三相分离器脱除CO_2的工艺优化研究

Process Optimization of Three-phase Separator to Remove CO_2 with Simulation Experiment

油田采出液中高含量CO2对平台生产设施和海管造成了严重的腐蚀,需要对平台三相分离器进行工艺调整,以最大程度的脱除CO2。通过实验室模拟分离器在90℃,操作压力分别为0.55 MPa、0.45 MPa、0.35 MPa、0.2 MPa、0.1 MPa条件下,对现场分离器入口油样分离实验研究得出:操作压力越低,能够从油样中分离出来的气体总量越多,在0.2 MPa左右时分离出气体中CO2摩尔含量比达到最大为51.4%。同时还研究了在分离器后增设二级分离器对进一步脱除CO2起到的作用效果。实验表明,二级分离器操作压力越低,从油样中所分离出来的CO2比例越大,操作压力从0.1 MPa降到0.03 MPa时,二级分离器可将现场分离器油相出口中的油中CO2脱除率从47.5%提高到60.9%,但与此同时分离出的有用重组分气体含量也会相应的增加。

High concentration level of CO2 in produced fluid can cause severe corrosion in production process of the platform and subsea pipeline. In order to cut down the level of CO2, the process of the three-phase separator on offshore platforms should be adjusted. In the simulation study, oil samples were taken from field three-phase separator inlet at 90℃, 0. 55 MPa, 0. 45 MPa, 0. 35 MPa, 0. 2 MPa and 0. 1 MPa, respectively. The results showed that the lower operating pressure, the more gas could be separated from the oil samples. At about 0. 2 MPa, CO2 molar content ratio in separated gas could reach maximum value （51.4%）. Furthermore, the study on adding two-stage separator at downstream of three-phase separator for further CO2 removal showed that under the circumstance, the operating pressure of the two-stage separator decreased from 0. 1 MPa to 0. 03 MPa, CO2 removal ratio from oil samples taken from field three- phase separator outlet could increased from 47.5% to 60. 9%. At the same times, the content of useful constituents in the separated gas was also increased.