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Yuhuan 1,000MW Ultra-Supercritical Pressure Boilers, China




Key Data


All four 1,000MW coal-fired ultra-supercritical pressure boilers at Yuhuan in China have come online. Located on the coast of East China's Zhejiang Province, the last unit began commercial operation in November 2007. The plant cost ¥9.6bn (€900m), and the units run at about 45% efficiency. Yuhuan has China's first 1,000MW ultra-supercritical pressure boilers. Units 1 and 2 went on line in 2006, and units 3 and 4 in 2007. The site is now generating 22 billion kWh of electricity a year. The plant is operated by China Huaneng Group, China's largest power producer. "It is claimed that Yuhuan Units 1 and 2 are the world's cleanest, most efficient and most advanced ultra-supercritical units.".

Yuhuan has China's first 1,000MW ultra-supercritical pressure boilers. Units 1 and 2 went on line in 2006, unit 3 in 2007, with unit 4 planned for 2008. When unit 4 is working, the site will generate 22 billion kWh of electricity a year. The plant is operated by China Huaneng Group, China's largest power producer.

Ultra-supercritical pressure boilers

Supercritical operation of large thermal baseload power plants during the 1980s used steam temperatures of typically 550ºC, leading to around 40% thermal efficiencies. Ultra-supercritical steam conditions now use supercritical pressures up to 300bar, with 600°C steam and reheat steam temperatures. This gives a net efficiency of 46%.

Siemens reports that just a 1% gain in efficiency for a typical 700MW plant reduces 30-year lifetime emissions by 2,000t NOx, 2,000t SO2, 500t particulates and 2.5 million tons CO2.

"It is claimed that Yuhuan Units 1 and 2 are the world's cleanest, most efficient and most advanced ultra-supercritical units."

New units also incorporate high-efficiency dust removal and desulphurisation. This has led to the claim that Yuhuan Units 1 and 2 are the world's cleanest, most efficient and most advanced ultra-supercritical units.

The MHI boilers have a main steam pressure of 27.5MPa, a main steam temperature of 605°C and a reheat steam temperature of 603°C. The boilers were made and commissioned collaboratively by MHI in Japan, who provided the designs and key products, and Harbin Boiler Co. (HBC) in China. Unit 4 was constructed by MHI and HBC. MHI plans to supply above 12GW of boilers to China under the HBC collaboration.

Siemens is supplying four 1,000MW ultra-supercritical steam turbines. These use a tandem compound, four-cylinder arrangement. Steam enters the high-pressure turbine through two main steam valves, with exhaust steam being reheated and fed to a double-flow intermediate-pressure turbine. From there, it goes to two low-pressure turbines. The steam turbines at the Yuhuan power plant were jointly designed and manufactured by Shanghai Electric Group and Siemens Power Generation Group.

China building ultra-supercritical industry

About 70% of China's total energy consumption comes from coal, and the country still has huge reserves. Burning it, however, has severely damaged the environment, Chinese people themselves and people in surrounding countries. In northern China, cities like Beijing and Shenyang have some of the highest readings for total suspended particulates and SO2 in the world, with coal burning being a major source of this. In southern China, large areas have growing acid rain problems.

"Because of its reserves, China continues to rely on coal and is using advanced technologies to reduce pollutants."

China does have extensive unexploited reserves of natural gas. Gas power stations are more efficient and cleaner than coal stations, but some industry observers are saying that using gas for power production is wasting an inherently clean form of energy.

Because of its reserves, China continues to rely on coal and is using advanced technologies to reduce pollutants. China is now building around ten similar coal-fired plants using different international manufacturers, and amassing its own design and construction expertise.

Ovation control system

Emerson Process Management's Ovation expert control system was implemented at Units 1 and 2 in February 2007. Emerson won the $7m contract to automate the plant in April 2005.

The Ovation system monitors and controls the data acquisition system, modulating control system, sequence control system, furnace safeguard supervisory system and electrical control system for all major plant components. That includes the boiler, turbine, generator and balance of plant processes.

Ovation gives users high levels of plant availability, reliability and environmental compliance. The system provides seamless interface with the most widely adopted bus standards, allowing smart device technologies to be incorporated into processes.

Proportion of >200MW coal plant ordered (yellow is subcritical, red supercritical).
China is embracing large unit ultra-supercritical technology.
Worldwide coal-fired capacity by region 2002–2025.
New coal-fired capacity additions through 2025 (Siemens).
Of the 1,000 units working in China, ten 600MW-class are supercritical.
Ultra-supercritical plants have higher efficiencies than supercritical and subcritical ones.