By: Curtis F.
This is my Display Board at the Mid Columbia Science and Engineering Fair
Table of Contents
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Hypothesis: My hypothesis was that the Lignetics brand pellets would have the longest burning time.
Experiment Design: My experiment had to do with burning materials,
taking quantitative data, and time measurements.
All I wanted to do in my experiment was to find how long the
different pellets burned and how much heat they produced.
I was very picky to make sure that the mass was as close to exactly
the same as possible.
I couldn’t burn the pellets in an enclosed area so all the heat
went to the water because if I did that the pellets wouldn’t have gotten
enough air to burn.
Conclusion: My hypothesis was that the Lignetics brand pellets would
burn the longest. According to the results of this experiment, I am going
to reject my hypothesis. It turned out to be the Bear Mountain brand that
burned the longest.
My hypothesis was that the Bear Mountain brand pellets would produce
the most heat in the time that they burned. According to the results of
this experiment, I am going to reject my hypothesis. It turned out that
the Natural Glow brand produced the most heat. I was also wrong when I
thought that because the pellets were composed of more than one type of
wood they would burn hotter.
These results show that the Natural Glow brand pellets are the best
for heat production and the Bear Mountain brand for burning time.
My hypothesis was that the Bear Mountain brand pellets would produce
the most heat in the time that it burns.
I hypothesized this because I thought since this brand of pellets is
composed of more than one type of wood that it would burn longer than pellets
that are composed of only one type of wood.
| Item | Quantity |
| Lignetics Pellet Fuel | 6.2g x6 |
| Dear Mountain Pellet Fuel | 6.2g x6 |
| Natural Glow Pellet Fuel | 6.2g x6 |
| Bunsen Burner | 1 |
| Ring Stand | 1 |
| Ring stand rings | 2 |
| 5’x5’ Wire mesh | 2 |
| Displacement can | 1 |
| Thermometer (?C) | 1 |
| Water | 100ml x6 |
| Propane Bottle | 1 |
| Matches | 6 |
| 1 Hole Rubber Stopper | 1 |
| Ring stand Clamp | 1 |
| Triple Beam Balance | 1 |
| Plastic Dish | 3 |
| 250ml Beaker | 250ml Beaker |
Preliminary procedures:
1. Set up all needed equipment as shown in Figure 1.
Experiment Procedures:
1. Mass 6.2g of one brand of pellets and place them on the screen.
2. Put 100ml of water in displacement can, and record the temperature.
3. Use a Bunsen burner to light the pellets by holding it under the
pellets for 30seconds. (Note: However much the temperature of the water
went up while lighting the pellets has to be subtracted for accurate results.)
4. Let pellets burn until they go out.
5. Record how much the temperature of the water went up. Take the volume
of water and multiply it by how many degrees the temperature went up to
get the amount of heat energy produced.
6. Record the time that the pellets burned.
7. Repeat steps 1-6 for other two brands of pellets.
Figure 1
What are pellets composed of?
All pellets are biomass materials. This means that they are made of
regularly grown plants and trees. Standard pellets are made of sawdust
and ground up wood chips. These materials are waste from the trees that
are used to make lumber, furniture and other products. Pellets are held
together by naturally occurring resins and binders (lignin), so they often
don’t need any additive to keep it together. In other areas nut hulls and
other materials are made into pellets, and in some stove designs, unprocessed
shelled corn and fruit pits can be burned. The availability of biomass
waste materials in mills around where people live affect their choice of
fuel and the price. Also, the stove designs people chose depend on the
availability of the correct kind of fuel for that specific design.
Where can you get pellets and what size bag do they come in?
Pellet fuels and other biomass waste products are received, sorted,
grinded, dried, compressed, and bagged in pellet mills across the country.
Over 680,000 tons of fuel is produced each year by over sixty pellet mills
across the country. Pellets can be bought at many different locations
such as feed and garden supply stores, stove dealers, nurseries, building
supply stores, and some discount merchandisers. Usually pellets are bagged
and sold in forty-pound bags. They can also be bought by the ton. In some
mills, pellets are sold in twenty-pound bags for convenience.
What are the pellet standards and why are there standards?
Chemical constituents and moisture content in the different materials
vary, but the Pellet Fuel Institute (PFI) has come up with some characteristics
and fuel standards that have to be met by all fuel produced. These standards
are there to make sure that all the pellets are uniform in the final product.
Any fuel produced must pass tests for density, dimensions, fines, chlorides,
and ash content. Density, all the pellets have to have a consistent hardness
and energy content. The minimum is 40lbs/cubic ft. Dimensions, pellets
cannot be any longer than 1½” and a diameter of ¼”to 5/16”
to make sure that you get as much fuel as what it says your getting and
to prevent jamming in pellet delivery systems. Fines, limit the amount
of sawdust used in making the pellet to prevent problems with the pellet
flow and to reduce dust when loading. Chlorides limit the salt content
to avoid rusting in the stove and vent. Ash Content; has a major effect
on maintenance frequency.
What does ash content have to do with pellets?
The measurable characteristics put out by the PFI, except ash content,
are the same for both fuel grades. Premium grade fuel, which is less
than 1% ash content, is usually produced from softwood or hardwood sawdust
that has no tree bark in it. Premium grade fuels ash content varies from
about .3% in western softwoods, to about .7% in eastern hardwoods.
95% of the pellet production is now premium grade pellets. Premium pellets
can be burned in stoves that call for either standard or premium. Standard
grade fuel, which is up to 3% ash content, is mostly made from materials
that result in more residual ash, such as saw dust that has tree bark in
it or things like nut hulls, which are agricultural residue. Stoves that
are designated for standard grade pellets are the only stoves that standard
grade pellets should be used in. As the stove designs keep improving ash
tolerance, the availability of standard fuel is predicted to increase.
The grade of the fuel is determined by the ash content because the role
it plays in maintenance frequency. For determining maintenance frequency
of removing ash from the venting system and appliance, ash content is the
main factor. With early stove designs, fuel compatibility was a critical
factor in the operation of the stove. Advances in stove technology have
made fuel choice easier and there is now a wider selection, but fuel grade
and ash content is still to be put under some consideration. Lots of different
things have an effect on maintenance frequency, such as size of the ash
drawer, fuel feed and grate design, proper venting, and correct operation
and maintenance. The best source of information about stoves and their
fuel compatibility would be an experienced pellet stove professional.
What else is not constant in pellet production?
Another pellet characteristic that is not kept constant by PFI standards
is Btu. The Btu (heat) content of pellets may vary from about 8,000 to
about 9,000 Btu. This depends on the area it is produced in and the type
of materials that are used. Trace minerals are one of many other characteristics
that vary in pellet production. Clinkering, which is the formation of clumps
in the pellet ash, can cause the blockage of air inlets, and is caused
by some kinds of trace minerals. The tendency of fuel to form clinkers
is not predictable by analysis in labs. Routine maintenance can be
increased by clinkering, but recommendation made by professionals about
the correct fuels to go with stove designs can minimize the problem. Despite
the nature of raw materials, pellet mills strive for consistency. Little
difference from bag to bag of fuel doesn’t matter, but the differences
are smaller and much more insignificant than when problems are found in
the original material. When burned in well-designed, operated and maintained
stoves, pellets consistently deliver enjoyable and predictable comfort.
What is the average cost of pellets?
The price of pellets is currently anywhere from $120-$200 per ton with
an average of $150. Just like other heating fuels, prices of pellets vary
by the season, availability, and region. To ensure their winter stock,
pellet buyers buy pellets during the warm seasons while the prices are
low, because they stack easy for storage. Only part of the cost picture
is the selling price. Cost of energy is the primary issue, and it is measured
in dollars per million British thermal units ($/MM Btu). When bought at
the average price and burned in a typical stove, pellets usually cost about
$11.50/MM Btu. This price is competitive with average energy costs of some
other fuels and it costs less than electric energy. Even though real world
experiences vary widely, tables and charts can assume average appliance
efficiencies and fuel cost. The insulation, tightness, size, layout, level
of comfort desired, and the local climate must be taken into account in
the actual cost of heating a home. Even though they are hard to quantify,
other economic factors are worth consideration. The use of dwindling fossil
fuels, often imported from foreign countries, is being reduced by the use
of biomass pellets. The cost of waste disposal, even though rising, is
being reduced by every ton of waste material that is used in the pellets.
What is so special about Pellets?
The first good thing about pellets is their convenience. Bags
of pellets are easy to stack and store. One ton of pellet bags can be stacked
in a space of 4ft x 4ft x 4ft. This space is about half that needed to
store a cord of wood. A dry garage, basement or utility room, or a shed,
could house the bags of pellets. Clean and easy loading is also another
great attribute of the pellets. Loading the pellets only has to be done
once a day depending on what the settings of the stove are set at. The
lower the settings, the less often you have to fill the stove. Because
the pellets are so small, the fuel feeding is very precisely regulated.
Also, the air that helps with combustion can be regulated for the best
burning efficiency because the amount of fuel in the dish is predictable
and constant. The combustion quality is due also to the low moisture content
of the pellets. The pellets usually have 10% moisture content when corn
wood has about 20% to 60% moisture content. High heat and low unwanted
emissions are a result of all these things. Pellet fuels also have other
environmental benefits other that clean burning. As a biomass fuel, through
renewable raw materials, pellets offer the advantages of sustainable energy
supplies. Pellets are a by-product of these renewable materials, not a
primary user. In 1993-1994, over 6.5 billion cubic yards of waste
was taken from land fills and made into home heating pellets. Pellet burning
offers the pleasure of fire viewing and participation in heating and providing
comfort for the home, and it is all part of the hearth received from using
pellet stoves.
What are Heat Calories?
When people think of calories, usually they think of food. Food
calories are not the only kind of calories. Food calories are the amount
of energy you get from the food right? Well, heat calories measure the
energy in heat. One heat calorie is the amount of heat energy it take to
raise 1ml of water 1° C. Food calories are actually kilocalories. Which
means, if a food has 100 calories in it, it actually has 100,000 calories
in it.
Summary
Well, if you still have questions about something you should
talk to a specialist in pellets. I know some about pellets but I’m not
the world’s leading expert on them.
Lignetics Wood Fuel Pellets, Lignetics Pellet Company, La Canada, CA, 2001
“Pellet Fuels Institute”, Available @ http://www.pelletheat.org/fuel/fuel.html, December