气体杂质对CO_2管道输送系统安全的影响

目前CO2管道输送呈现出快速发展趋势,相关问题也日益备受关注。目前国际上还没有关于CO2管道输送混合气体组分的统一标准,而我国在CO2输送管道的建设方面还处于空白,关于CO2中各种杂质对其输送过程的影响特别是对安全的影响也尚不清楚。为此,在对国外CO2长输管道运行现状进行调研的基础上,对管道实际输送CO2混合气体中的杂质类型、杂质含量以及不同的CO2混合气体组成要求进行了总结,分析了含有不同杂质(H2、H2S和SO2等)的CO2混合气体物性参数(密度、黏度和蒸气压)和相态特性的变化规律,重点从管线腐蚀、CO2水合物形成及CO2溶解于水等方面研究了不同杂质对CO2管道系统设计运行的影响,尤其是游离水对CO2输送管道安全运行的影响,并参照国外CO2管道输送系统的标准规范提出了管道输送的CO2混合气体的纯度和含水量要求。

Impacts of gas impurities on the security of CO2 pipelines

It is such a rapid progress in CO₂ transport via pipelines that the relevant issues have attracted much concern in China and around the world. Up till now, no universally accepted codes have yet been formulated for the combinations of CO₂ stream in pipelines. What′s more, in China there is no experience in CO₂ pipeline design and construction. Therefore, little has ever been known about the impurities in the CO₂ stream via pipelines and their effects on CO₂ transport. In view of this, through an investigation into the status quo of foreign long distance CO₂ pipeline operation, we summarized the amount and type of impurities in the CO₂ stream as well as different requirements for combinations in the stream. Then, we analyzed the physical parameters like density, viscosity and vapor pressure of the CO₂ stream containing various types of impurities such as H₂, H₂S, SO₂, etc. and the changing rules of their phase behavior. The emphasis was put on the impacts of different impurities on the CO2 pipeline design and operation in the aspects of pipeline corrosion, hydrate formation, the dissolution of CO₂ in water, and so on, especially the effect of free water on the safe operation of CO₂ pipelines. Furthermore, by reference to the foreign criteria or codes of CO₂ pipeline transport system, the requirements for the purity of gas components and water content were presented for the CO₂ stream via pipelines.