Mitsubishi Heavy Industries Technical Review Vol. 52 No. 1 (March 2015)24

Deployment of World’s Largest Post-combustion
Carbon Capture Plant for Coal-fired Power Plants*1*2

TAKASHI KAMIJO

MASAYUKI INUITAKAHITO YONEKAWA*3*4

TAKUYA HIRATA*5

TATSUYA TSUJIUCHIOSAMU MIYAMOTO*6

CO2 Capture and Storage (CCS) is expected to be useful for the reduction of CO2 emissions
from thermal power stations. Mitsubishi Heavy Industries, Ltd. (MHI), together with Southern
Company of the U.S., participated in an integrated demonstration test of capture, transportation,and storage of CO2 from the flue gas of a coal-fired power plant. The project attained a cumulative
operation time of 10,000 hours and a CO2 storage amount of 100,000 tonnes or more by October
2013. In addition, in July 2014 MHI also received an order for the world’s largest post-combustion
CO2 capture plant (with a CO2 capture capacity of 4,776 tonnes per day) from an Enhanced Oil
Recovery (EOR) project mainly promoted by NRG Energy Inc. and JX Nippon Oil & Gas
Exploration Corporation. This paper presents the results of the CO2 capture and storage
demonstration test and MHI’s future actions.

|1. Introduction
MHI adopts the KM CDR Process® (Note), a CO2 capture process that uses the uniqueamine-absorption liquid “KS-1TM” developed together with the Kansai Electric Power Co., Inc.1
Figure 1 outlines the flow of MHI’s CO2 capture plant. MHI has put CO2 capture technologies into
practical use for emissions from natural gas-fired and heavy oil-fired plants. There are elevencommercial CO2 capture plants currently in service including the first commercial plant deliveredin 1999. Recovered CO2 is commonly delivered for the enhancement of fertilizer production, etc.
However, a CO2 capture plant (with a capacity of 500 tonnes per day) delivered to Qatar in 2014
has also started operation for the enhancement of methanol production.
Technology for the capture of CO2 from the combustion flue gas of fossil fuel is also
attracting attention as a countermeasure to global warming. According to the latest Energy
Technology Perspectives released by International Energy Agency (IEA), if current energy
consumption continues as is, the annual amount of CO2 emissions in 2035 is estimated at 40
gigatonnes, with a further increase to 50 gigatonnes or more by 2050. As a result, it is projectedthat the average temperature will rise by 3.6 to 5.3 degrees Celsius. To limit the predicted
temperature increase to 2 degrees Celsius by 2050, reduction in CO2 emissions is paramount. By
2050 it is expected that the amount of CO2 emissions reduced due to the spread of CO2 Capture andStorage (CCS) technology will likely increase to around 14 percent of all CO2 emissions.2 In
particular, the amount of CO2 emissions from thermal power stations accounted for 39 percent of
all CO2 emissions in 2011. Again, for example plans for regulations to be imposed on
CO2 emissions from thermal power plants in the U.S. are moving forward.
*1 Chief Staff Manager, Chemical Plant Project Management Department, Chemical Plant & Infrastructure Division, Energy & Environment*2 Environmental & Chemical Plant Division, Mitsubishi Heavy Industries America, Inc.
*3 Environmental & Chemical Plant Division, Mitsubishi Heavy Industries America, Inc.
*4 Hiroshima Research & Development Center, Technology & Innovation Headquarters*5 Chemical Plant Basic Engineering Department, Chemical Plant & Infrastructure Division, Energy & Environment*6 MHI Solution Technologies Co., Ltd.

Mitsubishi Heavy Industries Technical Review Vol. 52 No. 1 (March 2015)
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MHI collaborated with Southern Company, which is a major electric power company in thesoutherneastern U.S., and the Electric Power Research Institute (EPRI) to construct ademonstration facility for the capture of CO2 from the flue gas of a coal-fired plant (with a capacityof 500 tonnes per day) at Southern Company subsidiary Alabama Power’s Plant Barry in Mobile
County, Alabama, and conducted a demonstration test of CO2 capture and storage technologies.
Note: KM CDR Process® is the trademark of the CO2 capture process developed together with the Kansai
Electric Power Co., Inc., and is registered in Japan, the U.S., the European Community (CTM), Norway,
Australia, and China.

Figure 1

Flow of MHI’s CO2 capture process (KM CDR Process®)|2. Demonstration project of integrated CO2 capture and storage
process(1) Project outline
The CO2 capture demonstration project, in which MHI constructed the facility together
with Southern Company, was the world’s first integrated demonstration test for the capture,compression, transportation, and storage of CO2 from the flue gas of a coal-fired power plant.
Table 1 Outline of CO2 capture demonstration
facility for Southern Company
Item
Plant location
Plant owner
Process
Absorption liquid
Plant scale
Flue gas amountCO2 capture ratio
CO2 capture amountCO2 concentration

Description
Mobile County (Alabama, U.S.A.)
Southern Company subsidiary
Alabama PowerKM CDR Process®
KS-1TM solvent
Corresponding to 25 megawatts(MW)116,800 Nm3/h
90 percent
500 tonnes/day (150,000 tonnes/year)
10.1 mol%-wet

Figure 2 External view of CO2 capture
demonstration facility for Southern
Company

Table 1 shows an outline of Southern Company’s CO2 capture demonstration facility and
Figure 2 shows the external view of the demonstration facility. The CO2 transportation andstorage was conducted as part of the Regional Carbon Sequestration Partnership Phase III

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Program of the Department of Energy (DOE) and the Southeast Regional Carbon Sequestration
Partnership (SECARB), which is a partnership between the governments of eleven Southernstates.
(2) Operation status
This demonstration facility started the capture of CO2 from the plant in June 2011 andsubsequently the underground storage of captured CO2 in August 2012. The CO2 capture plantattained a CO2 capture amount of 500 tonnes per day and a CO2 capture ratio of 90 percent,according to the initial plan, and verified its energy saving performance requiring steam
consumption of 1 ton per CO2 ton or less through a test conducted while changing the main
operation parameters.(1) Figure 3 shows the trend of CO2 capture and storage results from thestart of operation through to the end of October 2013. The total operation time exceeded 10,000
hours by the end of October 2013 and the cumulative CO2 capture amount reachedapproximately 200,000 tonnes.

Figure 3

Operational trend results(3) Verification test of amine-emission reduction technology
The flue gas discharged from the CO2 absorption column commonly contains a small
amount of amine solvent, resulting in the loss of amine solvent to the atmosphere. In a pilot test
plant in MHI’s research and development center in 2010, MHI found a phenomenon whereby
SO3 mist included in flue gas caused an increase in amine emissions. Since then MHI has beendeveloping an amine-emission reduction technology ahead of its competitors. In thedemonstration project in the U.S., the developed amine-emission reduction technology wasverified. Figure 4 shows the verification test results. It was demonstrated that theamine-emission reduction technology can reduce amine emissions by approximately 1/10 incomparison with the existing process of MHI.

Figure 4 Verification test results of amine-emission reduction technology(4) Verification test of load-following control system
The operational load of a coal-fired power plant is adjusted according to daily electric
power demand. As a result, operating conditions in the boiler are always changing and therefore

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the properties of flue gas, such as CO2 concentration, changes. For this reason, an automatic
load-following control system is effective for maintaining the optimum operating conditions of
the CO2 capture plant. MHI developed an optimum operation control system for theCO2 capture plant and conducted a verification test of the control system in the U.S.
demonstration project. Figure 5 shows the operational trend without the control system, andFigure 6 shows the operational trend with the control system. Both Figure 5 and Figure 6
exhibit the CO2 capture amount and the CO2 capture ratio on the left, and the CO2 concentration
included in the flue gas and flow volume of the flue gas on the right. Figure 5 shows theCO2 capture amount and the CO2 capture ratio change along with change of flue gas conditions.
Figure 6, in contrast, shows that the CO2 capture amount and the CO2 capture ratio is constantly
maintained. In this way, it was verified that the control system is effective for stable operation.

Figure 5

Operation trend (with load-following control system turned off)

Figure 6

Operation trend (with load-following control system turned on)(5) Future efforts
Before attaining a CO2 storage amount of 100,000 tonnes in October 2013, various
evaluations and verification tests in addition to the tests described above were conducted.
Therefore, knowledge of the operation of CO2 capture plants and the practical application ofthis to large CO2 capture plants, used for the flue gas of coal-fired plants, was obtained. Today
the CO2 capture demonstration facility in the U.S. is used to develop and verify newtechnologies. Currently (2014-2015) the CO2 capture demonstration facility is proceeding witha project integrated with a power generation system, looking at a reduction in the lowering of
the power generation efficiency that occurs when the CO2 capture technology is applied. This ispart of a verification program of the DOE.
Figure 7 shows the block flow diagram of the verification project. In this verification
program, the existing boiler water is heated by the waste-heat recovery from the existing fluegas with MHI’s advanced flue-gas treatment system (HES)3 and from the CO2 capture plant.
With the utilization of HES in MHI’s process, an improvement of 30 percent or more is
expected in terms of efficiency in power generation compared to competitor’s existing
technologies where 90 percent of the CO2 in flue gas is captured. In addition, the introductionof HES enables further elimination of impurities such as SO3 from flue gas, resulting in the
reduction of the load on the CO2 capture plant.

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Figure 7

Block flow of integrated project|3. Efforts for larger CO2 capture plant
Since starting the operation of a 2 tonnes per day pilot test plant together with the Kansai
Electric Power Co., Inc. in its Nanko Power Plant in 1990, MHI has been conducting CO2 capture
tests from various flue gases and improving CO2 capture performance. As described above, there
are eleven commercial CO2 capture plants currently in service. In addition, MHI has accumulated
knowledge of CO2 capture plants used for coal-fired power plants using a pilot test plant with acapacity of 1 ton per day at the MHI Hiroshima Research & Development Center and a verification
test plant with a capacity of 10 tonnes per day in the Matsushima Thermal Power Plant of ElectricPower Development Co., Ltd. For CCS and CO2 EOR, a larger CO2 capture plant with a capacityof thousands of tonnes per day needs to be applied, therefore further scale-up of CO2 capture plants
is required. MHI has made it possible to construct a reliable plant with a capacity of thousands oftonnes per day by utilizing knowledge about scalability obtained in the practical application of theflue-gas desulfurization equipment (a product of the present Mitsubishi Hitachi Power Systems,Ltd.) as well as the invaluable knowledge obtained in multiple verification tests of various scales.
MHI received an order for the world’s largest CO2 capture plant (with a CO2 capture capacityof 4,776 tonnes per day) from an EOR project mainly promoted by NRG Energy Inc. and JX
Nippon Oil & Gas Exploration Corporation in July 2014. Table 2 shows an outline of the plant, andFigure 8 shows a conceptual drawing of the completed plant. This CO2 capture and storage projectis partially funded by a grant from the Clean Coal Power Initiative (CCPI) of the DOE, and isscheduled to start operation around the fourth quarter of 2016. The plant will capture CO2 from fluegas corresponding to a 240 MW slipstream and inject the captured CO2 into an oil fieldapproximately 130 km away from the power generation plant. Due to the CO2 EOR effect,enhancement in oil production from 500 barrels per day to 15,000 barrels per day is expected.

Figure 8 Conceptual drawing of completed CO2 capture plant for EOR project in Texas, U.S.A

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Table 2 Outline of CO2 capture plant for EOR project in Texas, U.S.A
Item
Plant location
Plant ownerGas source
Process
Absorption liquid
Plant scale
CO2 capture ratio
CO2 capture amount

Description
Thompsons (Texas, U.S.A.)
Petra Nova (joint venture between NRG Energy Inc. and JX
Nippon Oil & Gas Exploration Corporation)
NRG WA Parish power generation plant
610 MW(Net) coal-fired power generation facility
KM CDR Process®
KS-1TM solvent
Corresponding to 240 MW
90 percent
4,776 tonnes/day

Figure 9 shows the process structure of this CO2 capture plant and the related facilities.4 The
steam and electricity required for the operation of the CO2 capture plant are supplied from theauxiliary gas turbine and exhaust heat recovery boiler, and therefore CO2 can be recovered without
decreasing the power generation output from existing power generation facilities.
It is expected that CO2 EOR, which is a combination of EOR and CO2 capture from a power
generation plant or a chemical plant, will be widely used and the market for utilizing CO2 capture
plants will grow. MHI continues to improve the technologies for CO2 capture plants and promotes
the commercialization of large CO2 capture plants that are suitable for the CO2 EOR and CCS
markets.

Figure 9 Process structure of CO2 capture plant for EOR project in Texas, U.S.A|4. Conclusion
MHI, together with Southern Company, operated a CO2 capture demonstration test facility
with a capacity of 500 tonnes per day constructed at Southern Company subsidiary Alabama
Power’s Plant Barry in Mobile county, Alabama, and attained a cumulative CO2 undergroundstorage amount of 100,000 tonnes. Through the demonstration project, the reliability of the KM
CDR Process® for a coal-fired plant was proven and various new technologies, including
amine-emission reduction technology, were also verified. These verification results are reflected inlarge CO2 capture plants, enhancing their reliability. MHI continues technological development forthe deployment of the large scale CO2 capture plants.

References
1.
2.
3.
4.

Kamijo et al., Mitsubishi Heavy Industries Technical Review Vol.50, No.1 (2013) p.27-32
The Global Status of CCS 2014, Global CCS Institute, (2014) p.20-27
Tsuchiya et al.，Mitsubishi Heavy Industries Technical Review Vol.34,No.3 (1997) p.158-161
U.S. Department of Energy “W.A. Parish Post-Combustion CO2 Capture and Sequestration Project Final
Environmental Impact Statement Volume I” (Feb, 2013), DOE/EIS-0473