超声波增湿撞击流泡沫捕捉塔处理含铍废气研究

Purification of Be-containing offgas by ultrasonic atomization-impinging stream foam tower

采用超声波雾化除尘技术,研制了最大处理风量为300 m3·h-1的超声波增湿撞击流泡沫捕捉塔含铍废气处理样机,按照国家标准方法对超声波增湿撞击流泡沫塔的进、出气口进行采样,使用电感耦合等离子谱仪对其除铍性能的影响因素进行了研究。结果表明,雾化加湿量的增加有利于除铍效率的提高,但同时也使净化后气体的绝对湿度增加;超声波加湿器安装在距离塔体3 m以上方能最大限度地提高除铍效率;当颗粒物粒径在0.4μm以上时,除铍效率较高,而在0.4μm以上时,除铍效率显著降低;除铍效率随进气口初始铍浓度而增加;气体流速的增加有利于提高除铍效率,但气体流速过高将导致净化后气体绝对湿度显著增加,最佳气体流速为12 m·s^(-1)。当气体流速为12 m·s^(-1)时,最佳塔内水位为40 cm。研究结果为超声波增湿撞击流泡沫捕捉塔在钍基熔盐堆(Thorium Molten Salt Reactor,TMSR)核能系统项目含铍废气上的应用提供了实验依据。

Background： LiF-BeF2 is used as coolants for Thorium Molten Salt Reactor （TMSR）. The offgas from TMSR containing beryllium which is harmful to both human health and the environment must be purified before being discharged. Purpose： A new type wet duster-ultrasonic atomization-impinging stream foam tower was developed. Methods： The beryllium removal properties were investigated by sampling according to national standards The increase of atomization amount is helpful for improving beryllium removal efficiency. Results： In order to control the absolute humidity offgas after purification, the optimal atomization amount is set at 80 mL·min^-1. The ultrasonic humidifier should be installed 3 m away from the foam tower. Particles with diameter bigger than 0.4 μm can be removed effectively. The beryllium removal efficiency of offgas increases with the initial beryllium concentration and the offgas velocity which is optimized at 12 m.s^-1. The optimal water level in the tower is 40 cm when the offgas velocity is 12 m·s^-1. Conclusion： The results indicate that ultrasonic atomization-impinging stream foam tower is suitable for purifying offgas containing beryllium in TMSR.