Mitsubishi Heavy Industries Technical Review Vol. 56 No. 3 (September 2019)1

Current Status of Integrated Coal Gasification Combined
Cycle Projects

MIKIO AMAMOTO*1

MASAYA TAKAHATA*2

TAKASHI FUJII*3

TAKESHI KUMAGAI*4

Regarding the situation of integrated coal gasification combined cycle (IGCC) in Japan, a250 MW power generation plant applying air-blown gasification technology started domestic
commercial operation for the first time in April 2013, and construction of two large IGCC 543 MW
units is advancing as a Fukushima IGCC project. On the other hand, a demonstration testoperation of 166 MW in First Step of the Osaki CoolGen Project using oxygen-blown gasification
technology was completed in October 2018, and a CO2 separation and capture facility to beinstalled in Second Step is under construction. This paper introduces the most recent situation ofthe IGCC project of Mitsubishi Hitachi Power Systems, Ltd. (MHPS).

|1. Introduction
IGCC is a thermal power generation system that combines a combined cycle system and acoal gasification process to achieve higher efficiency and lower carbonization than conventional
pulverized coal-fired thermal power generation. Efficiency can be improved through combined
power generation combining power generation with a gas turbine using coal gasification gas andpower generation with a steam turbine using exhaust heat from a gas turbine. As a result, fuelconsumption is reduced and CO2 emissions can be reduced (lower-carbonization emissions). It isalso advantageous in that low-grade coal such as low-ash melting point coal, which was difficult touse in conventional pulverized coal-fired thermal power generation, can be used, and that ash canbe effectively used (raw materials for cement, etc.) and warm drainage can be reduced in terms ofenvironmental load reduction.
Since the 1980s, MHPS has been working on the development and practical application of
IGCC using two coal gasification technologies, air blowing and oxygen blowing, to improve
efficiency, operability (i.e., fast load change rate and minimum load), reliability (i.e., operation rateand continuous operation time), safety and environmental performance. The development of IGCC
is expected to contribute to the effective use of coal resources, which have large reserves and arecheaper than other fuels, and to the reduction of environmental impact through the reduction ofCO2 emissions achieved through higher efficiency.

|2. Current status of the Osaki CoolGen project
The Osaki CoolGen Project has been implemented by Osaki CoolGen Corporation(established in 2009 by The Chugoku Electric Power Co., Inc. and Electric Power Development
Co., Ltd.) since fiscal 2012 as a subsidized project by the Ministry of Economy, Trade andIndustry, and since fiscal 2016 as a subsidized project by the New Energy and Industrial
Technology Development Organization (NEDO). This project consists of three steps as shown inFigure 1, and the First Step is the Oxygen-blown IGCC demonstration test, the Second Step is theOxygen-blown IGCC with CO2 Capture demonstration test in which CO2 capture facility is added*1Director, Oxigen Blown IGCC Project Management Department, Project Management Division, Mitsubishi Hitachi Power*2Oxigen Blown IGCC Project Management Department, Project Management Division, Mitsubishi Hitachi Power Systems,Ltd.

*3

Manager, Power Systems Project Engineering Department, Project Management Division, Mitsubishi Hitachi Power Systems,Ltd.

*4

Chief Staff Manager, Kure Boiler Engineering Department, Boiler Technology Integration Division, Mitsubishi Hitachi PowerSystems,Ltd.

Systems,Ltd.

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 3 (September 2019)
2to this IGCC, and the Third Step is the Integrated coal Gasification Fuel Cell combined cycle(IGFC) with CO2 Capture demonstration test in which a fuel cell is further combined. The FirstStep demonstration test began in March 2017 and the Second Step demonstration test will begin inDecember 2019.
In the large demonstration experiment of oxygen blown coal gasification technology in theFirst Step, MHPS carried out the design, manufacture, installation and trial run of asingle-chamber, two-stage spiral flow entrained-bed gasifier with 1,180 tons/day coal throughput, a
166 MW combined cycle power generation facility, electric and control facilities. It is also incharge of engineering for general management of the demonstration plant.

Figure 1

Facility configuration of Osaki CoolGen project

Table 1 gives the main specifications of First Step of this project and Figure 2 is a
panoramic view of the site. The demonstration test of 166MW class oxygen blown IGCC was thefirst in Japan, and the following were verified in First Step: Basic performance related to plantperformance and environmental performance, facility reliability, plant controllability andoperability, multi-coal applicability and economic efficiency. The achievement of all the items ofthe development goals was confirmed. In terms of basic performance, a net thermal efficiency of
40.8% (higher calorific value base) was achieved, and in terms of environmental performance, theexhaust gas property was less than 8 ppm of SOx, less than 5 ppm of NOx and less than 3 mg/m3Nof soot at a conversion of oxygen (O2) concentration of 16%. In the reliability confirmation throughthe long-term durability test, a maximum of 2,168 continuous operation hours and 5,119
cumulative operation hours was recorded, and the demonstration test operation was completed inOctober 2018.
The oxygen blown IGCC consists of a coal gasifier, gas clean-up unit and gas turbine(1300°C class H-100 series), steam turbine, generator and HRSG (Heat Recovery SteamGenerator).
Table 1 Main specifications of First Step of Osaki CoolGen Project
Main Specifications
Rated output
Gasifier
Gas purification
Gas turbine
Generating efficiency

166 MW (gross)
Oxygen-blown single-chamber, two-stage spiralflow entrained bed
Wet chemical absorption method (MDEA)
H-100 (1 on 1)
Net efficiency 40.8% (Higher calorific value baseand actual value)

Schedule
Commencement of construction

March 2013

Commencement of demonstration tests

March 2017 (First Step)

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 3 (September 2019)
3Figure 2

A panoramic view of Osaki CoolGen Site

MHPS has been developing a gasification system of oxygen blown IGCC for practicalapplication since the 1980s as seen in Figure 3. Starting with the gasification element test using thePDU (Process Development Unit) with a coal throughput of 1 ton/day, we participated in theHYCOL project (project on commission from NEDO/HYCOL Association) with 50 tons/day andthe EAGLE project (joint research project with NEDO/Electric Power Development Co., Ltd.) with150 tons/day, and steadily carried out the scale-up verification of the gasifier.

Figure 3

Development of oxygen blown gasification system

The oxygen blown gasifier is a system using high-concentration oxygen as a gasifying agent
for coal, and as shown in Figure 4, MHPS’s original single-chamber, two-stage spiral flowentrained-bed with multiple burners installed in the upper and lower stages of a vertical cylindricalgasifier is adopted. The characteristics of this gasifier are: (1) the temperature necessary for melting
the ash in the lower part and the ratio of oxygen and coal in the upper and lower parts areappropriately allocated so that the gasification reaction condition becomes highly efficient in theupper part according to the coal type, (2) the retention time of coal particles is ensured bygenerating a spiral flow in the gasifier to promote the gasification reaction, and the upwardscattering of char and molten slag is suppressed, and (3) the slag discharge hole in the bottom of thegasifier is kept warm and heated by high-temperature gas flow (auto-circulation flow) in thegasifier to achieve the stable flow of slag. Therefore, technical issues in the leading systems in
Europe and United States were improved. Its actual cold gas efficiency (= calorific value ofgasification gas/calorific value of coal) of 82.7% is at the highest level in the world. In addition, asfor the quench gas for cooling to be supplied to the outlet of the gasification part, although otheroverseas companies require almost the same quantity as the gasification gas, MHPS has achieved
the reduction of power consumption by drastically reducing this amount to about 1/10.

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 3 (September 2019)
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Figure 4

MHPS oxygen blown gasifier

In gas-clean up unit, impurities (ammonia, hydrogen sulfide, hydrochloric acid, etc.)
contained in coal gasification gas are removed in a gas turbine to conform to the environmental
standards of exhaust gas after combustion, and power is generated in a gas turbine using purifiedcoal gasification gas as fuel. The retained heat of the combustion exhaust gas is recovered by
HRSG to generate steam, and power is also generated in a steam turbine.
The advantage of IGCC is that a wide variety of coal types can be used. Since ash is melted
in a gasifier and discharged as slag, it is especially suitable for coal with a low ash melting point,
and low-grade coal (including sub-bituminous coal and brown coal), the use of which has been
restricted in conventional coal fired power generation, can also be applied. Through theimprovement of the efficiency of the system, the CO2 emissions per generated electric power arereduced in comparison with conventional coal fired power generation. It is also possible to reduce
the water consumption and drastically reduce the warm drainage, and this technology has highenvironmental applicability.
The advantage of oxygen blown IGCC is that its load change rate is high and its response isfast. This technology can fulfill the load adjustment function required for thermal power generation
plants in the current electric power grid system stability situation where renewable energy has
become common, though countermeasures are required for power grid system to ensure its
stability, as the electric power supply quantity fluctuates with changes in the weather. By
establishing this technology, a social contribution in environmental load reduction can be expectedby replacing decrepit conventional coal fired power generation plants with oxygen blown IGCC.
In addition, oxygen blown gasification technology is expected to have wide applications andspread, because the higher efficiency of the power generation system can be expected by
combining it with fuel cell technology. This is also because of its affinity with the CO2 separationand capture technology in carbon dioxide capture, utilization and storage (CCUS), whichconstitutes part of the global warming countermeasures for the realization of the Paris Agreement ishigh and due to the fact that application to the chemical industry is also possible. Brown coal is oneof the unused resources that can be mined in large quantities. Making use of brown coal to producehydrogen in coal producing countries and supply it to the market can be a fundamental technology
for realizing a hydrogen society, and as such it can be said to be a technology with high ripple
effects in the future.

|3. Current status of the Fukushima IGCC project (Nakoso, Hirono)
The joint enterprise (comprised of four companies: MHPS, Mitsubishi Heavy Industries
Engineering Ltd., Mitsubishi Electric Corporation and Mitsubishi Hitachi Power Systems
Environmental Solutions Ltd.) with MHPS as the managing company received orders for two
543MW IGCC plants from Nakoso IGCC Power GK and Hirono IGCC Power GK through an EPC
construction contract (including civil engineering work) in December 2016. In this project, one
IGCC plant adopting air blown technology will be constructed at Nakoso IGCC Power GK on landadjacent to the Nakoso Power Station (Iwaki City, Fukushima Prefecture) of Joban Joint PowerMitsubishi Heavy Industries Technical Review Vol. 56 No. 3 (September 2019)
5Co., Ltd., and at Hirono IGCC Power GK on the premises of JERA Co., Inc.’s Hirono Power
Station (Futaba-gun, Fukushima Prefecture). This project resulted in the “world’s most advanced
coal-fired power plant” in Fukushima, and aims at leading the world in clean coal technology while
contributing to the economic revitalization of Fukushima Prefecture and the creation of anindustrial base. Table 2 lists the main specifications of the Fukushima IGCC project.
Table 2 Main specifications of Fukushima IGCC project
Main Specifications
Rated output

543 MW (gross)Gasifier

Air-blown two-chamber, two-stage spiral flow entrained bed

Gas purification

Wet chemical absorption method (MDEA)

Gas turbine

M 701 F (1 on 1)

Schedule
Start of operation

2020 Nakoso IGCC
2021 Hirono IGCC

In this project, the experience of Nakoso No. 10 of Joban Joint Power Co., Ltd. isincorporated in various parts to improve reliability, and drastic output and efficiency improvements
are attempted through the adoption of a high-efficiency gas turbine. The former IGCC
demonstration plant for the “Entrained bed coal gasification power plant demonstration project(under the direct control of the Ministry of Economy, Trade and Industry) (fiscal 1999 to fiscal2009)” was converted into a commercial plant of Nakoso No.10 in fiscal 2013.
The gasifier adopts Japan’s original air blown coal gasification technology, COReGASIFICATION TECHNOLOGY™, and the gas clean up unit mainly treating H2S gas in the gas
from the gasifier adopts the wet chemical absorption method by MDEA (Methyl diethanol amine)as a solvent same as Nakoso No. 10.
The gas turbine adopts a combustor for coal gas which applies low calorie gas firing
technology such as blast furnace gas (BFG) to the high-efficiency M 701 F series gas turbine withabundant achievements. In the 500 MW class IGCC combined with the latest high-efficiency gas
turbine, the CO2 emission intensity can be drastically reduced compared with conventional
coal-fired steam power generation.
With regard to the manufacturing of coal gasifier, a “coal gasifier shop” was constructed at
the Nagasaki Works of MHPS, and an integrated IGCC production system was established toprepare for mass production (Figure 5). To cope with high temperature and high pressure operation
condition, in addition to elemental technologies such as welding cultivated through the productionof conventional boilers for coal fired plants, we developed automatic welding equipment andintroduced a production system utilizing IT. The coal gasifier is modularized to the maximum
weight which can be transported to simplify the construction work at the construction site.
The gasifier pressure vessels manufactured for Nakoso IGCC were shipped sequentially from
June 2018 (Figure 6), transported by sea to Onahama Port and transported inland to the site(1). The
gas turbine, steam turbine and generator were transported in December 2018 (Figure 7), and large
equipment transportation was completed in April 2019. Construction work, mechanical work andelectric work are progressing smoothly at present. The commissioning will commence in fiscal
2019, and the related parties are working together for the start of commercial operations in
September 2020. Hirono IGCC is also under construction and will start operations in September
2021. The construction situation of Nakoso IGCC as of the end of March 2019 is presented inFigure 8, and an overview of the construction area is depicted in Figure 9 (1).

Mitsubishi Heavy Industries Technical Review Vol. 56 No. 3 (September 2019)
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Figure 5

Coal gasifier shop

Figure 6

Figure 7

Transportation of large equipment

Figure 9

Overview of Nakoso IGCC Construction Area

Figure 8

Gasifier pressure vessel

Construction of Nakoso IGCC|4. Future developments
MHPS will promote IGCC in Japan and overseas, and will continue to enhance thesophistication of its air-blown and oxygen-blown IGCC technologies to contribute to the reductionof global environmental impact and CO2 emissions, as well as to the enhancement of economic
development.

References(1)

Nakoso IGCC Power GK，http://www.nakoso-igcc.co.jp/en/