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Buna
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REMOVAL OF RADIOACTIVE METHYL IOD IDE FROM STEAM-AIR SYSTEMS*
R. D. Ackley, R. E. Adans, and W. E. Browning, Jr.
Reactor Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee

RELEASED FOR ANNOUNCEMENT
IN NUCLEAR SCIENCE ABSTRACTS
*Research sponsored by the U. S. Atomic Energy Commission under contract with the
Union Carbide Corporation.
LEGAL NOTICE
This report was prepared as an account of Government sponsored work. Neither the United
Slates, por the Commission, nor any person acting on behalf of the Commission:
A. Makes any warranty or representation, expressed or implied, with respect to the accu-
racy, completeness, or usefulness of the information contained in this report, or that the use
of any information, apparatus, method, or process disclosed in this report may not Infringe
privately owned righls; or
B. Assumes any liabilities with respect to the use of, or lor damages resulting from the
uso of any information, apparatus, method, or process disclosed in this report.
As used in the above, "person acting on behalf of the Commission" includes any em-
ployee or contrector of the Commission, or employee of such contractor, to the extent that
such employee or contractor of the Commission, or employee of such contractor prepares,
disseminates, or provides access to, any Information pursuant to his employment or contract
with the Commission, or bio employment with such contractor.
ABSTRACT
When fissior.-product iodine is accidentally released into the air of a
containment vessel, a generally small but still significant proportion of the
iodine may occur as methyl iodide. Methyl iodide penetrates the usual charcoal
adsorbers to an unacceptable degree unless the relative humidity is low.
Recently, certain specially impregnated charcoals have been observed to have the
capability of effectively trapping radioactive methyl iodide from air streams of
fairly high relative humidity at temperatures as high as 115°F. In the event of
a nuclear reactor accident, however, the methyl iodide trapping problem may be
complicated by the production of steam with attendant elevation of the air
temperature. The objective of this work was to investigate methyl iodide trapping
by impregnated charcoals under these more severe conditions. Results are reported
for two series of tests. Temperatures and pressures for one series were around
212°F and 14.4 psia, and, for the other series, generally around 280 °F and 60 psia.
Three varieties of impregnated activated charcoal were observed to be useful for
trapping radioactive methyl iodide from flowing steam-air under the more extreme
of these conditions provided the charcoal had not been damaged and provided the
relative humidity was not too high. Two of the three charcoal varieties
(designated BC-727 and MSA 85851) are commercially available and are impregnated
with one or more iodine-containing substances. The other variety was laboratory-
prepared and impregnated with triethylenediamine, a material which had been
reported to be a highly efficient impregnant. In the tests corresponding to 280 °F
and 60 psia, methyl iodide loadings on the charcoal of around 3.5 mg/g and steam-
air velocities in the range 27 to 45 fpm were generally employed. For these
.
conditions and for calculated relative humidity values approaching 80%, a 2-in.
.
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depth of any one of the above three charcoals exhibited ChI removal
efficiencies in excess of 94%. The results confirmed that the deleterious
effect of high relative humidity on radioactive methyl iodide trapping becomes
more pronounced as relative humidity increases. Experimental charcoals with
elemental iodire or potassium iodide as the impregnant appear vseful but were
tested less extensively than the other impregnated charcoals. Brief
consideration was given to some additional information and data that might be
needed in connection with methyl iodide trapping in steam-air systems and a
few areas for possible future investigation were mentioned.
INTRODUCTION
When fission-product iodine is accidentally released into the air of a
containment vessel, the iodine may assume a variety of forms. The most important
of these include elemental iodine vapor, iodine : 2302bed on or occluded in
particles, and a generally small but significant proportion as methyl iodide.
Authorization for nuclear reactor operation may require the installation of
engineered safeguards with the capability of removing practically all of the
radioiodine from air thus contaminated. The problem may be further complicated
by the production of steam and elevation of the air temperature as a result of
the nuclear accident. Elemental iodine is readily trapped from air streams by
activated charcoal, even at relative humidities approaching saturation, and
iodine-laden particles may be removed by high efficiency filters. However,
methyl iodide is not removed effectively from air streams by the more usual types
of charcoal, unless the relative humidity is low, and it is not stopped by the
filters. Consequently, considerable research has been performed in an effort to
obtain a solution to this rather urgent problem. As a result, at least two
successful methods for removal of radioactive methyl iodide from air streams
corresponding to fairly high relative humidities have been developed. The two
methods are very similar in that they both involve the use of specially-impregnated
activated charcoal for trapping the radioactive methyl iodide but differ in that
they involve two very different reaction mechanisms.
One of the methyl iodidega) removal methods was developed as the result of
work at Oak Ridge National Laboratory. This method is based upon isotopic
exchange and utilizes charcoal that, as commercially available, is impregnated
with a form or forms of iodine. The mechanism is indicated to be as follows:
.. CH 1311 + 1271 (on charcoal) - Ch_127.5 + 1321 (on charcoal).
50
That is, when molecules of CH>I enter the charcoal bed, they encounter
non-radioactive
I atoms of a form of iodine affixed to the charcoal surface.
Some of the encounters result in exchange of the two types of iodine atoms.
Thus, the methyl indide which is radioactive when it enters the charcoal tends
to be transformed into non-radioactive methyl iodide which ultimately emerges
downstream of the charcoal while the radioactivity remains behind.
The other method, which utilizes the alkyl halide-organic amine reaction, was
developed by researchers of the United Kingdom Atomic Energy Authority. They
reported that charcoal impregnated with morpholine, piperidine, piperazine, or
4-aminopyridine was effective for removing methyl iodide from air streams at
high relative humidity. More recently, triethylenediamine was reported to be an
especially good impregnant, as judged by its high efficiency for methyl iodide (4)
removal. It also has the advantage of being relatively non-vclatile, having a
boiling point of 1740C.
Both of the radioactive methyl iodide trapping methods have been investigated
rather thorougly for conditions of fairly high relative humidity, a pressure of
one atmosphere, and ambient or only moderately higher temperatures. However,
· "conditions of temperature and pressure considerably higher than these have been
postulated for the atmosphere in a reactor containment vessel following a certain
type of nuclear accident. As a consequence, investigation of radioactive methyl
iodide removal by impregnated activated charcoals has been extended so as to
include tests made under more severe conditions, and the essentials of the results
obtained are reported herein.
These tests may be divided into two series. Some of the more pertinent
conditions that were employed in the first series of tests were: approximately 212°F
and 14.4 psia, and relative humidities, with one exception, within the range
60 to 90%. Analogous conditions for most of the tests of the second series were:
-6-
approximately 280°F and 60 psia, and relative humidities ranging up to 100%.
In addition to methyl iodide, lesser quantities of ethyl and propyl iodides
bave, on occasion, also been observed in conjunction with elemental radioiodine,
but they have not received very much attention. This is because of the small
arounts involved and because removal methods for methyl iodide would gererally
alsu tend to be applicable to the removal of radioactive ethyl and propyl iodides.
DESCRIPTION AND IDENTIFICATION OF THE ACTIVATED CHARCOALS
The following will more fully identify and describe the various activated
charcoals that are concisely designated in subsequent sections of this report.
Activated Charcoal(s)_
MSA 85351
BC-727
Description
This is an impregnated charcoal from Mine Safety
Appliances Company and is the material that was used
in the early tests where radioactive methyl iodide
renoval due to isotopic exchange was observed.
Several different lots, all 8-14 mesh, have been
tested. Except to say that the charcoal is impregnated
with one or more iodine-containing substances, the
nature of the impregnation is not precisely specified
here due to proprietary considerations. A similar
remark is also applicable to the other cormercially
impregnated charcoal.
This charcoal, 8-14 mesh, is from Barnebey-Cheney
and is impregnated with iodine-containing substance
or substances.
This charcoal, unimpregnated and either 6 x 16 or
12 x 30 mesh, is from Pittsburgh Activated Carbon
Company.
A few of these have been prepared and tested. The
method of impregnation consisted of immersing the
base charcoal, which was PCB, in a solution of the
impregnant, stirring, and allowing the solvent to
evaporate. An example of the manner of designation
for a laboratory-prepared impregnated charcoal follows:
5% 12, PCB, 6 x 16, corresponding to percent by
weight and nature of impregnant, base charcoal, and
mesh size, respectively.
PCB
Laboratory-impregnated
Charcoals
-
-
-
-
-7-
RADIOACTIVE METHYL IODIDE REMOVAL TESTS AT TEMPERATURES AROUND 212°F
The way in which each of these tests was conducted is illustra’ced in Fig. 1.
The charcoal in the test beds was pre-equilbrated with respect to moisture
content by passing air at the relative humidity for the test through the charcoal
for a sufficient period of time prior to methyl lodide injection. The three test
beds, all with a diameter of 1 in., were, successively, 1/2, 1/2, and i in. in
depth. Methyl iodide, label.led with CH,1321, was introduced over a period which
was usually 2 hr; its rate of introduction was measured by gas chromatography
with electron-capture detection which is particularly useful for methyl iodide.
After the methyl iodide introduction period, the flow of air (with no deliberate
change in relative humidity) was continued for an additional period, usually 4
hr. The downstream or backup charcoal beds, replaced for each test, contained
both MSA 85851 and PCB charcoal to an extent sufficient to trap quantitatively the
radioactiv methyl iodide penetrating the test beds. Finally, the setup was
disassembled and the amounts of 1)-I radioactivity in the test beds and the down-
stream sections were determined by means of a gamma spectrometer equipped with a
scintillation crystal.
.
The more pertinent of the results obtained are presented in Tables l' and 2.
The data in Table 1 show that MSA 85851 impregnated charcoal effectively traps
radioactive methyl iodide under the conditions employed in the tests. Under dry
conditions (test LIPS-I), very high efficiencies are obtained. Because of the
mechanism involved, isotopic exchange, the efficiencies quoted are for ch, 1341;
but, of course, that is the substance for which retention in the charcoal is
desired. To a first approximation, at least, the percentage removal efficiency
for CH IS 'I should be independent of the specific activity of the inlet methyl
iodide.
-8-
The data in Table 2 show that the laboratory-impregnated charcoals also
exhibited good efficiencies. Again, the lodine-containing charcoals are
effective only for ch, 1311 (not CH 1271). In the case of the triethylenediamine
impregnated charcoal, however, the efficiencies would correspond to overall
methyl iodide removal (i.e., of both ch.271 and ch, 1327).
RADIOACTIVE METHYL IODIDE REMOVAL TESTS AT TEMPERATURES AROUND 280 °F
Testing Procedure and Results
The manner of conducting each of these tests is illustrated in Fig. 2.
While the charcoal in the test beds was not always pre-equilibrated with respect
to moisture content prior to methyl iodide injection, the rate of steam flow was
such that the charcoal would have been equilibrated in a period of time that was
short relative to the time corresponding to methyl iodide injection. The rate of
methyl iodide introduction was obtained from its known concentration in a
supply tank and the flow rate of the air-CHI mixture.
The "dehumidifier"
in Fig. 2 consisted of a water-cooled condenser supplemented by a drying column.
(A similar arrangement regarding dehumidification was used in the 212°F tests.)
Temperatures at various points in the setup were monitored by means of thermo-
couples. As in the 212°F tests, the methyl iodide was labelled with CH,
1311
and the chɛrcoal test beds, with a diameter of approximately 1 in., were,
successively, 1/2, 1/2, and 1 in. in depth. With one unimportant exception, the
backup charcoal beds were prepared with unused MSA 85851 impregnated charcoal.
Times for methyl iodide injection and for subsequent additional steam-air flow
differid slightly from those used in the 212°F tests. After stopping the flows,
the 1371 distribution in the setup, including the condenser and drying column,
was determined as mentioned previously. A selection of the results obtained is
given in Tables 3, 4, and 5.
-9-
Discussion of Results
Comments on the effect of relative humidity and on the calculated relative
humidity values presented in the tables appears to be in order. Relative
humidity is a very important factor in methyl iodide trapping by activated
charcoal since the trapping efficiency decreases with increasing relative
humidity, the effect becoming most pronounced in the higher relative humidity
region. This decrease is associated with the increase in the amount of water
adsorption (with increasing relative humidity), and adscrbed water interferes
with the interaction of methyl iodide and the charcoal to an extent depending
upon the amount of adsorbed water.
Comparison of each pair of values herein for calculated relative humidity and
observed amount of water adsorption with analogous data from available water
adsorption isotherms on activated charcoal indicates rather definitely that these
calculated relative humidities generally tend to understate the actual relative
humidities that were involved. If the actual relative humidities were higher
than those tabulated, these results (in Tables 3, 4, and 5) would tend to cause
the situation regarding methyl indide trapping to appear more unfavorable than
it really is, considering that trapring efficiency decreases with increasing
relative humidity. But, from a nuclear safety standpoint, if there is to be a
bias in the data, the indicated direction of the bias is the one which is the
more desirable.
Considering the results in Tables 3, 4, and 5 as a whole, there does not
appear to be a pronounced difference in methyl iodide trapping capability, under
the conditions pertaining, between the three charcoal types tested. For all
cases where the calculated relative humidities are less than 90%, the corresponding
CH, 1941 removal efficiencies for 2-in. depths of charcoal are 93.0% or higher.
-10-
In the case of this particular value, for test HIPS-8, where the extent of water
adsorption was 90%, the actual relative humidity was probably in excess of 90%,
as based on the aforementioned water adsorption isotherm data. The methyl iodide
J.oadings employed in these tests might be characterized as being relatively high,
especially in the case of HTPS-5 of Table 4.
The air-steam velocity for this
test was also high. However, operating under these two rather extreme conditions,
of methyl iodide loading and of velocity, did not result in greatly impaired
rer.oval efficiencies.
737
As judged from the results herein, from earlier results, and from
unpublished results, the ch!) I trapping capabilities of the three types of
charcoal, MSA 85851, BC-727, and triethylenediamine-impregnated PCB, appear to be
essentially independent of temperature over the range 75 to 290°F. Also, the higher
pressures employed in the HTPS series of tests did not produce any readily
apparent effect. Remarks made earlier, in conjunction with the 212°F tests,
regarding the methyl iodide species trapped by different charcoals are also
applicable to the tests at higher temperatures.
The results of Tables 3, 4, and 5, exclusive of those for test HTPS-5 due
to its conditions making it less comparable, are surmarized in Fig. 3. The
composite curve in the figure depicts the severe loss in CÆI removal
efficiency encountered when the relative humidity approaches 100%.
BRIEF DISCUSSION OF FUTURE INVESTIGATION
If conditions are such that bulk condensation of water occurs, the charcoal
might then be subjected to a washing action which could have serious effects,
especially if the impregnant is susceptible to loss by leaching with water.
For example, the CH, 1321 removal system might provide for recirculation and,
following an accident, the relative humidity of the circulating air might, for
-11-
some reason, fluctuate between 90 and 100%. Intermittently, some Ch.1311
removal might be accomplished, but this process would be less effective 1f the
impregnated charcoal has been damaged.
This leaching effect may have been
involved in those of the HTPS series of tests where the water adsorption values
were in excess of 100% by weight. However, to what extents the lowered CH, 1371
removal efficiencies were due to the possible washing action or were due to
interference from adsorbed water are difficult to delineate. Also, insufficient
information is available concerning the effect of prolonged air-steam flow on
the permanency of the retention, in the charcoal, of the radioactivity originating
' from trapped radioactive methyl iodide. Investigation of these and related
aspects of methyl iodide trapping under air-steam conditions is being initiated.
SUMMARY AND CONCLUSIONS
At least three varieties of impregnated activated charcoal are useful for
trapping radioactive methyl iodide from flowing steam-air over a wide range of
temperature, 75 to 290°F, provided the charcoal has not been damaged and provided
the relative humidity is not too high. Iwo of the three impregnated charcoals
are commercially available and are designated BC-727, supplied by Barnebey-Cheney,
and MŞA 85851, supplied by Mine Safety Appliances Company. The other charcoal,
which was laboratory prepared, was impregnated with triethylenediamine,
Experimental charcoals with elemental iodine or potassium iodide as the impregnant
appear useful at tempe.'atures up to 212°F but were not tested at higher
terperatures. In a series of tests with the pertaining temperatures and pressures
around 280°F and 60 psia, methyl iodide loadings on the charcoal of around
3.5 mg/g and steam-air velocities in the range 27 to 45 f'pm were generally
employed. For these conditions and for calculated relative humidity values
-12-
approaching 80%, a 2-in, depth of any one of the above group of three
charcoals exhibited CH, 1911 removal efficiencies in excess of 94%. The results
confirmed that the deleterious effect of high relative humidity on radioactive
methyl iodide trapping becomes more pronounced as relative humidity increases.
Further investigation of methyl lodide trapping is to include the following
areas: effect of leaching by condensed steam on subsequent ch 1321 removal
performance of impregnated charcoals and effect of prolonged steam-air flow on
retention by impregnated charcoals of trapped 1321, that originates from Ch 1321.
.
-
.
-
.
-13-
References
l.
R. E. Adams, W. E. Browning, Jr., Wim. B. Cottrell, and G. W. Parker, The
Release and Adsorption of Methyl Iodide in the HFIR Maximum Credible
Accident, USAEC Report ORNL-TM-1291, pp. 24-26, 40, Oak Ridge National
Laboratory, October 1, 1965.
R. D. Ackley, R. E. Adams, W. E. Browning, Jr., G. E. Creek, and G. W.
Parker, Retention of Methyl Iodide by Charcoal Under Accident Conditions, in
Muclear Safety Program Semiannual Progress Report for Period Ending December
31, 1965, USAEC Report ORNL-3915, pp. 61-80, Oak Ridge National Laboratory,
March 1966.
D. A. Collins, R. Taylor, and L. R. Taylor, United Kingdom Atomic Energy
Authority; The Removal of Methyl Iodide from Reactor Effluent Gases, in
International Symposium on Fission Product Release and Transport Under
Accident Conditions, Oak Ridge, Apriï 5-7, 1965, USAEC Report CONF-650407
(Vol. 2), pp. 853-868.
R. D. Collins, Trapping Radiciodine (letter), Nucleonics,23: 7 (1965).
4.
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-14-
Figure Captions
·
1.
Simplified Drawing of Setup for Investigation of Removal of Radioactive
2.
Methyl Iodide from Flowing Air-Steam by Impregnated Charcoals at
Temperatures Around 212°F.
Simplified Drawing of Setup for Investigation of Removal of Radioactive
Methyl Iodide from Flowing Air-Steam by Impregnated Charcoals at Temperatures
Around 280°F.
Effect of Relative Humidity on the Removal of Radioactive Methyl Iodide by
Impregnated Charcoals at Temperatures and Pressures Around 280°F and 60 psia.
· HOOD
EXHAUST
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Table 1. Efficiency of MSA 85851 Impregnated Charcoal for Removing Radioactive Methyl Iodide from
Flowing Steam-Air at Temperatures Around 212°F
LIPS-2
LTPS 3
LTPS-4
LTPS-5
13
23
33
221
Te
75
<0.1
39
145
Test Designation
LTPS-1
Charcoal Lot No.
23
Temperature, OF
212
Proportion as Steam, % < 0.1
Calculated Relative
humidity, %
Steam-Air Velocity
(superficial), fpm
Methyl Iodide:
Injection time, hr
Inlet Concentration
in Steam-Air, mg/m3
Amount Injected per
g of Charcoal (a), mg 0.8
Time of Flow After
Stopping Methyl Iodide
Injection (b), hr
4
CH32311 Removal Efficiency,
For bed depth of 1/2 in. 91.67
For bed depth of 1 in. 99.38
For bed depth of 2 in. 99.99
11
0.5
0.5
0.6
0.6
·
50.8
63.6
88.7
99.3
76.8
96.7
99.8
38.7
80.7
99.0
82.7
63.9
86.8
98.6
99.1
a.
b.
Based on 13 g for 2 in. depth of charcoal, i in. in diameter.
For each of these tests, the overall time of steam-air flow after initiation of methyl iodide
injection totaled 6 hr.
Pressure for each test was approximately 14.4 psia.

Table 2. Efficiency of Laboratory-Impregnated Charcoals for Removing Radioactive Methyl Iodide from
Flowing Steam-Air at Temperatures Around 212°F
LTPS-7
5% 12, PCB,
6 x 16
LTPS-8
1% KI, PCB,
12 x 30
LTPS-9.
5% TED®, PCB,
Test Desi ination
Impregnant, charcoal,
mesh size
Temperature, °F
Proportion as Steam, %
Calculated relative humidity, %
Steam-Air Velocity (superficial), fpm
Methyl Iodide:
Injection time, hr
Inlet Concentration in Steam-Air, mg/m?
Amount Injected per g of charcoal (a), mg
Time of Flow after Stopping Methyl Iodide
Injection (b), hr
CHZ-S-I Removal Efficiency, %
For bed depth of 1/2 in.
For bed depth of 1 in.
For bed depth of 2 in.
FOON 588
65.7
89.8
99.0
93.6
72.43
95.35
99.89
98.9
a.
b.
Based on 13 g for 2 in. depth of charcoal, 1 in. in diameter.
For each of these dests, the overall time of steam-air flow after initiation of methyl iodide
injection totaled 6 hr.
Triethylenediamine.
c.
Pressure for each test was approximately 14.4 psia.
279
61
61
នននន ៖
3.2
Table 3. Efficiency of MSA 85851 Impregnated Charcoal for Removing Radioactive Methyl Iodide from
Flowing Steam-Air at Temperatures Around 280°F
Test Designation
HTPS-1
HTPS-2
HTPS-3
Charcoal Lot No.
23
23
23
Temperature, °F
288
284
Pressure of Steam-Air, psia
Proportion as Steam, %
Calculated Relative Humidity, %
85
Steam-Air Velocity (superficial), fpm
Methyl Iodide:
Injection time, hr
Inlet concentration in steam-air,
mg/m3
Amount injected per g of charcoal
(a) mg
3.2
Time of Flow After Stopping Methyl Iodide
Injection (b), hr
3.5
CHz > I Removal Efficiency, %
For Bed depth of 1/2-in.
62.9
49
For Bed depth of l-in.
52
For Bed depth of 2-in.
98.9
97.1
54
Water Adsorption Relative to Dry
Charcoal, % by wt.
> 30
> 51
> 108
Based on 13 g for 2-in. depth of charcoal, 1 in. in diameter.
b. For each of these tests, the overall time of ste am-air flow after initiation of methyl iodide
injection totaled 5 hr.
c. Actual relative humidity was probably 100% (see text for details).
ř
86.5
85.0
88.6
> 41

Table 4. Efficiency of BC-727 Impregnated Charcoal for Removing Radioactive Methyl Iodide from
Flowing Steam-Air at Temperatures Around 280°F
HTPS-5
253
HTPS-7
HTPS-8
HTPS-9
HIPS-6
289
61
288
279
Test Designation
Temperature, °F
Pressure of Steam-Air, psia
Proportion as Steam, %
Calculated Relative Humidity, %
Steam-Air Velocity (superficial), fpm
Methyl Iodide:
Injection time, hr
Inlet concentration in steam-air,
781
42
mg/m3
1.5
70
3.2
3.0
3.5
3.2
3.5
3.6
Amount injected per g of
charcoal (a), mg
Time of Flow After Stopping Methyl
Iodide Injection (b), hr
CHZS I Removal Efficiency, %
For Bed depth of 1/2-in.
For Bed depth of l-in.
For Bed depth of 2-in.
Water Adsorption Relative to Dry
Charcoal, % by wt.
74.2
71.2
93.3
97.9
51
91.6
98.7
. 79.2
89.9
93.0
55.1
71.9
75.0
34
89
109
a.
b.
c.
Based on 13 g for 2-in. depth of charcoal,l in. in diameter.
For each of these tests except HTPS-5, the overall time of steam-air flow after initiation
of methyl iodide injection totaled 5 hr and for HTPS-5, it totaled 4 hr.
Actual relative humidity was probably higher (see text for details).
-
-
-
-
-
-
-
-
Table 5. Efficiency of Triethylenediamine-Inpregnated Charcoal (5% by wt. on PCB, 6 x 16 mesh) for
Removing Radioactive Methyl Iodide from Flowing Steam-Air at Temperatures Around 280°F
HTPS-10
288
HTPS-11
288
HTPS-12
273
61
71
73
Test Designation
Temperature, OF
Pressure of Steam-Air, psia
Proportion as Steam, %
Calculated Relative Humidity, %
Steam-Air Velocity (superficial), fpm
Methyl Iodide:
Injection time, he
Inlet concentration in steam-air, ..
102(c)
mg/m2
75
3.8
3.
ܟ
3.2.
3.2
*
72
Amount injected per g of charcoal
(a), mg
Time of Flow after Stopping Methyl Iodide
Injection (b), hr
CH3 +5 I Removal Efficiency, %
For Bed depth of: 1/2-in.
For Bed depth of l-in.
For Bed depth of 2-in.
Water Adsorption Relative to Dry
Charcoal, % by wt.
58.2
85.3
40.0
71.5
94.7
ܟܢ ܢܘ
98.2
17
22
119
a.
b.
Based on 13 g for 2-in. depth of charcoal, 1 in. in diameter.
For each of these tests, the overall time of steam-air flow after initiation of methyl iodide
injection totaled 5 hr.
Actual relative humidity was probably 100%.
c.

LT :
END
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DATE FILMED
10/21 / 66




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