含气体杂质超临界CO2管道输送特性研究

Research on impact of gas impurities on pipeline transportation characteristics of supercritical CO

CO2管道输送是碳捕集利用与封存(CCUS)过程中的一个重要环节。对诸如从高含CO2的天然气等烃类中捕集的CO2,所含杂质组分主要为CH4,根据标准设定组分杂质含量,用PR方程计算不同杂质含量的CO2多元体系的物性参数。结果表明,在一定温度压力下,密度和黏度会发生突变,比热容会出现极值,与纯CO2对比,在CO2中加入杂质改变物性突变位置。设定甲烷的物质的量分数为1%,其他杂质SO2、He、H2、CO、N2、O2、Ar、N2、C2H6和H2S物质的量分数分别为1%、3%和5%,利用HYSYS计算CO2三元体系的管输参数,发现除SO2外其他杂质使超临界CO2管道输送压降增加,H2S对管道输送压降影响很小,H2和He对管道压降影响较大,气体杂质对超临界CO2管输温降基本没有影响。因此,在管道运行过程中,应尽量避免CO2中H2杂质的存在。所得结果为超临界CO2管道设计和安全高效运行提供科学依据。

CO2 pipeline transportation is an important link in the process of carbon capture, utilization and storage(CCUS). For the CO2 obtained from hydrocarbons, such as natural gas with high CO2 content, had a main impurity of CH4. According to the standard, the contents of impurities in the CO2 gas were set, and the physical parameters of the multicomponent systems of CO2 with different concentrations of impurities were calculated by PR equation. The results showed that at a certain temperature and pressure,the density and viscosity of the systems will change abruptly, and the specific heat capacity will appear the extreme value. Compared with pure CO2, the CO2 containing impurities changes the mutation positions of physical properties. HYSYS was used to calculate the pipeline transportation parameters of CO2 ternary systems by setting the content of CH4 as 1% by mole and other impurities of SO2,He, H2, CO, N2, O2, Ar, N2, C2H6 and H2S as 1%, 3% and 5% by mole, respectively. It was found that the impurities other than SO2 increase the pressure drop of supercritical CO2 pipeline transportation, little increase by H2S and great increase by H2 and He, and all of the impurities have little effect on temperature drop of supercritical CO2 pipeline transportation. Therefore, in production and pipeline transportation of CO2, H2 impurity should be avoided as far as possible. The results provide a scientific basis for the design and safe and efficient operation of supercritical CO2 pipeline.