3
Page
GJ75FJ
5. To determine the drum length required in feet, divide the combustion volume required
(see step 2) by the cubic feet per foot of drum (Step 4).
400 ft
3
÷ 38.5 ft
3
/ ft drum length = 10.4ft combustion flighting required.
For most applications this method produces good results, however for unusual
configurations or firing rates the flame lengths for the burners should be checked to ensure
that the planned combustion length and diameter is within the burner’s capability. (see
attached flame length tables).
Combustion Zone Produces Flame Intensity
The Eco-StarII
TM
or MegaStar
TM
is capable of high flame intensities. Flame intensity is
defined as Btu/hr ·ft
3
of combustion space. This is determined by finding the Btu/hr firing rate
that is used and dividing it by the cubic feet of combustion space available. A normal
maximum flame zone intensity is 250,000 to 300,000 Btu/ft
3
on natural gas and 175,000 to
250,000 Btu/ft
3
on oil firing. Propane fired burners require 150,000 to 200,000 Btu/ft
3
. This
intensity can be higher under ideal conditions, or lower if pollution requirements necessitate
very low CO and THC levels.
Ideal conditions mean that the burner chosen will run near
its maximum firing capability
.
Running the burner near its maximum capacity will
allow for higher efficiency, promote optimum mixing and result in lowest emissions.
Due to the variety of rotary drying applications, the proper number to use for sizing the
combustion zone is based somewhat on experience. It is a good idea to consider normal
available flame shapes for the size burner that is desired as well.
When sizing a burner and combustion zone for stringent emission regulation applications,
allow extra space for the flame to fully combust. Applications that require low CO and THC
benefit from larger combustion zones. In situations where (flue gas recirculation) is added to
reduce NOx, a larger combustion zone is also helpful. Combustion intensities in these cases
will be lower. Do not be concerned when removing several more feet of veiling flighting to
complete the combustion flighting as the new combustion flights will allow extra material
heating and drying from conductive heat transfer. Veiling flights can be added to make up
the difference in the balance of the drum (Consult Hauck).
Summary of Contents for Eco-StarII 100B
Page 11: ...Page 11 MS 9 Figure 3 Simplified Gas and Air Flow Chart Atmospheric Conditions GL86 ...
Page 12: ...Page 12 MS 9 Figure 4 MegaStar Gas Orifice Meters Graph ...
Page 30: ...Page 30 MS 9 Figure 14 Vapor Pressures of Propane Butane and Butane Propane Mixtures ...
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