表面型低温过滤器的滤饼特性实验研究

Experimental Research on the Characteristics of Filter Cake on Surface-type Cryogenic Filter

通过搭建的低温不锈钢丝网过滤器过滤特性实验台,采用液氮为待净化的液体,二氧化碳为杂质成分,进行了过滤器表面的滤饼特性测试,实验测试了不同的工况下,恒速过滤和恒压过滤时的液氮流量和过滤器前后压降.根据过滤理论,分析了恒速和恒压过滤的特点,并根据达西定律推导出压降公式和t/V-V曲线,分别计算恒速和恒压过滤阶段的滤饼比阻和过滤介质阻力.结果表明,不锈钢丝网过滤器能有效净化液氮中的二氧化碳颗粒,且所得的滤饼可视为不可压缩的,滤饼比阻和过滤介质阻力在各个阶段均可视为定值,其计算值弥补了低温下滤饼特性数据的不足.

This paper researched on the characteristics of filter cake on a test bench with a cryogenic stainless steel wire mesh filter. Liquid nitrogen and carbon dioxide which is solidified under liquid nitrogen temperature were adopted as feed slurry. In the experiment, flow rate of purified liquid nitrogen and pressure drop across the filter are measured for constant-velocity and constant-pressure process respectively. Evolution trends are analyzed according to filtration theories, and functions of pressure drop and t/V-V are derived according to Darcy law, to calculate the specific resistance of filter cake and filter medium during these two different processes. The results show that the stainless steel wire mesh filter can purify solid carbon dioxide from liquid nitrogen effectively, and the filter can be seen as incompressible. The specific resistance of filter cake and filter medium are constant in the two processes, and the values can cover the shortage of filter cake characteristics at cryogenic temperature.