Final Report
PLUME RISE FROM KEYSTONE PLANT
by Betsy Woodard Proudfit
Sign X Laboratories, Inc.
Contract No. PH 86-68-94
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203 767-1700
LABORATORIES, INC.
ESSEX. CONNECTICUT O6426
Final Report
On
Plume Rise From Keystone Plant
Contract No. PH 86-68-91*
15 March 1969
(Revised December 1970)
by
Betsy Woodward Proudfit
Prepared for: U. S. Department of Health, Education and Welfare
Public Health Service
Environmental Health Service
National Air Pollution Control Administration
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CONTENTS
INTRODUCTION 1
References 2
PART I - EQUIPMENT AND PROCEDURES 3
EQUIPMENT 3
FLIGHT PROCEDURES 4
DATA REDUCTION 5
Reduction of Pressure Height 5
Reduction of Dry Bulb Temperature 6
Reduction of S02 Data 7
Reduction of Traverse Data . 8
Reduction of Wind Data 9
PART II - PRESENTATION OF DATA 14
INTRODUCTION 15
Tabulation of Traverse Data 15
Temperature Sounding Diagrams 15
Diagrams of Traverses 16
Plots of Plume Heights and Potential Temps, vs. Time . 16
Additional Diagrams 16
DAILY SUMMARIES 17
NOTATIONS - PART II 20
TABULATIONS AND DIAGRAMS 21
25 May 68 21
26 May 68 25
16 October 68 28
17 October 68 34
18 October 68 38
20 October 68 43
21 October 68 53
22 October 68 58
23 October 68 65
24 October 68 70
PART III - ANALYSIS 73
BEHAVIOUR OF HOT PLUMES UNDER STABLE CONDITIONS 73
Abstract 73
Introduction 74
Data Acquisition 74
Definition of Terms 76
Reduction of Data 77
Analysis of Results and Comparison with Various
Formulae . 79
The Use of Diagrams 83
Examples 83
Conclusions 86
Acknowledgements 86
References 86
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INTRODUCTION
A study to determine plume rise from a large power plant was
undertaken by Sign X Laboratories, Inc., under contract from the
U. S. Public Health Service.
The study was part of a larger research program conducted by the
National Air Pollution Control Administration (NAPCA) to determine the
extent and effects of power plant emissions from tall stacks. Additional
participants in the Large Power Plant Effluent Study (LAPPES) during
the 1968 field experiments were Stanford Research Institute^ and
Meteorology Research Inc.3
The power plant studied was the Keystone Generating Station near
Shelocta in western Pennsylvania. The station has a capacity of 1800
megawatts from two identical units. Each unit consists of one 244 meter
stack and two 99-meter-tall natural draft cooling towers. During the
May, 1968 field experiments Unit #1, only, was operating. Unit #2,
only, was operating during the October, 1968 field studies.
The station is situated in a shallow valley. The surrounding
terrain is hilly; the peaks of some of the hills within several
kilometers of the site rise to about 100 m. above the stack base level
(or about 150 m. below the top of the stack).
An instrumented helicopter was used to obtain a record of tempera-
tures and sulfur dioxide concentration in the plume. The records were
then evaluated to determine plume heights under a variety of atmospheric
conditions. To assist in determining the plume boundaries, a device
was used which detected charged particles in the plume. (At the request
of NAPCA, about 50% of the electrostatic precipitators, which have an
efficiency rating of 99.5%, were shut down during most of the observa-
tion periods.)
Data flights were made on seven days during May, 1968 and eight
days during October, 1968. Data from ten days (two in May, eight in
October) have been selected for inclusion in this report.
This report is composed of three parts. Part I describes the
equipment and techniques used to obtain the data and the methods
employed to reduce the data. Part II presents the data from ten flight
days. Included are general descriptions of each day, temperature
soundings and plume heights and S02 maximum concentrations obtained
from traverses through the plume.
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Part III presents an analysis and evaluation of twenty cases from
seven flight days. For the cases analyzed, the average wind speed
varied from 4.8 to 12.5 meters per second and the stability from about
0.15 to 1.5 degrees C. per 100 meters. This section, which is a paper
that was presented at the North American Fuel Technology Conference,
Ottawa, Canada, June, 1970, includes a summary of data acquisition and
reduction in addition to an analysis of results.
References :
1. Schiermeier, F. A. and L. E. Niemeyer, 1970: Large Power Plant
Effluent Study (LAPPES), Vol. 1 - Instrumentation, Procedures,
and Data Tabulations (1968). National Air Pollution Control
Administration Publication No. APTD 70-2.
2. Johnson, W. B., Jr. and E. E. Uthe, 1969: Lidar Study of Stack
Plumes. Prepared for DHEW, NAPCA by Stanford Research Institute
of Menlo Park, Calif., under contract No. PH 22-68-33.
3. Niemann, B. L. , M. C. Day and P. B. McCready, Jr., 1970:
Particulate Emissions, Plume Rise, and Diffusion from a Tall
Stack. Prepared for DHEW, NAPCA by Meteorology Research, Inc.
of Altadena, Calif., under contract No. CPA 22-69-20.
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PART I - EQUIPMENT AND PROCEDURES
EQUIPMENT
The instrument package was flown in a 3-place (side by side) Bell
47 G helicopter which carried the pilot and the principal investigator,
who acted as observer. The package, designed and fabricated by Sign X
Laboratories, is similar to that used by PHS on the LAPPES Project and
almost identical to that flown for the last several years by TVA.
Five variables, four at any one time, were recorded on two ,2-pen,
10 inch, recorders. The variables were dry bulb temperature and SC>2
on one recorder and pressure height and wet-bulb depression or
"space charge derivative" on the other.
1. Temperature: thermistor; time constant 0.1-0.2 seconds; 3
overlapping scales; 1°C = 0.5 inch.
2. SO2: electroconductivity; time constant 2.0-2.5 seconds;
4 ranges, full scale (10 inches) 0-1.0, 0-2.5, 0-10, and 0-25 ppm.
3. Pressure height; double bourdon cell; electrical output
linear function of pressure height according to standard atmosphere;
time constant 0.1 sec.; 3 overlapping scales; 100 m = 1 inch.
4. Wet-bulb depression; 30 junction thermopile; time constant
0.1-0.2 sec.; 1 scale; 1°C = 0.5 inch.
5. Space charge; device measured change in space charge; not
intended to be quantitative; instantaneous response.
There were two event markers on each recorder, one gave time marks
every two minutes, the other was used for location, observations, etc.
The chart speed was two inches per minute; the pen slewing speed 0.5
seconds for full scale deflection. The two pens, on each recorder, were
overlapping so that both pens traversed the full 10-inch chart width.
As a result the pens were off set a tenth of an inch (i.e. 3 seconds).
This off set was taken into account during data reduction.
The two recorders were mounted in front of, and facing, the ob-
server. The S02 unit and the inverter, for converting the helicopter's
24-volt DC power supply to 115 volts AC, were mounted on the seat between
the pilot and the observer. The pressure height transducer was also
mounted in the cockpit and was connected to the aircraft static line.
The dry bulb temperature and wet bulb depression sensors were in a
radiation housing mounted on the helicopter skid, well forward of the
rotor downwash during normal operating speeds. The intake for the SC>2
analyzer and the space charge transducer were mounted next to the
temperature housing.
The helicopter and instruments are shown in Figs. 1 and 2. Examples
of the chart record are shown in Fig. 3.
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FLIGHT PROCEDURES
The first flight of the day, during both the May and October
series, commenced around dawn, weather permitting.
The equipment was turned on before take-off for a pre-flight
check. During the flight from the airport to the Keystone site
(about 15 min.) additional checks were made and meteorological con-
ditions were noted.
The helicopter landed at the plant site and the aircraft's
altimeter was set to 1000 feet (305 m.), the height of the stack
base. The recorder pens for all four variables were moved simulta-
neously to establish the same time base for the two recorders and for
pen off-set.
On many of the mornings ground fog obscured the plant site. The
helicopter would then hover over the fog bank and, because warmer air
would be brought down by the rotor, the fog would dissipate in the
immediate area. This technique was successful except in one or two
cases when the fog was exceptionally thick. (This technique, of
dissipating fog, has been used by many helicopter pilots for a number
of years.)
A temperature sounding was then made, just upwind of the stack,
to a height of about 100 m. above the plume top, cloud cover permitting.
Two basic patterns were used to define the plume dimensions:
1. Slanting traverses. Starting from about 6 to 8 km. downwind
a series of climbing and descending traverses were made through the
plume, toward the stack. The track over the ground was generally
fairly straight but the primary object was to traverse through the
most dense part of the plume, rather than flying a straight course.
The plume was often bifurcated, particularly within the first several
kilometers of the stack. A chart of the area on which concentric
circles, every kilometer, had been drawn, was used during the flights
and position, usually every kilometer, was noted on the chart record
by the event mark and in a notebook.
When a slanting traverse was made close to the stack, within 0.5
or 1.0 km., it was generally in the downwind direction, starting with
a descending traverse from over the stack.
2. Horizontal traverses. This series of traverses was made
across the plume at fixed distances, e.g. 4 km., downwind. A traverse
was made just above the plume and wa.s followed by traverses at 200 foot
intervals unti] the base of the plume was reached. This was generally,
but not always, followed by an ascending series, 100 feet, 300 feet,
etc. higher until the plume top was reached. Thus a cross-section
was obtained every 100 feet, or 30 meters. Position was noted several
times during each traverse.
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Generally three series of slanting traverses, and two horizontal
series, were flown during the first flight which lasted -«1.5 hours.
Sometimes a constant level traverse, downwind, at the plume top was
made. A second sounding was usually made during the latter part of
the flight.
The second flight, about one hour later, lasted about two hours
and was similar to the first. During the May session inversion breakup
generally occurred prior to the second flight. During the October
session it usually occurred near the end of the second flight. On
some days a third flight was made.
Indicated air speed during all traverses and soundings was between
55 and 60 mph ( ^ 24 to 27 m/s).
DATA REDUCTION
Times (EST) and flight notes were transcribed on the chart records,
The pressure height was traced onto the temperature and S02 chart
record, to aid in reduction. Height and temperature were at the same
time. S02, on the leading pen, was 3 seconds ahead.
Reduction of Pressure Height
The pressure height transducer, whose output is recorded on the
chart, cannot be set to a particular height when the ambient pressure
varies. It records absolute pressure, expressed in meters, according
to the standard atmosphere. In order to obtain height above a surface,
changes in ambient pressure must be taken into account.
The pressure heights at stack base level and at the airport were
read from the chart records, at various times, for each flight day.
These readings must be taken when the helicopter engine is off or at
a low power setting. At full power, when on the ground or when hover-
ing close to the ground, there is an increase in pressure of about
one half millibar at the static position. This results in an indicated
reading that is about 4 meters too low. The static is positioned so
that correct readings may be obtained during normal flight speeds.
Graphs were made of pressure heights at stack base level vs time
for each day. (Graphs for the October session are presented in
Fig. 4 ) Also plotted on the graphs are pressure height at the air-
port minus 122 meters. (Height of airport: 427 m. ASL, stack base:
305 m. ASL). Pressure remained fairly constant on most days; on
22 Oct. a lowering of pressure gave a difference of 60 meters in
6.5 hours.
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The value of the pressure height, H, shown on these graphs is
then subtracted from the indicated readings in order to obtain height
above stack base level, Z. No corrections have been made for the
departure of the actual air temperature from the standard. The height,
Z, should therefore be considered the pressure height above the stack
base level. The difference between height, Z, and true height is small.
The following computation gives an example.
On the morning of 20 October 1968 the surface temperature was
about 12°C colder than standard (although at plume top level it was
about 1°C warmer). If this temperature difference (i.e. the deviation
from standard) is taken into account, then the true height of the
plume top would be about 7 m. lower than the pressure height above
stack base, Z.
The case above probably represents the greatest difference in
height (between true height and pressure height, Z) of all the cases
presented in this report. It would be reasonable to expect that the
height error, due to a departure of the actual temperature from the
standard, was less than 5 m. in the majority of cases. The probable
pressure height error may be taken to be ± 10 m.
The heights that are given in the tables in Part II of this report
are pressure heights above stack base level, Z. When potential tem-
perature values were determined (see Analysis, Part III) the pressure
height, H, was used.
Reduction of Dry Bulb Temperature
At air speeds above about 35 mph ( ^ 15 m/s) the temperature probe
is in undisturbed air. Temperature readings taken when the aircraft
is hovering close to the surface may be in error. "Surface" tem-
peratures, for example those given in Part III, are therefore the
temperatures measured 20 m. above the stack base level.
No correction has been made for the effect of dynamic heating.
All soundings were made at an indicated air speed between about 24
and 27 m/s. The change in temperature due to a change in the air
speed over this range is not greater than ± 0.1°C.
An absolute accuracy greater than + 0.5°C is not claimed; however,
it would be reasonable to expect that temperature measurements taken
by the PUS helicopter and the Sign X helicopter would agree within
a few tenths of 1.0°C. (The units were from the same manufacturer, the
operational procedures were similar and a comparison flight was con-
ducted .)
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Reduction of SOgData
All SC>2 values presented in this report are indicated readings.
The air sample (flow rate: 2500 cc/min.) and reagent (distilled
water, flow rate: 25 cc/min.) are mixed. Any gas which changes the
conductivity of the reagent will affect the accuracy of the S02 reading.
However, the only gas which appears practically to cause a significant
interference is C02 When determining low ambient S02 values it is
necessary to measure the CC>2 background. This can be done by means of
a scrubber, or bubbler, which selectively removes the S02. A series of
calibration curves are then employed to determine the S02. For example,
on the 1.0 ppm scale, the chart record would indicate 18% full scale
for 0.2 ppm S02 and 0.0 ppm C02, 27% for 0.2 ppm SC>2 and 400 ppm CC>2,
and 42% for 0.2 ppm SC>2 and 1000 ppm C02.
At higher SO2 values the change in the indicated chart reading
varies less with the change in C02. For example, on the 10.0 ppm scale
when the SO2 is 2.0 ppm, there is a 4% change in the full scale reading
when the CC>2 varies from 0.0 to 2000 ppm.
During the plume rise studies described in this report it was
not necessary to determine the ambient SO2 and CO2 values; therefore
a bubbler was not used. The background, or ambient, readings recorded
(and presented in Part II) are due to both SO- and CO2.
In these studies, one is concerned with SO2 values in the plume.
There will of course be an increase in the CO2 concentration in the
plume. As the S02 value increases, the effect of changes in the CC>2
concentration decreases. For example, close to the stack, a con-
centration of 30 ppm SO2 and 2100 ppm CC>2» above ambient, may be ex-
pected. At these high SO2 values the indicated reading is the same
whether the C02 is several hundred, or several thousand, ppm. Downwind,
the S02 and C02 values will decrease and it is reasonable to assume
they will decrease proportionally. For example, at a point downwind
where the SO2 concentration in the plume has decreased to 1.0 ppm,
above ambient, then the CO2 concentration will have decreased to
70 ppm, above ambient. On the 10. ppm scale, when the SO2 concentration
is 1.0 ppm, a 70 ppm change in C02 is equivalent to the width of the
pen on the chart record.
For all practical purposes the effect of C02 interference, in these
plume studies, may be neglected. The increase of SO2 in the plume may
be determined by simply subtracting the indicated background (ambient)
reading.
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The conductivity of the solution in the analytical cell of the
SC>2 analyzer is temperature dependent. Compensation for temperature
changes was not incorporated in the analyzer used in these studies.
Sufficient tests have not been conducted to determine the degree of
dependency.
At the start of each morning flight the reagent (distilled water)
was comparatively cold. After the dinalyzer was turned on, the tem-
perature of the reagent would increase due to heat generated by the
recirculating pump. It would be reasonable to expect that the most
rapid temperature changes (in the analytical cell) occurred shortly
after start up. Approximately 25 minutes elapsed between start up and
the first series of traverses. It would be reasonable to assume that
the relative accuracy of the SC>2 values measured during the traverses
on any one flight was about * 10%.
It is, of course, not necessary to obtain absolute SC>2 values in
order to determine plume rise. The above discussion has been made to
facilitate understanding in case the S02 data presented in this report
is used for other studies.
Reduction of Traverse Data
Horizontal Traverses: The maximum SC>2 value, recorded on each
traverse, was read from the chart record and plotted vs. height.
Examples of some of these plots are presented in Part II. Numerical
values of SC>2 max. and height, for each series of horizontal traverses,
are presented in tables in Part II. The indicated background SC>2
readings, obtained on the lowest and highest traverses, are also given.
Slanting Traverses: From the positions noted during a series of
slanting traverses, a profile (height vs. distance downwind) was drawn.
The heights of the plume top and bottom were determined from the SC>2
and "space charge" records and marked on the profile. The height and
magnitude of the maximum SC>2 were also noted on the profile. Examples
of some of these profiles, which also show a rough outline of the plume,
are presented in Part II.
In addition to the 2-2 1/2 second time constant of the SO2
analyzer, there is a delay time of 2 seconds. That is, it takes 2
seconds for the air sample to travel from the tube intake to the
analytical cell. This delay does not distort the data; it simply
offsets it by 2 seconds. When the plume was entered a delay time of
2 seconds was allowed; 3 seconds offset (equal to normal pen offset)
was allowed when determining the height of the maximum SC>2 When the
plume is left, a "tail-off" appears in the SC>2 trace. By comparing
the SO2 and space charge traces, it is possible, with a little practice,
to take account of the "tail-off" effect.
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The heights of plume top, bottom, and SC>2 maximum have been tabu-
lated, for various distances downwind and are presented in Part II. The
heights, to the nearest 10 meters, and distances, to the nearest one
tenth kilometer, that appear in the tabulations were read from the
profiles.
Reduction of Wind Data
Wind speeds and directions were supplied by PHS personnel. A
discussion is presented in Part III, Section 2. Graphs of wind speed
and direction vs. time, for October 16, 20 and 22, 1968, are presented
in Fig. 5.
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USPHS METEOROLOGY PROGRAM AIR RESOURCES RESEARCH STUDY
OF PENELEC KEYSTONE PLANT IN INDIANA, PENNSYLVANIA
Sign X Lab. Bell G2 Helicopter
Fig. 1
Sign X Lab. Model 6500B Package in G2, showing SC>2 Analyzer,
DC-AC Inverter, and Power Distribution Box, and Dry Bulb Temperature,
Wet Bulb Depression, and Space Charge Probes mounted on strut.
Fig. 2
10
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6 km
HI
5
i
Ml
3
in
2.5
Fig. 3 Traces of pressure height, temperature, SC>2 and space charge derivative,
from chart record between about 0707-0711 ISST, 20 Oct. 68, during a series of
slanting traverses from about 7 km downwind of the stack to 2.5 km.
11
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H,m
200
100
300
200
16 Oct.
17 Oct.
' _ , ,.
18 Oct.
20 Oct.
300
200
200
300
200
300
200
21 Oct.
* _ _
22 Oct.
« ._ -
23 Oct.
2k Oct.
H,m
300
200
300
06
08
10
12
EST
06
08
12
200
Fig.4. Solid dots indicate pressure height, H, at stack base level. Crosses and circles are pressure
heights recorded at the airport, the difference in elevation having been taken into account. (Crosses: PHS
landing area. Circles: gas pump area.)
12
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u,m/s
10
8
6
4
2
*
20°
o
1 i i l | l
A ' OCT
t
o''
-
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. M * o ^^ ^^*M*?V"~ ^^^^ | ^
^ ^^^^^^^
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1 . 1 1 1 , 1 1
07 08 EST 09 10 1
20 OCT
'*** ~
^ / X.."?-
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- ^^ " "^\^^^J-- -
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1
60' 60°
40 40
20 20
1
u, m/s
10
o
8
6
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I
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22 OCT
- ,.-'"'-
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. us
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07 08 EST 09 10 1
Fig. 5
single theodolite measurements
double theodolite measurements
Wind speed at plume top level (m/s)
5 wind speed at stack top level (m/s)
j average wind speed between stack top and
plume top, from pibals
< average wind speed computed from helicopter
fj3 « vo^^* i nn a 1 cln oa 1^ f wi nrf rfi T^^f^^l on 3.t DlllITl6 tOD
Ql i c t« w J.UIICLX oiiccii. ^ wxiiu. u j. i. cv« i_x wn d ^> ^* J* 1^*1*^ *»\^^*
level minus wind direction at stack top level)
u,m/s
12
10
8
6
1
13
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PART II - PRESENTATION OF DATA
INTRODUCTION 15
DAILY SUMMARIES 17
NOTATIONS 20
TABULATIONS AND DIAGRAMS . 21
25 May 68 21
26 May 68 25
16 October 68 28
17 October 68 34
18 October 68 38
20 October 68 43
21 October 68 53
22 October 68 58
23 October 68 65
24 October 68 70
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PART II - PRESENTATION OP DATA
INTRODUCTION
Data from ten (of fifteen) flight days are presented in Part II.
All data is included except that obtained when:
1. the plume was looping
2. the main plume and the cooling tower plume merged and
remained saturated
3. the plume was in cloud
A short general description of all flight days is also presented.
The following data tabulations and diagrams are presented in Part II.
Tabulation of Traverse Data
For slanting traverses, the height, above stack base level, of the
plume top, bottom and maximum SO2 concentration and the value of the
maximum concentration, are given for various distances downwind of the
stack. Distances are to the nearest 0.1 km. and heights to the nearest
10 m.
For horizontal traverses, the value of the maximum S02 concentra-
tion obtained on each horizontal traverse through (and normal to) the
plume is given for various heights above stack base level. The
distance, X, from the stack, for each series of horizontal traverses,
is noted. The indicated SO2 reading obtained outside of plume
(i.e. the background, or ambient reading) is given for the highest
and lowest traverse in each series. The vertical arrows under the
height column indicate the order in which the individual traverses were
made. For example, on 17 Oct., page 36: the first traverse was made at
570 m. at 0643 EST. The subsequent traverses were made at descending
levels to 270 m. The next traverse was at 420 m. and the last at
490 m. at 0655 EST.
The SO2 values, in parts per million, are indicated readings
(See p. 7). If a value is in parenthesis, it indicates that the
recorder pen went off scale.
Temperature Sounding Diagrams
Plots of temperature soundings, made upwind of the stack, are
presented. The temperature, in degrees centigrade, is shown vs.
pressure height above stack base level.
15
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Diagrams of Traverses
Some plots of horizontal and/or slanting traverses are presented.
The diagrams of horizontal traverses show the maximum indicated SO2
concentration encountered on each traverse, vs. pressure height above
stack base level.
The dashed, or dotted, line in the plots of slanting traverses,
indicate the path of the helicopter. The short bars represent plume
top and bottom. On some of the plots the value of the maximum SO2
concentration is given; on other plots the position where the maximum
value was encountered is indicated by a circle. A rough outline of
the plume is,drawn.
Plots of_ Plume Heights and Potential Temperatures vs. Time
Plume heights (top, bottom, and height of SO2 max.) and potential
temperatures (at surface + 20 m., stack top, and plume top) were de-
termined and plotted as a function of time for each day analyzed. Two
of these plots, for 20 October and 22 October, appear in this section;
a third, for 16 October, is shown in Part III.
The potential temperatures that are shown on these diagrams were
obtained from soundings and also from additional readings obtained when
in the vicinity of the stack (not in plume).
Additional Diagrams
Several diagrams, (e.g. Figs. 22-24) that have appeared in previous
reports, are also included.
16
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DAILY SUMMARIES
Note: The observations of cloud cover and precipitation, presented
in the following short daily summaries, were made in the
vicinity of the plant site, not at the Jimmy Stewart Airport.
22 May 1968
A short mid-day flight and an afternoon flight were made to check
instruments, familiarize pilot and observer with terrain, and secondarily
to obtain plume data. The stack precipitators were on so that the plume
was not highly visible. During the first part of the afternoon flight
there was a light drizzle to moderate rain; it then partially cleared.
The plume was looping during part of the flight. No data is presented
here.
23 May 1968
There was an overcast, light rain, and some fog in the valleys
during a flight from 0745 to 0925. There was a ground based inversion
to about 200 m. Above about 400 m., the lapse rate approached the
dry adiabatic. The plume top, at about 3.0 km downwind, was at about
760 m., and plume thickness was about 300 m.
25 May 1968
Fog in the valleys prevented a sounding to ground level during
the first flight. The sounding, from 0651 to 0658 EST was obtained
when climbing downwind from the stack (adjacent to, but not in, the
plume). The first flight was cut short to enable the lidar crew
to make observations. During the third flight, from 1035 to 1235 EST,
the temperature sounding was neutral. Winds were light; the plume
was looping. Data from the first two flights are presented in this
section.
26 May 1968
There was a 6/8 high overcast at the start of the first flight.
The plume was fanning. At the start of the second flight,, about
'0900 EST, there was almost complete overcast. The plume was looping.
17
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28 May 1968
There was complete overcast and a light drizzle. Visibility in
the plume was zero, or nearly zero. During the first flight it was
often impossible to fly above the plume; during the second it was
never possible because of cloud base. The ceiling was less than
300 m. above stack top.
29 May 1968
There was early morning ground fog. Temperature soundings, at
0600 hrs. and 0830, were roughly isothermal. The cooling tower plume
remained saturated and appeared to go higher than the main plume.
There was merging of the two plumes.
31 May 1968
At 0600 hrs. the sounding showed a lapse rate similar to the moist
adiabatic, with a shallow inversion at 400 m. There was a complete
overcast. The cooling tower plume saturated the downwind region.
The two plumes merged; the cooling tower plume went higher than the
S02 plume. At 0745 hours a sounding was made. Temperatures approached
the dry adiabatic rate; there was an inversion between 500 and
600 meters. The base of the lower cloud was at 350 m.
16 October 1968
There was early morning ground fog, especially in the vicinity
of the plant. The plume was fanning. The second flight continued
until inversion break-up, at about 1030 hours.
17 October 1968
There was light drizzle, with some intermittent light rain during
the first flight. Cumulus formed at the top of the plume at 0930 hours
during the second flight.
18 October 1968
There was again light drizzle with intermittent light rain. The
drizzle continued during the second flight. There was some condensation
in the plume at about 1000 hours.
18
-------
20 October 1968
There was some early morning ground fog with clear skies above.
During the second flight, at about 1000 hours, there was condensation
intermittently at the plume top. There was indication that there
was some merging of the cooling tower plume with the main pliime. Also
during the second flight the plume appeared (visually) to break into
"rolls" or "waves" normal to the plume length.
21 October 1968
There was 4/8 high overcast at the start of the first flight.
Later in the morning, around 1000 hours, clouds were forming in
the plume.
22 October 1968
There was early morning ground fog. Plume "tilt", probably due
to wind shear, was more apparent on this day than any other presented
in this report. There were comparatively rapid changes, with time, of
surface pressure and plant output. There was also an increase in the
average wind speed during the second flight (0930-1000 hrs. EST) .
An appreciable wind increase occurred just above plume top level. This
increase may have accounted for the apparent descent of the plume at
about 0950. A third flight, made shortly after noon, showed adiabatic
conditions. Horizontal traverses, at 3.4 km downwind, showed the plume
extended above 850 m. and below 150 m.
23 October 1968
There were strong winds during the first flight. It was clear.
There was some merging with the cooling tower plume but evaporation
occurred within a few kilometers. Winds were lighter during the second
flight. Some cumulus formed above, and in top of, the plume.
24 October 1968
A deep ground based inversion extended about 50 m. above the stack.
Above this stable layer the lapse rate was close to neutral. The plume
was lofting.
19
-------
NOTATIONS - PART II
X Distance from stack, kilometers
Z Height above stack base level, meters
S t Temperature sounding from stack base level to above plume
top level (cloud permitting)
S 4 Temperature sounding from above plume to stack base level
(cloud permitting)
Traverses along X axis:
T *V Series of slanting traverses toward stack
T\/1 Series of slanting traverses away from stack
T \ Slanting traverse away from stack
T ?» Constant level traverse away from stack
Traverses normal to X axis:
T^? Series of horizontal traverses across plume
Time is Eastern Standard.
20
-------
TABULATIONS AND DIAGRAMS - PART II
Date: 25 May 68 Time: 0659-0704 Type Traverse
Distance
Downwind
km
3.2
3.6
2.8
2.0
1.8
1.7
1.0
0.9
0.8
Date: 25 May 68
5.5
5.3
5.1
4.9
4.6
4.5
3.7
3.5
3.2.
2.C>
2.0
1.5
1.4
1.2
0.7
0.6
0.4
Top
m
570
530
530
Time:
610
560
560
560
520
490
Height
Bottom
m
450
400
410
of
Max.
m
490
470
450
0854-0902 Type
430
410
280
310
400
370
510
510
430
550
490
410
Max.
so2 so2
ppm
3.7
2.5
3.6
Traverse :
2.3
2.5
3.7
4.7
5.0
15.5
21
-------
Date : 25 May 68 Time: 0920-24 Type Traverse:
Distance Height of Max.
Downwind Top Bottom Max S02 S02
km m m m ppm
1.7 650
1.5 590 5.00
1.1 360
0.5 310
0.2 360 25.0
0.1 390
22
-------
Date: 25 May 68 Time: 0706-18 Type Traverse:
X = 1.2 km
Height, m Max. S02
Background
.SO,
i
590
520
440
390
360
0.18
3.64
(10.0+)
6.98
1.60
0.18
0.18
Date: 25 May 68
Time: 0903-19
X = 1.1 km
i
560
500
430
380
350
t
570
540
490
420
.
0.18
0.18
8.23
0.19
6.98
8.64
1.82
1.07
0.76
Type Traverse:
0.18
0.18
0.19
23
-------
ro
\
\
_ 0651-58
St
Fig. 6
11 12 13
\
\
i *"^
V
\
\ 0843-46.
\
1OO's m.
6
temp., °C
12 13 14 0
25 May '68
x
--- 0*103-11
= 1.1
1
Fig. 7
2 4
max. ppm
8
24
-------
Date: 26 May 68 Time: 0618-26 Type Traverse :
Distance Height of Max.
Downwind Top Bottom Max. S02 S02
km m m m ppm
4.8 510
4.6 400 1.25
4.5 370
4.2 370
4.0 420 1.35
3.9 460
3.2 . 460
3.0 410 1.50
2.8 370
2.7 380
2.5 450 2.90
2.4 470
1.8 460
1.6 390 6.50
1.4 340
0.7 500
Date: 26 May 68 Time: 0628-29 Type Traverse:
0.2 410
0.4 350 17.8
0.5 320
Date: 26 May 68 Time: 0653-55 Type Traverse :
1.8 510
1.7 430 4.45
1.6 380
1.4 430 (10.0+)
1.0 520
Date: 26 May 68 Time: 0700-09 Type Traverse:
4.0 550
3.9 530 2.38
3.7 420
3.5 390
3.3 460 2.48
2.6 530
2.5 460 4.00
2.2 370
1.9 440 4.32
1.7 500
1.4 530
1.1 390 7.76
0.9 320
25
-------
Date: 26 May 68 Time: 0631-0650 Type Traverse:
X = 2.0 km
Background
Height, m Max SC>2 SO2
100 0.06 0.06
240 0.22
280 4.92
350 5.04
380 4.20
420 5.33
470 1.00
510 0.32
550 0.06 0.06
26
-------
x100
6
5
4
3
2
1
i . ' I
\
\
\
m
I
\
\
t
\
\
\
\
\
St 0610-15 -^
^'
V
\
/
\
i
/
/
/
/
\
^^"^^
\
/
'^i i i
1 \ ' '
\
\
\
\
\
I
i
\
\
"\
\
\
St 0710-15 j
/
/
/
J
C^
i
i
\
\
\
i
\
\
/
\ *
10
14 16
temp., °C
12
14
\
- \
\
\
\
\
\
\
\
\
\ ST 0844 - 50
i
\
\
\
\
?
\
\
\
\
\
i
i . i . i
t-, m.
x1OO
6
5
4
3
2
1
Fig.8
26 May *68
14
16 18
temp.. aC
p. 27
-------
Date: 16 Oct. 68 Time: 0659-0705 Type Traverse;
Distance
Downwind
km
5.5
5.3
5.1
4.8
4.7
4.5
3.5
3.3
3.1
2.7
2.3
1.8
1.5
1.2
1.0
0.8
0.6
0.2
Top
m
490
460
460
510
490
440
Height of
Bottom Max . 502
m m
420
370
380
420
400
330
340
400
400
340
350
380
Max.
S02
ppm
4.61
4.72
5.20
6.68
(10.0+)
(25.0+)
Date: 16 Oct. 68 Time: 0716-23 Type Traverse:
7.5 540
7.2 450 2.56
7.0 420
6.8 420
6.5 450 3.29
5.8 . 540
5.7 540
5.3 470 3.21
5.1 420
4.9 420
4.3 480 3.15
3.8 550
3.5 540
3.0 460 3.27
2.4 350
2.0 340
1.4 410 6.21
0.6 530
28
-------
Date: 16 Oct. 68 Time: 0738-42 Type Traverse:
Distance Height of Max.
Downwind
km
4.6
4.3
4-1
3.7
3.4
2.9
2.3
2.1
1.7
1.4
1.0
Top Bottom
m m
480
390
390
500
380
390
520
Max . S02
m
430
420
450
430
SO 2
ppm
2.42
2.62
3.25
7.84
Date: 16 Oct. 68 Time: 0912-16 Type .Traverse:
5.7 540
5.3 470 1.79
5.0 410
3.5 410
2.9 480 2.69
2.5 540
1.7 550
.1.6 530 3.86
1.0 390
Date: 16 Oct. 68 Time: 0918-19 Type Traverse:Ni
0.5 540
0.8 500 7.98
2.0 340
29
-------
Date: 16 Oct. 68 Time: CW33-38 Type Traverse:
Distance Height of Max.
Downwind Top Bottom Max. SO2 S02
km m m m ppm
6.0 540
5.8 500 2.29
5.6 450
4.7 400
4.0 490 3.11
3.6 540
2.6 510
2.4 480 2.00
2.1 380
1.4 400
0.7 500 4.41
0.5 550 4.96
0.3 570
Date: 16 Oct. 68 Time: 1005-1011 Type Traverse :
6.1 600
6.0 560 0_83
5.9 530
5.1 460
4'2 560 1.17
3.9 610
3.0 570
2'9 540 1.13
2.7 450
2.0 460
1-1 620 2.9
0.8 650
Date: 16 Oct. 68 Time: 1027-32 Type Traverse
6.6 700
6.1
5.5 4f>0
4.4 4RO
3.2
2.4
1.6
0.9
580
670
780
840
890
1.10
1.30
].59
2.08
2.55
0.7 910
30
-------
Date: 16 Oct. 68 Time: 0650-56 Type Traverse
X = 2.9 km
Height, m Max. S02
1
570
540
500
430
370
310
0.10
2.42
2.70
3.60
1.10
0.36
Background
so?
0.10
0.10
Date: 16 Oct. 68
Time: 0707-12
X = 2.0 km
560
490
440
370
310
0.13
2.57
3.40
2.20
0.15
Type Traverse:
0.13
0.15
Date: 16 Oct. 68
Time: 0730-37
X = 2.9 km
510
480
450
380
320
0.10
0.10
2.98
1.80
0.29
Type Traverse:
0.10
0.13
31
-------
Date: 16 Oct. 68
Time: 0920-30 Type Traverse:
X = 2.9 km
Height, m
T 1
270
320
380
450
490
510
550
580
600
620
Date: 16 Oct. 68
i t
640
580
550
480
450
420
400
350
320
260
Date: 16 Oct. 68
1
v
630
580
530
450
390
320
Max. S02
0.18
0.18
i.n
2.72
3.23
3.23
2.13
1.18
0.19
0.18
Time: 0940-55
X = 2.0 km
0.20
1.90
2.01
2.20
2.40
2.09
1.88
0.71
0.52
0.29
Background
S02
0.18
0.18
0.18
Type Traverse
0.20
0.20
Time: 1012-24 Type Traverse
X = 3.0 km
0.47
1.83
1.13
0.58
0.71
0.22
0.20
0.20
32
-------
z
xlOO'm
Fig. 9
S| 0725-28
St 0904-09
S I 0959-1002
10
15
temp. °C.
20
16 Oct.'68
Z,m
COO
400
3.A6
3-21
i
3V2.9
200
Fig. 10
X, km
T *S 0716-23
33
-------
Date: 17 Oct. 68 Time: 0635-41 Type Traverse:
Distance
Downwind
km
5.8
5.6
5.3
4.4
3.9
3.6
3.4
2.6
2.4
1.9
1.8
1.4
1.1
Date: 17 Oct.
5.0
4.5
4.3
3.5
2.7
2.3
1.5
1.2
Date: 17 Oct.
0.8
1.1
Height of Max.
Top Bottom Max. S02 S02
mm m PPm
470
420 0.46
350
3(>0
450 (1.0+)
490. 1.91
520
510
460 2.26
350
340
450 6.82
510
68 Time: 0658-0705 Type Traverse:^/
360
460 1.35
500
500
300
300
460 4.5
520
68 Time: 0705-07 Type Traverse: ^i
500
480 7 . 30
34
-------
Date: 17 Oct. 68 Time: 0722-29 Type Traverse:1^/
Distance
Downwind
km
6.6
6.3
5.8
5.4
4.9
4.2
4.1
3.5 .
3.1
2.5
2.3
1.7
1.4
1.1
Height
Top Bottom
m m
390
380
560
570
380
400
560
540
360
of
Max. S02
m
480
460
540
520
430
Max.
so2
ppm
0.90
1.23
2.21
5.17
6.45
Date: 17 Oct. 68 Time: 0906-13 Type Traverse:
9.0 660
8.6 590 0.47
6.5 460
6.0 530 0.87
5.2 660
4.3 650
3.7 510 0.98
3.0 410
2.3 490 2.24
2.0 550
1.5 580
1.4 560 4.58
Date: 17 Oct. 68 Time: 0915-16 Type Traverse:Ni
0.9 510
1.0 490 7.15
2.4 290
35
-------
Date: 17 Oct. 68 Time: 0643-55 Type Traverse:
X = 2.9 km
Height, m.
J, T
570
520
490
460
420
380
320
270
Date: 17 Oct. 68
t i
210
310
380
420
450
470
500
540
570
590
Date: 17 Oct. 68
t *
250
320
380
440
490
520
540
560
600
630
650
690
710
770
Background
Max. SO? SO2
0.09 0.08
1.80
2.33
2.78
1.36
0.87
0.49
0.09 0.09
Time: 0708-19 Type Traverse
X = 2.0 km
0.10 0.10
0.69
1.11
2.77
3.58
3.38
3.18
3.63
0.89
0.10 0.10
Time: 0917-40 Type Traverse
X = 3.0 km
0.52 0.20
0.43
0.43
0.60
0.69
0.91
2^00
1.34
1.39
1.46
2.37
1.18
0.82
0.18 0.18
36
-------
Fig. 11
ST 0628-33
ST 0856-0902-
Si 0952-56
Z.m
600
400
200
Fig 12
T 5^
X= 23 km
0643-52
0652-55 « «
temp., "C
Max.
2
ppm
Z.m.
17 Oct. '68
600
400
200
0-90
Fig. 13
T*s/0722-29
3 4
X, km.
37
-------
Date: 18 Oct. 68 Time: 0657-0701 Type Traverse
Distance Height of Max.
Downwind Top Bottom Max. SO2 SC>2
km m m m ppm
5.0 620
4.8
4.3 420
3.9 430
3.5
3.4 540
2.9 600
2.4
1.7 360
550 1
520 0
500 3
.61
.93
.58
Date: 18 Oct. 68 Time: 0708-15 Type Traverse:!^/
510 1.32
510 1.22
490 1.32
550 1.12
520 2.13
6.8
6.5
6.0
5.8
5.5
5.1
4.7
4.4
3.9
3.4
2.9
2.5
2.3
1.8
430
450
590
600
400
430
620
580
370
Date: 18 Oct. 68 Time: 0717-19 Type Traverse :
0.9 510
1.2 480 5.01
2.6 510 2.73
3.7 640
38
-------
Date: 18 Oct. 68 Time: 0734-40 Type Traverse:
Distance
Downwind Top
km m
6.2 630
5.9
5.6
5.3
5.1
4.3
4.0
3.6
2.5 530
Height of
Bottom Max . S02
m m
520
430
430
490
500
380
350
Max.
so2
ppm
1.39
1.21
0.80
Date: 18 Oct. 68 Time: 0907-13 Type Traverse:
8.9 750
7.7 460 0.85
7.2 360
6.7 370
5.5 550 0.60
5.3 580
4.1 560
3.7 480 0.94
2.8 310
1.4 520 3.62
1.1 570
Date: 18 Oct. 68 Time: 0914-16 Type Traverse: \
0.9 530
1.1 490 6.36
2.2 300
39
-------
Date: 18 Oct. 68 Time: 0642-55 Type Traverse
X = 3 km
Background
Height, m Max. SC>2 SO?
0.10
270
3 'JO
460
520
570
640
700
490
540
610
660
0.10
0.40
1.62
1 . 'J'3
1.93
2.12
2.13
2.50
2.40
0.09
0.09
0.09
0.09
Date: 18 Oct. 68 Time: 0720-33 Type Traverse:
| f X = 4.0 km
700 0.11 0.11
640 1.64
600 1.22
560 2.26
540 2.77
510 2.03
490 1.06
450 1.02
390 0.54
320 0.20 0.12
40
-------
Date: 18 Oct. 68 Time: 0920-34 Type Traverse
X = 5.7 km
Background
Height, m Max. S02
320
380
460
510
570
640
700
760
820
0.26
0.34
0.61
0.69
0.96
0.73
0.54
0.53
0.14
0.15
0.14
Date: 18 Oct. 68 Time: 0948-1002 Type Traverse:
X = 3.9 km
4r
940 0.15 0.15
880 0.63
830 0.16
760 0.99
700 0.88
640 1.11
560 1.03
510 0.90
460 0.67
380 0.60
320 0.32 0.16
41
-------
S t 0634 -39 - -
St O858-0903.
S T 1014 - 21
Fig. 14
I . i
14 16 20 22
temp.,8C.
Z, m.
600
600
400
200
Fig.15
T f+
= 4.0km
0720-28
0728-33
i
X II
1 2
Max. ppm
18 Oct. '68
Z, m.
600
..
*.
400
200
L/lll-,
N
- /
\- -
o _
T V 0708-15
T V 0717-19
X. km.
42
-------
Date: 20 Oct. 68 Time: 0635-39 Type Traverse:V
Distance
Downwind
km
4.6
4.3
4.2
3.7
3.6
3.1
2.3
1.9
1.7 .
1.5
1.0
0.7
Top
m
460
470
480
470
Height of
Bottom Max . S02
m m
370
340
350
370
400
330
320
420
Max.
so2
ppm
4.10
4.53
7.00
11.25
Date: 20 Oct. 68 Time: 0654-59 Type Traverse
430 2.32
420 3.70
380 4.18
440 5.64
350 (10.0+)
6.9
6.8
6.4
6.0
5.5
5.1
4.5
4.1
3.9
3.4
2.8
2.6
2.3
1.7
1.5
460
460
460
480
480
340
340
330
330
320
43
-------
Date: 20 Oct. 68 Time: 0701-02 Type Traverse:
Distance
Downwind
km '
0.3
0.9
1.3
Date: 20 Oct.
8.1
8.0
7.5
6.7
6.1
5.9
5.4
5.0
4.6
4.0
3.6
3.1
2.5
2.3
1.7
1.2
1.0
0.6
Date: 20 Oct.
7.6
7.4
7.3
6.3
6.1
5.9
5.4
5.1
4.9
4.0
3.6
3.3
2.8
2.6
2.4
1.8
1.2
1.1
Height of
Top Bottom Max. SO2
mm m
470
350
300
68 Time: 0706-13 Type
490
460
350
330
430
460
460
400
300
310
370
460
490
440
320
310
390
450
68 Time: 0727-33 Type
460
440
390
390
430
460
4 GO
400
370
3HO
440
470
470
440
360
320
450
470
Max.
S02
ppm
18.6
Traverse
2.85
3.60
3.60
4.88
4.23
8.40
Traverse
2.97
3.30
3.72
4.23
5.31
8.28
44
-------
Date: 20 Oct. 68 Time: 0903-08 Type Traverse
Distance
Downwind
km
6.8
6.3
6.2
5.0
4.5
4.2
3.9
3.5
3.2
2.6
2.1
1.9
1.5
1.0
0.8
Top
m
520
480
500
450
450
Height
Bottom
m
350
360
340
330
320
of
Max. S02
m
410
460
420
430
380
Max.
S02
ppm
0.89
0.88
2.28
2.73
6.90
Date: 20 Oct. 68 Time: 0927-32 Type Traverse:
7.0 480
6.9 450 3.42
6.4 380
5.7 380
5.5 400 3.56
5.1 450
4.6 480
4.4 440 3.80
4.1 370
3.5 350
3.1 420 3.04
2.4 480
1.9 500
1.3 410 5.13
1.0 350
45
-------
Date: 20 Oct. 68 Time: 0948-52 Type Traverse:1^/
Distance
Downwind
km
Height of
Top Bottom Max. SC>2
mm m
Max.
S02
6.7
6.5
G.O
5.2
4.3
4.1
3.7
3.6
3.2
1.9
1.3
.8
480
360
340
480
490
370
380
450
460
460
470
1.38
2.18
2.37
3.48
530
Date: 20 Oct. 68 Time: 0953-54 Type Traverse: ^
0.5
1.2
1.3
2.5
510
500
500
500
Date: 20 Oct. 68 Time: 1016-22 Type Traverse:
9.2
8.6
8.3
7.5
5.9
5.6
3.6
2.8
2.7
2.2
1.9
1.2
630
600
620
630
650
490
1.52
400
390
470
600
590
1.83
2.48
470
46
-------
Date: 20 Oct. 68 Time: 0616-25 Type Traverse:
X = 4.0 km
Background
Height
J,
530
470
420
340
320
Date: 20 Oct.
4
500
440
380
310
, m
t
500
450
380
68
T
480
420
350
Max . SO2 SO2
. 0.06 0.06
0.06 0.06
2.27
3.53
3.13
2.96
0.26
0.14 0.09
Timfi: 0642-51 Type Traverse
X = 4.0 km
0.05 0.05
1.40
2.28
3.52
4.80
1.90
0.09 0.09
-------
Date: 20 Oct. 68 Time: 0911-24 Type Traverse:
X = 4.0 km
Height
4
520
440
370
310
280
Date: 20 Oct.
4<
240
310
370
440
500
Date: 20 Oct.
4
610
490
440
370
310
280
, m
T
500
470
410
340
68
t
340
410
470
68
T
600
530
480
410
350
Background
Max. S02 S02
0.10 0.10
0.10
4.92
3.55
2.65
1.13
0.43
0.37
0.35 0.16
Time: 0935-45 Type Traverse
X = 2.9 km
0.18 0.18
0.18
0.42
0.63
1.12
3.66
2.64
0.22 0.10
Time: 0956-1013 Type Traverse
X = 4.1 km
0.11 0.11
0.39
1.36
1.69
2.57
2.41
.1..H2
1 . 'J8
0.37
0.31
0.24 0.19
48
-------
St 0630-33
Si 0733-36
Fig. 17
I
6810
temp., °C.
Z,m.
600
400
200
0
St 0856 09OO -
Si 1021 24
Fig. 18
8 1O 12
temp., °C.
2, m.
60O
20 Oct. '68
400
200
Fig. 19
0948-52
0953-54
X , km.
49
-------
e
290
0700
time, EST
0800 0900
1000
285
280
275
Z.m.
400
300
I
eP
9,
plume top
max. SO2
plume base-
e.°K.
290
285
280
2. m.
600
50O
400
300
FIG.20. Potential temperatures at plume top, 8p, stack top,9s, and stack base
level plus 20 m., 0g, as a function of time. Plume heights were obtained from
horizontal and slanting traverses. The first flight was from 0630 to 07^5 EST
and the second from 0900 to 1030 EST, 20 October 1968.
FIG. 21 (below). I so lines of S02, drawn from a series of seven horizontal
traverses between 06^2-51 EST, 20 October, 1968.
100m.
200
50
-------
Distance downwind, km
.5
'C
10
so2>
ppm
Fig. 22
Traces of temperature, SC>2, and space charge derivative recorded
while making a constant level traverse, at 510 m., from over the
stack downwind to about 2.5 km. The traverse was made through
the top of the plume and shows a temperature deficit of about
1.0°C, indicating plume overshoot. Time: 0954 KST, 20 Oct. 68.
51
-------
11
10
ppm
2
Fig. 23
Temperature, S02, and space charge de-
rivative recorded during a horizontal
traverse through, and normal to, the
plume at a distance of 4.1 km. downwind.
Height = 490 m. Space charge device
indicates positively charged particles
in the plume. Time: 0957 EST, 20 Oct. 68.
ppm
Fig. 24
Temperature, S02/ and space charge derivative recorded during a horizontal
traverse through the plume at a height of 370 m. and distance of 4.1 km.
Time: 1000 liST, 20 Oct. 68. The space charge device indicates the presence
of both positive and negative particles, the latter probably from the cool-
ing tower plume.
(Note: Flights through the cooling tower plume have shown negative charge -
opposite to that in the main SO2 plume. Twenty-five minutes after the above
traverse, a pass was made through the moisture plume, 150 meters above the cool-
ing tower - roughly the height of the main stack. The space charge device
went off scale, negatively, and the temperature trace showed an increase of
12°C. Taking the time constant of the temperature transducer and the re-
corder into account, the increase would be a degree or two higher; the
virtual temperature increment was about 4"C. Therefore the effective tem-
perature difference was about 17-18°C above ambient.)
52
-------
Date: 21 Oct. 68 Time: 0640-45 Type Traverse:^/
Distance Height of Max.
Downwind
km
5.1
4.1-
3.7
3.2
2.5
2.0
1.6
1.1
0.9
0.4
Date: 21 Oct. 68
6.8
6.1
5.9
4.9
3.9
3.1
2.5
1.4
Date: 21 Oct. 68
7.6
6.9
6.5
5.7
4.9
4.7
4.3
3.4
2.9
2.7
l.'J
1.7
Top Bottom Max. SO2 S02
mm m PPm
610
410
500
600
570
480
400
390
430
560
Time: 0702-10 Type
440
460
510
680
490
340
420
630.
Time: 0715-21 Type
710
550
490
480
690
740
740
530
410
440
580
. 620
2.42
3.19
4.49
6.94
Traverse:*^
2.11
3.13
4.59
Traverse : *\/
1.45
2.98
3.26
5.23
4.15
53
-------
Date: 21 Oct. 68 Time: 0723 Type Traverse;
Distance Height of Max.
Downwind Top Bottom Max. SC>2 SO2
km m m m ppm
0.6 490
0.7 480 8.40
1.2 400
Date: 21 Oct. 68 Time: 0908-14 Type Traversei
7.4 910.
6.2 570 2.02
5.6 370
4.3 550 2.65
3.7 670
2.7 430 2.99
2.0 260
0.9 520 5.98
0.8 550
Date: 21 Oct. 68 Time: 0915-16 Type Traverse:
1.1 510
1.3 480 6.14
2.8 230
Date: 21 Oct. 68 Time: 0918-22 Type Traverse:
4.7 280
3.5 570 2.56
2.8 680
2.0 540 4.38
1.1 330
54
-------
Date: 21 Oct. 68 Time: 0648-59 Type Traverse
X = 3.3 km
Height, m
4, t
700
630
600
580
550.
520
500
460
390
340
Date: 21 Oct. 68
320
360
390
420
450
480
520
550
580
600
630
690
Background
Max . 503 S02
6.07 0.07
1.02
0.07
2.06
1.08
1.68
3.86
1.11
0.60
0.07 0.07
Time: 0725-37 Type Traverse
X = 3.3 km
0.10 0.10
0.10
0.50
1.20
1.59
2.46
2.24
2.38
3.80
2.76
1.70
0.10 0.10
55
-------
Date: 21 Oct. 68 Time: 0853-0904 Type Traverse:
X = 4.0 km
Background
Height, m Max. SO? SO?
930 0.19 0.08
900 0.78
830 1.81
760 2.28
690 2.71
630 1.19
560 1.14
510 0.27
450 0.32 0.10
Date: 21 Oct. 68 Time: 1005-18 Type Traverse;
X = 4.2 km
880 0.10 0.10
820 2.09
760 0.80
700 1.26
630 1.81
560 0.95
510 0.38
440 0.31
380 1.10
310 0.38 0.11
56
-------
St 0634*39
! ST 0740-44
Fig 25
8
Z, m.
800
600
400
200
Fig 26
21 Oct. '68
St 0846-52
St 0946-48 -
8
10
Z.m.
T\/07O2-10
T -» 0712-13
X. km.
-------
Date: 22 Oct. G8 Time: OG44-50 Type Traverse :
Distance Height of Max.
Downwind
km
7.5
7.4
7.2
4.8
4.2
4.0
3.2
3.0
2.7
1.8
1.6
1.0
Top
m
480
470
490
470
Bottom Max . SC>2
m . m
450
380
380
450
460
390
350
390
so2
ppm
0.80
2.04
2.77
5.78
Date: 22 Oct. 68 Time: 0654-58 Type Traverse:\/
460 1.96
430 3.12
5.4
5.3
5.1
4.2
4.0
3.6
2.9
2.2
1.5
1.1
0.7
490
480
490
470
410
390
350
350
410 6.34
58
-------
Date: 22 Oct. 68 Time: 0718-24 Type Traverse:
Distance Height of Max.
Downwind
km
6.9
6.5
6.4
5.5
5.0
4.8
4.2
3.9
3.7
2.8
2.7
2.4
1.8
1.7
1.3
Date: 22 Oct.
7.1
7.0
6.8
5.7
5.3
4.7
3.7
3.5
3.0
2.5
1.9
1.4
Date: 22 Oct.
0.8
1.2
1.6
2.6
3.4
3.9
Top Bottom Max. S02 S02
mm m PPm
510
410 3.38
480
480
450 3.33
490
500
430 1.92
370
360
380 3.39
440
470
440 4.88
320
68 Time : 0903-0910 Type Traverse
490
450 2.70
380
380
440 3.64
520
520
480 4.00
350
350
450 (10.0+)
530
68 Time: 0911-0913 Type Traversi
500
430 9.03
340
380
470 4.33
'340
59
-------
Date: 22 Oct. 68 Time: 0932-0940 Type Traverse:
Distance
Downwind
km
9.6
9.3
8.6
8.1
7.2
6.5
6.1
5.7
5.0
4.4
3.3
3.1
2.7
2.1
1.8
1.6
1.1
1.0
Date: 22 Oct.
9.8
9.4
9.1
8.3
7.8
7.3
6.7
6.5
6.3
5.5
5.1
4.6
3.8
3.8
3.4
3.1
1.7
1.5
Height of
Top Bottom Max. SO2
m m m
610
540
380
360
490
600
640
550
370
360
560
610
620
460
370
350
520
550
68 Time: 1000-1008 Type
600
480
390
380
450
520
530
480
410
360
420
520
490
480
350
320
570
590
Max.
so2
ppm
4.21
2.99
2.79
4.17
6.96
(10.0+)
Traverse
3.23
3.86
3.12
2.31
3.38
6.16
60
-------
Date: 22 Oct. 68 Time: 0700-0715 Type Traverse:
3.4 km
Background
Height
1
580
510
450
380
320
Date: 22 Oct.
t
250
320
380
460
510
F m
t
610
540
480
420
360
68
4
280
340
420
480
580
Max. SO2 SO2
0.08 0.08
0.74
2.58
2.26
3.33
2.32
3.06
2.50
1.32
0.13 0.07
Time: 0726-0740 Type Traverse
X = 3.4 km
0.10 0.09
0.10
1.56
1.22
2.87
4.00
3.35
1.73
0.70
0.08 0.08
61
-------
Date: 22 Oct. 68 Time: 0915-29 Type Traverse;
X = 3.4 km
Height,
Max. SO?
i
620
570
490
450
370
310
T
600
530
460
420
340
0.11
0.11
3.18
2.26
3.49
3.32
1.01
1.70
1.19
0.21
0.12
Background
SO,
0.11
0.12
Date: 22 Oct. 68
Time: 0945-57
X = 4.8 km
Type Traverse:
560
490
440
360
310
520
480
330
0.13
0.94
0.94
5.20
3.18
1.23
0.39
0.20
0.13
0.17
62
-------
-800
-600
-4OO
-200
temp.. "C.
8 10 12
10 12
ST
0634 - 39
I ' T
ST
0855-0900
12
J2 14
I \ ' T
Z. m.
800
600
400
- 200
Fig. 30
12 14
22 Oct. '68
Z, m.
600
400 -
200 -
10700-08
T0708-15 »
ppm.
63
-------
e/K.
290 -
285-
280-
275-
Z,m.
5OO
400
300
I
0700
Fig. 32
plume top
max SO2
plume base
I
I
I
0800
0900
time.EST
e.°K.
290
285
280
Z, m.
600
-400
1OOO
22 October 1968
Potential temperatures at plume top, 6p, stack top, 9S, and stack base
level plus 20 m., 0g, as a function of time. Heights of plume top,
base and maximum SO2 concentration are shown vs time. The first
flight was from 0630 to 0745 EST and the second from 0900 to 1030.
-------
Date: 23 Oct. 68 Time: 0641-50 Type Traverse :\/
Distance
Downwind
km
7.1
6.9
6.7
5.9
5.5
5.1
4.6
4.2
4.1
3.6
3.2
2.9
2.4
2.1
1.9
1.6
1.3
1.1
Date: 23 Oct .
7.5
6.6
6.4
6.0
5.7
5.1
4.9
4.3
3.7
3.4
2.8
2.2
2.0
1.4
1.1
1.0
Height of
Top Bottom Max. S02
mm m
610
500
430
420
510
650
650
500
470
410
550
650
630
500
410
370
480
530
68 Time: 0710-20 Type
510
400
450
580
610
440
400
400
540
630
640
470
400
410
470
490
Max.
so2
ppm
0.76
(1.0+)
1.41
2.55
4.57
5.04
Traverse
0.50
0.91
1.30
1.78
3.57
6.77
65
-------
Date: 23 Oct. 68 Time: 0908-15 Type Traverse
Distance
Downwind
km
7.1
6.2
5.6
3.8
2.7
2.1
1.5
0.6
0.3
Top
m
900
920
810
Height of
Bottom Max . SO2
m m
650
460
420
750
450
350
Max.
S02
ppm
0.38
1.53
4.77
Date: 23 Oct. 68 Time: 0941-48 Type Traverse:
6.4 400
5.1 330
3.9 610 1.11
2.9 840 1.18
2.1 1060
66
-------
Date: 23 Oct. 68 Time.- 0653-0707 Type Traverse:
X = 4.0 km
Background
SO,
0.08
Height, m
t
250
310
380
440
500
560
630
690
Max . S(
0.20
0.39
0.43
1.62
1.56
1.38
1.01
0.06
0.06
Date: 23 Oct. 68 Time: 0723-42 Type Traverse:
X = 2.0 km
T I
0.12
310
390
450
500
580
630
700
160
220
290
350
420
480
530
0.11
0.38
0.39
0.70
0.52
0.83
0.63
1.53
2.56
2.83
2.89
2.33
0.94
0.08
0.08
67
-------
Date: 23 Oct. 68 Time: 0917-37 Type Traverse;
X = 2.1 km
Height, m Max. SO2
Background
S02
250
310
380
450
520
570
640
690
760
830
880
950
1020
0.20
0.94
0.48
1.08
0.73
0.12
1.
1.
2.
.74
.87
.52
0.52
1.12
0.68
0.72
0.10
0.10
68
-------
1 1
ST 0633-37
St 0900-05
Fig. 33
1
4 6 8 10
temp., °C.
Z. m.
800
600
400
200
I I
Fig. 34
\
\
T ^ 0653- 0707
X = 4.O km
, I . I
0 1 2
Max. SO2, ppm
Z,m.
23 Oct. '68
600
400
200
Fig. 35
1
0641-50
0710 - 20
j_
I
X. km.
69
-------
Date: 24 Oct. 68 Time: 0645-50 Type Traverse :\/
Distance Height of Max.
Downwind Top Bottom Max. 862 S02
km m m m ppm
6.4 950
4.9 640 1.29
4.4 500
3.3 500
2.1 790 2.57
1.7 890
Date: 24 Oct. 68 Time: 0717-21 Type Traverse:\/
4.3 520
3.4 700 2.02
2.5 880
1.2 520 8.18
Date: 24 Oct. 68 Time: 0736-38 Type Traverse:
3.6 970
2.4 660 2.17
1.5 440
70
-------
Date: 24 Oct. 68
Time: 0655-0714 Type Traverse:
X = 4.0 km
Background
Height, m Max. SO2 SO2
390
470
520
580
640
710
780
840
900
960
1020
1070
0.11
0.14
0.62
0.59
1.36
1.50
1.67
1.15
1.94
1.83
0.86
0.05
0.07
0.05
Date: 24 Oct. 68
t
390
460
520
580
640
710
760
840
890
Time: 0723-35
X = 2.5 km
0.09
0.32
1.40
2.24
3.13
2.75
2.19
2.20
0.06
Type Traverse:
0.08
0.06
71
-------
Z, m.
1ooo^
800
600
4OO
200
Fig. 36
St 0637-43
St 0742-47
6 8 10
temp., °C
12
Fig. 37
T ^±
X =4.O km
O655-0714
I .
24 Oct. '68
T i±
X=2.5 km
0723-35
J
Z.m.
Fig. 38
1 2
Max, SO2, ppm
1OOO
800
\
6OO
4OO
200
-------
PART III - ANALYSIS
BEHAVIOUR OF HOT PLUMES UNDER STABLE CONDITIONS^
Z/
Betsy Woodward Proudfif*
ABSTRACT
Using an instrumented helicopter, measurements have been
made of the Keystone plant near Indiana, Penn. The data show that
plume rise is primarily a function of stability in a highly stable environ-
ment. As the environmental stability decreases the effect of the mean
wind speed on the plume rise increases. It is argued that values for the
mean wind speed and average stability in the vertical region from stack
top to plume top be used when predicting plume rise. The term,A0» the
difference in potential temperature between stack top and plume top, is
introduced. Employing the concept that A0 is the maximum potential temp-
erature difference that can be penetrated, it is shown how plume rise can
be estimated easily and quickly with the aid of diagrams.
J/ Paper No. ICFTC-NAFTC-4 sponsored by the Institute of Combustion
and Fuel Technology of Canada for presentation at the NORTH AMERICAN
FUEL TECHNOLOGY CONFERENCE, Ottawa, Canada, May 31-June 3,
1970. The Institute shall not be responsible for opinions or statements
advanced in papers it sponsors.
2/ Sign-X Laboratories Inc., Essex, Conn., U.S.A.
73
-------
I. Introduction
This paper describes and evaluates plume rise during stable conditions.
Previous research has been interested, primarily, in obtaining plume rise
in a neutral or unstable environment so that the concentration of pollutants
on the ground downwind of the stack could be determined. Under stable con-
ditions, the plume from a tall stack will generally not reach the surface.
It is, however, necessary to consider plume rise under stable conditions in
order to answer the following important questions. Will the plume penetrate
a stable layer? What will be the height of, and pollution concentration in,
the plume at various distances downwind just prior to inversion break-up
(fumigation)?
A method of calculating plume rise under stable conditions, based on
data obtained from studies of the Keystone plant near Indiana, Penn., will
be presented.
2. Data Acquisition
Under contract from the U.S. Public Health Service, Sign X Laboratories,.
Inc. undertook a study of the plume rise from a large power plant in
western Pennsylvania during May and October, 1968. The Keystone Generating
Station has a capacity of 1800 row from two identical units; associated with
each unit is one 800 ft. (2kk m.).stack and two 300 ft. cooling towers. Only
one unit was operating during the two field expeditions.
A Bell kJ-G helicopter was instrumented so that continuous measurements
of temperature, wet-bulb depression, pressure height,and sulfur dioxide could
be recorded. The time constants of the first three parameters are less than
0.2 seconds; the time constant of the S0£ unit is between 2 and 2.5 seconds.
Also recorded was the output from a device that measured the change in space
charge and which has virtually instantaneous response. Since the particles
in the plume have a charge (positive), the device can provide good measure-
ments of the plume boundaries.
The sensing probe was mounted on a strut of the helicopter, well forward
of the downwash. The helicopter was flown at an airspeed of 55 to 60 mph
during all traverses and soundings. Each flight lasted about 1 1/2 hours.
Temperature soundings were made upwind of the stack at the beginning and
end of each flight. In addition, upwind temperatures at plume top height
and stack top height were obtained at intervals throughout the flight.
Two basic types of traverses were flown in order to define the plume
geometry and $62 concentration. One consisted of a series of horizontal
traverses through, and normal to, the plume at a fixed distance downwind.
These traverses were made at intervals of 30 meters from the top to the
bottom of the plume.
The data obtained from one such series taken at 3*4 km downwind are
shown in Figs. 1, 2 and 3. Examples of raw data gathered during three of
this series of ten traverses are shown in Figs, la, b, c. The maximum S02
74
-------
I km
8
H
100 i
5
0
Fig. I
Fig. 3
Fig. la, b, c. SO, and space
charge derivative during horizon-
tal traverses through top, center,
and bottom of plume respectively
at a distance of $.k km downwind.
Fig. 2. The maximum 502 va'ue as
a function of altitude obtained
on each traverse during ten hori-
zontal traverses through the plume.
(The circles at 775m, 680m and 550m
are the max. values drawn in Fig.
la, b, c.)
Fig. 3- Isolines of $©2, drawn
from SC>2 values obtained during
the series of ten horizontal
traverses.
75
-------
values from these three traverses, plus those from the seven other traverses
during the series, are plotted in Fig. 2. Fig. 3 shows isolines of S02, drawn
from values obtained during the series. The viewer is looking down the plume.
There was considerable directional wind shear at the time, which probably
accounts for the plume tilt.
The second pattern consisted of a series of climbing and descending traverses
through the plume from a distance of about 8 km. downwind. This pattern would
take 5 or 6 minutes to complete, compared to 10-20 minutes for completion of
a series of horizontal traverses.
Wind speeds and directions were obtained by PHS personnel every half hour
using double theodolites. Interpolated values for every 50 meters were
supplied. There was often early morning ground fog which prevented one or
both theodolites from tracking the pibal. When this happened the average wind
speed throughout the plume depth was obtained by determining the ground speed
of the helicopter during a series of slanting traverses and subtracting the
indicated airspeed. Comparision of these derived values with those obtained
by double theodolite showed differences that were usually less than about .0.5
m/s.
The stack parameters (velocity and temperature of effluent} were supplied by
PHS. The velocity was about 20 m/s and the temperature about 125°C above
ambient. Stack diameter is 10.3 meters.
3. Definition of Terms
Plume rise is dependent upon the wind speed and atmospheric stability in the
vertical region from stack top to plume top. This height difference is
often measured in hundred of meters when large sources are considered (and we
are concerned here only with comparatively large sources).
The wind speed at stack top level may differ from the mean wind in the
vertical region from stack top to plume top by a factor of two or more. There-
fore the mean speed, u , has been used in all computations in this paper.
The plume may often penetrate a suable layer and enter a neutral layer
aloft or it may rise through a neutral or slightly stable region to one of
increased stability. In either situation the potential temperature gradient,
ae/dh, at stack top level (or at any fixed height) is not representative of
the atmospheric stability which determines plume height. In this paper the
stability parameter includes the term A6/&h, where A8 is the difference in
potential temperature, and aK the difference in height, between stack top and
plume top. (See Fig. *».)
Plume rise Is generally defined as the height of the plume centerline
above the stack top. This height, designated &hm in this paper, is defined
as the height of the plume top above stack top, Ah, minus one half the plume
thickness, AZ. (ahm= ah- az/2)
76
-------
The two heights, Ah and &hm, will generally change with increasing distance
downwind. Under moderate or highly stable conditions the plume will rise and
then may descend. It will have "overshot" its equilibrium level. Temperatures
of up to 3°C below ambient have been measured in the upper portion of the plume
in this "overshoot" region. At Keystone this region was 1 or 2 kilometers
downwind; the equilibrium level was reached at 3 or ^ km and beyond this dis-
tance the plume height and thickness remained fairly constant.
Under neutral or slightly stable conditions the plume top height and
plume thickness increase with increasing distance downwind. At Keystone,
temperature excess was generally measured in the plume center about 2 km.
downwind. At about 3 km. the difference was negligible.
Therefore, plume rise, for all cases from neutral to highly stable,
was determined from plume boundaries measured at a distance of from 3 to
k km. downwind.
k. Reduction of Data
Plume heights and potential temperatures were determined and plotted as a
function of time for each flight day. An example is presented in Fig. 5-
This diagram shows the potential temperatures at plume top level, 6p, stack
top, 8S, and 20 meters above stack base, 8g, all measured just upwind of the
plant. It can be seen that there was a strong ground based inversion at
the start of the first flight and that the second flight continued until
inversion break-up. It should be noted that 9g and 6_ are at fixed heights
whereas the height of 6p varies as the elevation of the plume top increased
as a function of time.
From approximately 60 hours of such flight data, 20 cases have been
selected for analysis. (See Table I.) The average wind speed varies from
-------
-J
GO
wind speed and temperature (left half of figure) are shown as a function
of pressure height. The sloping lines are dry adlabats. I.e. each line
represents a constant value of potential temperature. The outline of a
typical plume, under stable conditions, is shown on the right. (Pressure
height may be taken to be equivalent to actual height.)
H
«Z
I
»e/»h
*e/az
V.
NOMENCLATURE
height of plume top above stack top ()
height of plume center)Ine above stack top ()
height above stack base ()
pressure height ()
plume depth ()
potential teaperature at plume top (*K)
potential teaperature at stack top (*K)
potential temperature at stack base plus 20m (*K)
stack gas teaperature (*X)
blent temperature at stack top (*K)
lapse rate between stack top and plume top
potential temperature gradient
stack gas velocity (a/si
acceleration of gravity (a/sz)
mean wind speed between stack top and plume top («/»)
Mind speed at plume top (m/s)
wind speed at stack top (m/s)
diameter of stack (m)
- stability parameter
- buoyancy
-ftfl.
Ah
J»0
M*
Ml
1ST
Fig. 5
16 Oct. 1968
Potential temperatures at plume top,6 , stack top, 8,. and stack
base level plus 20 m., ., as a function of time. Heights of
plume top and bottom, obtained from horizontal and slanting tra-
verses, are shown as solid bars. The heights of max. S02 are
shown as dashed bars. The plant output. In megawatts, is also
presented. The first flight was from 0630 to 07*5 EST and the
second from 0900 to 1030.
-------
Fig. 7 shows a plot of the maximum 502 concentrations obtained during
slanting traverses for two days. One plot represents concentrations
obtained during a 'tO min. period on 20 Oct. when the average wind speed
was about 8 m/s and stability about 1.5 deg./IOOm. The other plot re-
presents data during a kQ min. period on Oct. 23 when the average wind
speed was about 12 m/s and the stability 0.4 deg./IOOm. Further analysis
of these, and other plots, should yield values of ffy and 6 for various
wind and stability conditions.
5. Analysis of Results and Comparison with Various Formulae
The data for the 20 cases presented in Table I may be plotted in
numerous ways. One plot is shown in Fig. 8, which shows the difference
in potential temperature between stack top and plume top, £6, as a
function of stability. This is not a usual presentation; its value as
an aid for predicting plume rise will be discussed subsequently. For
the moment, it should be noted that at the higher stabilities (i.e. above
about 0.8 deg./IOOm) the potential temperature difference remains fairly
constant and is independent of wind speed. As the stability decreases,
the effect of wind speed increases.
The height of the piume center!ine, above stack top, Ahm, for each of
the 20 cases, is plotted in Fig. 9 as a function of stability. The two
dashed lines represent the centerline height if the ASME formula (1)
for stable conditions
Ahm=2(F/OG)-33 []]
i s applied.
The two dotted lines represent the result from Holland's equation (2):
[1.5 + 2.68 x 10"3p ]V[
V T
[2]
Values were chosen for the exit velocity, Vs, and temperature excess,
Ts~Ta» °f the effluent so that F, the buoyancy flux, would equal 2.2 x
103, the average value of the Keystone data. The atmospheric .pressure, p,
in [2] was chosen to be 984 mb., the approximate pressure at the Keystone
stack top level.
Holland suggests that a value between 0.8 and 0.9 times the ahm obtained
from the equation should be used for stable conditions. To obtain the slope
for the two. dotted lines in Fig. 9 values of 1.0, 0.9, and 0.8 times the
Ahm from 12] were applied when the stability equaled 0.1, 0.23 and 0.6
deg./IOOm respectively.
The same conclusion may be drawn from Fig. 9 as from Fig. 8; i.e. the plume
rise at the higher stabilities is independent of wind speed but at lower
stabilities the wind speed becomes increasingly important. The data fits
the Holland formula best at low stabilities and fits the ASME best at
higher stabilities. The former is often used to determine plume rise
under neutral conditions because it is "conservative", i.e. it tends to
underestimate. It should not, however, be applied to highly stable con-
ditions, especially at low wind speeds.
79
-------
xx x.x
' X
X
ri i A A A ' A 'fc
Stability.
o u< 6.0 m/a x 8. 0 m/allm/a
Fig. 6 (above). Plume thickness, az, as a function of
stablIity.
e u< 6.0 m/s
6.0 m/s< D « 8 m/s
ii 8.0 m/s < u< II m/s
o u > 11 m/s
Fig. 8 (above). The difference In potential temperature between stack top
and plume top vi stability, for various (approximate) wind speeds.
0,
IO
\
\
«v
23 Oct.
\
\
\
2 4 6 I 10
km. a»wnwlnd
r'y- / Maximum vdluct vl SO, nblained during
(raveisr-. on 20 Oct. (circle*) anil 23 Oct. (crosses) as
a function of distance downwind of the slack.
I CO
HI
s
4
i 3*i-
Stability. dao/,00,,,
"TA-
Fla>«
o u < 6. 0 m/a
A 6. 0 m/»< u < 8 m/a
x 8. 0 m/a< u < 11 m/a
Q u > 11 m/a
Fig. 9 Observed plume rise, for Keystone data, as a function of
stability. The two dashed lines represent the ASMS formula for stable
conditions; the two dotted lines represent Holland's formula.
80
-------
(It should be noted that if plume rise is calculated from the ASME
equation [1] using data from the Keystone studies, and compared to the
measured plume rise, then 20% of the calculated values are within 10%
of the measured values, when values for the wind speed.and potential
temperature gradient at stack top level are employed. If, however, u and
68/Ah are used instead, then 60% of the calculated values lie within \0%
of the observed.)
Fig. 9 indicates that &hm for the Keystone data is proportional to
about the -0.6 power of the stability and the zero power of u above
about 0.8 deg./lOOm. As the stability decreases the data indicates
that the magnitude of the stability exponent should decrease and that
the magnitude of the wind speed exponent should increase.
J_f_ we assume that the plume rise from a comparatively tall stack,
which emits an effluent at a velocity at least 1.5 or 2.0 x the wind
speed at a temperature significantly above ambient, is dependent only
on the stability, G, average wind speed, u, and buoyancy flux, F, then
we may wri te:
ahmo
-------
- 200 -
- 100 -
n»io
If, II
FI9- I0
Plum rise v>. F1'2 u"' G
Keystone data for stabili-
ties between .16 and .tk
deg./IOOm
-
Plum rise v>. (F/uG)1'3
Keystone data for stabili-
ties between .6 and 1.2
deg./IOOm
Plum rl» vs. F1'* C"3/B
Keystone data for stabili-
ties between .76 and 1.54
deg./IOOm
.-!/*
N _
>00l
4
S
4 -
3
2
X
/
\
\
. '. A
Wind
Tm». °C
Figure 13
B2
Wind toeed and temperature are jhown at function of prenure height. H. Caie I Ihowl the probable
plumr uulllnr from a ISO m. slack and the Case III thoui the plume outline If the Itack lop were at
/bO m.
-------
This now becomes a mathematical exercise and it is better left to the
mathematician. Suffice it to say that the exponents a, b and c, and
the constant, C, are a function of both wind speed and stability.
The writer would prefer to use a series of diagrams, based on both the
formulae and observed meteorological data, when plume rise is to be
determined. This approach is described in the next section.
6. The Use of Diagrams
It has been strongly recommended that the mean wind speed, u, and
stability, a8/Ah, between stack top and plume top be employed when calcu-
lating plume rise. However, actual values of u and A6/Ah cannot be
obtained until the plume top height is known. Furthermore, it has been
suggested that the appropriate equation, e.g. [1], [3], [b], is a function
of the stability, 4.8/Ah, and perhaps also u. It would be a time consum-
ing process to arrive at the calculated plume rise height, Ahm, when
there .is a significant change in the wind speed and stability with height.
In Fig. 8 it has been shown, for the Keystone data at stabilities above
about 0.8 deg./lOOm, that the potential temperature difference between
stack top and plume top, &6, is independent of wind speed. (It should
be noted that under highly stable conditions the wind speed seldom
exceeds about 8.0 m/s.) Furthermore, A6 remains comparatively constant.
above about 0.8 deg./lOOm. It is roughly 3.2°K. Since stability is
defined asAdAh, a good first approximation for plume top height for
stabilities above about 0.8 deg./lOOm may be easily obtained:
Ah s 3-2/stabi1ity
Fig. 8 is applicable when the buoyancy flux, F, is approximately
2.2 x 10^. It is based on the Keystone data where the range of F, for
the points plotted, is from 1.98 x 10^ to 2.7 x 103.
By applying [5] and utilizing Fig. 6 Cah = Ahm + AZ/2) we may obtain
a diagram that gives 66 as a function of the buoyancy flux for various
stabi 1 i ties. (See Fig. ]k.)
Let us proceed with some examples.
6.1. Examples
We will determine the stack height and buoyancy flux required in
order that the effluent from a proposed fossil fuel plant wilt penetrate
a ground based stable layer. Assume that the proposed site is in a
valley that lies roughly north and south.. The valley walls may be
only a few hundred meters high, but their height is such that there is
generally down valley flow during the night and early morning hours.
Measurements made at the proposed site show that the typical profiles
of wind speed and temperature, during the autumn months, are similar
to those drawn in Fig. 13- An isothermal layer extends to about ^SOm.
Above tliis layer the lapse rate is neutral (adiabatic) and there is
an increase in wind speed. Assume also that the wind direction above
the stable layer is westerly (i.e. cross valley).
83
-------
Case I
Let us determine the plume rise if the stack top were at.150 m and the
exit velocity and temperature excess of the effluent were such that the
buoyancy flux, F, equaled 1.6 x 10*. When the temperature profile is
isothermal, then the stability, A6/Ah, is about 1.0 deg./lOOm.
The diagram Fig. 14, shows the difference in potential temperature
between stack top and plume top, &6. as a function of the buoyancy
flux and stability. If F = 1.6 x 103 then It can be seen that the
potential temperature difference, &6 , is 2.82° when the stability,
A8/Ah, is 1.0 deg./lOOm. The height of the plume top above stack top,
Ah, is obviously 282m (2.82° ? I0/100m) which is 432 m. above the ground
(ISO + 282). The plume depth, AZ, is about 200 m. when the stability
is 1.0 deg./lOOm. (see Fig. 6); therefore the height of the plume
center!ine above stack top, Ahm, is 182 m. Uhm = Ah - Az/2). The plume
outline is showh in Fig. 13. It has not penetrated through the stable
layer, it will probably run along the valley, the depth is comparatively
shallow and, when fumigation occurs, the ground level concentrations may
be unacceptably high.
Case II
To insure that the plume top enters the neutral layer and reaches
above, say, 500 m, Ah must equal 350m., (500m - 150m). At 500m 6p
would equal 28*4.9° and at stack top level, 6S = 282°; therefore
&8 = 2.9, (6p - 9S), and &6/Ah must be .83 deg./lOOm. Referring
to Fig. 14 it can be seen that this point, (.83, 2.9), lies roughly
at F = 2.2 x 103. A buoyancy flux greater than this would insure that
the plume top would reach 500m and enter the neutral layer.
Case I II
Let us assume that the stack top were raised to, say, 250m. With a
similar buoyancy flux, (2.2 x 103), the plume top would obviously
penetrate into the neutral layer which has a potential temperature of
285°. The potential temperature difference wi11 equal 2.0°, (6p * 285°
and 8S = 283°) and the average stability, ad/Ah, will decrease "because
of an increase in Ah). Fig. 14 cannot be used, because it is applicable
only at moderately high stabilities (above about 0.8 deg./lOOm).
So far we have not been concerned about the wind speed, u, because
we have been dealing with moderately high stabilities. We turn now to
Fig. 8, which is a plot of A6 vs. stability, A8/Ah, for various mean
wind speeds and is applicable when the buoyancy flux is approximately
2.2 x 103.
If 46 = 2.0° and u * 7 m/s, then the stability, A6/Ah = 0.4 deg./lOO
and Ah = 500ml If u*8 m/s then Ad/oh = 0.5 and Ah = 400m. The mean
wind speed, u, between stack top, at 250m, and estimated plume top,
at 650m or 750m. (250m + 400 or 500m) should now be determined from the
wind profile in Fig. 13. If Ah = 500m, then u «8.2 m/s and if Ah = 400m,
then 0*7.5 m/s. To narrow the 100m range of estimated Ah, we refer
again to Fig. 8 and find A0/Ah when u*7.8 m/s (and 66 = 2.0°). It is
about .46 deg./lOOm; therefore Ah -440m. .
84
-------
AG.
deg.
4.2
3.4
3.O
2.6
--0.8
1.2
Fig. 14
1.6
2.0
2.4
IOJ
2.8
The potential temperature difference, A6, between stack
top and plume top is shown as a function of the buoyancy
flux, F, for various stabilities. The stability is de-
fined as &9/Ah, where Ah is the difference in height be-
tween stack top and plume top. Therefore, the height
di f ference, ah, equals a8 f stability. This diagram is
based on the data shown in Fig. 12, which fits the
equation,
ahm = 2.36 (F1'" G'3'8) - 114
From Fig. 6, the plume thickness, A.Z, has been determined
for the various stabilities and
ah =
Time
EST
16 Oct.
0650-0740
0915
0930
0955
1010
1030
17 Oct.
061*5
0715
0915
18 Oct.
0650
0725
20 Oct.
0650-0720
0905-0940
0955
10.10
1020
23 Oct.
0650-0740
0910-0930
24 Oct.
0650-0730
26 May
0700
u
m/s
6
5
5
5
5
4
8
8
7
9
9
8
6
5
5
6
12
7
4
7
.0
.2
.2
.4
.2
.8
.5
.8
-.0
.8
.5
.0
.8
.8
.8
.2
.5
.0
.9
.5
A6
deg.
3-3
3-2
3-2
3-1
3-0
2.7
1.8
2.0
2.1
1.7
1.5
3.5
3-4
3-5
3.4
3.2
1.7
1.1
2.4
3-0
A6/Ah
xlO'2
1.20
1 .05
.96
-83
.76
.41
.64
.60
.45
.45
.38
1.54
1.42
1.35
.96
.85
.42
.16
34
1.07
'/G
xlO3
2
2
3
3
3
7
4
4
6
6
7
1
2
2
3
3
6
18
8
2
.47
.82
.10
.59
90
.30
.62
-98
.57
.57
.85
-94
.10
.20
.11
.51
.80
.10
.56
.73
X
2
2
2
2
2
2
2
2
2
2
2
1
2
1
1
1
2
2
2
1
?03
.21
.24
.24
.23
.23
.23
.15
.17
.15
.15
.15
.98
.03
.99
99
.99
.34
.70
59
.99
&z
m
180
220
230
300
300
550
225
300
420
250
310
150
165
180
295
300
420
650
480
150
&h
m
275
305
335
375
395
665
280
335
465
375
395
230
240
260
355
375
400
690
700
280
*hm
m
185
195
220
225
245
390
168
185
255
250
240
155
158
170
207
225
190
365
460
205
Table I
oo
ui
-------
From Fig. 6, ztr360m, so that ahm«260m., (kbOm - 360m/2). The
suggested plume outline is drawn in Fig. 13- The exact value of Ah
(or ahm) is not important. It wi11 be about bkQm (or 260m) at a
distance of about 3 km. downwind and will continue to rise.
Thus, in our hypothetical example, we have determined that if the
stack top height is 250m., and the buoyancy flux about 2.2 x 10^, then
the plume will rise above the stable layer into a region of increased
wind speed where it will be carried across the valley. The plume depth
will be comparatively great and when fumigation occurs, .the ground
level concentrations will probably be acceptable.
7. Conclusions
Plume rise is dependent upon the mean wind speed and average stability
in the vertical region from stack top to plume top.
A single formula will not accurately predict plume rise for all
ranges of stability and wind speed. A series of equations must be
employed; the specific equation to be used is dependent upon the mean
wind speed and average stability.
By introducing the concept of a8, the maximum potential temperature
difference that can be penetrated, the plume rise can be estimated
comparatively easily and quickly with the aid of diagrams that are
based on observed data and a series of equations.
8. Acknowledgements
The field studies at Indiana, Penn., and the subsequent reduction of
data, were supported by the U.S. Public Health Service under contract no.
PH 86-68-9^. Further analysis and preparation of this paper were sup-
ported by Sign X Laboratories, Inc.
References
1. The American Society of Mechanical Engineers, Hay, 1968:
Recommended Guide for the Prediction of the Dispersion of Airborne
Effluents.
2. Holland, J.Z., 1953: A meteorological survey of the Oak Ridge
area. 55^-559 Atomic Energy Comm., Report ORO-99, Washington, D.C.
86
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