POWER January 2011 - 53

CARBON CAPTURE
Oxy-Combustion: A Promising
Technology for Coal-Fired Plants
For more than a decade Babcock & Wilcox Power Generation Group Inc. and
Air Liquide have been developing oxyfuel technology with the goal of
using it to concentrate CO2 from pulverized coal-fired power plants and
achieve up to 90% CO2 capture and storage. This technology was recently
selected for demonstration as part of FutureGen 2.0.
By D.K. McDonald, PE and Steve Moorman, Babcock & Wilcox Power Generation Group Inc. and Arthur Darde and Sebastien de
Limon, Air Liquide Engineering & Construction Cryogenics Europe
I
n late September 2010, the U.S. Department
of Energy (DOE) signed cooperative
agreements with Ameren Energy
Resources, to construct FutureGen 2.0 using
full-scale oxy-combustion technology on an
existing coal-fired power plant, and with
the FutureGen Alliance, for the design and
construction of a CO2
hub that will transfer and store the CO2
pipeline and storage
captured
by the repowered plant. The project is
set to " oxy-combust repower " a mothballed
unit at Ameren's Meredosia Power Plant located
near Jacksonville, Illinois. Babcock
& Wilcox Power Generation Group (B&W)
and Air Liquide Process & Construction
(AL) are among the partners in the development
of FutureGen 2.0 (Figure 1). The new
plant will be designed to produce 200 MW
gross/140 MW net, capture 1.3 million tons/
year of CO2
and emit near-zero NOx
, SOx
,
mercury, particulates, and other hazardous
air pollutants.
B&W, AL, and the FutureGen Alliance are
now working on completing Phase 1 of the
project, which includes initial engineering
and validation of the project's scope, cost,
schedule, and commercial viability. Phase 1
is expected to be completed in the third quarter
of 2011.
Assuming that Phase 1 is found to be
technically and commercially sound, Phase
2 will be authorized by the DOE for detailed
design and collecting the numerous
permits required to construct the project.
Concurrently, Ameren will request that the
Illinois utilities commission change current
law to allow some form of cost recovery for
the project. Phase 3 includes procurement
of materials and construction of the plant,
which will require the approval of the DOE
and Ameren's board of directors. DOE officials
believe that Phase 3 could begin as
early as mid-2012 and the plant could be in
service and begin the 2.5-year test period in
the first quarter of 2016.
52
Technology Development
There are currently three main options for
capturing carbon from coal-fired systems: integrated
gasification combined cycle (IGCC),
post-combustion capture, and oxy-combustion.
IGCC is a greenfield or repowering option that
has long been favored for carbon capture and
sequestration (CCS), but recent demonstration
project costs have been much higher than
anticipated, and performance estimates have
fallen far short of expectations. Post-combustion
systems using ammonia- or amine-based
solvents hold promise for both new and retrofit
applications, and several demonstrations
are under way. Oxy-combustion-combustion
of the fuel with a mixture of nearly pure oxygen
and recycled flue gas rather than air-is
predicted to have the highest overall efficiency
and promises to be the low-cost option. Unlike
post-combustion capture, oxy-combustion
technology cannot be demonstrated on a slip
stream from a larger plant (see sidebar).
Through participation in various consortia
focused on this technology, B&W and AL
have made major advancements in oxy-combustion
and are currently two of the world
leaders in this field. Together, B&W and AL
performed pilot-scale oxy-coal combustion
tests on a 1.5-MWth pulverized coal (PC)-
fired boiler and completed several economic
and performance studies of oxy-coal PC-fired
power plants from retrofit to full-scale greenfield
applications.
In late 2006, B&W modified its existing
30-MWth (100 MBtu/hr input) Clean Environment
Development Facility (CEDF) for
oxy-firing and in 2007 completed testing with
bituminous, subbituminous, and lignite coals
with the cold recycle process configuration.
Further testing was completed in spring 2008
with the warm recycle process. Extensive
study of several oxy-process configurations
and heat integration options began in 2008.
Over the past two years, the team has
completed the basic design of a 100-MW net
www.powermag.com
1. Future plans. This artist's concept drawing
of FutureGen 2.0 was presented by the
FutureGen Alliance at an October 28, 2010,
project briefing. Source: FutureGen Alliance
demonstration plant and a 700-MW gross
commercial reference plant using the oxycombustion
technology. In July 2009, B&W
and AL, together with Black Hills Corp.,
proposed a near-zero-emission 100-MW net
oxy-combustion demonstration plant to the
DOE under its Clean Coal Power Initiative
Round 3 solicitation. That project was not selected.
However, given the positive results of
the pilot-scale tests and the work completed
on previous proposals submitted to the DOE
for oxy-combustion testing, the oxy-combustion
technology was selected by the DOE to
become part of FutureGen 2.0.
As noted earlier, the FutureGen 2.0 Phase 1
design, cost estimating, and scheduling work
is under way as of this writing, and we'll report
of the specifics of that design when that
phase of the project is completed. In this article,
we focus on the history and fundamentals
of B&W's oxy-combustion design.
Oxy-Combustion Is Ready for
Demonstration
B&W first explored oxy-combustion technology
in 1979 with hopes of using the CO2
stream
for enhanced oil recovery, but low oil prices
made it uneconomical. In the mid-1990s, as
interest in CO2
emissions and their impact on
climate change was increasing, B&W reconsidered
the possibilities of the technology as
a means of concentrating CO2
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POWER January 2011

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