Supercritical carbon dioxide cycle photothermal power generation technology research and development project officially launched

- Sep 19, 2018-

Gas Circle News, recently Beijing Energy Savings and France Power held a launching ceremony on the research and development project of supercritical carbon dioxide cycle solar thermal power generation technology in Beijing. This is an international cooperation in the field of solar thermal power generation. The two companies will jointly develop high-efficiency photothermal power generation technology based on their respective technologies in the field of light and heat, aiming at reducing the cost of CSP, and also making changes to the world climate environment. Important contribution.

There are two types of solar power: photovoltaic power generation and solar thermal power generation. Photovoltaic power generation uses sunlight to illuminate a semiconductor material to generate a current through a photoelectric effect. Photovoltaic power generation is difficult to store energy on a large scale, and the energy consumption of silicon refining is large. Photothermal power generation uses the radiant energy of solar energy, which is heated by a concentrator and a heat absorber, and then generated by a heat engine.

Supercritical carbon dioxide Brayton cycle power generation technology is one of the most advanced photothermal power generation technologies. On May 25, 2018, China Electrical Engineering Society released "10 major engineering and technical problems in the field of energy and power", supercritical CO2 solar heat. Power generation technology is listed as one of them. Supercritical CO2 is a fluid that coexists in both gaseous and liquid states. Its density is close to that of liquid, its viscosity is close to that of gas, and its diffusion coefficient is about 100 times that of liquid. It is characterized by easy to reach critical conditions, inactive chemical properties, colorless, odorless, non-toxic, safe, inexpensive, high purity, and easy to obtain.


The supercritical CO2 Brayton cycle requires only 500 to 800 degrees Celsius outside the temperature, which is easily achieved using existing solar concentrators and heat sink technology. Due to the high density of supercritical CO2 and simple cycle, the unit is light in weight and small in size (only 1/10 of the steam turbine); low installation and maintenance costs; can be used for cooling, efficiency can be more than 50%; high power density and power range Large (10MW to hundreds of MW) can be used as the main power station. Supercritical CO2 units are now close to commercialization. The cycle currently used for solar thermal power generation is mainly the subcritical Rankine cycle and the Stirling cycle, with an efficiency of 35% to 45%.

The performance improvement of the supercritical CO2 Brayton cycle can be significantly higher than the commercial steam cycle, and can be used as a new generation of replacement products, which can make solar thermal power generation cheaper. The R&D project starts with a simple supercritical CO2 Brayton cycle, tapping potentials step by step, improving system performance, and adding technical measures that can greatly improve efficiency: (1) increase turbine inlet temperature: from 500 degrees Celsius to 700 degrees Celsius or higher . (2) The compression process is completed in two steps. There is a main compressor and a split compressor. (3) Use compressor intermediate cooling. (4) The turbine is also divided into two stages, and the discharged working fluid is reheated. (5) The compressor and the turbine are split-type, so that they are each operated at an optimized speed. (6) Increase the bottom cycle, such as the Rankine cycle or the series of supercritical CO2 cycles. Its excellent characteristics and the possible subversion of power generation technology have been more and more widely recognized, and the speed of its technology development and commercial application process is gradually accelerating.

At present, the United States, the United Kingdom, Germany, Japan, South Korea, Spain and other countries have carried out research on supercritical carbon dioxide power generation technology, and some countries have already carried out prototype manufacturing and testing. At present, the domestic power system's understanding of supercritical CO2 cycle technology is still at the primary level. There are few institutions for R&D and demonstration of the system. The CSP industry and the power industry should pay attention to the research and development of supercritical CO2 cycle power generation technology. And applications, a technology that could bring about changes in power generation systems. The supercritical carbon dioxide Brayton cycle has considerable application prospects in nuclear reactors, solar power generation, industrial waste heat power generation, and ship propulsion systems due to its high efficiency, small system size and low noise.

Attached: EDF: Electricite De France was founded in 1946 and is one of the world's leading power companies, providing integrated solutions including power investment, engineering design and power management and distribution.

Beijing First Aviation Aiqiwei Energy Saving Technology Co., Ltd. is a well-known domestic air-cooling manufacturing enterprise and a domestic first-class integrated thermal and thermal technology supplier. The world's third, Asia's first 10MW molten salt tower type photothermal power station has been built. The national demonstration project already under construction, 100MW molten salt tower type photothermal power station will be built in the second half of this year. These scientific research conditions and the acquisition of the CSP demonstration project provide extremely valuable conditions for the development of supercritical carbon dioxide Brayton cycle photothermal power generation technology.