MW Supercritical Carbon Dioxide Compressor Test Progress Made by Institute of Engineering Thermophysics

Supercritical carbon dioxide Brayton cycle power generation technology is an international frontier technology that countries in the world are competing to study. The technology uses supercritical carbon dioxide as the circulating medium. Under the same conditions, the efficiency is 5% ~ 10% higher than that of the traditional steam Rankine cycle power generation technology, while the equipment volume and weight are greatly reduced. Thanks to these two outstanding advantages, the technology has broad application prospects in the fields of solar thermal power generation, small and medium-sized nuclear power, and ship power.

Compressors and turbines are the core components of the supercritical carbon dioxide Brayton cycle system. The experimental research technology is difficult and the input cost is high. There have been few reports on relevant experimental research at home and abroad for many years. The new working medium power generation team of the Institute of Engineering Thermophysics of the Chinese Academy of Sciences began to carry out experimental research on the key technology of megawatt supercritical carbon dioxide power generation in 2016. China's first megawatt supercritical carbon dioxide compressor test platform, and put into operation. After the completion of the experimental platform, a series of experiments including control system commissioning, system joint debugging and joint test, carbon dioxide filling and supercritical carbon dioxide state modulation, high-speed rotor no-load and light-load testing were carried out, which verified the process flow of the experimental system Feasibility and reliability, obtained a series of precious experimental data, changed the current situation of supercritical carbon dioxide centrifugal compressor numerical analysis lacking reliable experimental data.

Recently, the team completed the test of the first megawatt supercritical carbon dioxide compressor prototype in China. The compressor achieved full load test operation for the first time, with a total inlet pressure of 7.3 ~ 7.9MPa, a total inlet temperature of 305.4K, and the experimental inlet state was supercritical, and the compressor operation was stable near the critical point; the maximum compressor outlet pressure reached 14.9 MPa, total pressure ratio is about 1.9, flow rate reaches 12 ~ 17 kg / s, isentropic heat insulation efficiency is 70 ~ 80%. The experimental results show that the compressor's isentropic efficiency, working boundary, gap leakage, etc. are basically consistent with the theoretical design, thus achieving the first verification of the supercritical carbon dioxide compressor aerodynamic design theory and method.

The success of this compressor experimental test is an important stage achievement of domestic megawatt supercritical carbon dioxide Brayton cycle power generation technology research. First of all, in addition to the 100kW level test data of the SANDIA laboratory in the United States, there is no publicly reported test data of large-scale equal-size compressors, and the compressor efficiency measured in this experiment has obvious advantages. A large amount of original experimental data has been accumulated during the test, which is of great significance for the verification of numerical simulation and design theory by relevant units at home and abroad, and then optimization of design. Secondly, the stability of compressor operation near the critical point has always troubled researchers in this field. The key scientific problem of this experiment, the results of this experimental test provide a preliminary answer to this question; Finally, as the first domestic MW supercritical carbon dioxide compressor general test platform, this test fully verified the stability and the test platform Reliability, with the ability to provide experimental testing services for supercritical carbon dioxide compressors, is of great significance to the development of this field.

Figure 1 MW compressor testing site

Figure 2 Compressor test result curve