下一代光热电站颗粒/超临界CO2流化床换热系统的设计与性能研究

Abstract This paper proposes and builds the first megawatt thermal (MWth) class particle/supercritical carbon dioxide (sCO 2 ) fluidized bed heat exchanger system for next generation concentrated solar power (CSP) plant. In this CSP plant, particles were chosen as the heat absorbing medium for solar collectors, and transfered heat to sCO 2 through the heat exchanger, and then the heated sCO 2 enters the turbine to work. The heat exchanger body is in a form of fluidized bed where the sCO 2 tube bundle absorb heat from the high-temperature particles under the action of fluidized air. Particles flow around the wall in the heat exchanger, and sCO 2 flows from top to bottom within the two bins, and fluidized air is recycled to improve the heat exchanger efficiency of the system. The overall structural design of the system are described in detail. The experiments were run beginning from 2021 in Beijing Yanqing, China, and experimental results showed that at the CO 2 outlet temperature is 552 °C, the efficiency is 83.2 % and the power of the heat exchanger is 1045 kW when the temperature of particles reached 685 °C, and the maximum value of the overall heat transfer coefficient was calculated to be 103.6 W/m 2 ∙K. Numerical simulation is conducted to analyze the particle velocities, temperature distributions, and overall heat efficiency in the heat exchanger. This research provides the valuable insights for the design and operation methods of next generation CSP plant combined with sCO 2 Brayton cycle.