GE P&W FuelSolv - Opportunity Coal Slag Control at Lakeland McIntosh Unit #3 - Manual (Page 2)

Page 2 Technical Paper
1982. Steam production is 2.5 MMlbs/hr at 1,005
deg F and 2,640 psig. The boiler fires about 100
tons pulverized coal per hour at maximum load, and
the boiler train is equipped with SCR, cold-side elec-
trostatic precipitators and a wet flue gas desulfuri-
zation (Wet FGD) scrubber system. The plant is
equipped with ZONAL*, GE Energy’s combustion
monitoring and optimization system. The unit was
also recently outfitted with a hydrated lime sorbent
injection system to mitigate SO3 emissions.
Lakeland McIntosh provides power to more than
120,000 residents of the City of Lakeland. McIntosh
has been a visionary in power generation, including
previous evaluations of co-firing biomass and mu-
nicipal waste with pulverized coal. In 2002, Lake-
land McIntosh was ranked as the 10
th most efficient
and reliable coal-fired unit out of the nation’s top
200. (Lakeland) Lakeland’s management and oper-
ations team remain committed to evaluating fuels
and treatment programs for environmentally re-
sponsible and cost-effective power generation for
the City of Lakeland.
Coal Properties and “Opportunity” Coal
The three most common types of coal mined in the
United States are bituminous, sub-bituminous, and
lignite. Different geological conditions over time
(heat and pressure) caused coal to form differently
across the country. In general, higher rank bitumi-
nous coal is found on the East Coast and Midwest.
Bituminous coals can be used as a thermal coal
(power generation) or metallurgical coal (coking and
steel production). (World Coal) Lower rank sub-
bituminous coals (such as Powder River Basin coal)
are found out West while lignite is typically found in
the Gulf Coast and North Central US, (Figure 1).
Figure 1: Coal Reserves in the United States
(American Coal Foundation, www.teachcoal.org)
“Harder” coals include Anthracite and Bituminous
coals such as Central Appalachian (CAPP), Northern
Appalachian (NAPP) or Illinois Basin (ILB). Histori-
cally, harder coals have been more valuable than
lower rank coals due to their clean burning (low
ash) and high heating value (HHV), used extensive-
ly in transportation and power generation.
Although CAPP, NAPP and ILB coals are all bitumi-
nous coals, their chemical properties vary. Each
will possess a unique composition based on the
geological deposit. Elements such as sulfur, chlo-
rine and iron can affect properties of combusted
coal such as emissions and slag production. The
ash fusion temperature (AFT) is the temperature
where the solid ash melts and “fuses” into a liquid
phase. Higher rank coals have AFT’s ranging from
low 2,100 to 2,800 degrees Fahrenheit. A thor-
ough understanding of the chemistry of coal is
needed to properly evaluate a fuel and design a
successful fireside treatment program. Lakeland’s
primary fuel (CAPP) and opportunity coals (NAPP
and ILB) are given in Figure 2.
Coal Type CAPP NAPP ILB
HHV, BTU/lb 12,256 12,023 11,450
Ash, wt% 18.2% 12.7% 8.4%
Moisture, wt% 8.8% 7.2% 12.5%
Sulfur, wt% 1.6% 1.8% 2.9%
AFT ( o F) 2,600 2,482 2,400
Basicity Ratio 0.13 0.26 0.38
Mineral Content (combusted coal)
SiO
2
54.6% 50.8% 49.6%
Al
2
O
3
29.4% 24.3% 17.4%
Fe
2
O
3
5.2% 14.2% 19.1%
CaO 1.0% 1.4% 2.8%
MgO 1.0% 1.0% 0.9%
Na
2
O 0.3% 0.2% 0.8%
K
2
O 3.5% 2.8% 2.2%
Coal Seam Name Blanton
Creech
Ramsey Armstrong
Crimson
Macopin
Williamson
Figure 2: Lakeland McIntosh Typical Fuel Properties