Control strategies and dynamic experimental tests on the wide-range and rapid load regulation of a first pilot multi-megawatts fossil-fired supercritical CO2 power system

Abstract

Supercritical CO2 (sCO2) power system is a research front in recent years due to its high efficiency and flexibility which is considered as a transformative power system in terms of consumption of the fluctuated and intermittent renewables. The merits of sCO2 power systems have been widely shown by small-scale test loops. However, it is still very lack of the investigations on the control strategies based on real-time dynamic operational data of large-scale multi-megawatts pilot power system, especially for wide-range and rapid load regulation to demonstrate the feasibility of large-scale utilization and commercialization. A worldwide first pilot multi-megawatts SMART (Supercritical CO2 Modular Advanced Research and Test) fossil-fired power system has been built and operated for more than 1000 h at TPRI (Thermal Power Research Institute), Xi’an, China with turbine inlet parameters of 20 MPa/600 °C/600 °C. The influence of key parameters on the dynamics of the system are experimental studied. In-depth tests of the wide-range load regulation and rapid load regulation of the SMART@TPRI power system are performed. The test results show that the key target parameters such as turbine inlet temperatures, compressor inlet temperature and pressure, sCO2 mass flow rate and exhaust flue gas temperature can be well regulated by a set of well-developed control modules to ensure an efficient and safe operation during load variations. The SMART@TPRI power system can run stably and flexibly within the whole range from 0 %Pe to 100 %Pe. The averaged load ramp and load reduction rate achieves 6.35 %Pe/min and −6.37 %Pe/min, respectively, which is almost 3 ∼ 4 times than that of steam power system, under the control strategy of sliding pressure with fixed turbine inlet temperature by a combination of several novel well-developed control modules.