Anshan Iron & Steel Group
Corporation, China,
Construction and Operation
Experience of 300 MW Blast
Furnace Gas Firing Combined
Cycle Power Plant
HARUO OTSUKA* 1
HIROSHI TANABE* 1
SYOUICHI HARADA* 1

SATOSHI TANAKA* 1
JUNJI OBATA* 2
CHE XUEWEN* 3

In recent years in China, a chronic shortage of electric power and national necessity has required steel mills tosecure electric power by themselves. The need for high efficiency power generation plants has been growing as well as
concerns for environmental preservation. Meanwhile, having successfully developed the most advanced, high efficiency blast furnace gas firing M701S (F) gas turbine, Mitsubishi Heavy Industries, Ltd. (MHI) conducted a feasibility
study of a gas turbine combined cycle plant together with China's Anshan Iron & Steel Group Corporation. As bothparties confirmed its effectiveness as a result of the study, we signed an official contract in May 2004 to introduce theworld's largest blast furnace gas firing combined cycle power plant (BFG Firing CCPP), the first in China. Ever since
the power plant was taken over on May 10, 2007 it has continued successful commercial operation.
of the gas turbine, generator, steam turbine and fuel-gas
compressor, and FOB (free on board) delivery of the equipment supplied by MHI, and dispatching technical advisors
for installation and supervisors for commissioning.
On the other hand, the customer had the responsibility for the design, manufacture and procurement ofrelevant equipment for the bottoming cycle including thesurface condenser and heat recovery steam generator(HRSG), water supply and drainage system, utilities
other than the power train, and took charge of all site
work including civil, construction, and commissioning.
Figure 1 shows the scope of supply of this plant.
As for the customer supplied equipment, five design
liaison meetings were held periodically and separate
technical coordinations when necessary, these collaborations helped the power plant to be completed
successfully.
2.3 Overall plan of power plant
As for the overall design, including the general arrangement, to ensure plant reliability and site work
quality, previous designs were used as much as possible.
However, the following design changes were inevitable.
(1) Since the project was constructed in an extremely
cold area, all the plant auxiliaries such as pumps
needed to be installed indoors and equipped with acomplete heating system. The water piping, which
had to be installed outdoors, was laid undergroundbelow the freezing depth.
(2) In a previous project, almost all the plant auxiliaries
did not include any standbys. However, the plant auxiliaries for this project were all provided with standbys
due to Chinese made pumps and other relevant equipment for the bottoming cycle being adopted.

1. Introduction
A blast furnace gas firing gas turbine uses low calorie
off gas generated in steel mills. MHI is the world's leading company in terms of technology for utilizing blast
furnace gas and has received many orders and established a successful operating record. Although this is
the first order for a full-scale, BFG firing CCPP in China,
the design, procurement and construction proceeded successfully and the plant was officially taken over on May
10, 2007. Plant thermal efficiency reached 51% (LHVbase) which is the world's highest level for a BFG firing
CCPP, and it has been confirmed that this power plant
contributes to environmental preservation and energy
conservation. This paper introduces the construction andoperation experience of this plant.

2. Features and outline of the project2.1 Features of the project
The project has the following features.
(1) It is the world's largest class for a BFG firing CCPP
and was the first order in China.
(2) The first design cooperation for power generation
plant with the design and research institute of an iron& steel company in China.
(3) The first installation of a power generation plant inan extremely cold area (the minimum monthly average temperature is less than -15oC).
(4) Collaborative plant adopted Chinese-made products
as related equipment for the bottoming cycle.
2.2 Scope of supply
MHI had the responsibility for the design and manufacture of the power train equipment consisting mainly*1 Takasago Machinery Works*2 Power Systems Headquarters*3 Anshan Iron & Steel Group Corporation

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 44 No. 4 (Dec. 2007)1

Low pressure steam
High-temperature reheat steam

Steam for starting

Exhauststack

High pressure steam

Cooling tower

Inlet air filter
Steam turbineGas turbine

Fuel-gas compressor

Generator
Heat recovery
steam generator(HRSG)
Low-temperature reheat steam

Surfacecondenser

Condensedwater pump
Electrostatic
precipitator (EP)Gas cooler

HCOG blower

Coke oven gas(COG)
Blast furnace gas(BFG)

Cooling water pump
Industrial
raw water

Feed waterpump

PitFig. 1 Scope of supply
The colored sections show the equipment
within MHI's scope of supply.

PitIn principle, the basic arrangement inside the turbine generator building and the large piping routearrangement of the blast furnace gas installed outdoors, which greatly affected the overall design,
basically adopted the design concept of the previous
project. These correspondences caused little reworking at the site, helping the installation work to becompleted more or less as scheduled. Providing thepumps and other equipment with standbys improved
the total plant reliability.

written in Chinese for the plant control system.
3.2 Plant configuration
This plant is a single-shaft type combined cycle power
plant which consists of a gas turbine, generator and steam
turbine, and a fuel gas compressor through a step-up geardevice located on the same axis. A steam turbine starting
system was adopted to drive the single-shaft by the existing steam. Figures 2 and 3 show the turbine floor layout
and a longitudinal sectional drawing of the total assembly.

3. Features and outline of the plant
3.1 Features of the plant
The features of the plant are as follows.
(1) Adoption of combined cycle power plant equipped withthe most advanced, high efficiency blast furnace gas
firing gas turbine model M701S (F).
(2) Adoption of a gas turbine inlet air heater, considering the start up and load operation during extremely
low atmospheric temperatures.
(3) Realization of total integrated plant control including customer supplied equipment such as HRSG.
(4) Adoption of monitoring and control graphic screens
Fuel-gas
compressor
Step-up geardeviceFig. 2 Turbine floor layout
Viewed from front to rear, the gas turbine, generator, steam
turbine and fuel-gas compressor are coupled with a single shaft.

Steam turbine

Gas turbine

Generator

Fig. 3 Longitudinal sectional drawing of complete assembly

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 44 No. 4 (Dec. 2007)2

3.3 Main specifications of major equipment
Table 1 shows the main specifications of the major
equipment including the customer supplied HRSG. SeeFig. 4 for the plant output characteristics which show thatthe power plant is able to generate a maximum output of
300 MW at an ambient temperature of 15oC or below.
3.4 Measures against low ambient temperatures
A gas turbine consumes a great deal of air as the driving source. While a lower ambient temperature helps
increase the power output, too low a temperature causes
the following problems.
(1) Decreasing the compressor surge margin due to increasing thrust force and pressure ratio limits themaximum power output.
(2) Combustion pressure fluctuations create an unstablecombustion zone during start-up and acceleration.
To cope with these problems, an inlet air heater wasinstalled to heat up the gas turbine inlet air in cold
weather.
As the steam source for heating, auxiliary steam isused during start-up and acceleration while low pressure steam is extracted from the HRSG during loadoperations. The used steam is reclaimed by the surface
condenser as a condensate to reduce the amount of waste
water as an environmental measure.
Figure 5 is schematic of the inlet air heating system.
Atmospheric air

Inlet air heater

Plant power output (MW)300

Low-pressure
steam

Maximum output 300 MW

TE

Auxiliary
steam

200

Gas turbine

LTM

100

0-15

01530
Ambient temperature (oC)Surfacecondenser

40Flashpipe

Fig. 4 Plant output characteristics

Fig. 5 Outline schematic of inlet air heating system

Table 1 Main specifications of major equipment
Major equipment

ParticularSpecifications

Power generation facility

ModelOutputSingle-shaft type combined cycle power plant
300 MW

Gas turbine

ModelOutput
Turbine inlet gas temperature
Rotational speed

Open cycle single-shaft type M701S(F) (MHI)
183.0 MW
1 300oC class
3 000 rpm

Model

Triple-pressure natural-circulation reheat boiler(China Hangzhou Boiler)
568.4 tons/hr
Details:
High pressure 239.9 tons/hr
Medium pressure 282.2 tons/hr
Low pressure 46.3 tons/hr

Heat recovery steam
generator(HRSG)

Steam flow rate

Model

Steam turbine

OutputSteam pressure/temperature

Rotational speed
ModelGenerator

Fuel-gas compressor

Single-casing reheat mixed-pressure condensing
type SRT-30.5" (MHI)
117.0 MWoHigh pressure 10.2MPa (a)/538 C
Medium pressure 2.95 MPa (a)/538oC
Low pressure 0.49 MPa (a)/245oC
3 000 rpm

CapacityCooling system
Rotational speed

Horizontal-shaft tubular rotary field type(Mitsubishi Electric Corporation)
340 000 kVA
Hydrogen gas cooled
3 000 rpm

Model
Rotational speed

Single-casing axial flow type (MHI)
5 025 rpm

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 44 No. 4 (Dec. 2007)

3Central control room (4F)
Large
screenLargescreen

TCS : Turbine Control System
TSI : Turbine Supervisory
PCS : Plant Control System
DLS-I/O : Data Logger I/O System
PDOS : Power Distribution Operation System
INT : Turbine Protection Interlock PanelOPS : Operator Station
EMS : Engineerign Maintenance Station
ACS : Accessory Station

Laser printerSwitchingdevice

OPSOPSOPS

OPS

ACS

CPU(DLS-I/O)
A B

CPU(PDOS)
A B

Electrical room (3F)

CPU(TCS)
A B

CPU(PCS)
A B

TSI

EMS
INT

Laser printerFig. 6 Control system configuration

3.5 Automatic control system
Figure 6 shows the control system configuration. MHI
supplied the total plant control system which has thefunctions of the automatic control, operation and monitoring of all the equipment directly related to power
generation including the customer supplied equipment
such as HRSG and boiler feed water pump.
The operating functions have the following featuresthat help reduce the operators' load.
(1) The function of the ALR (automatic load regulator)
control system requires the operators only to set thegenerator output (between 150 and 300 MW) to obtain the required output.
(2) The function of the APS (automatic plant start & stopsystem) enables all the functional control elements tobe operated automatically, from the condenser vacuum
up to reaching the ALR load operation while the plantis starting up, and from the ALR load operation to thecondenser vacuum break when the plant is shut down.
DYASYS-Netmation which was developed by MHI
based on the power generation plant know-how accumulated over many years was adopted as the plant control
system of this project.
The important components within the control system,

Fig. 7 Central control room (4F)The OPS desk panels are installed at the near side and two largescreens are installed at the far end.

such as the CPU (central processing unit), have built-in
redundancy to ensure high reliability.
The monitor and operation screens can display Chinese descriptions in addition to English, realizing auser-friendly operating system for the operators.
Figures 7 and 8 show the layout of the central operation room and sample system schematic screens in both
Chinese and English.
Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 44 No. 4 (Dec. 2007)

4English display

Chinese display

Fig. 8 Sample system schematic screens in both Chinese and English4. Schedule for construction and commissioning

tomatically up to the minimum operational load of
150 MW. Once reaching 150 MW, the load can bechanged between 150 and 300 MW depending on thepower demand.
The power plant also shuts down automatically.
During load down, the cooling down process is designed to make the mismatch between the steam andthe steam turbine metal temperature small so thatthe time to the next hot start is shortened. The expected time for starting (from ignition up to full-loadoperation) is approximately 90 minutes for a hot start,150 minutes for a warm start and 200 minutes for acold start.
(2) Plant performance
Table 2 shows the actually measured performance.
The plant output and plant thermal efficiency after
compensation to the standard conditions (ambient temperature at 15oC and LHV base) sufficiently satisfy theplanned values. The plant thermal efficiency reaches
51.2% compared to the planned 48.5%, and achieves
the highest level in the world for BFG firing CCPPs.

The project started construction in October 2004.
Although experiencing two severe winters during theconstruction stage, the construction work proceeded satisfactorily and the installation of all the facilities andequipments was completed by the end of April 2006.
Then, after testing and tuning each piece of auxiliary
equipment separately, full-scale commissioning started
in September, with the first synchronization in October.
Then, full load operation at 300 MW was completed in
November, and the results of almost all the commissioned
items proved to be without problems by the end of 2006.
After a period of suspending commissioning due torestrictions in the fuel gas supply, they resumed in April
2007. The 300 MW performance test and 168 hours continuous operation test was completed successfully on
April 10, 2007, then the plant was officially taken overon May 10, 2007.

5. Test operation results and operation records
5.1 Test operation results(1) Startup characteristics
This power plant adopts a steam turbine starting
system. After reaching the rated speed, it switchesfrom the existing steam to HRSG steam once the conditions of the HRSG steam become acceptable for thesteam turbine. The plant then increases its load au-Table 2 Actually measured performance
Guarantee item
Plant output
Plant thermal efficiency

Planned value

Measurement

300 MW
48.5 %

313.9 MW51.2 %

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 44 No. 4 (Dec. 2007)5

(3) Environmental characteristics
By effectively transducing the low calorific blast furnace gas to electric power, this power plant contributes
greatly to environmental preservation as follows.
First, this is a combined cycle power plant that effectively utilizes the blast furnace gas instead of thecoal fired thermal power plants popular in China. It isestimated that the plant emits approximately 1,900,000
tons less CO2 a year (assumed operation of 7,000 hours
per year) than that emitted by burning coal in a coal
fired thermal power plant of the same output.
Second, although the environmental characteristics depend significantly on the composition of theblast furnace gas, as it contains nitride and sulfur
compounds, its combustion produces less thermal NOx
than burning natural gas because of its low calorificvalue. Thus, this plant indicates the significantly low
NOx value of 15 ppm (15% O2 base, without a de-NOxsystem).
5.2 Operation records
Table 3 shows the availability of the plant for about
five months from May 2007, when the plant was taken
over, to the end of September. While the plant availability depended on the scheduled shut down due tomaintenance of the blast furnace shortly after taking overthe plant we experienced the degradation of plant availability because of initial failures and other incidents.
After that, the plant reliability improved gradually, finally reaching 100% in September 2007.

Haruo Otsuka

Satoshi Tanaka

Table 3 Plant availability

Month and year

Availability (%)

May 2007June 2007
July 2007
August 2007
September 200782.3
93.0
91.9
95.2
100.0

6. Conclusion
As the first full-scale, BFG firing CCPP with the highest capacity and thermal efficiency in China, this project
has attracted much Chinese public attention. The favorable transition to commercial operation has realized
the effective use of surplus blast furnace gas and selfsustaining electric power while contributing significantly
to environmental preservation and energy conservation.
Prompted by the acceptance of this project, many blast
furnace gas firing power plants are now under commercial operation and/or construction in various regions ofChina. As the second stage of the project for Anshan
Iron and Steel Group Corporation, the construction of a150 MW, M701S (DA) combined cycle power plant has
also started in Yingkou, Liaoning Province. In line withthe China National Energy Saving and Recycling Economic Policy led by the National Development Reform
Commission, it is sure that these projects will play animportant role in accomplishing stable electric power
supply and economic growth in China.

Hiroshi Tanabe

Junji Obata

Syouichi Harada

Che Xuewen

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 44 No. 4 (Dec. 2007)6