MIL-HDBK-1003/7
Table 5
Stoker Selection Criteria
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*
*
Type of Stoker
Fuel Requirements
* Unit Size
*
Type of
Type of
* Range PPH
*
Feed
Grate
Size
Characteristics
*
*
* 25,000-
*
Front
Traveling 1" to 0" top Free burning to medium
*
* 160,000
Gravity
size with
caking (free swelling
*
*
maximum 60%
index less than 6) ash 6
*
to 15% volatile matter 28 *
though 1/4"
*
*
round hole
to 40%. Ash fusion
*
*
screen
(reducing atmosphere H =
1/2W) minimum 2750 deg. F *
*
*
*
minimum Btu/lb 11,500
*
*
*
* 25,000-
Overfeed
Traveling 1-1/4" to
Bituminous A & B
* 160,000
*
spreader
3/4" X 0"
subbituminous or lignite
*
with maximum volatile matter 25% to 40% *
*
*
40% through
ash 6 to 15% ash fusion
*
*
1/4" round
(reducing atmosphere H =
*
1/2W) minimum 2750 deg. F *
hole screen
*
*
minimum Btu/lb 11,500
*
*
*
*
*
*
Maximum
*
*
Stoker
*
*
Btu/Hr ft2
Grate
*
Type of Stoker
Burning
* Unit Size Type of Type of Rates
*
of furnace Heating
limited
* Range PPH
(turndown) *
2
Feed
Grate Btu/ft /Hr Volume
Surface
*
*
* 25,000-
*
Front
Traveling 450,000
35,000
100,000
6 to 1
* 160,000
*
Gravity
*
*
*
*
* 25,000- Overfeed Traveling 700,00
*
300,000
100,000
2.8 to 1
* 160,000 spreader
*
3.5 to 1
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Notes:
1. The underfeeds and chain grate stokers are not generally applicable to widely
fluctuating loads, i.e., process type loads which may vary in capacity more than 50%
during any 30 minute period. For applications of swing loads with less than the 30
minute period, use spreader stoker.
2. Where availability of proper coal suitable for a particular type stoker is
indeterminate, consideration should be given to the spreader type stoker.
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