Experimental Study on Restart Performance of Absorber Sphere Pneumatic Conveying

In the high-temperature gas-cooled reactor pebble-bed module (HTR-PM), absorber sphere shutdown system is the second shutdown system. Absorber spheres are transported back to storage vessel by pneumatic conveying when reactor needs to be started. The restart reliability of absorber sphere pneumatic conveying is quite important. Experimental system for absorber sphere pneumatic conveying has been built to investigate the gas-solid flow characteristics of pneumatic conveying. Restart experiments were conducted to study the restart performance of pneumatic conveying. Ambient air was used as source gas and absorber sphere was replaced by glass sphere. The inlet steady gas velocity of the sphere feeder was in the range of 17∼27 m/s. Pneumatic conveying could be restarted in all the experiments, which showed the good reliability of the pneumatic conveying process. The maximum relative deviation of the spheres pile heights in the riser was 4.1%, which showed a good repeatability. Pressure drop of feeder during steady stage was in the range of 4∼8 kPa. Furthermore, the restart experiments were also conducted in the full scale experimental system with helium as the source gas and the pressure of 2 MPa, the results also showed the good reliability of pneumatic conveying process.