In the last few days of August, in the China Resources Power (Xuzhou) Co, Ltd. located in Xuzhou City, Jiangsu Province, and the site of Shenergy Anhui Pingshan Power Plant Phase II Project in Huaibei City, Anhui Province, dozens of kilometers away therefrom, were crowded with excitement. The academician and expert delegation organized by the China Energy Research Society and the Beijing Energy and Environmental Society conducted on-site visits, site inspections, and held technical seminars.
Hua Jianmin, vice chairman of the Standing Committee of the 11th National People's Congress, Qin Zhongyi, chief energy engineer of the former Ministry of Energy, Shi Yubo, Zhou Dadi, executive vice chairmen of China Energy Research Society, Chen Jinxing, vice chairman of China Energy Research Society, Ni Weidou, He Duohui, Chen Niannian, and Su Wanhua, academician of Chinese Academy of Engineering, Mao Jianxiong, professor of Tsinghua University and other experts, praised the thermal power technology progress represented by China Resources Power (Xuzhou) Co, Ltd. and Shenergy Anhui Pingshan Power Plant Phase II Project and promoted and advised on the latest technological achievements of thermal power.
Why are important professionals coming together? This shows the significance of these technical issues that everyone cares about.
"Coal-fired power generation can also be made into a green project, so that thermal power generation can generate new vitality and be tenable", said Hua Jianmin, vice chairman of the Standing Committee of the 11th National People's Congress, at the report and exchange meeting on the high-temperature subcritical comprehensive upgrade and reconstruction project held by China Resources Power (Xuzhou) Co, Ltd. on August 28.
By applying Shanghai Shenergy Power Technology Co., Ltd.'s high-temperature subcritical technology transformation, 3# Unit of China Resources Power (Xuzhou) Co, Ltd. successfully passed the 168-hour full-load trial operation on August 10, and the net coal consumption rate could be reduced to 287 g / kWh. According to Hua Jianmin, the project is a typical embodiment of independent innovation in thermal power technology.
"The high and low position sub-axis layout secondary reheating technology adopted by Shenergy Anhui Pingshan Power Plant Phase II project can be described as a feat in the history of thermal power", said Ni Weidou, academician of the Chinese Academy of Engineering and honorary chairman of the Beijing Energy and Environmental Society on August 29 in Huaibei Shenergy Power Generation Co., Ltd..
The Shenergy Anhui Pingshan Power Plant Phase II project will build a secondary reheating ultra-supercritical high and low-position double-shaft turbo-generator unit with the world's largest single-unit capacity of 1.35 million kilowatts, which is listed as a "National Demonstration Project" by the National Energy Administration. At present, the project is progressing in an orderly manner.
The successful implementation of the "high temperature subcritical transformation" and the steady advancement of the "high and low position sub-axis layout" have been regarded by many academicians and experts as a milestone in the advancement of thermal power technology. These two technologies have also made Xuzhou and Huaibei which are less than 100 kilometers apart into “new landmarks of energy” for the advancement of thermal power technology and even for the energy revolution.
How to deal with in-service subcritical units?
"During June 4 to June 7 this year, the IEA Clean Coal Centre held the 9th International Clean Coal Technology Conference in the United States. Experts from the Electric Power Research Institute (EPRI) took the initiative to communicate with experts from Shanghai Shenergy Power Technology Co., Ltd. (Shenergy Technology), and admitted that they encountered a major bottleneck in the research of increasing the steam temperature technology of subcritical units." Feng Weizhong, general manager of Shenergy Technology, introduced at the said report and exchange meeting that the technical transformation of the subcritical unit, which accounts for the world's largest thermal power unit, has encountered worldwide difficulties.
With the continuous progress of material technology and the improvement of the theory of thermal power, the parameters of steam have undergone the development process from low pressure, medium pressure, high pressure, ultrahigh pressure, subcritical, supercritical and ultra-supercritical. The development of clear energy is becoming more and more urgent and the development of high-parameter large-scale units has become an integral part of the national energy conservation and emission reduction strategy. However, how to deal with a large number of in-service subcritical units is a major issue.
Relevant information shows that at present, China still has about subcritical units with installed capacity of 350 million kilowatts (mainly 300,000 kilowatts and 600,000 kilowatts), and the number of merely subcritical units with installed capacity of 300,000 kilowatts reaches 880. Coal consumption of such units is significantly higher than that of supercritical and ultra-supercritical units.
"It is necessary to adopt mature and applicable energy-saving transformation technologies such as steam turbine partial flow reconstruction, boiler flue gas waste heat recycling, motor frequency conversion, and heating reconstruction according to the actual situations of plants, and implement comprehensive and systematic energy-saving transformation of subcritical and supercritical units with installed capacity of 300,000 kilowatts and 600,000 kilowatts. The net coal consumption rate after the transformation will strive to reach the advanced level of the same type of units", as clearly required in the Action Plan for Energy Conservation, Emission Reduction, Upgrade and Transformation of Coal Power (2014-2020) for the implementation of comprehensive energy-saving transformation for subcritical units.
In order to fully tap the energy-saving potential of the in-service subcritical coal-fired generating units, make scientific unit reformation, life extension and retirement, and further improve efficient and clean development of coal power, the National Energy Administration issued, in 2015, the Interim Provisions on the Reconstruction, Life Extension, and Retirement of Subcritical Coal-fired Power Units (Guo Neng Dian Li [2015] No. 332).
The reporter noted that it is required in the Action Plan for Energy Conservation, Emission Reduction, Upgrade and Transformation of Coal Power (2014-2020) that: "By 2020, the average net coal consumption rate after the reconstruction of in-service coal-fired generating units will be less than 310 g / kWh, of which the average net coal consumption rate of in-service units (except air-cooled units) with installed capacity of 600,000 kilowatts or more after transformation will be less than 300 g / kWh. "
According to the analysis by Professor Mao Jianxiong of Tsinghua University, according to the rule that the average net coal consumption rate of a unit is generally 15 ~ 20 g / kWh higher than the net coal consumption rate under rated conditions, the above requirements mean that the net coal consumption rate of in-service coal-fired power generation units under rated conditions must be lower than 290 g / kWh. This goal is relatively easy to achieve for in-service ultra-supercritical units, but it is a huge challenge for subcritical units.
According to relevant research data, due to low parameters and generally low flow efficiency of steam turbines, the net coal consumption rate of wet-cooled subcritical units with installed capacity of 300,000 kilowatts under rated conditions is generally higher than 320 g / kWh (some even higher than 340 g / kWh), which is far away from the requirement in the Action Plan (generally higher than 30 g / kWh).
"Xuzhou sample" provides global benchmarking
"World's First", "The Miracle of Thermal Power"- For the past few days, in China Resources Power (Xuzhou) Co, Ltd., what first attracted people were the identification plates with these keywords . Academicians and experts also took a group photo there.
So what kind of technology is this?
In recent years, the industry has continuously proposed various technical solutions to improve the efficiency of subcritical units, but all have obvious shortcomings.
According to the information from Beijing Energy and Environment Society, in case of conventional steam turbine flow-through reconstruction, the energy-saving benefits are generally only about 10 g / kWh, far from meeting the national requirement of 310 g / kWh for coal consumption, and it is difficult to maintain the efficiency gains of the transformation. The cross-generation upgrade and transformation into a quasi-secondary reheat super (ultra-super) critical unit has a huge amount of transformation and cost, which is almost equivalent to reconstruction, but the final performance is unsatisfactory and not economically feasible. As for the solution of heating to 566/566 degrees Celsius, its energy saving effect is limited (about 15 g / kWh), but the cost is high. It still cannot meet the standard and the cost performance is too low.
According to the introduction from Hu Min, secretary of the party committee and president of China Resources Power Holdings Co., Ltd. (referred to as CR Power), he has discussed with Feng Weizhong on issues such as temperature rise and other related issues for improving the efficiency of in-service subcritical units." I am also a fan of Professor Feng Weizhong", said Hu Min solemnly at the above meeting.
After years of research, Feng Weizhong proposed a "high temperature subcritical" transformation technology route in 2010. The key is to keep the main re-steam pressure of the unit basically unchanged, to raise the main re-heated steam temperature of the unit to 600 degrees Celsius of the existing ultra-supercritical units, and to make integrated application of the series of technologies for energy saving and emission reduction as verified by Shanghai Waigaoqiao Third Power Generation Co., Ltd. as mature, which can greatly improve the energy efficiency and environmental protection level of the units.
In view of feasible, advanced, and highly cost-effective "high-temperature subcritical comprehensive upgrading and transformation plan", CR Power took the lead in cooperating with Shenergy Technology led by Feng Weizhong to first implement the high-temperature subcritical comprehensive upgrading and transformation in 3# Unit of China Resources Power (Xuzhou) Co, Ltd.
This was praised by Shi Yubo, executive vice chairman of the China Energy Research Association as "CR Power is the first to eat crabs." Hua Jianmin referred to Feng Weizhong's series of technologies as "swift horse" and compared CR Power to "talent scout."
"Our 3# Unit is a domestically produced subcritical coal-fired pure condensing unit with installed capacity of 320,000 kilowatts. It was completed and put into operation in June 2004. In 2016, its average net coal consumption rate was 325 g / kWh. The goal for comprehensive energy-saving upgrade and reconstruction of high-temperature subcritical units is to achieve a ultra-supercritical unit level with net coal consumption rate of no more than 287 g / kWh under design conditions after the transformation is completed", introduced by Li Yi, general manager of China Resources Power (Xuzhou) Co, Ltd.
The high-temperature subcritical comprehensive upgrade and renovation project implemented in China Resources Power (Xuzhou) Co, Ltd. started customized design in April 2017, and the shutdown and renovation construction started officially at the end of November 2018. Installation and commissioning were completed on August 3, 2019. In addition to the advanced coal consumption level of the unit, the transformation also effectively increased the working temperature of the denitration device under low load, broke the bottleneck of the unit's ultra-low load operation, etc., and comprehensively improved the energy saving, environmental protection and flexibility of the unit.
"I noticed several data at the scene. The first is the coal consumption for power generation on the display screen, namely, 296 and 293. If according to the identification and acceptance standards for thermal power plants, the atmospheric conditions must be converted to the standard atmospheric pressure and temperature, conversion has not been made, but the coal consumption after conversion is expected to be below 290 grams, about 285-287 grams. This is an important data that can reflect that the reconstruction project has saved a lot of coal consumption", said Hua Jianmin in his speech.
Link: http://www.cpnn.com.cn/zdyw/201909/t20190903_1151942.html