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Purpose
This is a technical memorandum
concerning the Air Burners FireBox augmented with Diesel burners to
support combustion of municipal solid waste (MSW) where allowed.
Typically, the Air Burners FireBoxes are used for the burning of
clean wood waste. The air curtain technology significantly reduces
smoke generated from the burning process and helps to oxygenate and
speed the fire. In remote locations, especially at overseas
installations, such as temporary work camps for oil & gas
exploration, our machines are used to consume MSW.
The simplest and cheapest method is to
use wood waste as the “fuel” to support the burning of MSW with low
calorific value. This process works extremely well and is very
inexpensive, helping developing countries get a basic system in
place to handle MSW. The United States Military has deployed dozens
of our machines in Iraq and Afghanistan for MSW reduction. But the
difficulty in certain regions is the lack of wood waste to use as a
fuel, resulting in a much slower through-put. Nevertheless, the
process still a significant improvement over open burn pits and
smoldering garbage dumps.
For such applications that cannot use
wood as their primary fuel source, we offer our FireBoxes fitted
with auxiliary Diesel fuel burners. The Diesel burner provides the
heat to ignite the low calorific value MSW. Once the MSW is burning,
the Diesel burner will retreat to a “low fire” status reducing the
Diesel fuel consumption by approximately 80 percent. If the heat
load reduces, the Diesel burner will go back to full fire mode,
until proper heat is restored. The Air Curtain creates a secondary
burn chamber that will help to trap most of the particulate matter
reducing the visible smoke.
Our air curtain technology is well
proven and our machines have been subjected to extensive testing by
numerous environmental agencies worldwide. We are a CRADA partner
with the US EPA, we work closely with the US Forest Service (USFS
Tech Tip 0251-1317), the Department of the Interior, the Department
of Energy and the US Military. Our machines are currently used by
numerous communities, State agencies and National Parks.
The following pages will describe in
more detail the “Standard FireBox” and the FireBox with the Diesel
burner option.
Air Curtain Burners were designed principally as a pollution control
device. The primary objective of an air curtain machine is to reduce
the particulate matter (PM) or smoke that results from burning clean
wood waste. It is sometimes hard to visualize without seeing a
machine in operation (see video at:
here),
but the standard machines do not burn anything, rather they control
the results of something burning. You could look at it as a
pollution control device for open burning.
Clean wood waste is loaded into the
FireBox, an accelerant like Diesel is poured onto the wood and the
pile is ignited. Once the fire is ignited the waste burns naturally,
no additional fuels are used. This is very similar to starting a
campfire. The air curtain is not engaged until the fire has grown in
strength or the air curtain may blow the fire out.
Once the fire has reached suitable strength, usually in 15 to 20
minutes, the air curtain is engaged. The air curtain then runs at
steady-state throughout the burning operations and the waste is
loaded at a rate consistent with the rate of burn. The Air Curtain
will create a secondary burn chamber trapping the particles of smoke
and causing them to re-burn. Our smallest machine will allow burning
at a rate of 1/2 to 1 ton per hour, our largest machine can run in
excess of 10 tons per hour.
Principle
The purpose of the air curtain is to
stall or slow down the smoke
particles on their way out of the FireBox. In doing this the
particles are subjected to the highest temperatures in the FireBox.
Stalling the smoke particles in this region just under the air
curtain causes them to re-burn, further reducing their size to an
acceptable limit. The result is a very clean burn with opacities
well under 10 on the Ringelmann scale (as compared to open burning
which typically can run at 80 to 100 on the Ringelmann scale).
Operation
You can see in the picture to the
right a standard Air Burners
FireBox completely full and burning while in the background a pile
of wood is open burned. This is a photograph taken in Canada at a
hydro-electric dam where waterborne wood debris is regularly removed
from the reservoir.
The wood pile that is open burning
continued to burn for two weeks. That open burning pile could have
been eliminated with the FireBox in less than 20 hours with
significantly less impact on the environment. |
developing regions to burn low calorific waste. With our standard
machines this is best accomplished by using wood waste as the “fuel”
to support burning the low calorific waste. This is also the lowest
cost method, and it works very well. For the regions where wood
waste is scarce, we added the option for a fuel fired burner to
ignite and help burn the waste. The Diesel Burner is a good option
when you intend to burn strictly low calorific value waste. The
burner unit is integrated into the front Thermo Ceramic wall of the
burn chamber (see right picture). All of the controls can be
accessed from the front of the machine. Waste is loaded into the
FireBox over the top. It can be loaded by hand or by machine such
as a “Bobcat” .
