Environmental Engineering Reference
In-Depth Information
TABLE 9.1 Comparison of grate firing systems, fluidized bed systems, and pulverized
fuel flow combustion systems
Fluidized bed firing systems
(BFB and CFB)
Pulverized fuel firing
systems
Grate firing systems
Advantages
Advantages
Advantages
Little fuel preparation
expenditure
Clear design
High degree of
availability
Simple operation
Little auxiliary power
requirements
Low NO
x
emissions
Partial desulfurization by
limestone addition
Little fuel preparation
expenditure
Flue gas cleaning consists
only of flue gas particle
collection
High degree of availability
Large capacities
High power density
Good burnout
Usable ash
Disadvantages
Disadvantages
High limestone demand for
sulfur capture at excess air
Ash not usable without
further preparation
High fuel preparation
expenditures
Flue gas cleaning needed
for particulates, SO
2
,
and NO
x
Disadvantages
Advantages of CFB compared
to BFB
High combustion losses of
2-4% by unburned carbon
High flue gas
temperatures due to
limited air preheating
Unsuitable for fine-
grained fuels
Better burnout
Lower limestone demand for
sulfur capture
Better emission values
No in-bed heating surfaces at
risk of erosion
Better power control
Source: Reproduced with permission from Spliethoff (2010). © Springer Science + Business Media.
TABLE 9.2 Output ranges of firing systems
Firing system
Output range (MW
th
)
Entrained flow
40-2500
BFB
<80
Grate firing
2.5-175
CFB
40-750
Source: Reproduced with permission from Spliethoff
(2010). © Springer Science + Business Media.
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