Session: 17-13-01: Plant Performance, Fluid Dynamics and Thermal Hydraulics in Energy and Power Applications

Paper Number: 166399

A New Project of High-Temperature Retrofit on Two Air Cooling Subcritical Units That Burn Strong Slagging-Tendency Coal 

The world-first high temperature retrofit on a 320MW wet cooling subcritical unit has been successfully conducted by Shanghai Shenergy Power Technology in August 2019. By improving the steam temperatures from 538°C to 600°C, combined with a series of energy-saving techniques, the unit net efficiency (UNE) is greatly improved from 38.4% to 43.1% under rated condition. Meanwhile, the unit has passed the deep power reduction test under 20% of rated load at the end of 2019. This project, namely Xuzhou project, has set a benchmark of both high efficiency and high flexibility for existing subcritical units in the world.

In the past years, the promotion of high temperature retrofit on subcritical units has become one of our most important tasks. In July of 2024, a new project named Xinyi Project, has been launched. This project implements the high-temperature and efficiency promotion retrofit of two 330MW air cooling subcritical units that burn strong slagging tendency Zhundong coal. The two units struggle from mainly two problems: The first one is serious slagging phenomenon on boiler tubes, which limits the output of Boiler 1 to 77% and Boiler 2 to 86% of the design rated value and also reduces the boiler efficiency. The second problem is the low internal efficiency of the turbines. Despite the fact that the units are air cooling due to lack of water, the operating efficiency is 10% lower than the design value. The two problems lead to the serious lack of power generation capacity and low efficiency of the units.

To solve the boiler slagging problem, the team of Shanghai Shenergy Power Technology has conducted comprehensive research of the slagging mechanism, and developed improving measures related to pulverizing, combustion, heating surfaces arrangement and soot blowing systems accordingly. To improve the unit efficiency level, the steam temperatures will be enhanced from 538°C to 585°C, the turbine will be comprehensively modified, and several important energy-saving techniques also will be applied.

The above measures are expected to recover the power capacity of the units to design value of 330MW or even higher. Meanwhile, the unit net efficiency under THA condition is expected to be improved by more than 12% relatively, to higher than 39%. In addition, the deep power reduction capacity is expected to be as low as 20%, which can better support the low carbon power like wind and solar. Last but not least, excellent efficiency preservation performance can be expected especially for the turbine flow path.

Presenting Author: Weizhong Feng Shanghai Shenergy Power Technology Co., Ltd

Presenting Author Biography: Professor Feng Weizhong, Foreign academician of Russian Academy of Engineering, graduate student supervisor; distinguished professor of Shanghai University of Electric Power; Vice Chairman of China Energy Society; Director of Shanghai Engineering Research Center of Clean Coal-fired Power, enjoys state council special allowance.
He has won many awards and titles, including “National May 1 Labor Medal”, “Individual with Outstanding Contribution in National Low Carbon Economy”, “Prize for Scientific and Technological Innovation (Ho Leung Ho Lee Foundation)”, “National Excellent Science and Technology Workers”, “Shanghai’s Leading figure of science and technology”, “Advanced Individual of China’s First Ecological Civilization Award” (the only prize-winner in Shanghai and the power industry of China), and “Energy 70 Years' man of meritorious deeds in Independent Innovation” (the only prize-winner in Shanghai). In 2011, Han Zheng, then mayor of Shanghai, awarded him the individual award of the “Shanghai Mayor Quality Award” (the only winner of the year) in person; in June 2016, he won the “Prime Movers Award” of ASME, the first Chinese winner since the establishment of the award in 1954. He has published over 50 academic papers at home and abroad, possessed 66 domestic and foreign patents and been to Europe, USA, Japan and Australia to give academic reports on invitation for 12 times.

Authors:

Weizhong Feng Shanghai Shenergy Power Technology Co., Ltd
Li Li Shanghai Shenergy Power Technology Co., Ltd