • . -
\ i '
Sampl
BP
|
i 1
0 10 2
Sample
BP
0 2<
— — —
3 30 40 50 60 7<
Sample
BP
•••• ^M-«
,
3 7(
-5.9%__
-24%
) 80 9C
Sample
BP
>
-------
- 65 -
NOX SCRUBBING DATA SHEET
DATE: 12-17-71 SCRUB- NaOH @ PH8-9> same as sat'd Mg(OH>2
OBJECT: Compare hydroxide scrubbing at same pH
°NDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 120 °F Initial pH 8.9 Final pH
H2° 10 % C0 ^f % 0 I 7.
N° 4°4 N02 37° ppm S02 ppm
COMMENT:
(1) A NO = 6%
A N02 = 24%
(2) pH dropped 4 after 70 minutes on line.
(3) After 70 minutes on line, spectrophotometric analysis of
solution gave 0.3 x 10~3 M nitrate and 1.3 x 10-3 M nitrite.
NO: Na2S03 in HOAc -> dry ice trap -> NDIR
-------
12-20-71
Ca(OH).
ppm
x 100
es CM
O 0 O
23 23 W
10 5 10-
1 . •
9 | 9 -
1 ' 1 -
1 4 ? "
7 1 7 ~
636-
1 '
5 ' 5 -
424~
1 • -
1
3 I 3.
1 1 •
2 1 2 ~
1 ' "
i, ! n
1 i •
BP
"*
i«
-39%
1
] 2
BP
< — *
— •
0 2
-7.6%
-27%
0 40 6
BP
D 6
-7.9%
-29%
0 80 100 1
BP
_—-
20 1
-7.8%
-29%
20 140 160 180 200 220 2
BP
•* ^» ••
40 2
-7.7%
-29%
40 260 280 3(
BP
30
AW V V V V V I \
I I
I
tA^BMa. ^ro. •Vt^«wxt.«.«.
-------
- 67 -
NOX SCRUBBING DATA SHEET
DATE:
12-20-71
SCRUB: Sat'd spin. Ca(OH)2
OBJECT: Absorb
NOX
°ITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 121 °F Initial pH H.5 Final pH —
H2°
NO
COMMENT:
10
390
_ppm
NO,
(1) @ 0 + 20 min.
20 + 60
60 +120
120 +240
240 +300
A NO =
12
380
14%
7.6
7.9
7.8
7.7
_ppm
A NO,, =
2
SO,
39%
27
29
29
29
_ppm
(2) During first 100 minutes pH dropped from 11.5 to 7.5
(3) After 300 minutes on line, spectrophotometric solution
analysis gave 0.4 x 10~3 M nitrate and 4.6 x 10~3 M nitrite.
NO: HOAc - Na-SO. -> dry ice trap -> NDIR
-------
12-21-71
Sat'd
in 5N NaOH
ppm
x 100
CN CS
O O O
25 55 c/3
10 5 10 -
1 , ' -
9 1 9 _
1
i 1 -
848-
1
I
717-
1 ' 1 -
636-
1 . ' -
5 1 5 _
i ' 1 -
424-
1
1 1
3 i 3 _
1
1 1 -
2 1 2 _
1 i -
i
1 , 1 _
,' i -
III
BP
*- ->
I
M-l
14-1
O
4-1
a)
0)
f.
4-1
O
O.
-12% ^
M ^mmm ^^ ^m ^
*"*
**-»^^
A A A A "^ ^^ —27%
o o o o
C*l rH i— 1 O f^
r-t i— I iH i— 1 o
m
03
o
o
-100% -100%
D 20 40 60 80 100 120 140 160 180 200 220 24
\
BP
*"
" — oo
1
0
\
TL-ime irv
-------
- 69 -
NOX SCRUBBING DATA SHEET
°ATE: 12-21-71 SCRUB- A saturated soln. of Na2SO in
5N NaOH
OBJECT: Study Scrubbing by Strongly Basic Na~SO
°ITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. Varies °F Initial PH _ Final PH _
12 7, 0 3
357
N0 355 _ ppm S0 _ ppm
(1) At the higher temperature (129° F) the NO removal was
12%; N02 removal was 100%.
(2) A*? the temperature went down, the NO pullout increased
to 27% @ = 80°F.
NO: HOAc • NaS0 -> dry ice ->NDIR
-------
1-3-72
Sat'd
ppm
x 100
CM
-------
- 71 -
NOX SCRUBBING DATA SHEET
DATE :
1-3-72
SCRUB:
Sat'd
(approximately 2.3-> 2.5 molal)
OBJECT: Absorb NOX
NDITIONS: Scrub volume @ 1000 ml Total Gas Flow
p°t Temp. 122 °F Initial pH _ 10
H2° — . _ 10 % C0
NO
COMMENT:
12
3200 cm per minute
Final pH
i
0
340
_ppm
NO,
340
_ppm
J2
SO
7
/o
_ppm
(1) No SO generated.
(2) A NO = 21%
A N02 = 100%
(3) Na2S03 • 7H20 @ 196 gm/100ml (CRC handbook) = - 3.5 molal in
Na2S03 @ 40°C. This is higher than observed.
NO: Na2SO -> dry ice -> NDIR
-------
1-10-72
and
ppm
x 100
eg r-j
O O 0
10 5 10 ~
1 1 ' "
9 ' 9 —
1 ' 1 -
848 —
l
7 | 7 —
1 1 -
636-
1 l -
5 « 5 -
i ' l -
424 —
3 ! 3 -
' ' 1 -
212 —
1 • -
1 ' 1 —
1 ; 1 -
\\V
>
BP
t— -*
(
Off Scale
1 1
1 10 20 3(
\
p
BP
m ^v^v^
) 3(
\
Off Scale
-24Z
1 | 1 I 1
) 40 50 60 70 80 9C
i
BP
"""""" l
^*
K
1
1
t
-------
- 73 -
NOX SCRUBBING DATA SHEET
DATE- 1-10-72 NK
' — SCRUB: ^
3.60 molal NH.HSCU. 1.88 molal NH.HSO,
£J -J-.^
OBJECT.- Nox Absorption
JTIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
p°t Temp. 125 °F Initial pH 2.4 Final pH
H2° — 1Q 'I- C02 ^ % 02 3 %
^•"^ OOQ n
360 ppm N02 ppm S02 ppm
(1) Copies generation of S02 on mixing [HSO^~ + HS03'
804= + H2S03 ^ H20 + S02J.
(2) A N02 = 100%
A NO - 24%
generated S02 > 1000 ppm
N°5 Na2s°3 -> dry ice -> NDIR
-------
1-17-72
6 Molal NaOAc
ppm
x 100
JS
I
V \ \
-------
- 75 -
NOX SCRUBBING DATA SHEET
DATE: 1-17-72 SCRUB: 6 molal NaOAc
OBJECT- Absorb NOX
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 119 °F Initial pH ~~ Final pH —
12 3
_10_% C02 7. 02
o/" r\
N0 340 ppm N02 ppm S02 ppm
COMMENT:
A NO = 18% A N02 = 25%
NO: Dry ice -> NDIR
-------
1-18-72
ppm
X
CM
O
s=
10
1
9
1
8
1
7
1
6
1
5
1
4
1
3
i
2
100
0
5
i
I
1
4
1
1
I
3
1
1
2
1
1
1
o
cfl
10
i
9
1
8
1
7
1
6
i
5
1
4
I
3
1
2
-
_
-
—
-
•
—
-
^™
-
—
«•
—
-
—
BP
-27%
-49%
-40%
BP
50
60
70
80
-------
- 77 -
NOX SCRUBBING DATA SHEET
°ATE: — 1-18-72 SCRUB: 8.4 m NH, Cl
°BJECT: Absorb NOX
°NDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 123 °p Initial PH ~" _ Final pH —
H2° - _ 1° % C0 12 % 0 3 %
N° -- 33° ppm N0 _ 350 ppm S0 _ ppm
(1) A NO « 27%
A NO * 49 -> 40%
NO: Dry ice -> NDIR (= 23% conv. N02 -> NO)
-------
1-19-72
ppm
x 100
CN CM
o o o
S3 5= to
10 5 10 -
1 , • -
9 ] 9 -
1 1 -
848-
1 • -
1
i
1 1 -
1 1
636-
1 ' "
'
C ' C ^"
5 \ b
1 1 -
424-
i i
1 '
i
3 J 3 -
1 1 -
1
212-
BP
» ^" ^»«
1 ' -
i 1
1 ' 1 1
000 1
. \ . I
\
\
\
\
\
^^
^(R*™
^ ^
!^^^^
^ ^
^^-'^^
\ \ I
1 20
BP
•»— —
^•^•^•^
40 4
fa
o
VO
CT\
O
O
M-l
O
O
&
/\
X N
^ \
\
\
-57%
u
o
M
a)
-------
- 79 -
NOX SCRUBBING DATA SHEET
DATE: 1-19-72
SCRUB :
28 wt. % NH^OH
OBJECT:
Ammonia Scrubbing
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 75 °F
—. 10 %
initial pH
Final pH
H2°
NO
COMMENT:
co2
12
1
328
_ppm
330
ppm
2
S0r
_ppm
(1) An H2S04 trap was used to protect the NDIR from NH3 . The trap
was allowed to equilibrate with NO-N02 . On by-pass without
the H2S04, the NDIR read 83, with H?S04, 82 1/2. The N02
was unchanged.
(2) test pullout was @ rm. temp, and was 57% N02 , 74% NO.
(3) At elevated temperature (106°F) NOX absorption was 38% NO,
26% N0.
NH.j boil off is a severe problem.
NO: *See comment (1)* -> H2S04 -> dry ice trap -> NDIR
(- 23% of N02 conv. -> NO)
-------
Glacial HOAc
1-19-72
50% NaOH
ppm
x 100
CM CM
000
s z co
10 5 10 "~
1 , ' -
9 1 9 -
1 ' 1 -
848-
1 , ' -
7 I 7 -
II-
636 —
1 i -
5 j 5 -
1 ' 1 -
4 2 4 —
1 , ' -
o 1 3 —
i ' 1 -
212-
BP
glacial HOAc
*BP
1 ' -1 1 1
i | 1 .
1 I1 "I
000 — T^^
\ * • 1
\\ \ V
| -80%
0 10 2.0
\ \
BP
50 wt.% NaOH
28%
-23%
0 10 20 3C
\
00
o
-------
- 81 -
NOX SCRUBBING DATA SHEET
DATE: _l-19-72 SCRUB- HOAc 8lacial
°BJECT: Absorb NOX
3
Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
p°t Temp. 120 °F Initial pH — Final pH —
H~0 *•" m nr. 12 a/ « 3 o/
2 . /0 COr, /o 0^ L
NO 335 XT^ 370
. _. ppm N00 ppm S09 ppm
C°MMENT :
(1) NO level not effected
N00 = 80%
NO: Dry ice -> NDIR
-------
- 82 -
NOX SCRUBBING DATA SHEET
DATE: 1-19-72 SCRUB: 50 wt' % NaOH
OBJECT: Absorb NOX
CONDITIONS:
Pot Temp.
mo
NO
Scrub volume @ 1000 ml
120 °F Initial pH
10 % co.
345
ppm N00
3
Total Gas Flow @ 3200 cm
F ina 1 pH
12 „
la Vn
330
ppm S0?
P i
per minute
3 %
—
ppm
COMMENT:
(1) A N02 = 23%
A NO = 28%
NO: Dry ice -> NDIR
-------
1-24-72
NH.OAc, 8.4 Molal
ppm
x 100
CM CM 1
D O O
B S W
10 5 10 -
i _
1
, I g _
' 1 -
348-
1 ' -
7 ! 7 -
i 1 -
336-
l
31 C
1 1 -
i 2 4 -
i —
* 1 3 -
' 1 -
2* f*
i "
1
L 1 -
1 -
I
1
/
1
BP
•«- -V
(
1
— _ *— — * ' ""
1 1 1 1 1 1 1
) 20 40 60 8
BP
#- -v
••^^
MBMHI
D 8
1
-31%
-39%
I i I I I I i
0 100 120 140 16
1
/
BP
«
•T^
™ "" "~ ^ "~ 1
a
u
I
0
1
Time in Minutes
-------
- 84 -
DATE:
1-24-72
NOX SCRUBBING DATA SHEET
SCRUB: 8'4 Molal NH4 OAc
OBJECT:
Absorb NOX
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per m
123 —
°F Initial pH rinai nn
3
inute
Pot Temp,
H20
NO
10
362
_ppm
CO,
NO,
12
"I
to
360
_ppm
ptn
COMMENT:
(1) A NO = 31%
A N02 * 39%
NO: H2S04 (sat'd with NO & NO^ *• dry ice
NDIR
-------
1-25-72
CM CN
Z Z OT
10 5 10
7.0 Molal NH OAc, Dual Series Pots
-Jb-vr ^f -*-\S
1 ' "
9 ' 9 —
1
1 -
848 —
1 '
7 ' 7
|
1 -
636 —
1 ' '
5 1 5 -
I ,
1 -
424 —
3 1 3 -
1 I
1 "
919
i
i ! i -
1 i -
0 0 0 «.
1 ,
1 1
1 1
,-H
c
0
j*
c
o
4-1 4-J
PJ O,
4-1 T3
^ C
--? tS
PI 3
s-4 1-1
H
•••^••H
j=
H
-25%
-35%
1
I
-28%
-39%
1
•
CO
ol
~* Tj
4-1 I
O?
PQ 1
D J
r— n
H I
1
0 20 40 40
1 1 1
BP
BP
O 4-1
« M
-82%
•• ^ia» •
-77%
o^J
PU C
^» o
i-J
-<&
CO
i-H
Pn O
PQ CM
PQ
00
Ul
-59%
-56%
60 80 100 120 120
I I
Time in Minutes
140 160
i
180
-------
- 86 -
NOX SCRUBBING DATA SHEET
DATE: 1-25-72
SCRUB: 7.0 Molal NH.OAc Two Baths
OBJECT: Double Bath Run
CONDITIONS:
Pot Temp.
H20
Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per
123
Initial pH
NO
10
12
354
NO
340
PPtn
pro
COMMENT:
(1)
Two pots arranged in series sequence.
(2) From 120 -> 180 min. /i NO * 59%, A N02 * 56%. This is
more than the sum of the parts for each individual bath.
(3) Are probably stripping NH3 from first pot & transferring to ^
second pot to produce a scrub of NH^H + NH^OAc.. This is n ^
possible when each pot is run separately. Thus, the scrubb
are much more efficient in series because of NH^OH scrubber*
which is known to be a good scrub by itself.
(4) Could smell NH3 being stripped from first scrub. No odor
after passing thru
NO:
(sat'd with NO • N0_) > dry ice > NDIR
-------
1-26-72
28% NH^OH and
in Series
ppm 1
x 100 I
CN CM 1
O O O
Z "Z. in
10 5 10 —
1 ' -
? 1 9 —
1 .
1 -
8 4 8 —
*
i ""
1
7 1 7 -
' 1 -
6 3 6 -
.i',:
1 -
4 2 4 -
1
3 | 3-
1 -
212 —
1
1 ' 1
1 1 1
1 1 '
I i
; i
1 BP
— -
ex
CO
M
H
O
f
JJJ
FL,
>"%*>
-12%
ci
•H
O
CO
4J
O
o.
0
af
r\
i
_5
X
CM
*!•
rH
(1)
W
O
w
-74%
-80%
o
§
£
o
cfl
pq
0)
0)
r-
i
*
L-
o
c
i
BP
i
oo
i 1 I I 1
0 10 20 30 40 50 60
i i
Time in Minutes
-------
- 88 -
DATE:
1-26-72
NOX SCRUBBING DATA SHEET
SCRUB- 28 Wt* % NH4OH & H2° dual bath
sequence
OBJECT
Free pickup of NH» in water bath & subsequent scrubbing
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per tnmu
Pot Temp.
70
NO
COMMENT:
10
Initia 1 pH
CO,
12
330
NO,
355
_ppm
(1) To
Gas
Mix
Analyzers
H20
28% NH^OH
Pot "C" (NH40H) warmed from « 70°F ->86°F over = 20 min. &
then cooled down to 65°F.
The water (pot B) went from * 73°F -> 113°F over the run.
The H2S04 (pot A) went from = 73°F -> 83°F
(2) N02 is necessary for NO absorption.
NO: H2S04 -> HOAc • Na2S03 -> dry ice -> NDIR
-------
- 89 -
NOX SCRUBBING DATA SHEET
DATE: 1-26-72 SCRUB: 2-3 Molal Na2S
OBJECT: Absorb NO
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 120 °p Initial PH _ 12 Final pH _
H2° __ 10 % C02 _ 12 % Q2 _ 3 7o
N0 35° ppm N02 35Q ppm S02 ppm
COMMENT :
(1) An attempt to use drierite rather than the Dry Ice trap failed,
the drierite generating NO from N02 & also not stopping all
the H20. The system being fouled, the run was unsatisfactory.
(2) The one definite result is that 100% of the N02 was absorbed.
If any NO was absorbed, it was minor.
-------
1-27-72
14.8 Molal NaOH
ppm
x 100
CM CM
O O O
S Z to
10 5 10 —
9 | 9 —
. 1
1 1 -
848 —
1 i -
7 ! 7 —
i ' 1 -
636 —
1 ' -
I
5 i 5 -
I
1 1 -
424 —
Ii
1
3 ! 3 -
1
1 .
212 —
1 ' -
i -i _
• 1 1
BP
*- -rl
»•«• •
^••••"M
h
O Pu O
o o o
CO O "H
^
I
^ I
-47%
-28%
1 I 1 1 1 1 1
*
BP
[
o
c
<
••M^BBMi
V f
, S* 0* &C
Jt o ^C***
l^ r-\ .
, .-I
I
**^W
**~~ /
^ ---•"* -28
^*r**
-27%
1 1 I 1 1 1 1
BP
i
VO
o
M^MB^H^
\ \ \
0 20 40 60 80 80 100 120 140 160
\ \ \ V
-------
- 91 -
NOX SCRUBBING DATA SHEET
DATE: _1-27-72 SCRUB: 14.8 Molal NaOH (same cone, as
28 wt. % NHAOH)
OBJECT: Comparison of NaOH & NH^OH
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
pot Temp, varies °F Initial pH ~ Final pH -
H_0 10 7 rr\ "I n 7
£. 10 \J\Jn la \Jn la
N0 333 ^ppm NO- 360 ppm S02 ppm
(1) Had to use an open tube on the scrubber because the frit
tended to clog. (Probably with Na-CO )
(2) Temperature rose due to heat liberated upon CO- absorption.
NO: Dry Ice trap -> NDIR (- 25% N02 conv. -> NO in trap)
-------
1-28-72
2.3 Molal Na SO
ppm
x 100
CM CM
BO O
3 en
10 5 10 -
1 ' -
1 I
9 ' 9 -
1 ' 1 -
848 —
1 ' ' 1
717-
i ' 1 -
636 —
1 • -
1 1 -
424 —
1 ' -
1
313 —
1 ' 1 -
212 —
i1 : ; :
1- .1
V \ \
BP
e- — *
....
i
\
\
\
\ -18%
-100%
i i I i I
0 10 20 30 40 50 6
\
BP
*
I
K)
1
0
\
-------
- 93 -
NOX SCRUBBING DATA SHEET
DATE: 1-28-72 SCRUB- Na2S03> 2'3 Molal
OBJECT: Absorb NOX
COITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
pot Temp. 120-125 °F Initial pH _ 10 Final pH - _
3
H2° 10 "L C0 _ 12 % 0 _ %
N° 355 ppm N02 _ 500 ppm S02 _ ppm
COMMENT :
(1) A NO = 18% A N02 = 100%
(2) After 60 minutes on line, solution analysis gave 2.0 millimoles
of N03- and 0.4 millimoles of NO^.
NO: Wet Ice Trap -> NDIR
-------
1-31-72
Na SO , 2.3 Molal and 0.062 Hydroquinone
ppm
x 100
CM CM
0 O 0
65 S3 tfl
10 5 10 -
1 ' -
i
9 ! 9 -
i ' 1 •
848-
1 • ' "
7'7-
i 1 i
1 1 -
636-
1 ' -
1
515-
i ' i -
424-
1 - -
' I
3 1 3 _
i ' I -
212 —
' « ' "
i i i A
\
\ \ -1
\ » *
\ \ \
BP
•*^ •••
,
1
V
-8.8%
-100%
t \
0 10 20 3
V
BP
u-
c
o
J
^ '
0 3
\
a
o
b
ss
~S
\
I
i—
i —
^
*^
"*"*"*-.»., j
\ \ i
0 W 50 60 1(
\
BP
i
VC
j^1
I
i
1
i.-n.
-------
- 95 -
NOX SCRUBBING DATA SHEET
1-31-72 2.3 Molal Na0SO_ with Hydroquinone
. SCRUB: z 3
0.062 Molal
OBJECT;
"ITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
P°t Temn ~\?'\ or, •!-„,•)-,• o i r^u 10 Final pH ~
o, :
'2 PPm
Temp. 123 °F
10 «
- !^_PPm
Initial pH
CO,,
2. ~
NO.
1U
12 %
340 ppm
2
NO
(1) A NO =8.8%
A N02 - 100%
(2) NO not required for N09 absorption.
NO: Dry Ice Trap -> NDIR
-------
2-1-72
Various Levels of S0_ as Na0S00 and NH,HS00
-> 23 43
ppm 1
x 100 1
1
CM CM IBP I
O O O MS&\
ips
10 5 10 ~
1 i ' *
9 | 9 -
, ' ,
1 1 -
848-
1 ' -
7 j 7 -
1 1 H
6 3 6 —
' ' >' i
'' '1
424-
1 , ' '
3 i 3 —
i
. ' i
1 1 -
212-
1 , ' -
111 —
•
1
_
I 1 H
1
•K
i
o
3:
*i
c
i— i
6>S
•^
'
h-
BP
H
-H
S8^
o
O
CO
o
at
IS
^-s
^H
«
r-l
.i.
tM
O
iH
X
ao
\— *
g,
.-1
+
1 gm
I
1 An
Na2S03 1 Bp 1 1 BP
&Nofe,
f"~^ 1 f\
+6.8%
4~
/
/
/
/
/
w
/
/
/
*T-36%
<4-l
H-t
0
CM
O
....
HH^B*
U2
" •
MM
1
,.1,1 — W
• ' — '."-1-
(4-1
M-t
O
•H
rH
•H
4-1
ID
CM
0
10 gm Na2S03
No 0-
2
m
CO M-l
O 0
c/}
CM r
n) o
a a
a N<
o 1 *-~l
* 1 1
+ J 1
1
\ |
\ -35% ^*~'
<4-l
«n C
0 O
i
1
1
14-1
14-1
O
CN f* f
0 0
r? ^
J\ Q
.x^ \
-85% ^S^ \
\
\
' 0
2
""
BP
\f~ WJt&L
C
O
cs
0
x_
/"
r
yr
rc^
CM
BP I 1 BP
*l P
r fl I-.'^-
|| off ii
1 SC^
/
*
...
p*agp
«
o
1
~— •
i
V
0 10 10 20 40 60 60 70 70 80 100 120 140 160170 170180180190200 220
t&VTVvi.te.a
-------
- 97 -
NOX SCRUBBING DATA SHEET
DATE: __2-l-72 SCRUB: Varing levels of S03 = with Na?SO
£~ ~J
& NH,HSO^
't J "
JECT: See effect of concentration and of oxygen
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
pot Temp. 126 °F
H2° 10 7,
N° - 355
COMMENT:
Initial pH
CO,,
2
NO,,
—
12 -
/o
340 pp.
Final pH -
3
SO-
%
ppm
(1) With 1 gm/liter of Na2S03, the initial absorption is * 100%
N02 & 36% NO. This diminishes to « 29% N02 (same as H20)
with 6.8% generated (also same as H20) .
(2) The elimination of 02 from the 1st bath has no effect.
(3) 10 gm per litre of Na2S03 => 85% N02 & 35% NO for = 30 min.
It them starts behaving like the 1 gm bath.
The small level of NH4HS03 behaves similarly except generating
an off scale NO signal.
NO: Dry Ice Trap -> NDIR (= 24% conv. of N02 to NO)
-------
2-2-72
Hydroquinone
ppm |
x 100
CM CM
o o o
2 JS en
10 5 10 —
1 ' -
9 | 9 -
j .
II-
848 —
1 i -
7 ! 7 -
1 ' l]
636-^
1 ' -
i
5 \ 5 -
1
1 1 -
4 2 4 —
', •-
3 3 -
"" 1 *J
I ,
1 1 -
212-
1 ' -
1 1 1 -
1 ' 1 -
\\ \
m
BP
< »
~
;
1000 ml
of H20
6f W
• D/o
f
1 -24%
—
1
BP 0
* 4
0.008 molal
Hydroquinone
f
k
i
— J
l^ t
1
1
1
Ig,
u.
\ 0
\
\ °
\
\
Cf
ta
_i
o S>
o
h^. i
f
T
0
0 20 40 40
V \ \
'
-^
o
0
NO off o
«>. u.
) <,
B
oo
CM
f
I
t
1
1
I
1-
/\0, on
g
g\
ri
i
1
1
BP
l
v£>
00
1
,—
i
E
I'D o
1 4 CM
J s \
\ /^
1 1 \f\ ~~ — — — — — ~
60 80 100 120 140 160 180 200
\
-------
- 99 -
NOX SCRUBBING DATA SHEET
DATE: 2-2-72 SCRUB: Hydroquinone
OBJECT: Effect of anti-oxidant
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 124 °F Initial pH " Final pH ~
H2° _ 10 % C0
2
ppm N00 -J^O ppm S0_ ~ ppm
COMMENT:
(1) H20 blank @ A NO = 6.6%, A N02 24%
(2) On line with HQ & the A N02 = = 39%. The NO signal exceeded
the scale.
(3) With the NO off & the N02 on, 50% of the N02 was converted to
NO with a A N02 of = 50%.
(4) Solution turned red with Na-SO., addition.
NO: Dry Ice Trap -> NDIR
-------
2-3-72
2-Amino Ethanol
ppm
x 100
cs es
O O O
2 2 co
10 5 10
I «
9 9
II-
848
I
7 i 7
I ' I
636
I , '
i''5,
424
I , '
3 ! 3 —
II-
212 —
000
\
\
\
\
1
1
BP
I
n
J
™
^^
•
__
-
o
u
o
2
I
1
MM
-
-
••M
••M
-
i
\
from
129°F
-^ 134°F
^_ _t.
4.
tL
i—
O
0
u
c
u
O
1
a:
iH
6
O
+
--..^
c
O
O
-f-
128°FO
-40% T
1
-91%
1 1 1 1 1
o o
j^op 136^F 1401
f^f""mm~'
---"""'
0
o
' c
MH
li
O
o
1 —
1
I
1
r
i
i
i
i
i
•
i
i
i
i
0
^
o
0
.
"o
•-
M-l
"4-1
O
(
o
z
I
f~- 1
o
i
1 — 1
1
1
1
1
1
1
1
1
1
1
1
1
1 1 1 I 1 \
BP
O
O
1
••••••••••»
1 0 10 20 30 40 50 60 70 80 90 100 110 120 130
in.
-------
- 101 -
NOX SCRUBBING DATA SHEET
SCRUB: 2-Amino Ethanol
°BJECT:
Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
pot Temp. Varies °F Initial pH _ Final pH
H2° - 10 % C0 2
N0 N0 320 pprn SQ ppm
(1) Bath temperature with NOX absorption (NO C02). With C02,
it heated even more rapidly.
(2) The bath developed a mist over it when N02 was run in.
(3) A NO « 40% A N02 ~91%
(4) H2S04 (dilute) trap used to absorb amine vapors before
effluent enters gas analyzers.
(5) Color of bath changed from colorless to orange as run pro-
gressed.
NO: H2S04->Dry Ice—> NDIR
-------
2-4-72
1:1 2-Amlno Ethanol:H 0
ppm
x 100
(SI
tsl O
O O W
52 21
10 5 10 —
1 ' "
919 —
1 ' i -
8 48 —
1 ' -
1
7 ' 7 —
~
6 36 —
1 -
1
515 —
i ' I -
4 24 —
1 • -
1
313 —
1 ' 1 -
2 12-4
' , ' -
1 i 1 — 1
I ' | -
\ \ \
BP
t >
»_««
,
1
I
1
V
P4 pL|
O O
VO O
i — 1 rH (
1 i
<
I
-35%
0 10
\
1
4
^
o
CM 127 F
> I
5 |
I
V- -48%
\ -88%
\
1 \ \ \ \ 1 1 T I I I
20 30 W 50 60 70 80 90 100 110 i
»T«3 A — ^«-l ___«- -_
BP
___ .•
•^•^•i^^*
-20
\
O
N3
-------
- 103 -
NOX SCRUBBING DATA SHEET
DATE: 2-4-72 SCRUB- 1:1» 2"Amino ethanol: H20
Tf} 1 limp T*fl t"1 f) \
OBJECT: Absorb NO
n
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 126 °F Initial pH -- Final pH —
H2° 10 7° C02 ±2 ?° °2 - 7°
NO 340 ppm N02 330 ppm S02 ppm
COMMENT:
(1) With C02 present 35% of NO and 88% of N02 absorbed.
(2) Without C02, 48% NO and 88% N02 absorbed.
(3) Bath heats up from reaction with C02
(4) H2SQ trap removed atnine vapors from gas stream
NO: H2SO, —> Dry ice trap
NDIR
-------
2-4-72
1:3 2-Amino EthanolrH 0
ppm
x 100
csi
-------
- 105 -
NOX SCRUBBING DATA SHEET
DATE:
2-4-72
SCRUB: 1:3. 2-Amino ethanol^ water
(volume ratio)
°BJECT: Absorb NOv
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
p°t Temp. 127 °F Initial pH — Final pH —
H2° — 10 7o C02 12 %
NO
COMMENT:
347 pom
NO
350
ppm
2
SO,
%
ppm
(1) A NO (without C02) ;
A N02 X 86%
48%
(2) The addition of C02 caused bath heating
(3) Takes about 35 minutes to saturate dilute H2S04 trap with
NO and N02, before starting run.
(4) H2S04 used to remove amine vapor before analysis
NO: H2S04
Dry ice
NDIR
-------
2-8-72
Ca(OH) Slurry
ppm
x 100
CS OJ
o o o
10 5 10 —
9 1 9 —
I ' 1 -
8 48 —
7 j 7-
1 ' 1 -
6 36 —
1 . ' -
5 j 5-
II-
4 24 —
1 , ' -
3 1 3 —
1 ' 1 -
2 1 2 —
:.'H
\ V \
BP
i
I
-20%
-21%
iiiiiiili
0 10 20 30 ivO 50 60 70 80 90 1<
\
BP
. — .
30 1
- — ""
i
1 l
00 110 120 1
\
BP
•*"*•• ^
••^•MM^M^
30
\
o
o\
-------
- 107 -
NOX SCRUBBING DATA SHEET
DATE: 2-8-72 SCRUB- Ca(OH)2, 100 gm suspended in
1000 ml H20
JECT: — Slurry scrubbing
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
pot Temp. 124 °F Initial pH -- Final pH —
H2° - 12 7° C°2 12 % 02 2 %
N0 _ 353 ppm N02 365 ppm S02 ppm
COMMENT:
(1) The frit plugged and an open tube had to be used,
(2) A NO ^20% A NO ^ 21%
NO: NaOH-Na2S ^ Dry ice > NDIR
-------
2-9-72
ZnO Slurry
ppm
x 100
CM CO
O O O
!3 Z to
10 5 10—
1 1 ' -
9 1 9 —
1 ' 1 -
8 48-
1 i ' -
7 1 7 —
1 ' 1
i 1
6 36 —
1 1 ' '
'l ' 1 -
4 24 —
, ' -
1 ' 1 -
2 1 2 —
1 • 'i
'•'n
On f\
VJ V)
\ l *
\ \ \
BP
1
\
-7.1%
+*~
-16%
\\\\\\\\\\\\\
0 10 20 30 ivO 50 60 70 SO 90 100 110 120 130
\
BP
i-
c
ex
l
-------
- 109 -
NOX SCRUBBING DATA SHEET
DATE: 2-9-72 SCRUB: ZnO slurry (100 gm/lOOOQ .ml
H20)
OBJECT: Absorb NOv
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 121 °F Initial pH — Final pH —
H2° 10 1 C02 12 % 02 3 %
N0 353 ppm No2 370 PPm S02 ppm
COMMENT:
(1) A NO - 7.1%, A N02 = 16%
NO: Na2S-NaOH > Dry ice ^ NDIR
-------
2-9-72
Mg(OH) Slurry
ppm
x 100
CM CM
0 O 0
S S CO
10 5 10 —
1 . ' -
9 ;, -
' i i
848 —
1 . ' -
7 !7 H
1 J
6 3 6 H
1 ' ' J
5 ! 5 H
1 ' 1 -
424 —
i ,
i
3 I 3 —
I
II-
212 —
1 ' -
1 1
1 1 1 — 1
i 1
1 M
\\\
BP
> — -H
1
— '
1
i
I
-6%
-23%
[
r~ I i i ' i
0 10 20 30 AO 50 6
\
BP
6-
I
I
0
•Sisae.
-------
- Ill -
NOX SCRUBBING DATA SHEET
DATE: 2-9-72 SCRUB: Mg(OH>2 100 gm/liter slurry in
H20
OBJECT: Absorb NCv
°ITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
p°t Temp. 125 °p Initial pH _ — Final pH _ --
H2° — 10 1 C0 12
2
N0 — 330 __ ppm N02 _ 350 ppm S02 ppm
C°MMENT :
(1) A NO^ 60%, A N02 « 23%
NO: Na2S-NaOH > Dry ice ^ NDIR
-------
2-10-72
1.0 Molal Ammonium Citrate
ppm
x 100
CM CM
O O O
JS S5 W
-25%
-26%
BP
I
YO
I
2.O
UO SO 6O 1O EO 9O
\
-------
- 113 -
NOX SCRUBBING DATA SHEET
°ATE: 2-IQ-72 SCRUB: 1.0 Molal fNHA)9HC6H5Q7
(ammonium citrate^
OBJECT: Absorb NOV
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 126 °F Initial pH — Final pH —
H2° — 10 % C02 12 % 02 3 %
N0 358 ppm N02 350 ppm S02 ppm
COMMENT: (1) Pulled out 100% of 470 ppm S02 in run with NO and N02
but seemed to generate NO. 362 into sulfide trap produces
some H2S. Thus Na2S trap was followed by NaOH trap.
NO: Na2S > Dry ice >• NDIR
-------
2-15-72
with no 0 and with Hydroquinone
ppm
x 100
CS CM
o o o
10 5 10 —
' 1 ' "
9 19 —
i ' 1 -
848 —
717 —
1 ' 1 J
' 1
636
*-* -J \J ^^^^
1 • -I
5 ''5 "I
i • i 4
124—1
1 ' -
3 \3 -
1 ' 1 -
212 —
1 1 -
y , • 1
BP
«- •>
"1
1
^mmmm^^m
,
I
2.5 molal Na2SO
!
-16%
-100% 1
I'll!
0 10 20 30 40 50 6
\
fe!**
U-
0
I
2.5 molal Na SO.
in .06 molal TIQ3
-8.3%
- - -
-100% 1
l 1 1 I 1 1
0 10 20 30 40 50 6
\
fcP
i
M
K
i
3
\
-------
- 115 -
NOX SCRUBBING DATA SHEET
DATE: 2-15-72 SCRUB: 2.5 molal Na2S03 (without and
with hydroquinone)
OBJECT: Npx scrubbing with no 02 present and observe the effect of
hydroquinone addition
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 127 °F Initial pH 10 Final pH
H2° 10 % C02 12 7, 02 0 %
NO 358 ppm N0? 350 ppm SO^ ppm
COMMENT:
(1) The HQ lowered the efficiency of NO adsorption from 16%
to 8.3%,
(2) After 60 minutes on line (before HQ added) solution analysis
gave 4.2 millimoles of NO- and 1.1 tnillimoles of N02-
NO: Na S ^ Dry ice > NDIR
-------
2-18-72
ppm
x 100
CM CM
0 O 0
E3 S3 OT
10 5 10 —
1 , ' -
9 1 9 —
l ' 1 -
848 —
1 • ' -
7 ! 7 —
1 1 -
636 —
1 . -
l
5*5 —
1 ' 'J
424 —
I i
' 1
1 1 -
212 —
1 , ' -
1 i * H
i i J
\ \ \
1 BP
,
V
-6%
-100%
iiiiiiilliiii
O 10 20 30 M> 50 6O 70 8O 9O 100 110 120 130 1
BP
<*0
t
TA-m& -Vix 'Wixwxt&a
-------
- 117 -
NOX SCRUBBING DATA SHEET
DATE: 2-18-72 SCRUB: 2-5mNa2S°3
OBJECT: Study sulfite scrubbing with 02 In flue gas
o
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 127 °F Initial pH Final pH
H20 10 % C02 12 % 02 3 %
NO 350 ppm N02 350 ppm S02 ppm
COMMENT:
(1) A N02 = 100%, NO = 6%.
(2) NO & N02 meters not operating properly, sticking and
pulsing; results questionable.
NO: Na2S > Dry ice ^ NDIR
-------
3-3-72
Vary pH
ppm
x 100
CM CM
O 0 0
£5 ri ^
10 5 10 —
i , • -
9 I 9 —
Ml-
848 —
I . - '
717 —
I ' 1 -
636 —
1 , . -
515 —
i ' 1 -
1 1 • -
3 j 3 —
1 1 -
212 —
II ' -
111 —
\ ' \ -
000 —
9
1
BP
t- -}
._.._.
i !
1
4 —
1000 ml
1 molal
Na2S°3
6 8.0
• '
-15%
-- — ——————
,
T^T^^I^T™
12
'
BP
f- -i
1
\
P
1000 ml
1 molal
Na2S°3
5 8.0
1 »
.— — m M.v«Ml
1 1 1 I
1 V
7
\
BP
(. -)
1
1
5
»
-nr
BP
00
I
\
20
20
40
Ti.ttie
-------
- 119 -
NOX SCRUBBING DATA SHEET
DATE: __J-3-72 SCRUB: 1.0m Na2SQ3
OBJECT: Study effect of changing pH
ITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
p°t Temp. 124 °F Initial pH see chart Final PH
H2° 10 7. C02 12 % 02 3 %
. 355 ppm N02 400 ppm S02 ppm
(1) The NO readings were very noisy
(2) The pH made no difference in N0£ adsorption
(3) The NO absorption changed very slightly, decreasing with
decreasing pH.
The pH was increased with NaOH and decreased with HC1..
': Na2S trap—^ D :y ice trap ^ NDIR
-------
3-7-72
CaSO , Vary pH
ppm
x 100
t
\ 1
\ *
\ I
^ •
\ i
Y i
\ i
\ .
\ »
N I
\ |
\ •
\ ;
\ /
/"
20 40 60
1
BP
I- -3
»._
0
8 gm CaSO
@ pH 8
i i i i
20 40
1
BP
e ->
... _
0
8 gm CaSO
@ pH 7.2 J
1 i 1 1
20 40
1
BP
(.
_ ___
1
H
K.
C
1
Time In Minutes
-------
- 121 -
NOX SCRUBBING DATA SHEET
DATE: 3-7-72 SCRUB: CaSQ-j slurry; 8g/l
OBJECT: Observe effect of pH upon scrubbing
CONDITIONS:
Pot Temp.
NO
Scrub volume
125 op
10 %
490 ppm
• Dry ice
NDIR
-------
3-8-72
2-Amino Ethanol
CM
O
10
1
9
1
8
1
7
1
6
1
1
4
1
3
1
2
I
1
1
1
ppm
x 100
CM
0 0
& W
5 30 —
i _
1
1 27 —
1 1 -
4 24 —
1 ' -
! 21-
' 1 -
3 18 —
1 ' -
2 12 —
) ' ~
! 9 -
i -
16 —
1 ' -
] 3 —
1 -
, •
! 1
BP
*" "*
m^»^m*
••^^^^^H
C
o o o o
O O O CD
•••»
.-!
^
»•••*
0 20
1
|
1
1
t
.
0 220 240 260 280 300
' (Continued)
Time in Hlnutes
-------
ppm
x 100
o o cT1
SS S5 CO
10 5 30 ~
1 I -
1
9 ; 27 —
1 ' 1 -
8 4 24 ~~
1 i —
1 1
i
7 | 21 —
i 1 -
6 3 18 —
i i
1 *
5 \ 15 ~
1 ' |
4 2 12
1 i
1
i
3 ' 9 —
1 ' 1
216 —
1 f '
1 ! 3 —
i
1 ' i
1 : !
3-8-72
pot @ 126 -> 127°F for all of run
M-l
tt)
0)
i-H
OJ
£
B -47%
ft
•o
0)
1
•rl
4J
a
o
0
~ ' -89%
liiiiiiii iiiiiiiii
300 320 340 360 380 400 420 440 460 4*
BP
*~
**" •"•"•
i
ro
1
^^^^^^^^
iO
1
-------
- 124 -
DATE: 3-8-72
NOX SCRUBBING DATA SHEET
SCRUB: 2-Amino ethanol, 2570 by volume
in H20
OBJECT: Determine nitrogen content of solution before and after run,
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 130 °F Initial pH NA Final pH NA
HO 10 "/ CO 12 7
lLf*\J w /O \j\Jf\ /ft
NO 368 Ppm N00 370 ppm
2
SO,
NA
ppm
COMMENT:
(1) The scrubbing of NOX was fairly good in the beginning but
became worse with time. This was probably due to the heating
of the pot by an exothermic reaction of the amine with the
flue gas (prob. C02 plus amine). When the bath cooled
down, the scrubbing improved somewhat.
(2) The scrub turned progressively yellow with time and was
orange after 8 hours of running.
(3) Measurement of total nitrogen content before and after run
(in order to determine gain or loss of nitrogen) was
inconclusive.
NO:
Dry ice
NDIR
-------
- 125 -
NOX SCRUBBING DATA SHEET
DATE:
3-10-72
SCRUB
. S02 - N02 interaction in the lines
OBJECT
Observe reaction of pure S02 with N02 (5%) in the lines
CONDITIONS:
Pot Temp.
H^O
NO
Scrub volume
NA °F
0 %
0 ppm
@ 1000 ml Tota
Initial pH
CO,,
Wn varies
1 Gas Flow
NA
0 %
ppm
@ 3200 cm3
Final pH
o.
S00 var
per minute
0 7.
ies Dom
COMMENT:
(1) With pure S02 functioning with 5% N02 in the mix lines,
60 ppm of N02 is converted to NO, with a loss of
15 to 30 ppm of S02. Neither the temperature of the
blending meter (varied from 90 to 350°F) nor the
temperature of the analysis lines (75 to 150°F) made a
difference.
(2) The problem does not occur if the N02 of S02 are
sufficiently dilute before mixing.
-------
3-13-72
CaSO,
ppm
x 100
is p>t
o o o
K !Z W
10 5 30 —
I '
i
9 ' 27 —
i ' 1 -
8 4 24 —
1 i -
7 ' 21 —
• ' 1 -
6 3 18 —
1 • • -
I
5 1 15 —
1 1 -
4 2 12 —
1 , ' '
i
319 —
i ' 1 -
216 —
1 . ' -
113 —
i ' i -
1 ! !
1 ! 1
BP
£-. v
t* ^^
7.
1
^•M • m
C
6 5.3 5.
V
ii •• ' — * ^^^™ ^ i^^^*
I i i i i i i
) 20 40 60
1
BP
^ ^^
• ^T
)
MM^^H
^^m^^t
pH
T
_S •*-^>i
^*^f ^" %*^.
^^^ * ^
^^^ 1
\ ->'
i i i i i i i i i i i i i i i i
80 100 120 140 160 180 200 220 24
BP
fc^
c^
i
H
K>
1
•HM^H^^
0
t
Time in Kinutes
-------
- 127 -
NOX SCRUBBING DATA SHEET
DATE: 3-13-72 SCRUB: _CaS03 (8 gm per litre of H20)
OBJECT* CaC03 scrubbing with NOg solids SC>2 only
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °F Initial pH 7.6 Final pH
H20 10 % C02 12_% 02 3 %
NO NA ppm N02 330 ppm S02 500 ppm
COMMENT:
(1) The N02> in the beginning, was removed quite efficiently.
As the pH dropped, and the S02 broke through, the N02
scrubbing became worse.
NO: Na2S03 ^Dry ice—> NDIR
-------
3-15-72
CaO Plus CaSO- Doped with SC>2
ppm
x 100
JS|
O O
8 &
10 5
I ,
1 !
8 4
1
1
7 1
1 '
6 3
1
i
5 I
1
4 2
1 ,
3 :
i
2 1
1 ,
1 !
i
0 0
li
CM
O
w
10—
i •
9 —
i -
6 —
1 -
7 —
i •
6 —
i -
5 —
i
1 '
4 —
i
3 —
1
1 -
2 —
1
I
1 '
i
I
BP
^ *^
'
C
(
pH
3 y 50 ^ y 4.
5.7
^
5.5
^m
..
0
1 u
1
+
1
1 _
[ -71% .-
7 ... — .--
1 — — • *--" " *--> "
) 20 40 60 80 100 120 140 160 180 200 220
rr* J-_r-. 4 -A >Jt-4 -r>»i4- ^o
•
O
4.
^^4*
7
2t
BP
M^
1
H
N.
OC
1
tO
1
-------
DATE:
- 129 -
NOX SCRUBBING DATA SHEET
3-15-72
SCRUB-
- 31 ^ °f Ca° plus 8 ^ CaS03 in
litre of water plus S02J pH 6.4
OBJECT: NOy scrubbing with CaO doped with CaSQ-3.
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 126 °F Initial pH 6.4 Final pH 4.7
H20 10 7. CO,
NO --
12 7.
ppm
N0
380
ppm
°2
SO,,
3
_520 ppm
COMMENT":
(1) N02 was absorbed fairly constantly @ a level of 71%.
(2) The S02 dropped to zero and came up steadily with time
and decreasing pH.
NO: Na2S03 > Dry ice
NDIR
-------
3-16-72
Ca(OH).
ppm
X
C**J
0 0
ss 2
10 5
\ ,
i
9 1
1
8 4
1
1
7 i
1
6 3
i ,
i
5 i
I
4 2
1
3 !
1
2 1
1
i
1 »
I i
1
0 0
li
100
CN
o
in
•10-
1 -
27
1 -
£4
1 -
r -
^3—
i -
,15"""
1 -
A2~"
1 -
,9 ~
1 -
6
i
3 ~~
1
1 "
i
I
1
1
BP
pH
L.4 7.2 6.7 6.6 6.5 5ml 4.2
' ^F ^P ^P ^r ^P ^^
*
11.33 5.7 4.7 4.
T^_ ^B 1
T ^ 1
11.1
^P
10.5
7.7
i^^
w
,
/
*
'
/
'
/
/
-70% /
X^ /
X
_.-X
IIIIIIII Illl
^.i.
••^••^•B
1
1—
u
1
0 10 20 30 40 50 60 70 80 90 100 110 120 130
1 1
Time In Minutes
-------
- 131 -
NOX SCRUBBING DATA SHEET
DATE: 3-16-72 SCRUB: Ca(OH)2 [10 gm per litre of
OBJECT: Absorb N02-S02
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 125 °F Initial pH 11.4 Final pH 4.1
1Q % C02 12
NO NA _ ppm N02 _ 710 _ ppm S02 2400
COMMENT :
(1) After the initial pH drop, the N02 was absorbed to =86%.
When the pH went under 6 ^ 6.5, the N02 absorption dropped
to 70%. VV
(2) Initially, the S02 absorption was 100%. At = pH 5.7 it
started to drop and declined steeply below a pH of 4.7.
NO: Na2S03 > Dry Ice ^ NDIR
-------
3-17-72
Ca(OH) with an Open Tube
ppm
x 100
300
s is en
10 5 30 —
} 1 27 —
1 .
1 -
3 4 24 —
1 | -
7 1 21 —
1 ,
1 -
; i i Q
, i -
5 1 15 —
1 \ -
i 2 12 —
} i 9 —
1 •
1 -
» 1 6 —
i
L | 3 —
1 •
(«•
i i
11
i
BP
,2 6.
i
1
9.4
Ll.l
V
7.0
I I I i
0 10 20 30 40 5(
>
t
BP
t >
^_^
) 51
PH
6.
1
^ ^
^r^
1 1 1 1 1 1
)
p
!
H-
Nl
1
h.
3 60 70 80 90 100 110 120
1
Time in Hinutes
-------
- 133 -
NOX SCRUBBING DATA SHEET
DATE: 3-17-72 SCRUB: Ca(OH)? TIP em per litre nf
OBJECT: Observe effect of S02 upon N02 scrubbing.
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 132 °F Initial PH 11.2 Final PH 6.0
H2° 10 % C02 12 7. 02 3 %
NO NA ppm N02 740 ppm S02 ___800_____ppm
COMMENT:
The presence of S02 significantly improved N02 absorption.
NO: N32S03 » Dry Ice > NDIR
-------
3-22-72
Mg(OH) ; 7.4 gm per litre = 10 gin Ca(OH>2
M
o
10
1
9
1
8
1
7
1
6
I
1
5
1
4
1
1
3
•J
I
2
1
1
1
1
I
ppm
X
0
z
5
i
1
4
,
1
1
3
1
1
1
2
1
1
1
t
i
100
1
7 V T
8.5
T
57.8% pullout
100% pullout
Illlllll l|
0 10 20 30 40 50 60 70 80 90 100 1]
pH
P
eP->
MIH^^^M
1
H
<*
-P
1
.0
1 i
Time in Minutes
-------
- 135 -
NOX SCRUBBING DATA SHEET
DATE: 3-22-72 SCRUB: Mg(OH)2 slurry, 7.4 gm per
of H20
OBJECT: Mg(OH)2 scrubbing as compared to Ca(OH)? with NO-? - SO?
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 126 °F Initial pH 8.7 Final pH 7.3
H20 10 7. C02 12 % o 3 7.
NO NA PPm N0 830 ppm S0 2460
COMMENT:
(1) Absorbed 480 ppm N02 for the entire run. Pullout
is 57.8%.
(2) Solution analyses gave 6.1 millimoles of N03~ and 2.0
mlllimoles of N02~ after 110 minutes.
NO: Na2S03 —> Dry Ice > NDIR
-------
3-24-72
Oxidation in situ of NO
ppm
x 100
2.0 5
I
1.8
1.6 4
I
CM
o 2
CO
30-
I -
27-
I -
24—
•
I
1.4 i 21—
l '
1.2 3
t
1.0 «
I '
.8 2
I
i
I
I -
18-
I
I '
15—
12—
9 —
•
I -
6 —
.2 [
I
0 0
3 —
I i i
5 gm FeCl '6
in 1000 ml H
@ 122°F
0
1
20
T 1 l I I
140 160 180 200 220 240
I
Time in Minutes
-------
- 137 -
NOX SCRUBBING DATA SHEET
DATE: 3-24-72 SCRUB: Water with additions
OBJECT: To absorb NO
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 122 °F Initial pH Final pH
H..O 10 _% C00 12 % 0^ 3 f
NO 485 PPm N02 0 ppm SO., NA PDm
COMMENT:
(1) FeCl3 is not effective. Neither is plain 3% H202.
(2) 30% H202 does work, but not well. The addition of FeCl3,
catalyzes the system well.
(3) The KMn04 proved best.
NO: Na2S03—> Dry Ice—> NDIR
-------
3-30-72
MgSO,
ppm
x 100
CNl £M
3 0 O
a a to
LO 5 30
• i
) ' 27 —
1 i -
J 4 24 —
, i -
' ! 2.1-
> 3 18 —
, i -
i 15~
i -
2 12 — -
. i -
i 9 ~~
i -
16 —
i
i 1 "
! 3 "~"
1 i
1 -
I i
! 1
BP ^
«- — »
t
*'5
-f
)
1
5.3
6.3
pH
u>
00
10
Time in Minutes
-------
- 139 -
NOX SCRUBBING DATA SHEET
DATE: 3-30-72 SCRUB: MgS03 (5 gm/1000 ml
OBJECT: N02 - S02 Absorption
o
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 126 °F Initial pH 9.4 Final PH 3.75
H0 10 7. C02 _ 12 _ % 02
2
NO _ NA ppm N02 690 _ ppm S02 2610 DDm
COMMENT :
(1) N02 dropped quickly to zero and then increased steadily.
NO: Na2S03 —^ Dry Ice —» NDIR
-------
4-3, 4-5-72
CaSC>3 Long Term and Vary pH
ppm
x 100
es
O
I
o
w
1°'
30
( r
T -
4 2,4"
, I
I f\ i ~""
6 3
I
I
18*
15'
I
I
4 2 }2
' , I
- I ~ —
•2 X ^
1 > I
c _
1 i
Q Q Q
I '
BP
7.6
7.4
T
Q
I
20
40
60
BP
E- -»
75
I
i r
95
115 135 180
I I
Time in Minutes
300 320
-------
- 141 -
NOX SCRUBBING DATA SHEET
DATE: 4-5"-72 SCRUB: CaS03 (25 gm per litre of water)
OBJECT: N02 - S02 absorption
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 126 °F Initial pH 9.1 Final PH 7.25
H00 10 % CO, 12 % 00 3 7
2 i. — 2
NO NA PPm N02 86° ppm SO,, 1890 PDm
COMMENT:
(1) The N02 and S02 were absorbed to the level of 100%.
NO: Na2S03 —> Dry Ice —> NDIR
Page 1 of 3
-------
- 142 -
NOX SCRUBBING DATA SHEET
DATE: 4-5-72
SCRUB: Bath from page 1
OBJECT: Continue CaS03 scrubbing
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. _125__°F Initial pH 7.5 Final pH 3.5
NO
10
12
0
ppm
N0
710
ppm
S0
183
ppm
COMMENT:
(1) When pH went below * 7.2, the N02 level increased quickly
and settled down to = 46% absorption.
(2) After passing - pH 6.1, the pH dropped very quickly to
3.5, reducing the N0£ scrubbing to = 34% and generating
an off scale "NO" reading..
Page 2 of 3
-------
- 143 -
NOX SCRUBBING DATA SHEET
DATE: 4-5-72 SCRUB: Bath from Page 2 with 2 qm of
MgS03 added
OBJECT: pH variation with H2S04 (* 10%) and NaOH (= 10%)
CONDITIONS: Scrub
Pot Temp. 126
H^O 10
NO 0
vo lume
7,
_ppm
@ 1000 ml
Initial pH
C0rt
N0«
Total Gas Flow
6.1
12 70
700 ppm
@ 3200
Final
so9
3
cm per
PH
3
2250
minute
PPm
COMMENT:
{!) After going on line, the pH quickly dropped with the N02
appearing to head back to the level recorded on page 2.
(2) At - pH 4.4, "NO" broke through to an off-scale reading.
Turning the N02 off did not effect it. Turning the SOo'
off immediately brought the "NO" down.
(3) With the S02 and N02 off, a decrease in pH (with H?SO,)
causes the "NO" to again rise; increase pH with NaOH
again removes the NO.
Page 3 of 3
-------
4-7-72
Comparison of Mg(OH) and Ca(OH)
ppm
x 100
i I I fV4 lri I
4s
I
-------
- 145 -
NDY SCRUBBING DATA SHEET
DATE. 4-7-72 SCRUB: Mg(OH)2 and Ca(OH)2
Mg(OH)2 @ 14 gm/1
OBJECT: N02 - S®2 Absorption
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp,
126 °F Initial pH 9.35 Final pH 7.6
H o 10 % C02 12 % 02 3 %
NO NA ppm N02 680 ppm S02 2610__ppm
COMMENT:
•3
(1) At 2610 ppm S02 and a total flow of 3200 cm /min, we would
need 706 min of 100% absorption to yield 803" level of
25 gm of MgS03<
NO: Na2S03—> Dry Ice—^ NDIR
Page 1 of 4
-------
- 146 -
NOX SCRUBBING DATA SHEET
DATE: 4-7-72 SCRUB: Mg(OH)2 from Page 1 acidified to
pH 7 from 7.6 with H2S04
OBJECT: N02 - S02 Absorption
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 126 °F Initial pH 7.0 Final pH see chart
H20 10 % C02 12 % 02 3 %
NO NA ppm NO, 630 ppm S09 2460 ppm
COMMENT:
(1) Large volumes of gas were liberated with the addition
of the H2S04. The pH dropped rapidly and then came
back up slowly.
Page 2 of 4
-------
- 147 -
NOX SCRUBBING DATA SHEET
DATE: 4-7-72 SCRUB: Mg(OH)2 from Page 2 + more
Mg(OH)2 + pH 8.35
OBJECT: s crabbing NO
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 126 °F Initial pH 8.35 Final pH
HO 10 % C00 12 % 0 3
2 z 2 ./°
NO 37° ppm NO, ^ ppm S0_ 2460
J2 —tZ2iL__PPni
COMMENT:
(1) No NO was absorbed.
Page 3 of 4
-------
- 148 -
NOX SCRUBBING DATA SHEET
DATE: 4-7-72 SCRUB: Ca(OH)2 [17.8 gm Ca(OH)2 per
1000 ml H20]
OBJECT: Comparision of Ca and Mg systems
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °F Initial pH 11.2 _ Final pH 6.4
H20 _ 10 % C02 _ 12 _ % 02 _ 3 _ %
NO . NA _ ppm NO _ 680____ppm SO. 2460 ppm
COMMENT :
(1) With oxygen present, the Ca(OH)_ appears to be more efficient.
Page 4 of. 4
-------
4-10-72
Ca(OH),
ppm
x 100
CN CS
000
fa V5 W
10 5 30-
I , M
9 j J
I ' I 4
8 4 24'
I i
7 ! 21-
• ' i
6 3 18—|
I I
.':r
4 2 12
I , i
3 ' ,9
I ' i
216
1 , i
1 | 3
I ' i
Q Q Q
i i
BP
pH
V
BP
k—>
6.5
7.0
6.4
V
U-l
m
o
ts
o
30%
0
I
I I I I I I I
20 40 60 80 100 120 140 160 180
Time in Minutes
-------
- 150 -
NOX SCRUBBING DATA SHEET
DATE:
4-10-72
SCRUB: Ca(OH)? slurry (15 gm per litre
of H20)
OBJECT: Ca(OH)2 vs. ZnO
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow
Pot Temp. 126 °F Initial pH 11.2
NO
10
12
70
NA
ppm
N0
700
_ppm
3200 cm per minute
Final pH 6.5
°2
SO,
7=
2490
_ppm
COMMENT:
(1) After the pH dropped below 7, the N02 absorption was 63%.
(2) Without 02, absorption - 90% and later at pH of 6.4,
with 02 back on, the absorption was -69%.
(3) The S02 absorption was 100%.
NO: Na2S03
Dry Ice
NDIR
-------
4-10-72
ZnO
PH
T
-49%
BP
°2
on
BP
V
i
M
Ul
M
I
-63%
40
50
60 70 80 90
Time in Minutes
100
100
I
i
110
120
130
I
-------
- 152 -
NOX SCRUBBING DATA SHEET
DATE:
4-10-72
SCRUB: ZnO slurry (10 gm per litre water)
OBJECT: Ca(OH)2 vs. ZnO
CONDITIONS:
Pot Temp.
Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
126
NO
10
NA
_ppm
Initial pH 9.3
CO,
NO,
12
700
ppm
Final pH 6.2
°2 3
SO,,
2520 ppm
COMMENT:
(1) N02 pullout was initially =63%.
(2) This dropped to 49% with lower pH (6.2),
(3) With the 02 off, 68% of N02 absorbed.
(4) Back on with C>2, 63% N02 absorbed.
(5) S0» absorption was always 100%.
NO: Na2S03
-> dry ice
NDIR
-------
4-11-72
Ca(OH).
ppm
x 100
CN CS
D O O
3 Z W
0 5 30 —
*
, 1 -
\ | 27 —
1 i -
J 4 24 _
. i "
7 ' 21 —
| ,
1 -
6 3 18 —
1
, 1 -
5 1 15 —
i "
4 2 12 —
, i -
3 j 9 —
' 1
1 *
216 —
1
, 1 -
1 1 3 _
1 ,
1 '
Q Q 0 —
i i
! 1
6
BP 5
M ^
^ 4
— -_
mmmmmm
V
1 4.9 4.6 4
T ^ i
no
°2
§
o
^^•^
• ••
r~ . -«-^*
******
-^— ***
^ **^"~
I 1 i >• i i i i i i i i I i I I ~i
0 20 40 60 80 100 120 140 160 1
1
PH
5
-
BP
t- ->
(
H
U
u
1
0
Time in Minutes
-------
- 154 -
NOX SCRUBBING DATA SHEET
DATE: 4-11-72 SCRUB: Ca(OH)2 slurry pre-doped with SO?;
15 gm/1000 ml H20
OBJECT: To test Ca(OH)2 lower pH and high S03=
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 124 °F Initial pH 6.1 Final pH 4.5
H20 !Q 7. C02 12 % 02 3 %
NO NA ppm N02 670 ppm S02 2400 ppm
COMMENT:
(1) The slurry of Ca(OH>2 (15 gm/1000 ml H20) was stirred, and
through it bubbled an S02-N2 mixture until the pH was
between 6 and 7.
(2) M>2 scrubbing was on a par with former runs. The S02
broke through early and rose steadily.
NO: Na2S03—> Dry Ice—*- NDIR
-------
ppm
x 100
CS CN
O O O
a z w
10 5 30 —
1
1,1-
9 1 27 —
, 1 •
1 1 '
8 4 24 —
' , i -
7 1 21
i > i
1
1 1
6 3 18 —
i , i -
5i 15 —
i > <
1 1 -
4 2 12 —
' , i -
3«9 —
I *
1 1
216 —
I
1 t 1 -
1 ! 3 —
• .
' ' i -
1 i i
n
BP
f- — »
(
-J-J-" Na_S
2
pH = 9.32
+35 ppm
=95T -100Z *
1 1 I If |^ 1
) 10 20 30 40 50 60 70 80
1 1
BP
pH = 9.0
— -
1
t-
Lr
i
Time in Minutes
-------
- 156 -
NOX SCRUBBING DATA SHEET
DATE: 4-13-72 SCRUB: 1.88 molal Na2S
OBJECT: NC-2-S02 Absorption
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 131 °F Initial pH 9.32 Final pH 9.Q
H2° 8"10 % C02 _ 12 _ % 02 3 _ %
NO 0 _ ppm NO _ 650 _ ppm SO, 2250 ppm
COMMENT :
(1) The S02 absorption was 95% and for N02 was 100%.
Also generated 35 ppm NO.
(2) Also generated H0S.
NO: Na2S03 > Dry Ice —> NDIR
-------
CaC03 (10 g/1)
4-14-72
CaC03 (4 g/1)
ppm
x 100
20 40 60 80
Time in Minutes
• i i r i I i
160 180 200 220
(Continued)
-------
CaCO (Continued)
ppm
x 100
o o o
S S5 M
10 5 30 —
' • i -
9 ! 27 —
| •
I -
8 4 24 —
t
.
7 ' 21 —
1 i -
6 3 18—
,
, 1 -
5 | 15 —
1 i -
4 2 12 —
3 j 9 -
i -
216 —
. i -
i1 \~-
! 1
* i
i i
Off Scale
f Y
i
1 i
i i
! i
/ i
_ *
i i
L'j /~~"
1 ' ' •
i i /
t /
,' ' :
i i'
/fM/
i i;
i
-' /\
t
(
i
200 ?20 240 260 280 300
I Time in Minutes
-------
- 159 -
NOX SCRUBBING DATA SHEET
DATE- 4-13-72 SCRUB: CaC03> 10 gm in 1000 ml H20
4-14-72 ~
OBJECT: Calcium Carbonate Scrubbing
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 128 °F Initial pH 7.5 Final pH 6.2
_10 % C02 12 % Q2
NO NA ppm N07 650 ppm S0 2280
COMMENT:
The flow slowly degraded during the run (frit was
clogged) and the results are therefore inconclusive. The
run was continued on 4-14-72 after being run for 50 minutes.
NO: Na2SOo—>• Dry Ice => NDIR
Page 1 of 3
-------
- 160 -
NOX SCRUBBING DATA SHEET
DATE: 4-14-72 SCRUB: CaC03 from 4-13-72
OBJECT: CaC03 Scrubbing
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 128 °p Initial pH >7 Final pH 6.2
H20 10 % C02 12 % 02 3 7.
NO NA ppm N02 650 Ppm S02 2280 ppm
COMMENT:
(1) Scrubbing of N02 improved when 02 was removed from flue gas.
Page 2 of 3
-------
- 161 -
NOX SCRUBBING DATA SHEET
DATE. 4-14-72 SCRUB: CaCOs, 4 gm in 1000 ml H20
OBJECT: N02-S02 Absorption
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 128 °F Initial pH 7.2 Final pH 3.1
HO 10 % C00 12 % 00 3 7
*^ O ^^_'° y .— .. —i—•. .—— .•.. .11 • i i .1 . — o __^^_^^__^___^_ . a |B /o
NA ppm N0 65° ppm S0 2280
NO ppm N02 _ ppm S02 PDm
COMMENT:
(1) The addition of 40 rag (=3.3 x 10~ moles) of CaS03 at
60 min had no effect.
(2) At 80 min, the addition of 40 mg Na2S03 had a momentary
effect of reducing N02 by 10 ppm.
(3) The elimination of 02 caused a decline in the N02 level
that slowly rose again as the pH dropped.1
(4) At a very low pH (- 3.1) the S02 broke through to about
the bypass value and then started dropping off again. At
the same time, a surge of NO was generated.
Page 3 of 3
-------
4-17-72
H_0 with Plus Product Salts
ppm
x 100
280 300
320 340 360
Time in Minutes
-------
- 163 -
NOX SCRUBBING DATA SHEET
DATE:
4-17-72
SCRUB: 1000 ml H20 with salts added at
time intervals
OBJECT
. To check the scrubbing of water and various product salts
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
122 °F Initial pH 6.7 Final pH
% 0
Pot Temp.
H20
NO
10
7«
ppm
CO,
NO,,
12
650
_ppm
'2
S0r
2400
7
to
_ppm
COMMENT:
(1) N02 pullout, with or without 02 but with S02 is * 42%.
(2) S02 pullout with or without 02 and with or without CaCl2
is « 13%.
(3) The CaCl2 does not seem to effect the N02 pullout.
(4) Without S02, the N02 level slowly rises, though not very
much (- 40 ppm in 40 min).
(5) Without 02 and with MgS04; S02 pullout is -23%, and N02
- 46%.
(6) With 02 on and with MgS04, S02 level decreases to zero
(100%) and the N02 seems unchanged.
(7) At an absorption of 280 ppm N02 (1st 10 min) and 3200 c
of gas, using 4N02 + 2H20 •> 2HN03 + 2HN02 the theoretical
pH is 3.44, (3.5 was measured) assuming total ionization.
NO: Na2S03
Dry Ice
NDIR
-------
4-18-72
Mg(OH),
SEE
ex ex ex
ex ex ex
o o o
o o o
j-j _- j _j
XXX
O P O
2; !s OT
10 5 30 —
'.I-
i i
i
9 i 27 —
I '
1 1 -
8 4 24 —
1 '
, 1 "
7 1 1 21 —
1 1 1
1
6 3 18 —
i
1 , 1 -
5 1 15 —
i 1 •
1 I -
4 2 12 —
| i
' , 1 -
319 —
i ' i -
i
216 —
f
1 1 -
1 1 '
f 'i~
1 |
II
i 1
B
p
L_!
IM
I
9
•M
N02 + S02
w/o 02
o
1 bath
4
8.1 7.
V
I 1 1 1
NO
w/
BP
1
"• ~"
>
r
""
+ so
°2 2
o
2 bath
8.
6 8.5
' M
8^ 8^3
_ —
1 1 1
SO
on
in
ba
,BP ft
^MM
y
2°
h
.0
1 1
0 100 200 275 0 50 100 0 20 40
B
P
r\
1 bath
cont'd
w/ all
gases
T
••i
2
<— 4
BP
' •
8.
t
(
H
H
II
1
i i P
19-72 *
r
,
••^
1
2° bath cont'd
+ Hydroquinone
?H
7V8
r^
f
1 i M 1 1 1 1 1 1
0 330 100 120 190 300
1 110 1310 1
B
P
f —
7
••M
Time in Minutes
-------
- 165 -
NOX SCRUBBING DATA SHEET
DATE:
4-18-72
SCRUB: Mg(OH)2 slurry 15 gm/1000 cm3
of H20
OBJECT: Observe effect of oxygen
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 124 °F Initial pH 9.4 Final PH 7.9
H2°
NO
10
7
la
NA
_ppm
CO,
NO,
12
670
_ppm
°2
S0r
0
2370
_ppm
COMMENT:
(1) Both the N02 and S02 dropped to zero and remained so
for the 270 minutes of run time.
NO: Na2S03 —=> Dry Ice
NDIR
Calibration filter in S02 analyzer Indicated improper readout,
S07 value in question, is probably much higher.
Page 1 of 5
-------
- 166 -
NOX SCRUBBING DATA SHEET
DATE: 4-18-72 SCRUB: Mg(OH)2 15 gm/1000 cm3 H20
OBJECT:
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. _125__°F Initial pH 9.6 Final pH 8.1
H20 10 % C02 12 % 02 3 %
NO NA _ ppTO N0 640 _ ppm S0 2250 ppm
COMMENT :
(1) N02 dropped rapidly to - 250 ppm and then rose slowly
to 275 ppm.
(2) All the S00 was absorbed.
Page 2 of 5
-------
- 167 -
NOX SCRUBBING DATA SHEET
DATE: 4-18-72
SCRUB: Mg(OH)2> 15 gm/lOQQ cm3 of
OBJECT :
CONDITIONS: Scrub volume @ 1000 ml
Pot Temp. I25 °F Initial pH
H-0 10 % CO,
NO NA ppm NO, NA
Total Gas Flow @ 3200 cm3 per minute
8>0 Final pH 8.0
12 °L Oo 3 7
2. '"
own SO., 2370 ppm
COMMENT:
(1) All the S02 was absorbed.
(2) The bath came back to a pH of 9.3 when allowed to stand
over-night «? 20°C).
Page 3 of 5
-------
DATE:
4-18-72
- 168 -
NOX SCRUBBING DATA SHEET
SCRUB: Mg(OH)2, 15 gm in 1000 ml
H20; both from initial runs
OBJECT:
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °p Initial pH 7.2 Final pH 6.95
37
" L - Z
NO • "•
NA
_ppm
670
ppm
2
S0r
2490
ppm
COMMENT:
(1) pH at 7.2 after 20 minutes at thermal equilibrium and
no gas flow.
Page 4 of 5
-------
- 169 -
NOX SCRUBBING DATA SHEET
DATE: 4-lfr-72 SCRUB: Mg(OH>2
OBJECT: Scrub N0£ - SC-2 in presence of Hydroquinone (1.0 gram)
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °p Initial pH 8.1 Final pH 7.7
H20 1Q _ % C02 _ ~ _ 7° °2 3 _ 7o
NO NA _ ppm N09 _ 650 _ ppm SQ 2280
COMMENT:
(1) Addition of HQ increased N0_ absorption by
= 250 ppm.
Page 5 of 5
-------
4-24-72
2 Molal NH HS03> 0.5 Molal
c
o
10
9
8
7
6
1
1
5
4
3
2
1
0
ppm
x 11
s
o
z
5
1
1
1
4
1
1
3
1
1
1
2
1
1
1
1
1
1
1
0
i
I
1
30
CM
O
OT
30 —
i
1 -
27 —
1
24 —
1
1 -
i
1 "
18 —
1
I -
15 —
I
-
1
12 —
i
I
9 —
1
6 —
i
1 "
•5 « g-—
I mm
[
I
1
PL.
pa
i
•i
—
C
pH
'
i
93
5.85 5.8 5.75
'
+ NH.OH — j> pH 5
\\
\^
...
— —•-~— " ~~ -81%
-94%
— — -j
1 1 1 1 1 1 1 1 1 1 f 1 1 1
) 10 20 30 40 50 60 70 80 90 100 110 120 130 140 15
1
BP
( —
— — -
9
0
1
Time in Minutes
-------
- 171 -
NOX SCRUBBING DATA SHEET
DATE. 4-24-72 SCRUB: 2 molal NH4HS03 with 0.5 molal
(NH4)2S04
OBJECT: Maintain pH of solution.
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 122 °p Initial pH 5.93 Final pH 5.9
HO 10 % C00 12 % 09 3 %
H2u . 2 2
N0 — ppm N02 700 ppm S02 2370 ppm
COMMENT:
(1) The S02/absorption decreased steadily through the run
from 84% initially to 65% at 145 min. The addition of
base (NItyOH) at 145 min, increased pullout to 81% at
pH of 5.9.
(2) N02 pullout was =94%.
(3) It appeared that some NO was made, but within the
sensitivity of the instrument, it is not possible to
say exactly how much. Approximately 5-10 ppm is the
best estimate.
NO: Na2S03 —=> Dry Ice > NDIR
-------
4-25-72
2 Molal NH,HS00. 0.5 Molal (NH.)0SO,
43 424
CM CM
O O O
10 5 30 —
i i i -
9 j 27-
1 1 -
8 4 24~
1 . i -
7 ' 21-
1 i -
6 3 18 —
1 i
1 '
5 1 15-
1 ' i -
4 2 12 —
1 , i -
319 —
' i -
216 —
1 , i -
1 1 3 -
i ' i -
0 0 0 ~~
1 i i
BP
«- ~5
1
^•^^•M
0
1
7 pH
NO @ -100%
so0 e -100%
4 F L
NO @ ^ + 10 ppm
x 150°F UO°F
o
!L
s
1^-
r-
•s.
o
4-1
•
<
^^^^^^^^^^^^^^^^^^ III
5 10 15 20 25 30 3'.
BP
— ^^^—
I
h-
N.
1
i
Time in Minutes
-------
- 173 -
NOX SCRUBBING DATA SHEET
DATE: 4-25-72 SCRUB: 2 molal NlUHSOq + 0.5 molal
OBJECT- Observe effect of increased pH on solution used in run
4-24-72
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 124 °p Initial pH 7.7 Final pH
H20 10 _ % C02 _ 12 _ % 02 3 _ %
NO — ppm N0 _ 680 _ ppm S0 2340 ppm
COMMENT:
ppm N2 _ _ ppm 2
(1) S02 and N02 levels decreased after adding NltyOH;
AS02 and AN02 are 100% with 10 ppm NO generated.
(2) Solution temperature rise due to heat of neutralization.
NO: N32S03 > Dry Ice—>• NDIR
-------
4-25-72
30 Wt.% H0SO.
2 4
ppm
x 100
.5-
1 -
—
__
_
i
^™
~
.5 "
J
BP
Cr -^
(
1
. — . _
1 1 i i 1 1 i i I 1
) 10 20 30 40 50 60 70 80 90 100 i]
1
BP
*~
— —•
LO
Time in Minutes
-------
- 175 -
NOX SCRUBBING DATA SHEET
DATE: 4-25-72 SCRUB: H2S04 30 wt. % in water
OBJECT: NOX scrubbing with H2S04
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 120 °F Initial pH — Final pH —
H20 10 % C02 12 % 02 3 %
NO 350 ppm N00 300 Ppm SO,
_ppm S02 0 ppm
COMMENT:
(1) No NO was absorbed.
(2) Some N02 (- 50 ppm) was absorbed and approximately 18 ppm
of S02 was generated.
NO: Na2S03—^ Dry Ice —*• NDIR
-------
4-26-72
Mg(OH) with Hydroquinone
ppm
x 100
CM CM
O O O
Z Z en
10 5 30 —
1 •
1 1 I -
9 1 27 —
i ' i -
8 4 24 —
1 , i -
7 21 —
I i
1 1 -
6 3 18 —
i . i -
15-
, 1 •
1 1 -
1
4 2 12 —
1'
| -
3 i 9 -
1 ' I
1 1 -
21 £
1 , i -
1 i 3 —
i ' i -
III
9
i
BP
...
•^M
Btt
» V i8 v
8.7 8.1
V V
a-
re
oo
6
VO
?
Leak —
"~\- 1
s^/
1 1
o-
X
£
•
CM
+
/ "
J
O1
a
oo
a
.—i
•
+
O^
g-
oo
e
^
i/*^
o
+
(~\ flow down, NC»2 high
^-^| ^^tirrer stalled re-start
— L/
\s
1 I I I I 1 1 1 1 | 1 | 1 1 1 1 1 1 1 I 1 1 1 I 1 1 1
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300
' Time in Minutes
55
1
e ->
BP
^^"^"™ i
i-
CT
1
-------
- 177 -
NOX SCRUBBING DATA SHEET
DATE: 4-26-72 _ SCRUB: Me (OH) 2 slurrv. 15 gm
H20
OBJECT : Add various amounts of Hydroqulnone
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 122 °p Initial pH 9.38 Final pH 7.55
H20 10 _ % C02 _ 12 _ % 02 3 _ %
NO NA _ ppm N02 705 _ ppm SQ2 2220 ppm
COMMENT :
(1) Final N02 removal was * 70%, SO absorption was 100%.
NO: Na2S03—V Dry Ice > NDIR
-------
Mg(OH)
ppm
x 100
4-27-72
V
Hydroquinone; variation of HQ level and its net effect
PH
7.45
V
S1
01
0)
.-I
o
X
CM
•
r~-
rH
+
o
in
o
20
30
I
40
cr
ffi
00
-------
- 179 -
NOX SCRUBBING DATA SHEET
DATE: 4-27-72 SCRUB: Mg(OH)2 slurry, 3 gm in 1000 ml
of H20
OBJECT: Hydroquinone testing as an anti-oxidant
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 126 °p Initial pH 9.4 Final pH 4.5
H20 10 _ % C02 12 _ % Q2 3 _ %
NO NA _ ppm N02 _ 700 _ ppm SO. 2250 ppm
COMMENT :
(1) The increasing amounts of HQ added had greater effect
and also lasted longer.
NO: NaS0
2S03 — ^ Dry Ice - ^ NDIR
-------
CaC03 with and without CL and HQ
ppm
x 100
Time in Minutes
-------
- 181 -
NOX^SCRUBBING DATA SHEET
DATE: 4-28-72 SCRUB: CaC03 slurry 10 gm in 1000 ml
of H20 (with and without HQ)
OBJECT: Absorb N02-S02
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 124 °F Initial pH ?* Final pH 6.25
H20 10 % C02 12 % 02 3** %
NO NA ppm N02 700 ppm SO 2220 ppm
COMMENT:
* pH electrodes were not working correctly
(calculated pH @ 50°C = 10).
** 02 level was varied from zero to 3%.
(1) N02 scrubbing was better without the 02.
[~ 75% without and 64% with]
(2) The hydroquinone reduced the N02 to the 02 free level.
NO: Na2S03-^. Dry Ice—>-NDIR
-------
5-1-72
Ca(OH) , Vary 0_ and Hydroquinone
ppm
x 100
CM CM
O O O
53 a co
10 5 30 —
i i i -
9 | 27 —
' i -
8 4 24 —
•
1 1 -
1 '
7 | 21 —
i ' i -
6 3 18 —
1 , i •
i i
5 1 15-
1
1 i -
4 2 12 —
1 , i •
3 1 9 —
' i -
216 —
I
1 1 -
1 '
-L * ~J
1 ' '
1 1 -
1 ! '
1 : t
12
BP
«- -»
e
<—_Q
4-1
ff*
3
-H
?
8.2
W
7.9 7.25
T 7.3 *
^_
7,5
if
n
o
r
o
-86% j
20 40 60 80 100 120
TMTno
7.
1
O
EC
E
6
+
-71%
*
S
/
f
140 160
-f r» M-i r»n*-Q c
Pj
! 7.1
T
4-1
O
c-
O
-86%
i I i i i I i i
180 200 220 240
7.
-90%
i I 1 i I
260 280 300
)
t
BP
*- — >
^ ^^ —
I
M
00
to
1
-------
- 183 -
NOX SCRUBBING DATA SHEET
DATE: 5-1-72 SCRUB: Ca(OH)2 [10 gm per litre of water]
OBJECT: Vary 02 and Hydroquinone
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 123 °F Initial pH 12.2 Final pH 7.0
H20 10 % C02 12 % 02 3 %
NO NA ppm N00 700 ppm S00 2265 ppm
COMMENT:
(1) Without 02, absorbs approximately 86% N02, 100% S02;
with 02 - 71% N02 and 100% S02; with 02 and HQ = 86%
N02 and 100% S02.
NO: Na2S03—>- Dry Ice —•>• NDIR
-------
5-2-72
Urea in HNO_
I a t
ex ex ex
ex
N £SI
o o o
a \z> w
o o o
o o o
.
10 5 30 —
I j i -
9 j 27 —
I i -
8 4 24 —
7 21-
I i
6 3 18 —
5
I'
4 2
,
I 15
I
12 -
i
o „»^
•
I -
216 —
I , i -
3 —
I i
000
ri
•
NO only
NO
+
NO,
BP
BP
NO
2 only
i
>->
00
"T
40
T
50
T
60
-T
70
0
I
T
10
Time in Minutes
-------
DATE:
5-2-72
- 185 -
NOX SCRUBBING DATA SHEET
SCRUB: 28.5 gm Urea in 1000 ml 40%
OBJECT: N0x scrubbing with urea (NO only)
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 135 °F Initial PH NA Final pH NA
10 %
NO 475
H20
COMMENT:
CO,
12
7
/o
0
_ppm
NO,
NA
_ppm
2
SO,
NA
_ppm
(1) No absorption = 42%.
(2) Made * 360 ppm N02, equivalent to 75% of input NO,
(3) Frit had tendency to clog.
NO: Na2S03-
Dry Ice > NDIR
Page 1 of 3
-------
DATE: 5-2-72
- 186 -
NOX SCRUBBING DATA SHEET
SCRUB: Urea in HNOi
OBJECT: N0 + N0? Absorption
CONDITIONS:
Pot Temp.
Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
135
10
Initial pH
CO,
NA
12
Final pH
0
NA
NO
322
ppm
NO,
310
ppm
2
SO,
COMMENT:
(1) Used an open tube for 1st 5 minutes.
(2) No absorption without frit = 23%; made 10 ppm
(3) No absorption with frit - 54%; made 50 ppm NO-
NA
ppm
Page 2 of 3
-------
- 187 -
DATE: 5">72
OBJECT:
NOX SCRUBBING DATA SHEET
SCRUB: Urea in HN03
^sorption
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
135 °F Initial pH NA Final pH NA
7. C02 _ J^ _ % 02 3 %
S0
Pot Temp.
NO
COMMENT :
10
NA
ppm
PPm
NA
(1) Absorption of N02 - 47%.
(2) Made - 20 ppm NO.
(3) Tried adding S02 but frit plugged immediately,
ppm
Page 3 of 3
-------
5-3-72
Urea in
i e a
P. IX 0.
p.
CM fsl
O O O
O O O
O O O
rH H rH
LO 5 30 —
1 , i -
J | 27 —
1 i
1 -
3 4 24 —
7 I 21 —
1
1 '
io TO
> 1 15 —
t
1 "
i 2 12
. i "
» ! 9 —
16 —
i
1 1 -
1 3 _
• ' i -
i
! 1
BP
pH
3.
NO
only
35
i
BP
H
3.
9
NO
so2
1
•
/
V
BP
1
1
1
t
1
1
1
1
1
1
"
,
\
NO
N02
,
1
/\
BP
•f
I
I
1
NO
N02
so2
/
0 10 0 10 20 0 10 20 30 0 10
III It 1
Time in Minutes
00
00
-------
- 189 -
NOX SCRUBBING DATA SHEET
DATE: 5-3-72 SCRUB: Urea in H20 [231 gm in 1 litre
H20] 3.85 molal
OBJECT: Absorption of NO
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 122 °F Initial pH 3.85 Final pH 3.9
H20 10 % C02 12 % 02 3 %
NO: Na0SO^ —>• Dry Ice > NDIR
Page 1 of 4
NO 4-80 ppm N02 NA ppm S02 NA ppm
COMMENT:
(1) About 15 ppm of NO absorbed (= 3%).
-------
- 190 -
NOX SCRUBBING DATA SHEET
DATE: 5-3-72 SCRUB: Urea in H?0
OBJECT: Absorption of NO and S02
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 122 °F Initial pH 3.9 Final pH
10 % C02 12
NO 490 ppm N02 NA ppm S02 2154
COMMENT:
(1) Basically no absorption of NO.
(2) S02 level went nearly to zero and rose slowly.
Page 2 of 4
-------
- 191 -
NOX SCRUBBING DATA SHEET
DATE:
5-3-72
SCRUB: Urea in HgO (solution had already
been used for NO-S02 absorption)
OBJECT : Absorption of NO and N02
CONDITIONS: Scrub volume
Pot Temp. 122 °F
H»0 10 %
NO 339 PPm
@ 1000 ml Total Gas Flow (
Initial pH 3.9
CO. 12 %
NO. 390 PPm
3
a 3200 cm per minute
Final pH
0. 3 %
S00 NA PPm
COMMENT :
(1) NO absorption * 11%.
(2) N02 absorption = 36%.
(3) Generated 750 ppm S02 initially, which tappered off
while running.
Page 3 of 4
-------
DATE:
5-3-72
- 192 -
NOX SCRUBBING DATA SHEET
SCRUB: Urea in H20
OBJECT' Absorption of NO, N02 and S02
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 122 Op Initial pH 3.9 Final pH
H20 10 % C02 12 % ' 0, 3 %
NO 323 ppm N09 400 ppm
'2
SO,
2154
_ppm
COMMENT:
(1) No absorption - 7%.
(2) N02 absorption * 38%.
(3) S0_ absorption = 89% initially; decreased with time
Page 4 of A
-------
5-4-72
Mg(OH)2 with NO, N02,
pp
0
o
1-1
X
CN
10
1
9
1
8
1
7
i
6
1
5
4
1
3
1
2
I
1
i
o
m
0
o
»H
X
o
5
,
t
I
4
1
1
3
i
1
1
2
1
1
t
1
i
o
i
i
i
(
T
*
2
2
2
1
1
f
1
1
•
1
9
i
6
t
1
3
i
1
o
i
1
^
D
X
CM
o
.n
to —
I
7 —
4 —
-
1 —
8 —
•
5 —
•
2 —
•—
-
—
-
m^^m
*
^^H
BP
9
__. .
— —
—
1
••••••••
0
1
•rtU
pH
^r
Off On
* S02 i
,95 8,
9^0 8^8
\
V \
\
I
1
\
\ i v
\ \
\ 1 \ 1
1 ' ' ' i i i i i i i "™"T^ ~r
10 20 30 ^0 50 60 70 80' 90 100 110 120 130 140 15
Time in Minutes 1
BP
^ _
4
t
^•a
••••
0
vo
U)
-------
DATE: 5-4-72
- 194
NOX SCRUBBING DATA SHEET
SCRUB: 15 gm Mg(OH>2 in 1000 ml of
water (slurry)
OBJECT: NOX-SOX Absorption
CONDITIONS: Scrub volume & 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 122 °p Initial pH 9.95 Final pH 8.4
H20 10 7. C02 12 % 02 3 %
NO 350 ppm N00 340 ppm SO- 2220 ppm
COMMENT:
(1) More N02 was scrubbed then NO as would be expected
(40% NO + 76% N02 absorbed).
(2) As usual for this type of run, all the S02 was
scrubbed.
NO: Na2S03
Dry Ice
NDIR
-------
5-5-72
Mg(OH)2 with Hydroquinone (Endurance Run)
i. B
ex a
ex
o
o o
H O
X
X
«M
O O
10 5
1
9 '
1
1
8 4
' ,
7 i
1
1
6 3
i
5 «
1
4 2
i
3 '
i
2 1
1
i !
1
0 0
i
i
§.
ex
o
o
H
X
fM
O
VI
30 —
i -
27 —
i •
24 -
i -
21 _
1
1 '
18 —
i
1 '
15 —
I
1 '
12 __
1
1 -
9 _
1
1 -
6 _
1
1 -
3 _
1
1 '
0 _
i
1
BP
*"*
3?
—
mmm
•M Hi
0 ]
PH
7.7
7.6
VO
01
10 60 70 80 90 100
I I
140 160 180 200 220
Time in Minutes
320 340 360
380
-------
- 196 -
NOX SCRUBBING DATA SHEET
DATE: 5-5-72 SCRUB: 15 g Mg(OH)2 plus 1.0 g
Hydroquinone
OBJECT: Endurance Run
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 122 °F Initial pH 9.9 Final pH 7.6
H^O 10 % CO,, 12 %
2
NO NA ppm N02 675 ppm SO- 2280 ppm
COMMENT:
(1) N02 dropped to zero initially; it came off zero =* 80 min.
and rose slowly.
(2) The S02 dropped to zero and stayed there for the entire
run.
(3) Solution became more yellow as the run progressed.
NO: Na2S03 —> Dry Ice >NDIR
-------
5-9-72
Urea in H0SO.
2 4
& a
ft, E cL
ex ex
«M ft
O CM
2! 0 0
2 co
0
000
«H O O
X ^ ^
10 5 30 —
*
1 . 1
9 | 27 —
i i
8 A 24 —
i !
1 « 1
7 j 21-
1 i -
6 3 18-
1 , i •
5i 15 —
I •
' 1 '
A 2 12
, i -
3 | 9 _
1
i •
216 —
1 j
1 J 3 _
1 i
1 1 '
i i
BP
^» '
*» ~* "TF
no absorption
NO
only
pH = 1.8
1
I
1
1
1
I
t
i
I
1
BP
r >
NO + NO
BP
1
1
*^^m
JL.
0 10 20 30 0 10 20 30
I 1 I
^m
NO
only
BP
« ^
E
O
LT*
C")
-------
- 198 -
NOX SCRUBBING DATA SHEET
DATE: 5-9-72 SCRUB: Urea in H?SO/f: 1 Kg 10%
urea soln + 30 ml 6N H?S04
OBJECT: To absorb NOX with urea.
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. __125__°F Initial pH 1.8 Final pH Not Taken
H n 10 7 rn 12 '/ o ^ 7
"O '° IjUn *^- /o \Jn -3 I"
COMMENT:
(1) Essentially no absorption of NO.
NO: Na2S03 > Dry Ice >- NDIR
Page 1 of 6
NO 520 ppm N02 NA ppm S02 NA ^ppm
-------
- 199 -
NOX SCRUBBING DATA SHEET
DATE: 5-9-72 SCRUB: Urea in H?S04
OBJECT:
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °F Initial pH _ 1.8 Final pH _
10 _ % C02 _ 12
Page 2 of 6
NO 340 _ ppm N02 330 _ ppm S02 NA _ ppm
COMMENT :
(1) Some absorption of NO, - 15%.
(2) Some N00 absorbed, = 30%.
-------
- 200 -
NOX SCRUBBING DATA SHEET
DATE: 5-9-72 SCRUB: Urea in H2S04
OBJECT:
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °F Initial pH 1.8 Final pH
10 % C02 12
Page 3 of 6
NO NA ppm N02 680 ppm SO,, NA ppm
COMMENT:
(1) N02 absorption - 54%.
-------
- 201 -
NOX SCRUBBING DATA SHEET
DATE: 5-9-72 SCRUB: Urea in H2SC-4
OBJECT:
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm3 per minute
Pot Temp. 125 °F Initial pH 1.8 Final pH
10 % C02 12 7.
NO NA ppm N02 700 ppm SO 2190 ppm
COMMENT:
(1) NO - absorption = 40%.
(2) SO absorption * 21%.
Page 4 of 6
-------
-202 -
NOX SCRUBBING DATA SHEET
DATE: 5-9-72 SCRUB: Urea in H2S04
OBJECT:
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °F Initial pH 1.8 Final pH
H20 10 % C02 12
NO - 350 ppm N02 700 ppm S02 2190 ppm
COMMENT:
(1) N02 absorption ~ 44%.
(2) S02 absorption * 21%.
(3) NO absorption * 18%.
Page 5 of 6
-------
- 203 -
NOX SCRUBBING DATA SHEET
DATE: 5-9-72 SCRUB: Urea in
OBJECT:
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. __H5__°F Initial pH !•* Final pH
10 TL C02 12
NO 466 ppm N02 NA ppm S02 740 ppm
COMMENT:
(1) NO absorption was zero.
(2) S02 absorption * 10%.
(3) Information not on graph.
Page 6 of 6
-------
- 204 -
NOX SCRUBBING DATA SHEET
DATE: 5-15-72 SCRUB: Na2S, 2.1 molal
OBJECT: Sulfide scrubbing, Analyze dissolved NO-,
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 125 °p Initial pH — Final pH —
.10 % C02 12 % 02
NO ™ ppm N02 670 Ppm S02 — ppm
COMMENT:
(1) AN02 - 100%, with 23 ppm NO produced.
(2) Unable to analyze solution because of spectrophotometric
interference.
NO: Na2S03—>> Dry Ice >• NDIR
-------
6-22-72
(NH4)2S03-NH4HS02 Mixture
ppm
x 100
tN CS
o o o
& 'K U)
10 5 30 —
9 1 27 —
' i -
8 4 24 —
1 , i -
7 1 01
i i -
6 3 18 —
1 , i -
1 ' i -
4 2 12 —
1 i -
i
3 • i 9 -
i
1 '
216 —
1 , i •
1 ' 3 —
i
j
000 —
1 1
! 1
BP
f" ~4
.....
•M^M
0
\
pH = 6.3
-22%
^"'
^^^^^^^^^^^^^^^^^^^^^^^H
1 1
10 20 30
1
BP
t- ->
, pH =
—
m^^_
30
1
6.3
f\ / m
-24%
-97%
-JOTT" • — -•
40 50 60
BP
6—
NJ
o
Ul
Time in Minutes
-------
- 206 -
NOX SCRUBBING DATA SHEET
DATE: 6-22-72 SCRUB: NH^HSO^ Mixture
OBJECT: Study Influence of Sulfate
3
CONDITIONS: Scrub volume @ 1000 ml Total Gas Flow @ 3200 cm per minute
Pot Temp. 128 °F Initial pH 6.3 Final pH 6.3
H20 10 7. C02 12 % 02 3 %
NO 450 ppm NO. 500 ppm SO- 2860 ppm
COMMENT:
(1) AN02 was 100%; AS02 was 97%; and ANO was 24% after 1
hour.
(2) Ball sticking in the NO meter caused slight fluctuations
in readings.
(3) Scrubbing solution consisted of 11.2 wt.
14.6 wt. % (NH4)2S03, 16.6 wt. % (NH4)2 S04, and
57.6 wt. % water. Specific gravity was 1.24.
(4) Presence of sulfate had no discern able effect.
NO: Na2S03—^ Dry Ice —^ NDIR
------- |