The
Gutless Cutlass Web Site - Science Fair 1999
SMOG
BUSTERS
TABLE OF CONTENTS
Purpose................... 4
Problem................... 5
Hypothesis.................. 5
Background Research......... 6
The Experimental Procedure..... 8
Materials List............ 8
Graphs..................... 13
Results.................... 16
Conclusion.................. 17
Acknowledgements......... 18
Bibliography............. 19
THE PURPOSE
About 150 years ago, the air was clean and pure. Then people
started building factories and we began to put harmful pollutants into
the air. Some places today do not have breathable air because the
air is filled with pollution, called smog. Polluted air is bad for people,
animal and plants. It damages the food we eat. We need to clean up
the air we breathe(2).
Our air and waters are in danger. Air pollution is probably
greatest danger to our environment today(5). The air has been
infected by smoke from factory burners and gas fumes from cars and
trucks. Coal and fuel oil are burned to produce light, power, heat, hot
water, transportation - creating a lot of pollution. We are paying a
high price for these things. Air pollution has damaging effects on our
bodies too. So, to stay healthy, we need to clean up our air(3).
Many forests are dying because of pollution. Smogs like sulfur
dioxide, released by burning coal and oil in power stations and
nitrogen oxides from car exhausts enter our atmosphere and dissolve
in the rain to form acids(6). The acid rain falls on forests and lakes,
affecting the soil and water and kills trees, plants and fish. But
because the forests and lakes are habitats for many animals, they too
are affected and die(2) (5).
When we look up in the sky we see clouds and and blue. But
we don't always see the harmful things in the air. When power plants
burn coal to make electricity, and cars burn gasoline, invisible gases
are released into the air.
Carbon dioxide in the atmosphere traps some of the Sun's heat.
The level of these gases has been rising so much from pollution that
the Earth's climate may warm up as a result. People are trying to
reduce global warming by fitting industrial chimneys with filters that
clean up the fumes(5).
I want to work on reducing pollution in industry. There are 3
basic kinds of power generating plants - Hydroelectric, nuclear and
coal-fired. I want to focus on ways of cleaning up the exhaust from
our local coal-fired electric power generating plant.
THE PROBLEM
We need electricity in our everyday lives. But, generating the
electricity we need causes too much pollution. We need to find a
cleaner way to generate electricity. How can we reduce the pollution
from the exhaust from our power plants?
THE HYPOTHESIS
Choosing the right fuel, combined with more treatment of the
exhaust from power plants can make them have much cleaner
exhaust. I think wood and coal will be dirty fuels, and natural gas will
be cleaner. I think that the water spray will be the best at cleaning the
smoke.
BACKGROUND RESEARCH
How does a coal power plant work? A power plant makes one form of
energy, electricity, from coal, natural gas, or moving water, (7). In a natural gas
power plant like TEP(8), the natural gas is burned in a furnace at a very high
temperature. The heat rises and turns water in the boiler into steam, like your tea
kettle. This rushes thru turbines and makes them spin. The spinning motion
turns a generator which makes the electircity. The hot water is cooled for
recycling in large cooling towers. Turbines(7) are fan like blades on a metal shaft.
Because they are set at an angle, they turn when liquid or gas flows past them,
like a toy windmill. Steam turbines are spun by high-pressure steam produced
from boiling water. As the steam loses pressure, it flows past different sizes and
angles of blades, each one is designed to take the maximum energy from the
steam. The shaft of the turbines is connected to a generator. The energy of a
spinning shaft is converted into electrical energy by a generator. A magnet or
rotor, turns around inside a series of electrical coils. As the magentic field of the
rotor passes through the coils, it makes electricity in the coils. The rotor is an
electromagnet that needs electricity to make its magnetic field.
Air pollution is the contamination of our air by gaseous, liquid, or solid
wastes or byproducts that can endanger human health and health of plants and
animals, or it can reduce visbility or produce odors. Many air pollutants come
from sulfur dioxide from electric power plants burning coal or oil(2).
Burning coal, oil, and gasoline are most of the air pollution: 30% from
sulfur dioxide, 50% from nitrogen oxides, and 30-40% emitted to the air are
produced by fossil-fuel-fired electric power plants, industrial boilers, and home
furnaces. Also, 90% carbon monoxide and 50% nitrogen oxides and
hydrocarbons come from gas and diesel fuels in cars and trucks(5). To control the
air polution we can remove hazardous material before it is used, remove
pollutants after it is formed. Industrially emitted particulates may be trapped in
cyclones, electrostatic precipitators, and filters. Pollutant gases can be collected
in liquids or on solids, or incinerated into harmless substances(4).
Technology has begun to solve some problems and public awareness will
force governments to make more effective environmental planning. Because
complete elimination of air pollution would be impossible, compromises have to
be made. All kinds of emission controls can be used. For example, autos have
catalytic convertors to decrease emissions. Electrostatic precipitators and filters
are used in power plants to meet emission standards and low sulfur-content fuels
can be used to limit sulfur-dioxide emisssions.
Techniques for removing pollution in power generating plants include:
Long-cone cyclone separator, wet scrubber, electrostatic precipitator and
baghouse(4). The cyclone separator causes air emissions to whirl around, forcing
heavy particles to the outside and then removed below. The wet scrubber
washes particles out to the exhaust with a water spray. The electrostatic
precipitator electrically charges the particles and attracts them to charged plates,
removing them from the exhaust stream. The baghouse operates like a vacuum
cleaner, trapping particles in fabric filters placed in the exhaust stream.
THE EXPERIMENTAL PROCEDURE
BUILDING A BURN CHAMBER AND SMOKE MEASUREMENT CELL
First you must build your burn chamber and the measurement cell.
You will need the things in the list below:
MATERIALS:
3 Regular Empty Coffee Cans - Metal Tops Removed
1 Set of Legs from Camping Propane Lamp
2 2" Sheet Metal Screws
2 ¬" Sheet Metal Screws
1 A One Night Light Electrical String.
(String with plug, one socket and 1 "Night Light")
(My "Night Light" is a Minature 7W Bulb)
1 Cadmium-Sulfide Photo Cell
1 Ohm Meter which can read 1-10M ohms.
1 Hose Connector down to 1/8" pipe.
2 Feet of 1/8" pipe.
1 Fan Sprayer from Garden Irrigation system.
1 Stainless Steel Screen - 10 wire mesh/inch
1 Square Foot of "Cheese Cloth"
1 Roll of Metal Tape.
Newspaper to keep fires started.
TOOLS:
1 Screw Driver
1 Tin Snips.
1 Pair Plyers
1 Sharp Nail
1 Hammer
The steps for building the burn chamber and the measurement cell
are below:
1). Screw the legs of the Camping Lamp into the bottom of the first
coffee can using the 2" Wood Screw and the Screw Driver. This will be your
burn chamber.
2). Use the sharp nail and hammer and nail to punch three holes
in the bottom of the coffee can for air. Use the screw driver to make the
holes at least ¬ inch in diameter.
3). Use the Tin Snips to cut two holes in the second coffee can,
directly across from each other, half way up the side of the can, one « inch in
diameter, the other 2 inches in diameter. This can will become the measurement
cell.
4). Use the Tin Snips to cut up the third coffee can into pieces of tin.
4a). The first piece should be 3 inches by 2 inches. Roll this up into a cylinder
with a « inch diameter. Use one of the ¬ inch sheet metal screws to hold this
cylinder together. 4b). The second piece should be 2 inches by 6 inches. Roll
this piece into a 2 inch diameter cylinder. Use one of the ¬ inch sheet metal
screws to hold this cylinder together.
5). Put the night light bulb into the 2 inch cylinder. Cut tabs into the end
opposite the bulb and mount it in the 2 inch hole in the second coffee can. Use
the tin snips to cut a small piece of the third coffee can to seal the end of the bulb
tube.
6). Put the Cadmium-Sulfide Photo Cell in the « inch cylinder. Cut tabs
into the end opposite the cell and mount it in the « inch hole in the second coffee
can. Use the tin snips to cut a small piece of the third coffee can to seal the end
of the cell tube.
7). Use a can opener to cut « of the way around the top of the
measurement cell coffee can. Use the screw driver to pry up the top of the top of
the lid to let the smoke out.
8). Use the tin snips to cut tabs in the bottom end of the measurement cell
can to fit onto the burn chamber.
Your burn chamber and measurement cell are now ready for the burn
tests. After the burn tests, build the water scrubber.
1). Connect the Hose Connector to the hose. Hook the two feet of 1/8"
pipe to the connector.
2). Hook the fan sprayer to the other end of the hose.
3). Use the tape to tape the fan sprayer to the legs of the burn chamber.
*** Be sure the plastic pipe can't touch the burn chamber. (it will melt!) ***
BURN TESTS
*** Yes, Your Mom or Dad Must Help You With This Part ***
I used three types of fuel, Natural Gas, Wood and Coal. First I measured
the natural gas. I put the measurement can on top of the kitchen stove so that
the smoke from the gas flame on the kitchen stove would go through the
detector.
Here's how to do the measurement.
1). Write down the start time
2). Turn on the Meter. Write down the ohms from the meter with
the light off.
3). Turn on the Night Light.
4). Write down the ohms from the meter with the light on. Make sure
that the number with the light on is MUCH lower than the number with the light
off.
5). Now put your measurement cell can over the burn chamber with the
fire going (or over the stove). Write down the ohms from the meter with the
smoke going through the can. Make sure that the number with the smoke going
through the can is at least a little different than with no smoke.
For all the numbers in the measurement, I wrote down three numbers for
each one. Then I took the average of the three numbers for the best reading.
FILTER TESTS
Next it's time to do the filter tests. I used three types of filters, water spray
(or water scrubber), metal catalyst (wire screen) and a physical filter (the
cheesecloth).
For the wire screen and the cheesecloth, it's easy. Just place the screen
or the cheese cloth between the burn chamber and the measurement can while
the fire is going. Just repeat the measurement steps to get the numbers.
For the water spray, it is more difficult. You must aim the water spray
so that it is fan shaped and goes over the top of the burn can without very much
water going in the burn can (this will put the fire out!).
Do the measurements just like before, one with no water spraying and one
with the water spraying.
CALCULATING THE SMOKE
The smoke going up the measurement cell can blocks the light between
the Night Light and the measurement cell. But, the measurement cell reads out in
ohms with a high number for dark and a low number for light. So you must
calculate the light shining like this:
Light Shining = 1 / ohms (with light on)
But some of the light is blocked by the can walls, by the cuts in the can,
and by the line up of the light. So I subtract the reading with the light off:
Light Shining = [ 1 / ohms (with light on) ] - [1 / ohms (with light off) ]
When the smoke is going through the measurement can, more of the light
is blocked. You figure up the amount of smoke like this:
Smoke Amount = [ 1 / ohms (with smoke going ) ] - Light Shining
This number is a fraction. Multiplying the fraction by one million, gets you
PPM Smoke.
(data in excel has been eliminated for internet)
RESULTS
FROM THE BURN TEST
The measurement cell worked well. The dark number was 1,850,500
ohms (pretty dark). The light number (night light on) was 2,500 ohms. The cell
was measuring the light well.
The burn test worked. We measured the natural gas on the kitchen stove
first. This went well because there was little smoke. The number on the meter
with the stove going was only a little bit different than the number with the stove
turned off. With the stove off, the ohms number was about 2,550 ohms. With the
stove on and the smoke going through the measurement can, the reading went
down to about 2,550 ohms. I calculated about 4,500 PPM's of smoke (pretty
clean).
Then I did the coal test. The coal was dirtier. With no coal fire in the burn
chamber, 2,590 ohms in the first test about 2,970 ohms in the second and third
test. With the coal fire going on in the burn can, and the smoke going through
the measurement can, the reading went up to about 3,050 ohms (more than the
natural gas). I calculated about 10,000 PPM's of smoke from the coal (pretty
dirty).
Last I did the wood test. At first, the wood smoke was really dirty. With no
wood fire in the burn chamber, I read 3,050 ohms. With the wood fire going on in
the burn can, and the smoke going through the measurement can, the first
reading went up to about 3,310 ohms. This is about 32,000 PPM's of smoke. On
the next two tests, the fire had burned down some, and the reading were 4,610
PPM's and 13,670 PPM's. The wood fire was sometimes smokey and sometimes
not.
I calculated all the numbers from the burn test and put them on the next
page and I put the graph from the burn tests on the page after that.
FROM THE FILTER TEST
The smoke meter was not sensitive enough to measure how good the
cleaning of the filters would be with the natural gas. I wanted to use the smokier
of the burns anyway, so I used the coal and the wood.
The water scubber was the best filter of all. In the three wood trials, it
filtered out 24.4%, 98.2% and 82.6% of the smoke. The measurement cell was
not set up very good on the first test so I think the 98.2% and 82.6% number are
best.
The metal screen was not very good at all. It only filtered out 4% of the
wood smoke. The filter bag (made out of cheese-cloth) did almost nothing.
The water scrubber did great with coal too. It filtered out 83% of the
smoke, just like the third test of with the wood.
The metal screen did better with the coal smoke but still not very good. It
only filtered out 49% of the coal smoke. The filter bag, started to work with the
coal smoke. It only filtered out 24% of the coal smoke though.
CONCLUSION
Natural Gas is already a pretty clean way of making electricity. My
measurement cell could barely detect the smoke from the natural gas flame.
Here in Tucson, TEP uses mostly natural gas to make the electricity. I am
glad of that.
Both the wood and the coal were a lot dirtier than the natural gas.
Because wood and coal are dirtier, it would take a lot more equipment to clean
the air if wood or coal are used to make the electricity.
The water scrubber was the best of the air cleaners I tried. When I set up
the scrubber right, it cleaned most of the pollution out of the smoke.
Both the catylist metal and the physical filter (cheese-cloth) were not very
good at cleaning up the smoke.
I think that, even though my meter couldn't measure it, that water
scrubbing would still help clean the natural gas exhaust. We need our air to be
as clean as we can get it.
I'll bet that there are even better ways of cleaning the air from powerplants.
Other types of cleaners I'd like to try are; Electricity to clean the air, Compressing
the air and forcing it through tiny holes, or bubbling the air through the water,
rather than just spraying the water through the air. I hope that I can try some of
these next year.
ACKNOWLEDGEMENTS
I want to thank my parents for helping me to work on the
experiment. I would especially like to thank my Dad for helping me
build the burn chamber and teaching me how to do the
measurements.
I also would like to thank Anna Cunes from the Education
Department at Tucson Electric Power for providing me with some
information about how the power plant works and the videos about
electricity.
BIBLIOGRAPHY
1). Brisk, PhD., Marion A.; 1001 Ideas for Science Projects, Published by
Simon & Schuster Macmillan Co., NY, NY, 1994
2). The Earth Works Group; 50 Simple Things Kids Can Do To Save The Earth,
Published by Scholastic, Inc., New York, NY, 1991
3). Gamlin, Linda; Life on Earth, Published by Shooting Star Press, NY, NY,
1988.
4). Grolier Electronic Publishing, Inc., 1993, "Pollution - Environmental and
Treatment Systems for Air"
5). Infopedia, Funk and Wagnalls Encyclopedia, 1995, "Pollution Problems and
Air Pollution"
6). Internet www.ala.usmc.mil/envbr/air.htm; "Air Pollution", by Ralph D. Willis
7). Parker, Steve; How Things Work, Published by Random House Inc., New
York, NY, 1991
8). Tucson Electric Power Company resource videos and brochures
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