Study on the Process of Filling Carbon Dioxide Gas into Static and Flowing Liquid Nitrogen

摘要

When filling CO_2 gas into saturated liquid nitrogen, for the purpose of forming small and dispersed solid CO2 particles and uniform solid-liquid mixture, the mixing process, such as the size of solid particle and the blocking of pipeline should be researched. In this paper, CO2 gases are filled into static liquid nitrogen with stainless steel coil pipe, normal plastic pipe, and stainless steel capillary pipe respectively, and into flowing liquid nitrogen with the capillary pipe. Theoretically, CO2 gas will be frozen under liquid nitrogen temperature to form solid particles. It is found that, for static experiment, pipes with bigger inner diameter are blocked whether pre-cooled or not. For flowing experiment, the capillary pipe is blocked intermittently and inevitably due to high back pressure, the throttling effect and temperature decrease and recovery.