Electrify Europe, Vienna Austria 2018,
Revisiting IGCC Technology
Koichi SAKAMOTO, Takashi FUJII, Tetsuya KIZU
Mitsubishi Hitachi Power Systems, Inc.
Carlos KOENEKE
Mitsubishi Hitachi Power Systems Americas, Inc.
Abstract:
Considerable Integrated Gasification Combined Cycle (IGCC) research has been funded by
several governments and large companies for several decades; however, deployment of the
technology has not materialized despite large coal resources in many countries around the
world. This is evident by the construction of only eleven coal based IGCC plants since 1994.
Environmental concerns surrounding coal based generation, high initial costs and low reliability
of many of the existing assets have worked against investment and development of new plants.
Mitsubishi Hitachi Power Systems (MHPS) has continued the design and development of the
technology in a progressive and conservative way that has resulted in the reliable operation of
a 250 MW Air-blown gasification demonstration plant called Nakoso. This facility was converted
into a commercial plant called Joban Nakoso # 10 power plant upon completion of exhaustive
validation and thorough testing. The construction of a 166 MW Oxygen-blown plant named
Osaki Coolgen was completed in March, 2017 and is now under demonstration operation.
Based on the above mentioned successful projects, MHPS has started the construction of two
540 MW Air-blown IGCC projects in Japan. These projects leverage Nakoso’s experience;
incorporating high efficiency 50Hz class gas turbines for 48% net plant efficiency.
This technology enables the new plants to operate with several advantages compared to UltraSuper-Critical applications, including capability to burn a diverse range of coals, lower ash
volumes and generation of residue that can be used in civil construction projects, and others.
The use of Air-blown gasification enables high reliability operation by eliminating the
requirements of gasifier internal refractory insulation allowing elimination of the requirement
for a spare gasifier.
This paper will explain MHPS IGCC Technology and presents an update on the status of
construction of the two plants mentioned above, scheduled to start commercial operation in
2020 and 2021.
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Introduction:
A total of 31 large or medium scale IGCC power plants have been built around the world in
more than three decades (1). Thirteen of those 30 have been retired leaving only 18 of them in
operation. The decommissioning motivation for these plants varies, but it typically includes low
reliability associated to issues in the gasification and/or gas cleaning processes and high cost of
generation compared to other energy sources, especially in countries where natural gas is
abundant and cheap. Construction delays and cost overruns in recent projects have also casted
a negative image on the technology.
MHPS has dedicated considerable resources to IGCC for more than three decades and the
gasification technology development has been focused on power generation rather than based
on petrochemical industry applications.
Low Heating Value Gas Turbine Experience:
Firing low heating value gases in gas turbines designed for natural gas can be challenging.
Figure 1 below shows the combustibility range covered by MHPS industrial gas turbines ranging
from low heating value Blast Furnance Gas (BFG) to oxygen blown syngas applications.
Figure 1. Low Heating Value Combustibility in Gas Turbines
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MHPS experience firing low heating value gases in gas turbines dates back to 1958 when an 850
kW unit burning Blast Furnace Gas (BFG) was commissioned as a prime mover for a blast
furnace blower at Yawata Steel Corporation (present Nippon Steel Corporation). A 4 MW gas
turbine was later delivered for the same client. A 15 MW gas turbine was supplied to Sumitomo
Metal Industries, Ltd. Wakayama Works in 1965. These efforts were followed by extensive
development of gas turbines capable of firing low heating value in the 1970’s.
MHPS pioneered the use of high efficiency gas turbines firing low heating value syngas in 2003
with the introduction of one F Class M701FV gas turbine at the 430 MW single shaft at Nippon
Petroleum Refining CO. Ltd. Negishi Refinery IGCC power plant located in Yokohama, Japan.
This IGCC unit features other OEMs gasification equipment.
Negishi’s M701FV experience with low heating value gas was followed by the introduction of
the first F class gas turbine firing BFG at 1,300 °C (2372 °F) Turbine Inlet Temperature in 2004.
This 300 MW combined cycle named Kimitsu Power Station (Figure 2) includes a 56 meter long
single shaft configuration that also drives an 87.3 MW centrifugal BFG compressor through a
step-up gear box (2).
Figure 2. Aerial view of Kimitsu BFG Power Station
Since 1990, MHPS has manufactured and delivered 59 low-Btu gas fired gas turbines, totaling
more than 7,000 MW of generating capacity and accumulating more than 3 million hours of
operation as shown in Figure 3 below. Seven additional units are currently in production. They
will add another 665 MW.
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Figure 3. Low Heating Value Gas Turbine Experience installations since 1990
Air and Oxygen-blown Gasification Experience:
IGCC System Features
Key features of IGCC power generation that makes it most attractive include:
High Thermal Efficiency. Through the application of more efficient combined cycle
power generation equipment, IGCC can achieve higher overall net plant efficiency than
conventional pulverized coal-fired steam (Rankine cycle) plants.
IGCC offers potential for substantial improvements in plant efficiency by applying
advanced state-of-the-art gas turbines featuring 1,600°C (2,912°F) TiT. MHPS J fleet
operates at this temperature level since 2011 and has accumulated more than 500,000
Actual Operating Hours (AOH).
The next-generation 1,700°C (3,092°F) class higher temperature gas turbines are being
developed with funding from the Japanese government. This technology is expected to
further improve the efficiency of future IGCC designs.
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Coal Flexibility. While issues with ash slagging, and other operational limitations, make
low-rank coal largely unsuitable for conventional coal-fired plants, high temperature
slagging gasification processes, as typically used for IGCC plants, can use a wider range
of coals including low-rank types as shown in Figure 4.
Figure 4. MHPS IGCC experience of wide variety of coal
Environmental Performance. Higher plant efficiency achieved with IGCC vs.
conventional coal-steam plants involves further CO2 emission reduction. SOx and
particulate emissions are greatly reduced by virtue of the pre-combustion gas cleanup
processes inherent in the IGCC plant design. CO2 emission’s reductions could approach
10-20% compared to most advanced ultra-supercritical plants.
Significant NOx reduction is achieved due to the dilute nature of the syngas inherent in
air-blown gasification, and via dilution with nitrogen in the oxygen-blown case.
Compared to a traditional steam-only power cycles, the circulating water required for
plant cooling in case of gas turbine combined cycle system is reduced by 30 percent.
Easier Ash Disposal. MHPS design features slagging gasification, allowing coal ash
discharge in a form of non-leaching glassy slag, with only half the volume of fly ash from
conventional coal-fired plants. This slag is much more easily disposed of, and even has
the possibility for sale as a byproduct for commercial applications, such as road paving
materials or as a fine aggregate for concrete.
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IGCC Plant Experience:
MHPS air-blown IGCC technology has been proven by the successful long-term continuous
operation at the Nakoso 250MW IGCC plant. Larger, more sophisticated, highly efficient and
highly reliable air-blown IGCC commercial plants projects are now being implemented.
Two separate 500MW-class plants, each utilizing a M701F gas turbine operating on low heating
value syngas, are now under construction. They are scheduled start operation in September,
2020 and September, 2021.
MHPS has also developed oxygen-blown IGCC technology. A plant named Osaki CoolGen was
developed and started demonstration testing in March, 2017. This initial phase of the project
will be followed by demonstration testing with CO2 capture equipment, starting in 2019. A third
project step will include demonstration of an Integrated Gasification Fuel Cell (IGFC) with CO2
capture, in 2021.
Nakoso 250MW Air-Blown IGCC Plant
MHPS, in collaboration with the Japanese Government, nine electric utility companies, J-Power
and the Central Research Institute of Electric Power Industry (CRIEPI) developed an air-blown
IGCC demonstration plant optimized for electric power generation. The 1,700 ton/day, 250 MW
Nakoso IGCC plant (Figure 5), utilizing an M701DA gas turbine, was constructed as the final step
in a long and methodical development process before commercialization.
It is noteworthy that the 1,700 ton/day Nakoso IGCC demonstration project itself was the
culmination of almost 20 years of gasification process development. This started with a 2 t/day
process development unit (PDU) phase operated by CRIEPI during the 1980s, followed by a 200
t/day pilot plant at Nakoso which operated from 1992 to 1996. In 1999, MHPS had also
installed a 24 t/day verification test unit at its own facilities in Nagasaki.
The Nakoso IGCC demonstration project was led by Japan’s Clean Coal Power R&D Co. (CCP),
which was founded in June 2001. MHPS signed a turn-key EPC contract for the entire IGCC
plant, and supplied the air-blown gasifier, syngas cleanup system, gas turbine (model M701DA),
steam turbine and heat recovery steam generator (HRSG).
Table 1 below summarizes the results of the series of verification tests that started in 2007. The
plant reached its rated load of 250 MW and completed 2,000 hours of continuous operation in
2008, less than one year from initial startup – testimony to the high reliability of MHPS’s airblown IGCC design. Follow-on demonstration testing culminated with the successful running of
a 5,000-hour long-term durability test, completed in June 2010.
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Figure 5. Nakoso 250MW IGCC plant
In the spring of 2013, the plant was taken over by Joban Joint Power Company and renamed
Nakoso #10 plant, representing the first coal-based IGCC commercial operation in Japan. In
December 2013, record breaking 3,917 hours of continuous IGCC operation was achieved.
All key performance measures for the Nakoso plant such as net thermal efficiency,
environmental performance and start-up time, achieved or well exceeded target values. (Note:
42.9% LHV efficiency is equivalent to approximately 41.5% HHV efficiency, substantially higher
than the typical conventional coal-fired steam plant and comparable to the most advanced
ultra-supercritical plants.)
Tests burning 10 different kinds of coal, including 6 ranks of sub-bituminous confirmed the
flexibility of the MHPS air-blown gasification process. Japan imports its coal, so that this ability
to operate over such a wide range of coal properties is essential to flexibly operate as a
commercial plant under the imported coal diversity.
Output (Gross)
(Net)
Performance Efficiency
(Net, LHV)
Carbon
Conversion
Emission
SOx
NOx
(@dry, 16%O2) Dust
Targets
Achievements
250MW
220MW
250MW
225MW
> 42.0%
42.9%
> 99.9%
> 99.9%
< 8 ppm
< 5 ppm
< 4 mg/m3N
1.0 ppm
3.4 ppm
< 0.1 mg/m3N
Chinese, Canadian
Coal Kinds
Operational
Flexibility
Reliability
Start-up Time
Note
10 kinds of coal in total
Bituminous
6 Sub-bituminous
2 US (including PRB)
Indonesian (Adaro, etc.) 4 Bituminous
Sub-bituminous 3 Colombian,
2 Russian have been used.
< 18 hr
15 hr
Minimum Load
50%
36%
Ramping Rate
Long-term
Continuous
Operation
3%/min
3%/min
2,000 hr
3,917 hr
Cumulative operating
hours :
> 38,000 hrs.
Table 1 Targets & Achievements of 250MW Nakoso IGCC Plant
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Osaki 166MW Oxygen-Blown IGCC Plant
The Osaki CoolGen IGCC demonstration plant features a MHPS oxygen-blown single-chamber,
two-stage, swirl-flow entrained-bed type of gasifier (see sidebar of Figure 6) with a coal feed
rate of 1,180 t/day. The 166MW (gross) IGCC plant was completed in March, 2017 and is
currently undergoing demonstration testing.
For the CoolGen project, MHPS signed a comprehensive contract to design, manufacture, install
and test the gasification/gas clean-up train -- including turnkey supply of the combined cycle
power generation equipment based an H-100 gas turbine – in addition to overall engineering
and general management of the project.
The demonstration test program aims to verify the scale-up technology of the gasifier,
establishing the control technology for operating the gasifier, and the complete oxygen-blown
IGCC system (refer to Figure 7).
Following this first demonstration phase, the second phase planned for the project involves
demonstration testing with CO2 capture equipment, starting in 2019. And, as the third step, it is
planned to demonstrate Integrated Gasification Fuel Cell (IGFC) with CO2 capture, in 2021.
(Note: The CoolGen project is sponsored by the New Energy and Industrial Technology
Development Organization.)
Due to the more concentrated nature of syngas produced with an oxygen-blown gasification
process (essentially a 50/50 mixture of CO and H2), the pre-combustion removal of CO2 via
conventional gas processing equipment is more practical than with air-blown gasification,
where the syngas is highly diluted with the nitrogen from the air used in the gasification
process.
Figure 6. Osaki CoolGen IGCC demonstration project
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FY
2012
2013
2014
2015
2016
Work to be implemented
Detailed design and construction of oxygen-blown IGCC units
a nd facilities
Design &
manufacturing
Design &
manufacturing
Design &
manufacturing
Design &
manufacturing
Equipment &
electrical work
Civil &
architecture work
Civil &
architecture work
Civil &
architecture work
Civil &
architecture work
Gasification
operation
Equipment &
electrical work
Equipment &
electrical work
Comletion of
equipment work
Hydraulic tests
Power reception
2017
2018
De monstration
Verification of basic performance
Plant performance
Environmental performance
Verification of
coal variety compatibility
Verification of plant reliability
Prolonged endurance test
Verification of controllability &
operability
Load change rate
Starting/stoppingtimes
Economy evaluation
Figure 7. Schedule for Osaki oxygen-blown IGCC demonstration (Phase I)
Current Projects under construction in Japan:
Based on success of the 250MW Nakoso IGCC Plant, a consortium led by MHPS is now
implementing a very significant commercial power generation project in Japan comprising two
similar 500MW-class IGCC plants; one plant will be for Nakoso IGCC Power GK and the other for
Hirono IGCC Power GK (GK stands for Godo Kaisha in Japanese, a type of Limited Liability
Company or LLC).
This project will result in the development of industrial infrastructure and economic recovery in
the area. The new Nakoso IGCC plant will be built on property adjacent to Joban Joint Power’s
Nakoso Power Station in Iwaki City and the Hirono IGCC plant will be built on the site of TEPCO
Fuel & Power’s Hirono Thermal Power Station in Fukushima’s Futaba District. (See artist
concepts of each plant in Figures 8 and 9.)
Figures 8 and 9. Fukushima Revitalization Power Project:
Nakoso IGCC Power (L) Hirono IGCC Power (R)
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Each air-blown IGCC plant will have a generating capacity of 540MW, utilizing M701F gas
turbines. The process design for the gasification island (gasifier, gas cleanup, etc.) will use the
same concept, scaled approximately 2:1, as used at the 250MW Nakoso IGCC Plant. Nakoso
began construction in April, 2017 and Hirono will begin in April 2018 with start of operation
scheduled in September 2020 and September 2021, respectively.
MHPS, as project leader, is working closely with its three consortium partners: Mitsubishi Heavy
Industries Ltd., Mitsubishi Electric Corporation, and Mitsubishi Hitachi Power Systems
Environmental Solutions, Ltd. “In the process of building these two plants, every effort will be
made to further improve IGCC technologies, to enable even more efficient coal-based power
production, and further reduce environmental impact”, say MHPS project managers.
Following the successful demonstration and commercialization of the Nakoso 250MW airblown IGCC plant based on M701DA gas turbine, MHPS is now offering commercial plants using
both M501GAC (60Hz) and M701F (50Hz) gas turbines. Expected net plant efficiency for both
designs is 48% (LHV), as represented in Figure 10.
Major Specification
Output
Gasifier
Gas Clean-Up
Gas Turbine
Project Schedule
Operation Start
540 MW (gross)
480 MW (net)
Air-blown
MDEA
M701F GT (1 on 1)
2020 (Nakoso site)
2021 (Hirono site)
Figure 10. Specifications of the Fukushima Revitalization Power IGCC plants
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Summary:
 MHPS has the largest low heating value gas turbine fleet in the industry, including 59 gas
turbines with more than 7,000 MW installed base with an accumulated experience in
excess of 3 million hours. Seven additional units are currently in manufacturing for
additional 665 MW.
 MHPS has consistently worked on the development and testing of air- and oxygenblown gasification process focusing on high plant efficiency while targeting high
reliability.
 The air-blown gasification design successfully completed its demonstration and
commercial scale.
 Two air-blown 540MW IGCC plants are currently under construction aiming at COD in
2020 and 2021.
 The Oxygen-blown gasification operation is ongoing and being analyzed for future
deployment combined with CCS and/or fuel cell technology
References:
(1) Gas Turbine World 2018 Handbook reference to EPRI information. Page 25 and 26.
(2) Katsunori TANAKA, Koichi NISHIDA, Wataru AKIZUKI, Toyoaki KOMORI, Carlos KOENEKE;
Update on synthetic gas and low calorie gas applications to M701F Gas Turbines;
PowerGen International 2005.
(3) Toyoaki KOMORI, Katsunori TANAKA, Wataru AKIZUKI, Carlos KOENEKE; Update on
Design and Operating Experience of Low Calorie Gas Firing Gas Turbine for Steel Works;
PowerGen International 2007.
(4) Toyoaki KOMORI, Katsunori TANAKA, Wataru AKIZUKI, Carlos KOENEKE; Update on
Design and Operating Experience of Low Calorie Gas Firing Gas Turbine for Steel Works;
Association For Iron and Steel Technology Conference, Pittsburg, 2018.
(5) Koichi SAKAMOTO; Building on success: MHPS takes on two 500MW-Class IGCC projects;
Gas Turbine World 2018 Handbook.
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