CO_(2)环境中丁腈橡胶适用性研究

Study on the Applicability of Nitrile Butadiene Rubber in CO_(2) Environment

在碳捕集、利用、封存与提高原油采收率(CCUS-EOR)背景下,注入井橡胶封隔器失效问题严重。对丁腈橡胶(NBR)在CCUS-EOR体系CO_(2)环境中的性能和适用性进行研究,规定了NBR的适用范围,可为CO_(2)体系橡胶密封件的选择和使用提供参考。依据GB/T 34903.1-2017开展NBR在CO_(2)环境中的腐蚀老化试验,在CO_(2)环境腐蚀老化试验前后,观察试样的外观变化、记录质量变化,进行硬度测试、拉伸强度试验、断裂伸长率测试、维卡软化温度测试;对腐蚀试验前的试样和100℃30 MPa气相条件下试验后的试样开展了红外测试。结果表明:经过CO_(2)腐蚀试验后,NBR材料的质量增加,硬度降低,抗拉强度降低,维卡转变温度降低。温度和压力对CO_(2)环境试验后NBR材料性能的影响规律如下:随着压力增大,NBR的邵氏硬度减小,抗拉强度减小,密度增大;随着温度升高,NBR的邵氏硬度增大,抗拉强度减小,密度减小。CO_(2)试验后NBR的官能团和化学键变化不大,未发生老化。NBR在高温高压的CO_(2)环境中存在腐蚀和开裂风险,归因于高压环境中NBR发生了快速气体减压(RGD)损伤,NBR在中低温低压的CO_(2)环境中适用。

In the CO_(2) capture, utilization, storage and enhanced oil recovery(CCUS-EOR) environment, rubber packer failure in injection wells is a serious problem. The performance and applicability of nitrile rubber(NBR) in CO_(2) environments within CCUS-EOR systems were investigated, and the suitability range of NBR was established to provide guidance on the selection and application of rubber seals for CO_(2) systems. Corrosion and aging tests of NBR in CO_(2) environments were conducted following the standard GB/T 34903.1-2017. Before and after CO_(2) environment corrosion aging test, changes in sample appearance were observed, and mass variation was recorded. Additionally, hardness, tensile strength, elongation at break and Vicat softening temperature tests were performed. Infrared analysis was conducted on samples both before corrosion test and after exposure to gaseous conditions at 100 ℃ and 30 MPa. Results showed that after CO_(2) corrosion testing, the mass of NBR increased, hardness decreased, tensile strength decreased, and Vicat transition temperature declined. The influence of temperature and pressure on the properties of NBR materials after CO_(2) environmental testing was as follows: as pressure increased, the Shore hardness and tensile strength of NBR decreased, while density increased;as temperature increased, Shore hardness increased, tensile strength decreased, and density decreased. The functional groups and chemical bonds of NBR exhibited minimal changes after the CO_(2) tests, indicating no significant aging. However, NBR was found to face risks of corrosion and cracking in high-temperature and high-pressure CO_(2) environments, attributed to rapid gas decompression(RGD) damage of NBR under high pressure. NBR was deemed suitable for use in low-to-moderate temperature and low-pressure CO_(2) environments.