MIL-HDBK-1003/6
Table 14 (Continued)
Stoker Selection Criteria
+))))))))))))))))))0))))))))))))0)))))))))))))))0))))))))))))))))0))))))))))),
*
*
*
*Max Furnace Heat*
*
Max Grate
* Typical
* Burning Rates *Release Rates(1)*
*
*
* Unit Size *
*
* Type of Stoker
Btu/Hr
Btu/Hr
*
*
* per Cubic Foot* per Cubic Foot * Limit(2) *
Range
*
*(PPH) Steam *
*
* (Turndown)*
Volume
of Furnace
/))))))))))))))))))3))))))))))))3)))))))))))))))3))))))))))))))))3)))))))))))1
*
*
*
*
*
*
* 3,000 to *
*
* Banked
*
* Underfeed
360,000
30,000
* 25,000
*
*
* Fires to *
*
*
*
*
*
* Full-
*
*
*
*
* Load
*
*
*
*
*
*
*
*
* Vibrating-Grate * 10,000 to *
*
* Banked
*
450,000
30,000
* (front gravity
* 25,000
*
*
* Fires to *
* feed)
*
*
*
* Full-
*
*
*
*
*
* Load
*
*
*
*
*
*
*
* Traveling-Grate * 20,000 to *
*
* 6 to 1
*
450,000
35,000
* (Front Gravity
* 160,000
*
*
*
*
* Feed)
*
*
*
*
*
*
*
*
*
*
*
* Overfeed Spreader* 25,000 to *
*
* 2.8 to 1 *
700,000
300,000
* (traveling-
* 400,000
*
*
* 3.5 to 1 *
* grate)
*
*
*
*
*
*
*
*
*
*
*
.))))))))))))))))))2))))))))))))2)))))))))))))))2))))))))))))))))2)))))))))))-
Information in this table is gathered from several stoker manufacturers'
recommendations.
(1) All grate heat release rates are based on maximum continuous rating
(MCR) with allowance for 110 percent rating for 2 hour emergency peak per
24 hours.
(2) Further turndown beyond that indicated may be obtained dependent upon
allowable emission requirements and/or pollution abatement equipment
applied.
d) Spreader Stoker. The spreader stoker has a range of 25,000 lbs
of steam per hour (3.15 kg/s) and up. The spreader stoker is characterized by
a thin bed and partial burning of coal particles in suspension. See Figure
15. Since the smaller coal particles are burned in suspension, this stoker is
responsive to load fluctuations. This characteristic, together with a non-
clinkering thin bed on the grate, provides a unit capable of firing a wide
range of coal grades and types. The spreader stoker has high availability,
ease of operation, and good efficiency. The suspension burning causes a high
71
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