In order to transport dense-phase CO2 captured from power and industrial emission sources in the Carbon Capture and Storage (CCS) chain, pressurised steel pipelines are considered the most practical tool. However, concerns have been raised that low temperatures induced by the expansion of dense-phase CO2, for example following an accidental puncture or during emergency depressurization, may result in a propagating brittle fracture in the pipeline steels.ududThe present study describes the development of a hybrid fluid-structure model for simulating dynamic brittle fracture in buried pressurised CO2 pipelines. To simulate the state of the flow in the rupturing pipeline, a compressible one-dimensional Computational Fluid Dynamics (CFD) model is applied, where the pertinent fluid properties are determined using a thermodynamic model. In terms of the fracture model, an extended Finite Element Method (XFEM) is used to model the dynamic brittle fracture behaviour of the pipeline steel.ududUsing the coupled fluid-structure model, a study is performed to evaluate the risk of brittle fracture propagation in a (real-scale) 1.22m diameter API X70 steel pipeline, containing CO2 at 0°C and 11MPa. The simulated results are found to be in good agreement with the predictions obtained using a semi-empirical model accounting for the pipeline fracture toughness. From the results obtained it is observed that a propagating fracture is limited to a short distance. As such, for the conditions tested, there is no risk of brittle fracture propagation for API X70 pipeline steel transporting dense-phase CO2.
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机译:为了在碳捕集与封存(CCS)链中传输从电力和工业排放源中捕获的密相CO2,加压钢管被认为是最实用的工具。但是,人们担心,由密相CO2的膨胀引起的低温(例如在意外刺穿后或紧急降压过程中)可能导致管道钢中传播性脆性断裂。 ud ud混合流体结构模型的开发,用于模拟地下加压CO2管道中的动态脆性断裂。为了模拟破裂管道中的流动状态,应用了可压缩的一维计算流体动力学(CFD)模型,其中使用热力学模型确定了相关的流体属性。就断裂模型而言,使用扩展有限元方法(XFEM)对管线钢的动态脆性断裂行为进行建模。 ud ud使用耦合的流固模型,进行了评估脆性风险的研究。在直径为1.22m的API X70钢管道中(实际尺寸)在0°C和11MPa时含有CO2的情况下,裂缝扩展。结果表明,模拟结果与使用半经验模型得出的预测管道断裂韧性的预测结果非常吻合。从获得的结果可以看出,正在传播的裂缝被限制在短距离内。这样,对于所测试的条件,API X70管线钢输送密相CO2时没有脆性裂纹扩展的风险。
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