POWER May 2011 - 44

THE FUTURE OF COAL
eer Station and Southern Company's Plant
Barry. AEP is injecting the captured CO2
into
two distinct, deep saline reservoirs and monitoring
the underground acceptance of the
CO2
with rocks and fluids in the formation, and
its movement underground. The first injection
of CO2
from coal-derived flue gas was
performed in October 2010. In the Southern
project, CO2
line ~10 miles to a saline formation. EPRI
is working with the Southern States Energy
will be transported by pipeby
the porous formation, its interactions
Near-Zero Emissions
A critical element in research for future coal
generation is the development of NZE plants.
A number of factors drive the need for
Power Mag 2011 Membrana.ai 1 3/28/2011 12:14:29 PM
NZE R&D. In the short term, coal plants will
need to meet upcoming regulations covering
emissions of NOx
, SO2, SO3, mercury, seleBoard
to manage the storage site. Permitting
and environmental assessments are under
way, and the site is being prepared to accept
CO2
by the end of 2011.
nium, particulates, and a number of organics.
These regulations include the U.S. Environmental
Protection Agency's Maximum
Achievable Control Technology rule, proposed
in 2011, and the Clean Air Transport
Rule, proposed in 2010. In the longer term,
the need for NZE technologies has become
linked to commercializing PCC processes,
because several CO2
and NO2
.
Current air pollution controls can reduce
emissions of NOx
, SO2, SO3, and mercury to
very low levels, but usually not to NZE target
levels on all coals, consistently throughout
the year. Technology advances, enhanced
instrumentation, and, most likely, a final polishing
step would be required to attain NZE
target levels.
In the near term, to meet existing and upcoming
regulatory requirements, a number
of new technologies must be developed and
demonstrated, such as:
■ Controls consistent with 90%-plus mercury
reduction for all applications and fuels.
■ Selective catalytic reduction (SCR) catalyst
regeneration strategies, as well as
SCR catalyst management systems consistent
with year-round system operation
at 90+% NOx
removal, minimum SO3
generation, and maximum oxidation of
elemental mercury in the flue gas.
■ Robust, reliable flue gas desulfurization
systems for all coals, including those with
low sulfur.
■ More wear-tolerant, low-pressure-drop/
ultra-high-efficiency baghouses for control
of particulates from a wide range of
fuels; improved performance of electrostatic
precipitators (ESPs) for applications
not suited to baghouses or amenable to
upgrading in existing power plants; and
demonstrated wet ESPs for acid mist and
fine trace metal particulate capture.
■ Resolution of balance-of-plant issues and
long-term operability issues for recently
installed environmental controls.
For pollutants with newly proposed regulations
(such as selenium, acid gases, and
organics), R&D initially will focus more
on the underlying mechanisms as well
as independent assessments of emerging
emission controls.
Water Use in Coal Power Plants
Reducing water use is emerging as a top
priority for the power generation industry,
including coal-fired plants, due to shortages
in and competing demands for water. This
issue will become even more acute with the
drive to reduce carbon emissions. When
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capture technologies require
inlet flue gas with extremely low levels
of SO2
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