Since 2002, the domestic power generation equipment manufacturing industry has designed and manufactured 600,000 kW and 654.38+100,000 kW supercritical units for domestic power stations through cooperative production with foreign countries. At present, the order quantity has exceeded 100 sets. The design, construction and operation of these units have further deepened our understanding of the key technologies of supercritical and ultra-supercritical units.
At present, in the manufacturing of ultra-supercritical units, Harbin Electric Power Company, Dongfang Electric Power Company and Shanghai Electric Power Company, the three major domestic power generation equipment companies, have the ability to manufacture 1 10,000 kW ultra-supercritical thermal power units by introducing and digesting foreign technologies. At the end of 2006, three ultra-supercritical thermal power units 1 million kilowatts manufactured by domestic enterprises have been put into production one after another.
However, due to the strict restrictions on technology transfer abroad, the domestic design technology and core manufacturing technology have not been fully realized, especially the key materials of power station units, and there is still a lot of work to be done. From a global perspective, the trial production of ultra-supercritical parameter units began in the 1950s.
The design parameters of the first125,000 kw ultra-supercritical unit put into operation in USA 1957 were 3 1 MPa /62 1℃, and the parameters of the 325,000 kw unit put into operation in 1958 were 34.4 MPa /649℃. Due to the limitation of technical level at that time, the operation availability of these two units was relatively low.
At present, ultra-supercritical units have been widely used in many countries in the world. The maximum capacity reached 1.3 million kilowatts (1.972 in the United States), and the highest efficiency reached 49% (2006,5438+0 in Denmark). The countries that develop and apply this technology are mainly the United States, Japan, Germany and Denmark. .
Introduction of ultra-supercritical thermal power unit In supercritical and ultra-supercritical conditions, water directly changes from liquid to steam, that is, from wet steam to superheated steam and saturated steam, with high thermal efficiency. Therefore, the ultra-supercritical thermal power unit has the characteristics of low coal consumption, good environmental protection performance and high technology content, and the thermal efficiency of the unit can reach about 45%. Coal saving is the biggest advantage of ultra-supercritical technology, which improves the thermal efficiency by 2% to 3% compared with the most advanced supercritical units in China. If the thermal efficiency is increased by 1%, for a 300,000 kW thermal power unit, 6,000 tons of high-quality coal can be saved in one year. The development direction of ultra-supercritical unit is to further improve steam parameters while maintaining its availability, reliability, operational flexibility and unit life, so as to obtain higher efficiency and environmental protection performance.
Ultra-supercritical thermal power The so-called supercritical unit refers to the unit whose main steam pressure is greater than the critical pressure of water by 22. 12 MPa, while the subcritical unit usually refers to the unit whose outlet pressure is 15.7~ 19.6 MPa.
Traditionally, supercritical units are divided into two grades: one is conventional supercritical parameter units, the main steam pressure is generally around 24 MPa, and the main steam and reheat steam temperatures are 540 ~ 560℃; Second, ultra-supercritical units, the main steam pressure is 25~35 MPa and above, and the main steam and reheat steam temperatures are generally above 580℃. Under supercritical and ultra-supercritical conditions, water directly changes from liquid to gas, that is, from wet steam to superheated steam and saturated steam, with high thermal efficiency. Therefore, the ultra-supercritical unit has the characteristics of low coal consumption, good environmental protection performance and high technology content, and the thermal efficiency of the unit can reach about 45%.
Coal saving is the biggest advantage of ultra-supercritical technology, which improves the thermal efficiency by 2% to 3% compared with the most advanced supercritical units in China. If the thermal efficiency is increased by 1%, for a 300,000 kW thermal power unit, 6,000 tons of high-quality coal can be saved in one year.
The development direction of ultra-supercritical unit is to further improve steam parameters while maintaining its availability, reliability, operational flexibility and unit life, so as to obtain higher efficiency and environmental protection performance.
What exactly do supercritical and ultra-supercritical in power plants mean? They refer to the parameters of the thermal system of the generator set. The critical parameter points of water are 22. 12 MPa and 374.5438+02 degrees. Below this parameter belongs to subcritical, above this parameter belongs to supercritical. After the critical state, the specific gravity of water and steam is the same, so natural circulation cannot be used for boiler heating, and forced circulation must be used.
For the thermal equipment boilers and steam turbines of generator sets, the rated steam parameters exceed 22. 12Mpa, that is, supercritical. However, the steam pressure of general supercritical units is above 24Mpa, and the temperature is not high, which is still maintained at 545 degrees and 550 degrees. However, the steam pressure of ultra-supercritical unit is slightly higher than 25Mpa, and the temperature has greatly jumped to 600 degrees. This is the specific meaning of supercritical and ultra-supercritical
What exactly do supercritical and ultra-supercritical power plants mean? Supercritical and ultra-supercritical generator sets have been widely used in developed countries.
The reliability data of foreign units show that ultra-supercritical units can achieve high reliability like supercritical generating units. From the perspective of environmental protection measures, foreign ultra-supercritical units are equipped with flue gas desulfurization, denitrification and high-efficiency dust removal devices at the tail of boilers, which can realize low pollutant emission and meet strict emission standards.
For example, the emission index of ultra-supercritical units in Japan can reach 70mg/m3 of SO2 (standard state, the same below), 30mg/m3 of NO and 5mg/m3 of dust, indicating that ultra-supercritical coal-fired units can realize clean power generation like units burning natural gas and oil. At the same time, the ultra-supercritical unit improves the efficiency and correspondingly saves the water consumption for power generation.
Ultra-supercritical unit is a mature and advanced technology, which is comparable to subcritical unit in reliability, availability, thermal operability and unit life, and has more commercial operation experience. Ultra-supercritical coal-fired power generation technology is of great significance to realize the adjustment of thermal power structure in China and should be developed vigorously.
Through technology introduction and digestion and absorption during the Seventh Five-Year Plan and the Eighth Five-Year Plan, China has already possessed the design and manufacturing technology of subcritical 300MW and 600MW units. In 1990s, China introduced a batch of supercritical units and some design and manufacturing technologies, and basically mastered the design, installation, commissioning and operation and maintenance technologies of supercritical units.
During the Tenth Five-Year Plan period, the research and development of ultra-supercritical coal-fired power generation technology and the construction of ultra-supercritical 1000MW units in Huaneng Yuhuan Power Plant have made the overall level of China's power industry develop by leaps and bounds.
What does ultra supercritical mean? The development of ultra-supercritical power generation technology has a history of more than half a century. Since the 1950s, the development and research of ultra-supercritical power generation technology, represented by Britain, Germany and Japan, has exceeded the critical parameters from the beginning. The United States is the first country in the world to engage in the research and application of ultra-supercritical power generation technology. 1957, the world's first ultra-supercritical unit was built and put into operation in Philo Power Station, USA. The single machine capacity is 125MW. The steam parameters are 3 1MPa, 621℃/566℃1Basic concept: the critical parameters of water are: tc=374. 15℃, Pc=22. 129MPa. At the critical point and supercritical state, water directly changes from liquid to gas, while maintaining a single phase. Generally, the range where the pressure is greater than the critical point Pc is called supercritical region, and the range where the pressure is less than Pc is called subcritical region. Physically speaking, according to the steam parameters adopted by the unit, there are only supercritical and subcritical points. Because the number of ultra-supercritical parameter units is the largest in China, ultra-supercritical is artificially distinguished in China. Also known as optimized or effective supercritical parameters. At present, there is no international unified standard for the division of ultra-supercritical and supercritical parameters. It is generally considered that the state when the steam pressure is greater than 25MPa and the steam temperature is higher than 580℃ belongs to ultra-supercritical parameters. Ultra-supercritical generally refers to thermal power generation, and there is no such dividing point in physics, which only indicates a higher stage of the development of supercritical technology. It is the natural development and extension of conventional steam-powered thermal power units. 2 Specific parameters: When the steam pressure rises to 27MPa, it is called ultra supercritical. 3 Application features: 1. When ultra-supercritical technology is adopted, once-through boiler has no bubble link. 2. The material balance of each unit should be strictly controlled. 3. Need timely and accurate coordination and control.
Jianbi Power Plant History Jianbi Power Plant is one of the main power plants in East China Power Grid. The total capacity of the whole plant is 3980MW, except that six units in the first to third phases have been retired and dismantled.
At present, * * has six generators in service in four phases, namely, four phases (#7 and #8), five phases (#9 and # 10), six phases (#1and # 12) and seven phases (#/). Among them, #7~# 10 was designed and manufactured by the former Shanghai Boiler Factory in 1970s. At that time, it was the largest generator set made in China. Starting from 1997, the UP once-through boiler was transformed into a single-furnace double-cut controlled circulation boiler. The boiler efficiency has been improved from 89% before modification to 92.3 1%, and the peak-shaving capacity has been greatly improved, and the output of the unit has also increased by 30MW.
# 1 1 and # 12 are "big generation and small generation" engineering units with an output of 330MW. Construction started in 2003 and put into production in September 2004.
Among them, 1 1 unit won the only special prize of domestic units at the 36th annual national thermal power unit (300MW class) competition. In the seventh phase of "large pressure and small pressure" project, 2* 1000MW units were expanded on the site where the units were demolished, and Shanghai supercritical tower furnace was selected, model: SG-3040/27.46-m. ..
In mid-April, 2009, Jianbi Power Plant 1X 1000MW project was officially approved by the National Development and Reform Commission, and the participation of the second unit in the "evaluation" work was progressing steadily as planned. On May 26th, 2009, Jianbi Power Plant held a series of grand and enthusiastic activities to celebrate its 50th anniversary. On may 28th, 2009, a grand foundation laying ceremony was held for 1x 1000MW unit.
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