Mitsubishi Heavy Industries Technical Review Vol. 54 No. 3 (September 2017)33

TEPCO Fuel & Power, Inc. Futtsu Thermal Power Station,Group 2, H-100 Series Gas Turbine Replacement WorkM i ts u b i s h i H i ta c h i P o w e r S y s t e m s , L t d .

Due to its high efficiency being recognized, the H-100 series gas turbine has been adopted bycustomers who are aiming at improvement in the efficiency of existing power plants to replace
existing, older types of gas turbines. Recently, the H-100 (50 Hz) was adopted as the replacement
for the Futtsu Thermal Power Station Group 2 of TEPCO Fuel & Power, Inc. This replacement also
contributes to improvement in the plant efficiency of the power generation plant and a reduction inCO2 emissions. Currently, the renewal of No. 1 and No. 5 of Group 2 has been completed and theircommercial operation is underway.

|1. Introduction
Futtsu Thermal Power Station Group 2 of TEPCO Fuel & Power, Inc. has been in operation
for about 30 years since the commencement of its commercial operation. We replaced the existing
1100°C class gas turbine with the H-100 series gas turbine in a short period of time and achieved
high efficiency. The H-100 series gas turbine delivered this time is the first 50 Hz machinedeveloped by reflecting the operational results of the 60 Hz machines, the first one of which started
commercial operation in 2010. This report presents an overview of this replacement.

|2. Overview of replacement work
2.1

Basic policy of replacement work

Gas turbines No. 1 to No. 7 (7 axes) of Group 2 were replaced with H-100 series gas turbinessequentially. In this replacement, the following conditions were taken into consideration.
(1) The existing facilities would be reused as much as possible to minimize the scope of therenewal.
(2) The H-100 would be installed in the space of the existing gas turbine, and the peripheral
equipment would be reused.
(3) The heat recovery steam generator (HRSG) and the steam turbine would be reused. The
high-pressure superheater of the HRSG would be partially modified to achieve steam
conditions equal to the existing steam conditions, since the HRSG inlet gas temperature rises
due to the increased combustion temperature.
(4) As the gas turbine would be updated, the control device would also be partially modified.

2.2

Overview of H-100 series gas turbine

The H-100 series gas turbine was designed as the world's largest heavy duty two-axis gas
turbine based on the proportional expansion of the H-25 series gas turbine, which has seen global
deliveries of more than 170 units. There are two types in the H-100 series, 60 Hz and 50 Hz, andtheir basic specifications are shown in Table 1. Figure 1 shows a sectional view of the H-100series gas turbine and a photograph showing the upper half casing opened.
The air compressor air volume and the combustion temperature of the H-100 (50 Hz) wereincreased in comparison with the H-100 (60 Hz). The air compressor was a 17-stage axial flow
compressor corresponding to the pressure ratio of 20 in response to the increase in air volume, andwas adapted to variable speed operation. The combustor is a multi-can type that has ten cans. It
realizes, based on a dry low NOx combustor that has been proven in H-25 series gas turbines, etc.,

Mitsubishi Heavy Industries Technical Review Vol. 54 No. 3 (September 2017)34

even greater NOx reduction by improving the mixing characteristics of the fuel gas and air. Theturbine is an axial flow type and has a two-shaft, four-stage structure (two high-pressure stages andtwo low-pressure stages). To improve the efficiency, the high-pressure turbine adopts the structureof the H-100 (60 Hz), while the low-pressure turbine has design-optimized turbine blades.
The output is 118 MW, and the standalone efficiency of the gas turbine is 38.3% (LHV:Lower Heating Value). This is top-in-class efficiency among heavy duty type gas turbines of thesame class.
Table 1 H-100 series gas turbine basic specifications
H-100

Item

H-10060Hz50Hz

Type2-shaft heavy duty

Compressor

Axial flow 17-stage

Combustor

Multi-can (10 cans)

TurbineAxial flow 4-stage(2 high-pressure stages and 2 low-pressure stages)

Output105.8MW

118MW

Efficiency

38.2% (LHV)

38.3% (LHV)

4580/3600rpm

4580/3000rpm

Rated rotation speed
Output1 on 1 combined
cycle performance Efficiency

150MW

169.6MW

55.1% (LHV)

55.8% (LHV)

Output2 on 1 combined
cycle performance Efficiency

305.7MW

344.5MW

56.1% (LHV)

56.7% (LHV)
LHV: Lower Heating Value

Figure 1

H-100 series gas turbine|3. Overview of plant plan
Table 2 shows the plant performance before and after the replacement. The replacement
achieved performance beyond the initial plan and contributed to improvement in efficiency.
Table 2

Plant performance after replacement
Before replacement
Planned value

After replacement
Planned value

Actual value

167.6MW(15°C)

159.37MW
168.48MW
Plant output(15°C)(15°C)-4.91%+0.53%
Increase in output
Base(relative value)(relative value)
48.66%LHV
54.28%LHV
54.40%LHV
Plant efficiency(15°C)(15°C)(15°C)+5.62%+5.74%
Improvement in efficiency
Base(absolute value)(absolute value)
LHV：Lower Heating Value
Note: Plant performance after replacement is in new and clean condition.
(Bottoming deterioration has been compensated.)|4. Future development
The H-100 series gas turbine is being developed to meet needs for further increased
efficiency, higher output, and fuel diversification. Utilizing the characteristics of a two-shaft
machine that has separate high-pressure and low-pressure rotors, the H-100 series gas turbine isalso suitable for use as a driver for driving machinery, and can also be used in oil and gas plants.