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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100R70010
2O3 767-17OO
LABORATORIES, INC.
ESSEX. CONNECTICUT O6426
Final Report
On
Plume Rise From Keystone Plant
Contract No. PH 86-68-9^
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 SO2 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.^
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 SO2 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 SC>2 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 was followed by traverses at 200 foot
intervals until 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. SO2, 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 S02 Data
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 SC>2 reading.
However, the only gas which appears practically to cause a significant
interference is CC>2. When determining low ambient SO2 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 SO2. A series of
calibration curves are then employed to determine the SO2- 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 S02 and 400 ppm C02,
and 42% for 0.2 ppm SO2 and 1000 ppm CO2.
At higher S02 values the change in the indicated chart reading
varies less with the change in CO2- 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 CO2 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 C02 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 C02 concentration in the
plume. As the SO2 value increases, the effect of changes in the C02
concentration decreases. For example, close to the stack, a con-
centration of 30 ppm SO2 and 2100 ppm CO2, above ambient, may be ex-
pected. At these high S02 values the indicated reading is the same
whether the CC>2 is several hundred, or several thousand, ppm. Downwind,
the SO2 and C02 values will decrease and it is reasonable to assume
they will decrease proportionally. For example, at a point downwind
where the SC>2 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 CO2 is equivalent to the width of the
pen on the chart record.
For all practical purposes the effect of CO2 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
SO2 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 analyzer 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 SC>2 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 S02 max. and height, for each series of horizontal traverses,
are presented in tables in Part II. The indicated background SO2
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 SO2 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 S02
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 SO2• When the
plume is left, a "tail-off" appears in the SC>2 trace. By comparing
the S02 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 S02 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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H,m
-700
-600
Fig. 3 Traces of pressure height, temperature, SO2 and space charge derivative,
from chart record between about 0707-0711 EST, 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.
200
300
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
10
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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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
14
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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 S02 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 SO2 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 S02
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 issdrawn.
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, Ce.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
SC>2 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
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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 plume. Also
during the second flight the plume appeared (visually) to break into
"rolls" or "waves" nornUl 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 *>/ Series of slanting traverses toward stack
T\7I 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
3.0
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
2.6
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 of
Bottom
m
450
400
410
0854-0902
430
410
280
310
400
370
Max.
m
490
470
450
Type
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
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
I
590
520
440
390
360
Max. SO2
0.18
3.64
(10.0+)
6.98
1.60
Background
so2
0.18
0.18
Date: 25 May 68 Time: 0903-19 Type Traverse:
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
0.18
0.18
0.19
23
-------
\
_ 0651 - 58
st
Fig. 6
\
i
*
\.
x-
V
>
\
i
•
\ 0843-48.
\
1OO's m.
6
11 12 13 12 13 1-4 0
temp., °C
25 May 68
X= 1.1 Km.
•— OS03-11 I
-«-- o^n-n |
i .
8
max. ppm
10
-------
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: N/
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
t 1
100
240
280
350
380
420
470
510
550
0.06
0.22
4.92
5.04
4.20
5.33
1.00
0.32
0.06
0.06
0.06
26
-------
X100
6
5
4
3
2
1
I . ' I
\ -
\
\
\f
*\
•
\
*
\
\
»
St 0610-15 \
J^-
4
V
\
\
/
\
1
•'
•
/ -
/
/
/
1
V
^'-^^^
\
/
VVi 1 . I
1 \ •
\
\
*
\
\
\
•
I
\
\
\
*
\
•
\
St 0710-15 j
/
I
f
^/^
I
i
v..
/
i
i
\
\
\
/
\
\
/
/
\ -
i i
i • i i • i
\
- \
\
\
\
\
\
\
•
\
•
•
\
\ ST 0844 - 50
\
I
1
\
\
\
\
\
\
1
\
\
\
\
\.
\
.
i
t 1 , i . i V
i., m.
x1OO
6
5
4
3
2
1
10 14 16 12 14 14 16 18
temp., °C
Fig. 8
26 May '68
tempi, 8C
p. 27
-------
Date: 16 Oct. 68 Time: 0659-0705 Type Traverse:
Distance Height of Max.
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
Date: 16 Oct.
7.5
7.2
7.0
6.8
6.5
5.8
5.7
5.3
5.1
4.9
4.3
3.8
3.5
3.0
2.4
2.0
1.4
0.6
Top Bottom Max. SO2 S02
mm m ppm
490
420 4.61
370
380
420 4.72
460
460
400 5.20
330
340
400 6.68
510
490
400 (10.0+)
340
350
380 (25.0+)
440
68 Time: 0716-23 Type Traverse
540
450 2.56
420
420
450 3.29
540
540
470 3.21
420
420
480 3.15
550
540
460 3.27
350
340
410 6.21
530
28
-------
Date: 16 Oct. 68 Time: 0738-42 Type Traverse:
Distance Height of Max.
Downwind Top
km m
4.6 480
4.3
4.1
3.7
3.4
2.9 500
2.3
2.1
1.7
1.4
1.0 520
Bottom
m
390
390
380
390
Max. SO2
m
430
420
450
430
S02
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
0.5 540
0.8 500 7.98
2.0 340
29
-------
Date: 16 Oct. 68 Time: 0933-38 Type Traverse: \/
Distance
Downwind
km
6.0
5.8
5.6
4.7
4.0
3.6
2.6
2.4
2.1
1.4
0.7
0.5
Height
Top Bottom
m m
540
450
400
540
510
380
400
of
Max. SO2
m
500
490
480
500
550
Max.
S02
ppm
2.29
3.11
2.00
4.41
4.96
0.3 570
Date: 16 Oct. 68 Time: 1005-1011 Type Traverse:\/
6.1
6.0
5.9
5.1
4.2
3.9
3.0
2.9
2.7
2.0
1.1
0.8
600
610
570
650
560 0.83
530
460
560 1.17
540 1.13
450
460
620 2.9
Date: 16 Oct. 68 Time: 1027-32 Type Traverse;v
6.6 700
6.1 580 1.10
5.5 460
4.4 480
3.2 670 1.30
2.4 780 1.59
1.6 840 2.08
0.9 890 2.55
0.7 910
30
-------
Date: 16 Oct. 68 Time: 0650-56 Type Traverse
X = 2.9 km
Height, m Max. SO2
Background
S00
1
570
540
500
430
370
310
0.10
2.42
2.70
3.60
1.10
0.36
0.10
0.10
Date: 16 Oct. 68
560
490
440
370
310
0.13
2.57
3.40
2.20
0.15
Time: 0707-12 Type Traverse:
X = 2.0 km
0.13
0.15
Date: 16 Oct. 68
510
480
450
380
320
0.10
0.10
2.98
1.80
0.29
Time: 0730-37 Type Traverse:
X = 2.9 km
0.10
0.13
31
-------
Date: 16 Oct. 68 Time: 0920-30 Type Traverse:
X = 2.9 km
Background
Height, m Max. SO2 SO2
T
270
320
380
450
510
580
620
490
550
600
0.18
0.18
1.11
2.72
3.23
3.23
2.13
1.18
0.19
0.18
0.18
0.18
0.18
Date: 16 Oct. 68 Time: 0940-55 Type Traverse:
X = 2.0 km
I T
0.20
640
580
450
400
320
260
550
480
420
350
0.20
1.90
2.01
2.20
2.40
2.09
1.88
0.71
0.52
0.29
0.20
Date: 16 Oct. 68 Time: 1012-24 Type Traverse:
X = 3.0 km
0.20
630
580
530
450
390
320
0.47
1.83
1.13
0.58
0.71
0.22
0.20
32
-------
Z,m
COO
40O
200
Fig. 10
z
xlOO-m
Ill
Fig. 9
S | 0 725 - 28
St 0904-09
S 4 0959-1002
10
15
temp. °C.
20
16 Oct.'6 8
3-it
i
T V 0716-23
X, km
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
360
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: "^
500
480 7.30
34
-------
Date: 17 Oct. 68 Time: 0722-29 Type Traverse:
Distance Height of Max.
Downwind Top Bottom
km mm
6.6
6.3 390
5.8 380
5.4
4.9 560
4.2 570
4.1
3.5 . 380
3.1 400
2.5
2.3 560
1.7 540
1.4
1.1 360
Max. SC>2 S02
m ppm
480 0.90
460 1.23
540 2.21
520 5.17
430 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 :
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.
1 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 >l
250
320
380
440
490
520
540
560
600
630
650
690
710
770
Background
Max. SO? S02
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 ••
20 22
temp., 8C
Z.m.
600
400
200
Fig. 12
T 5±
= 2.9 km
0643-52
O652-56 »
1 2
Max. SO2, ppm
Z.m.
17 Oct. '68
6OO
400
200
Fig. 13
5.17
X
\
N
1.23
s
0-90
0722-29
X, km.
37
-------
Date: 18 Oct. 68 Time: 0657-0701 Type Traverse
Distance Height of Max.
Downwind
km
5.0
4.8
4.3
3.9
3.5
3.4
2.9
2.4
1.7
Top
m
620
540
600
Bottom
m
420
430
360
Max. S02
m
550
520
500
S02
ppm
1.61
0.93
3.58
Date: 18 Oct. 68 Time: 0708-15 Type Traverse:
510 1.32
510 1.22
490 1.32
550 1.12
520 2.13
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
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
38
-------
Date: 18 Oct. 68 Time: 0734-40 Type Traverse:
Distance Height of Max.
Downwind
km
6.2
5.9
5.6
5.3
5.1
4.3
4iO
3.6
2.5
Top Bottom Max. S02
mm m
630
520
430
430
490
500
380
350
530
so2
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. SO2 SO?
270 0.10 0.10
390 0.40
460 1.62
490 1.99
520 1.93
540 2.12
570 2.13
610 2.50
640 2.40
660 0.09 0.09
700 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
4O
-------
Date: 18 Oct. 68 Time: 0920-34 Type Traverse
X = 5.7 km
Background
Height, m Max. SO2 SO?
0.15
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
0.14
Date: 18 Oct. 68 Time: 0948-1002 Type Traverse:
X = 3.9 km
* . .
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
-------
Z. m.
St 0634-39---
St 0858-0903-
S t 1014 - 21
Fig. 14
14 16 20
temp.,°C.
22
Z, m.
800
6OO
40O
200
18 Oct. '68
Fig.15
r £+ 072O-28
'4.0km 0728-33 « —«
i i i ,
1 2
Max. ppm
600
400
\
\
\
o
/
o .
200
T V 0708-15
T V O717-19
Fig 16
1
X, km.
42
-------
Date: 20 Oct. 68 Time: 0635-39 Type Traverse:
Distance
Downwind Top
km m
4.6 460
4.3
4.2
3.7
3.6
3.1 470
2.3 480
1.9
1.7 .
1.5
1.0
0.7 470
Height of
Bottom Max. SO2
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+)
1.5 320
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
460
460
460
480
480
340
340
330
330
43
-------
Date: 20 Oct. 68 Time: 0701-02 Type Traverse:
Distance Height of
Downwind Top Bottom Max. SO2
km m m m
0.3 470
0.9 350
1.3 300
Date: 20 Oct. 68 Time: 0706-13 Type
8.1 490
8.0 . 460
7.5 350
6.7 330
6.1 430
5.9 460
5.4 460
5.0 400
4.6 300
4.0 310
3.6 370
3.1 460
2.5 490
2.3 440
1.7 320
1.2 310
1.0 390
0.6 450
Date: 20 Oct. 68 Time.: 0727-33 Type
7.6 460
7.4 440
7.3 390
6.3 390
6.1 430
5 . 9 460
5.4 460
5 . 1 400
4.9 370
4.0 380
3.6 440
3.3 470
2.8 470
2.6 440
2.4 360
1.8 320
1.2 450
1.1 . 470
Max.
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
-------
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
Date: 20 Oct.
7.0
6.9
6.4
5.7
5.5
5.1
4.6
4.4
4.1
3.5
3.1
2.4
1.9
1.3
1.0
Height of Max.
Top Bottom Max. S02 S02
mm m ppm
520
410 0.89
350
360
460 0.88
480
500
420 2.28
340
330
430 2.73
450
450
380 6.90
320
68 Time: 0927-32 Type Traverse
480
450 3.42
380
380
400 3.56
450
480
440 3.80
370
350
420 3.04
480
500
410 5.13
350
45
-------
Date: 20 Oct. 68 Time: 0948-52 Type Traverse:
Distance
Downwind
km
Height of
Top Bottom Max. SO2
m
m
m
Max.
SO-,
6.7
6.5
6.0
5.2
4.3
4.1
3.7
3.6
3.2
1.9
1.3
.8
480
480
490
360
340
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
Height
4
530
470
420
340
320
, m
t
500
450
380
Max. S02
0.06
0.06
2.27
3.53
3.13
2.96
0.26
0.14
Background
S02
0.06
0.06
0.09
Date: 20 Oct. 68 Time: 0642-51 Type Traverse:
X = 4.0 km
0.05
4
500
440
380
310
T
480
420
350
0.05
1.40
2.28
3.52
4.80
1.90
0.09
0.09
47
-------
Date: 20 Oct. 68 Time: 0911-24 Type Traverse;
X = 4.0 km
Height
4
520
440
370
310
280
Date: 20 Oct.
\,
240
310
370
440
500
Date: 20 Oct.
4
610
490
440
370
310
280
, m
t
500
470
£
410
340
68
f
340
410
470
68
T
600
530
480
410
350
Background
Max. SO2 SO2
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
1.82
1 . 98
0.37
0.31
0.24 0.19
48
-------
6810
temp., °C.
Z,m.
600
400
200
0
St 0856 090d -
Si 1021 24 —
Fig. 18
8 10 12
temp., "C.
Z,m.
600
20 Oct. '68
400
2OO
0948-52
T-r 0953 - 54
Fig. 19
I
3 4
X, km.
49
-------
e K,
290
0700
285
280
275
Z,m
400
300
0800
time, EST
er
ec
0900
1OOO
plume top
• max. SO2
plume base
9.°K.
290
285
280
Z, m.
600
5OO
400
3OO
FIG.20. Potential temperatures at plume top, 6 stack top,6s, and stack base
level plus 20 m., 9g, 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). Isolines of S02, drawn from a series of seven horizontal
traverses between 06^2-51 EST, 20 October, 1968.
100m.
|e_200
50
-------
Distance downwind, km
so2,
ppm
Fig. 22
Traces of temperature, S02, 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 EST, 20 Oct. 68.
51
-------
11
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, SC>2, 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 EST, 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
1.9
1.7
Top Bottom Max. SO2 SO2
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
Tr a ve r s e : *\/
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 Traverse:
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
J,
700
630
580
520
460
390
340
Date: 21 Oct.
?
320
390
450
520
580
630
690
, m
t
600
550
500
.68
4,
360
420
480
550
600
Background
Max. SO2 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: d725-37 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. SO2 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 °C
Z, m.
800
600
400
200
Fig 26
21 Oct. '68
St 0846-52
St 0946-48 _
8
10 °C
Z.m.
T \/0702-10
T -* 0712-13
X. km.
-------
Date: 22 Oct. G8 Time: 0644-50 Type Traverse:
Distance Height of Max.
Downwind Top Bottom Max. SC>2 SC>2
km mm. m ppm
7.5
7.4
7.2
4.8
4.2
4.0
3.2
3.0
2.7
1.8
1.6
1.0
480
450 0.80
380
380
450 2.04
470
490
460 2.77
390
350
390 5.78
470
Date: 22 Oct. 68 Time: 0654-58 Type Traverse:\/
5.4 490
5.3 460 1.96
5.1 410
4.2 390
4.0 430 3.12
3.6 480
2.9 490
2.2 350
1.5 350
1.1 410 6.34
0.7 470
58
-------
Date: 22 Oct. 68 Time: 0718-24 Type Traverse: \/
Distance
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
Height of . Max.
Top Bottom Max. SO2 SO2
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 Traverse
500
430 9.03
340
380
470 4.33
540
59
-------
Date: 22 Oct. 68 Time: 0932-0940 Type Traverse:
Distance Height of Max.
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
Top Bottom Max. S02 S02
m m m PPm
610
540 4.21
380
360
490 2.99
600
640 :
550 2.79
370
360
560 4.17
610
620
460 6.96
370
350
520 (10.0+)
550
68 Time: 1000-1008 Type Traverse
600
480 3.23
390
380
450 3.86
520
530
480 3.12
410
360
420 2.31
520
490
480 3.38
350
320
570 6.16
590
60
-------
Date: 22 Oct. 68 Time: 0700-0715 Type Traverse;
X = 3.4 km
Background
Height, m Max. SO2 SO2
A
580
510
450
380
320
t
610
540
480
420
360
0.08
0.74
2.58
2.26
3.33
2.32
3.06
2.50
1.32
0.13
0.08
0.07
Date: 22 Oct. 68 Time: 0726-0740 Type Traverse:
X = 3.4 km
250 0.10 0.09
280 0.10
320 1.56
340 1.22
380 2.87
420 4.00
460 3.35
480 1.73
510 0.70
580 0.08 0.08
61
-------
Date: 22 Oct. 68 Time: 0915-29 Type Traverse:
X = 3.4 km
Height, m Max. SO;,
1
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
-------
-600
-600
-4OO
-2OO
temp., °C.
8 10 12
10 12
St
0634 - 39
St
0855-0900
12
12 14
Z.m.
'800
600
4OO
200
12 14
22 Oct. '68
IO70O-08 •
T0708-15 «
200 -
ppm.
63
-------
e/K.
290
285
280-
275
Z,m.
500
400
300
plume top
max
plume base
I
I
I
0700
0800 0900
time, EST
-290
e.'K.
285
280
Z, m.
600
-400
Fig. 32
1000
22 October 1968
Potential temperatures at plume top, ep, stack top, Qs, and stack base
level plus 20 m., 6g, 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.
64
-------
Date: 23 Oct. 68 Time: 0641-50 Type Traverse: \/
Distance Height of Max.
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
Top Bottom Max. SO2 S02
mm m ppm
610
500 0.76
430
420
510 (l.0+)
650
650
500 1.41
470
410
550 2.55
650
630
500 4.57
410
370
480 5.04
530
68 Time: 0710-20 Type Traverse
510 0.50
400
450 0.91
580
610
440 1.30
400
400
540 1.78
630
640
470 3.57
400
410
470 6.77
490
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.
SO 2
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
Height, m Max. SO2 SO?
t
0.08
250
310
380
440
500
560
630
690
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.
.74
.87
2.52
0.52
1.12
0.68
0.72
0.10
0.10
68
-------
T
St 0633-37
0900-05
Fig. 33
I . i
4 6 8 1O
temp., °C.
Z. m.
800
600
400
200
•
I I
Fig. 34
\
T ^* 0653- 0707
X » 4.O km
. I , I
0 1
Max. SO2,
Z, m.
23 Oct. '68
60O
400
200
Fig. 35
1
0641-50
0710 - 20
I
X. km.
69
-------
Date: 24 Oct. 68 Time: 0645-50 Type Traverse: \/
Distance Height of Max.
Downwind Top Bottom Max. SC>2 SC>2
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
Height, m Max. SC>2
t
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
Background
S02
0.07
0.05
Date: 24 Oct. 68
Time: 0723-35
X = 2.5 km
Type Traverse:
390
460
520
580
640
710
760
840
890
0.09
0.32
1.40
2.24
3.13
2.75
2.19
2.20
0.08
0.06
0.06
71
-------
Z, m.
ioooi-
8OO
600
400
200
Fig. 36
Sf O637-43 —
' St 0742-47
6 8
temp.,
1O 12
Fig. 37
T ^±
X =4.0 km
O655-0714
i ,
24 Oct. '68
Z, m.
Fig. 38
T ^±
X = 2.5 km
0723-35
, I
1 2
Max. SO2, ppm
•1000
8OO
6OO
•400
2OO
to
-------
PART III - ANALYSIS
BEHAVIOUR OF HOT PLUMES UNDER STABLE CONDITIONS^
I/
Betsy Woodward Proudfif1*
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.
_!/ 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.
Z/ Sign-X Laboratories Inc., Essex, Conn., U.S.A.
73
-------
1. 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 mw 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 47~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 S02 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 SC>2 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.** 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
-------
K-
I km
8
H
100 >
•5
0
Fi8 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 3-^ km downwind.
Fig. 2. The maximum S02 value 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 S02 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.
0 x"
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 stable 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/ah, 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/A.h, where A8 is the difference in
potential temperature, and Ah the difference in height, between stack top and
plume top. (See Fig. 4.)
Plume rise is generally defined as the height of the plume centerline
above the stack top. This height, designated Ahm 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 Ahm, 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 k 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
*».8 to 12.5 m/sec. and the potential temperature lapse rate from 0.16 to
1.5^ deg./lOO m. Examples of fanning and lofting plumes are included. A
classical coning plume was never seen, but one case may be classified as
windy, near neutral. Looping plumes are, of course, not included because
unstable cases'are not considered in this analysis. There are, however,
examples (e.g. the 1st case on 16 Oct.) which represent the situation during
inversion break-up just prior to fumigation.
The duration of each case varies from about 5~10 minutes to 50 minutes.
If wind speed, stabi1ity, and plume heights remained fairly constant for
even as long as about 50 minutes (e.g. 1st flight on 16 Oct. - see Fig. 5),
then this was counted as one case rather than five cases of 10 minutes
duration.
There has been some smoothing of data, primarily measurements of plume
base. The base was not as distinct and consistent as the plume top, which
was usually readily identifiable.
The plume thickness, &z, for each of the 20 cases is plotted in Fig. 6
as a function of stability.
77
-------
00
*»«
Wind speed and temperature (t«ft half of figure) are shown as a function
of pressure height. The sloping lines are dry adiabats. 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.)
ah
ah,,
Z
H
*z
6.
0S
e.
Ts
T.
»6/»h
*8/az
V,
g
0
us
0
NOMENCLATURE
height of plume top above stack top (•)
height of plume center-line above stack top (•)
height above stack base (•)
pressure height (m)
pi UHB depth (•>)
potential temperature at plume top (*K)
potential temperature at stack top (*K)
potential temperature at stack base plus 20n (*K)
stack gas temperature (*K)
ambient temperature at stack top (*K)
lapse rate between stack top and plume top
potential temperature gradient
stack gas velocity (m/s)
acceleration of gravity (m/s')
mean wind speed between stack top and plume top (m/s)
wind speed at plume top (m/s)
wind speed at stack top (m/s)
diameter of stack (m)
- stability parameter
—2- -AS-
- buoyancy flu,.,V
.(f)2(T.T;
•>
1*4
MO
XM
SIX
500-
-Iwm* M.
i
07
Fig- 5
1ST
K>
16 Oct. 1968
-no
Potential temperatures at plume top,6 , stack top, 8S, and stack
base level plus 20 m., 6O, as a function of tine. Heights of
plume top and bottom, obtained from horizontal and slanting tra-
verses, are shown as solid bars. The heights of max. SOj 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 10JO.
-------
Fig. 7 shows a plot of the maximum S02 concentrations obtained during
slanting traverses for two days. One plot represents concentrations
obtained during a *»0 min. period on 20 Oct. when the average wind speed
was about 8 m/s and stability about 1.5 deg./lOOm. The other plot re-
presents data during a ^0 min. period on Oct. 23 when the average wind
speed was about 12 m/s and the stability 0.^ deg./lOOm. Further analysis
of these, and other plots, should yield values of
-------
-Ht
.2 A A M U>
S lability, 11 m/B
Fig. 6 (above). Plume thickness, AZ, as a function of
stablIity.
o u t 6.0 m/s
* 6.0 m/s< D < 8 m/s
x 8.0 m/s < u< II m/s
a u f 11 m/s
Fig. 8 (above). The difference in potential temperature between stack top
and plume top vs stability, for various (approximate) wind speeds.
•0,
MM,
IO
t
\
N
• X
X 2O Oct.
x«v
23 Oct. \
2 4 6 I 10
km. (fewnwlnri
^'9- 1 Maximum vdlucs of SO, obtained during
traverses on 20 Oct. (circle-.) and 23 Oct. (crosses) as
a function of distance downwind of the stack.
100-t
m
S =~
4 -
'»•"/• ^ ,
'Mm/. ^
i—r
-•»-•S
*
—. i
Stability,
o u < 6. 0 m/a
A 6. 0 m/a <: u < 8 m/§
i ' ib
x 8. 0 m/a < u < 11 m/B
0 u > 11 m/fl
"~TJC.
Fla>t
f'9- 9 Observed plume rise, for Keystone data, as a function of
stability. The two dashed lines represent the ASHE 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
d6/ah are used instead, then 60% of the calculated values lie within 10$
of the observed.)
Fig. 9 indicates that ahm 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 write:
ahm«xFa G'b u"c
When the stability is neutral, the exponent, b, will obviously equal
zero, so that by applying simple dimensional analysis:
Ahm - C (F u"3)
This is similar to the ASME equation for neutral stability (ref. 1)
where C = 150.
At high stabi 1 i ties the data indicate that the exponent, c, equals
zero, so that by applying simple dimensional analysis
C OF G-3/8) [3]
For intermediate stabilities we may write, for example
Ahm = C (F 1/2 G"1 G'1/11) [4]
and a whole series of equations, of which eq. [l] is a member.
The observed plume centerline heights, ah , are plotted in Figs. 10,
11, 12, applying [4] , [1] and [3] respectively. The constant, C, Is
4.5, 2.0 and 1.48 respectively.
We may "optimize" the fit in each figure by changing the constant, C,
depending upon either the wind speed (primarily at low stabilities) or
the stability (primarily at high stabilities). Or we may alter each
equation by adding a constant. For example, in Fig. 12, if we write:
6hm - 2.36 (F]/k G-3/8) -114 [5]
then all calculated values are within 10m. of the observed, at stabilities
above 0.8 deg./lOOm. The writer would hesitate to claim this accuracy
for the data.
81
-------
- 2OO -
- 1OO -
FfelO
f<9- 10 . . .ii
Plume rise vs. F1'2 u ' 6 '
Keystone data for stabili-
ties between .16 and .Cl
deg./lOOm
- ,/,
Plume rise vs. (F/uG)1'3
Keystone data for stabili-
ties between .6 and 1.2
deg./IOOm
Plume rise vs. F1/* G"3/8
Keystone data for stabili-
ties between .76 and 1.5**
deg./IOOm
1OO
. M
I I ^ I I T
- *
T 7X
/ V _
/ X
- - -
- S
Wind >*>«•<<. m/
Uma>. °C
82
Figure 13
wind speed and temperature are shown as a function of pressure height, H. Case I shows the probable
plume outline from a ISO m. stack and the Case III shows the plume outHne If the stack top were at
-------
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, a6/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 bean
suggested that the appropriate equation, e.g. [1], [3], [A], is a function
of the stability, A6/Ah, and perhaps also u. It would be a time consum-
ing process to arrive at the calculated plume rise height, £hm, 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, ^8, 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, A.8 remains comparatively constant
above about 0.8 deg./lOOm. It is roughly 3.2°K. Since stability is
defined asA9/Ah, a good first approximation for plume top height for
stabilities above about 0.8 deg./lOOm may be easily obtained:
Aha 3-2/stabi1i ty
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 Uh = Ahm + az/2) we may obtain
a diagram that gives A6 as a function of the buoyancy flux for various
stabi1i ties. (See Fig. H».)
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 will 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 ^50m.
Above this 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 1CH. 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, A6, as a function of the buoyancy
flux and stability. If F = 1.6 x 10* then it can be seen that the
potential temperature difference, A6 , 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° f l°/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
centerline above stack top, Ahm, is 182 m. Uhm « Ah - Az/2) . The plume
outline is shown 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 284.9° and at stack top level, 6S = 282°; therefore
A6 = 2.9, (8p - 8S), and A8/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 III
Let us assume that the stack top were raised to, say, 250m. With a
similar buoyancy flux, (2.2 x lO^), the plume top would obviously
penetrate Into the neutral layer which has a potential temperature of
285°. The potential temperature difference will equal 2.0°, (8p « 285°
and 6S = 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 stabiIt ties (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 A9 =• 2.0° and u* 7 m/s, then the stability, a6/Ah • 0.4 deg./lOO
and Ah = 500m. If u*8 m/s then A0/ah = 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 profileinFig. 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 A9/Ah when u* 7-8 m/s (and A9 = 2.0°). It is
about .46 deg./lOOm; therefore Ah -440m. .
84
-------
deg
4.2
3.8
3.4
3.O
2.6
1.2
Fig. 14
1.6
2.0
F. xlO3
2.4
2.8
The potential temperature difference, A0, 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 A8/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 (F1A G'3/8) - 114
From Fig. 6, the plume thickness, A.Z, has been determined
for the various stabilities and
Ah
AZ/2
oo
Time
EST
16 Oct.
0650-0740
0915
0930
0955
1010
1030
17 Oct.
0715
0915
18 Oct.
0550
0725
20 Oct.
0650-0720
0905-0940
0955
10.10
1020
23 Oct.
0650-0740
0910-0930
2k Oct.
0650-0730
26 May
0700
u
m/s
6.0
5.2
5.2
5.4
5-2
4.8
8.5
8.8
7.0
9.8
9.5
8.0
6.8
12.5
7-0
4.9
7.5
A6
deg.
3-3
3-2
3-2
3-1
3
2
2.1
1.7
1.5
3.5
3.4
3.5
3-A
6.2 3.2
2. 4
3-0
£/ .
/Ah
xlO"2
1.20
1.05
.96
.83
.76
.60
.45
.45
.38
1.54
1.42
1.35
•96
.85
.42
.16
.34
1.07
xlO
.A7
.82
-10
.59
-90
-30
4.62
4.98
6.57
6.57
7.85
94
10
20
11
51
6.80
18.10
8.56
2.73
F
xlO-
21
2^
2^4
23
2.23
2.23
2.15
2.17
2.15
2.15
2.15
1.98
2.03
1.99
1-99
1.99
2.34
2.70
2.59
1.99
Ah
180 275 185
220 305 195
230 335 220
300 375 225
300 395 2^5
550 665 390
225 280 168
300 335 185
420 465 255
250 375 250
310 395 240
150 230 155
165 240 158
180 260 170
295 355 207
300 375 225
420 400 190
650 690 365
480 700 460
150 280 205
Table I
-------
From Fig. 6, zir360m, so that ahm*260m., (MOm - 360m/2). The
suggested plume outline is drawn in Fig. 13. The exact value of Ah
(or
------- |