超临界CO_2管道放空特性研究

The Blow Down Characteristics of Supercritical CO_2 Pipeline

大规模长距离输送二氧化碳(CO_2)时一般采用管道输送,管内压降和温降是影响超临界CO_2管道放空安全问题的重要因素。与天然气管道相比,超临界CO_2管道放空时CO_2的降压可能导致管道内低温,甚至形成干冰从而对管道及设备造成损伤,危害管道安全。采用OLGA软件对超临界CO_2管道放空过程参数变化规律进行动态模拟,研究表明:初始压力越高或者初始温度越低,放空时间越长,管内越早产生气液两相,管内最低温度值越小,生成干冰的风险也越大。超临界CO_2管道放空时宜采取加热、保温等措施,使管道内流体保持气态泄放,从而有效防止干冰的生成以及管道低温损伤。

Pipeline is commonly used in large-scale long-distance transportation of carbon dioxide（CO_2）,pipeline pressure drop and temperature drop are important influence factors of supercritical CO_2 pipeline blow down issues. Compared with natural gas pipeline, the decompression of CO_2 pipeline may cause a low temperature in the pipeline,and even the formation of dry ice,which damages the pipeline and equipment. By the OLGA software,the parameters variation in the pipeline during supercritical CO_2 pipeline blow down is simulated.The results show that： The higher the initial pressure or lower the initial temperature, the longer blow down time, the earlier generation of gas- liquid two-phase in inner tube, and the smaller minimum temperature value,the greater the risk to generate dry ice.Heating or insulation and other measures should be taken to keep the gaseous fluid discharge during the blow down of supercritical CO_2, thereby the generation of dry ice and pipeline low temperature injury can be effectively prevented.