The technical solutions to the phase-II project of the CR Fuyang Power Plant have passed the review. The designed coal consumption for power supply under rated working conditions can reach 249 g/kWh, and the units' net efficiency reaches 49.33%.
A few days ago, the engineering technical solutions to the 2 × 660MW ultra-supercritical coal-fired units of the phase-II project of the Anhui Fuyang CR Power Plant (the "Fuyang Phase II Project") passed the review by a panel composed of 9 experts including academicians from the Chinese Academy of Engineering Ni Weidou and Qin Yukun.The review panel believed that the solutions were advanced and feasible. "The demonstration and implementation of this project is of great significance to the overall energy conservation, efficiency improvement, and emission reduction in thermal power plants in China, and it is recommended to implement such project as soon as possible."
It is understood that the Fuyang Phase II Project intending to adopt a series of technologies such as "single-shaft turbo-generator full high-level layout" and "condenser low-level layout" of Shanghai Shenneng Energy Technology Co., Ltd. ("Shenneng Energy Technology") is an upgraded version of the Anhui Pingshan Power Plant's phase-II "1,350 MW high and low-level secondary reheating ultra-supercritical units", a national demonstration project, and can achieve further improvement in unit operation efficiency and economic benefits. The designed coal consumption for power supply under rated working conditions in the technical solutions to engineering construction can reach 249 g/kWh, and the net efficiency of the units can reach 49.33%."
Getting rid of "pipeline" constraints
According to the traditional arrangement of coal-fired power units, the boiler and steam turbine need to be connected by a high-pressure steam pipeline. In order to improve the efficiency of power generation, the coal-fired power industry has developed a primary reheating technology and even a secondary reheating technology. There is one or more medium-pressure cylinders between the high-pressure cylinders and low-pressure cylinders of the steam turbine in the power plant. The number of large-caliber high-temperature and high-pressure pipes connected to the boiler has also increased."High-temperature steam pipelines are expensive to build and the total length increases, which not only causes resistance and heat loss, but also increases investment costs, and limits the efficiency and economy of the units." Feng Weizhong, general manager of Shenneng Energy Technology, told the reporter.
It is understood that on the basis of foreign mature two-shaft steam turbine generator technologies, Feng Weizhong innovated the "a new-type of steam turbine generator" solution, placing the high-pressure shaft system near the header on the outside of the boiler body, with the low-level shaft system maintaining motionless, that is, the "high and low-level" layout solution.
The high-pressure shaft system moves from the "foot" position of the original boiler to a height close to the "shoulder" of the boiler, and the required length of the high-temperature and high-pressure steam pipeline is greatly shortened, resulting in smaller resistance, less heat loss, lower pipeline construction costs, and significantly improved efficiency and economy of the units.
Increasing steam temperature is an important way to improve the efficiency of coal-fired power units. However, the rise in steam temperature places higher requirements on steam pipeline materials, and the price of pipelines also increases accordingly. It is understood that the current comprehensive costs of steam pipes of 600 degrees Celsius units are less than RMB200,000 per ton, while the price of the pipes of 700 degrees Celsius high-efficiency ultra-supercritical units under research and development that use expensive nickel-based super alloys is about RMB3 million per ton.
"This solution can eliminate most of the high-parameter, high-value pipelines, greatly save investment, and eliminate the major constraints for the development of 700 degrees Celsius units." Feng Weizhong said.
Currently, the 1,350 MW units adopting the "high and low-level" technical solutions for the phase-II project of the Anhui Pingshan Power Plant are under construction and are expected to be put into production by the end of 2020.The "full high-level" layout of the Fuyang Phase II Project that has passed the review is upgraded from the "high to low-level" layout solution. As the steam turbine adopts a single-shaft full high-level layout, the construction costs are relatively low. In addition, as all high-temperature and high-pressure pipelines are minimized, the economy of the units is further improved.
Setting a new benchmark for coal-fired power efficiency
The Fuyang Phase II Project is not the first cooperation between CR Power and Shenneng Energy Technology. In 2015 and 2016, two 1,000 MW units of Tongshan China Resources Power Co., Ltd. were completely transformed by using Shenneng Energy Technology's technical solutions. The coal consumption for power supply dropped by more than 10 g/kWh, with the standard coal saved by over 100,000 tons a year.
In 2016, the engineering construction of a new cooperation project between the two parties - two 1.05 million-kilowatt one-time reheating ultra-supercritical units of the CR Power Caofeidian Power Plant, started. The units' design coal consumption for power supply under pure condensing rated working conditions was as low as 263 g/kWh. On April 25 this year, # 3 units of the power plant completed a 168-hour full-load trial operation.
The low coal consumption of the new units of the Caofeidian Power Plant not only surpassed that of the Shanghai Waijiaoqiao No.3 Power Plant, but also was significantly better than the best level of secondary reheating units that have been put into operation in China. Its cost of unit kilowatt was only 78% of the secondary reheating units that have been put into operation. According to data from the National Energy Administration, the average coal consumption for thermal power units in China is 321 g/kWh. After the Fuyang Phase II Project is put into operation, the designed coal consumption for power supply at 249 g/kWh will once again refresh the coal consumption record of the Caofeidian Power Plant.
In addition to the coal consumption for power supply, the net efficiency of the units of the Fuyang Phase II Project can reach 49.33%. What does this figure mean?
According to the Letter of Reply to No.1910 Proposal (Category No.192 of Industry, Communications, Post and Telecommunications) at the Second Session of the 13th National Committee of the Chinese People's Political Consultative Conference (the "Reply") issued by the National Energy Administration in September this year, the Ministry of Science and Technology is, in concert with the relevant departments, researching and deploying major projects for clean and efficient use of coal in 2030, striving to make the "net efficiency of coal-fired power generation breakthrough 50%", and the "coal-fired power units achieve 20% - 100% peak regulation" in terms of coal clean combustion and efficient power generation by 2030.
The reporter learned that the net efficiency of the state-of-the-art thermal power units currently put into operation in China could reach about 46%, and the net efficiency of the new units of the Caofeidian Power Plant reached 46.7%, and the designed value of the net efficiency of the units of the Fuyang Phase II Project jumped to 49.33%, which was very close to the "50% breakthrough target in 2030".Some experts of the review panel said: "Internationally, a 1% increase in the net efficiency of coal-fired power units can be regarded as a technology improvement of one generation. After the completion of the Fuyang Phase II Project, it will become a new benchmark for coal-fired thermal power plants."
Inspiring the potential of small and medium units
In addition to the efficiency of the units, the # 3 units (320,000 kilowatts) of Xuzhou CR Power Co., Ltd. ("Xuzhou CR") have achieved in advance and transcended the goal of "achieving 20% -100% peak regulation by 2030" in the Reply. On September 30, the unit successfully achieved continuous safe, stable, and environmentally-friendly operation under a load of 60,000 kilowatts for more than 2 hours, and achieved ultra-low-load operation at the rated load of 19%.
It is understood that Jiangsu classifies coal-fired power units into three levels according to load regulation capabilities (40%, 35%, and 30%). However, few current domestic units can achieve the load regulation depth of 35%.The 19% low-load operation of # 3 units of CR Xuzhou has achieved a breakthrough home and aboard.
"It's like riding a bicycle. Riding fast is easy. It's more difficult to ride slowly without falling down."When explaining the units' peak-regulation depth to the reporter, Feng Weizhong compared the units' regulation process as the process of controlling balance when riding a bicycle. "Similarly, the difficulty in controlling coal-fired power plant boilers at low loads has also increased significantly. As the load level decreases, the risk of flameout becomes higher and higher."
In 2017, the "Project on Comprehensive Upgrade and Transformation for Energy Conservation of Subcritical Units" of the # 3 units of CR Xuzhou was launched. This project adopted Shenneng Energy Technology's high-temperature subcritical series technology to transform the units. The steam temperature increased from 538 degrees Celsius to 600 degrees Celsius under the same pressure, and in combination with other supporting series of energy-saving innovative technologies, the designed coal consumption for power supply under rated working conditions was as low as 287 g/kWh, which was 31 g/kWh lower than that before the transformation, reaching the coal consumption level of ultra-supercritical units. As the pressure remained unchanged, the transformation costs and the amount of engineering were also greatly reduced.
"In addition to a drastic reduction in coal consumption, we also consider in the design that in order to absorb more renewable energy, the power grid will require higher flexibility and ultra-low-load operation requirements for coal-fired power projects, so the boiler drum and the design of the steam turbine regulation grades were retained, which enables the units to give full play to the advantages of fast load response. In addition, a series of technologies such as ultra-low-load stable combustion and low-load denitrification are also prospectively designed and verified by the successful implementation of the project." Feng Weizhong said.
It is understood that as of the end of 2018, the installed capacity of subcritical units in China reached 350 million kilowatts, accounting for nearly one-third of the total installed capacity of coal-fired power projects, and there were 943 300,000 kilowatt-class subcritical units. "The successful transformation of # 3 units plays a typical demonstration role in enhancing the power generation efficiency of a lot of stock subcritical units in China, and is of deep influence for activating the vitality of subcritical units and enhancing resource utilization rate." The relevant person in charge of CR Xuzhou said.
Link: http://paper.people.com.cn/zgnyb/html/2019-12/02/content_1959600.htm