pwr_october-2023 - 30

COAL TOP PLANT
China's Pingshan Phase II
Sets New Bar as World's Most
Efficient Coal Power Plant
Courtesy: Shenergy
Pingshan Phase II, a cutting-edge 1.4-GW ultrasupercritical coal-fired unit, achieves a
remarkable net efficiency of 49.37%-making it the world's most efficient coal-fired
power plant. The state-of-the-art plant, which commenced operations in April 2022,
showcases the transformative potential of innovation in the realm of coal power,
utilizing mature 600C materials and equipment.
Sonal Patel
f there is a crowning moment in the
long haul to implement a potentially
groundbreaking technology, it's when
an independent assessment confirms its
effectiveness. At Pingshan Phase II, that
moment came on Dec. 13, 2022-eight
months after it was put into commercial
operation-when a Siemens and Stainmuler-led
unit performance acceptance
test confirmed the 1,350-MW ultrasupercritical
(USC) coal-fired unit's lower heating
value (LHV) net efficiency reached
49.37%, better even than its design value.
Developed and built by Shenergy Co.,
I
the extension of the Pingshan Power
Plant, located in the Huaibei Economic
Development Zone of China's Anhui
Province, is a single unit built in a highlow
biaxial arrangement with secondary
reheating. Brought online in April 2022,
the project operated and managed by
Shenergy subsidiary Huaibei Shenergy
Power Generation Co. is the largest single
unit of Shenergy's 8.3-GW coal-fired
fleet. According to Li Li, a Shenergy engineer,
it is also the Shanghai governmentowned
entity's most innovative unit.
That's especially remarkable, given
that Shenergy has in recent years built
several exemplary coal power projects.
In 2015, POWER recognized Waigaoqiao
No. 3 (also known as " Waisan " ), a twin
1,000-MW primary reheat USC unit in
Shanghai with a steam temperature of
600C that was brought online in 2008.
And in 2020, the magazine highlighted
30
Shenergy's efforts to boost the efficiency
of a 320-MW subcritical coal unit, Xuzhou
Unit 3, to beyond 43.56%-higher
than all existing Chinese supercritical
units, and even some USC units.
A Remarkable Legacy of
Innovation
Pingshan Phase II, as Li explained to
POWER, evolved from efforts led by
technology pioneer Professor Feng
Weizhong's efforts to boost coal plant
cost efficiencies. Feng, notably, led
development of the pioneering singlereheat
Waigaoqiao No. 3 project as its
deputy general manager, and he implemented
several innovative technologies
between 2009 and 2011 to continuously
boost the plant's performance, gradually
improving its average annual net operating
efficiency to 44.5%, with pollutant
emissions that today " meet and exceed
gas turbine emission standards, " Li said.
In 2005, however, as construction of
Waigaoqiao No. 3 was kicking off, Feng
also completed research on an " elevated
T-G " technology that aimed to address
challenges with the conventional doublereheat
system at USC units. Double reheat
technologies employ a single steam
reheat loop and second reheat loop, presenting
efficiency gains compared to the
single circuit of steam through a boiler
and turbine that conventional subcritical
pulverized coal combustion plants employed
until the 1950s.
" Although the use of secondary rewww.powermag.com
heating
technology is a mature technology,
the system is complex, requiring high
investment, " Li said. Arranging these
large-diameter thick-wall pipes within
the plant building is also quite difficult,
he noted. " Moreover, the resistance and
heat dissipation loss of the pipe also
devour a considerable part of the incremental
income of secondary reheating.
If the traditional design is carried out,
compared with the primary reheat, the
net efficiency gain obtained is difficult
to compensate for the increase in input.
That's why secondary reheat technology
has not been continued to be applied and
developed after their early application in
Europe, the U.S., and Japan, " he said.
Feng's innovation, patented in 2011,
sought to overhaul the system with a
combined elevated and conventional layout.
The design, known as an " Elevated
T-G unit, " essentially splits the turbines
into two trains. The front train comprises
a high-pressure turbine and intermediatepressure
turbine coaxial with one generator
as the front unit. It is mounted on
top of a two-pass boiler or near the outlets
of the tower-type boiler steam headers,
which is about 85 meters (m) above
ground level. The rear train comprises a
second intermediate-pressure turbine
and two low-pressure turbines coaxial
with another generator. The rear unit retains
its conventional position, which is
roughly 17 m above ground level.
" The turbine generator set technology
with high and low spindle arrangement
POWER | October 2023
http://www.powermag.com
PWR_ October-2023

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