Fracture Propagation and Arrest in High-Pressure Gas Transmission Pipeline by Ultra High Strength Line Pipes

Abstract

The fracture arrest of high pressure gas pipelines is one of the keen subjects for application of high strength line pipes. To examine the arrestability of high strength line pipes against crack propagation, several full scale fracture propagation tests have been conducted. The fracture propagation tests of X100 or X120 under high pressure revealed that the existing models of arrest energy prediction failed to predict the arrest energies. By careful investigations of the test results, it is found that the failure in prediction is mainly due to the uncertainty of crack velocity curve prediction. On the other hand, accuracy of predicted gas decompression curve is relatively high even in the case of high pressure condition. Experimentally, the arrest energies have been determined by full-scale fracture propagation tests with increasing toughness arrangement. Different from actual pipeline, extremely low toughness pipe has been employed in crack initiation pipe with intention of getting steady state propagation. However, arrestability of pipe might be underestimated in the increasing toughness arrangement test as the initial crack velocity increases. Together with recalibrated crack velocity curve, Sumitomo model (HLP method with Sumitomo’s crack velocity curve) predicts that even toughness arrangement, which is the case of real pipelines, could arrest the propagating shear fracture in high pressure gas pipelines by X100.

State-of-the-art review of fracture control technology for modern and vintage gas transmission pipelines

“…The results in References [59][60][61] showed that the modified fracture curve in Eq. (16) led to improved predictions of arrest toughness for high-strength pipeline grades X100 and X120 in comparison to the predictions by the original HLP model.…”

“…To improve the HLP model for application to high-strength pipeline grades X80 and X100, Makino et al [59][60][61] investigated the effect of pipe geometry on the prediction of arrest toughness. It was found that the accuracy of arrest toughness prediction by the HLP model depends on pipe diameter to wall thickness ratio D/t.…”

Investigation of the Effects of Pipe Wall Roughness and Pipe Diameter on the Decompression Wave Speed in Natural Gas Pipelines

“…Eqns. (5), (6) and (14) show that the direct effect factor () is related to the ratio of roughness to pipe diameter (f = ε/D) and pipe diameter (D). 8 .…”

“…A number of full-scale burst tests were conducted to investigate pipeline gas decompression since the 1970s [2][3][4][5][6][7][8]. However, full scale burst tests are prohibitively costly, except for major projects.…”

A study of the effects of friction, heat transfer, and stream impurities on the decompression behavior in CO2 pipelines

“…One such important factor which is receiving increasing attention 5,6 is the presence of impurities. [11][12][13][14] Based on shock tube experiments using diff erent surface roughness pipes, Botros et al 15 for example have recently shown that in the case of pressurized hydrocarbons, ignoring pipe friction may result in overestimating the decompression wave speed, with the eff ect becoming more signifi cant with increasing line pressure and reducing pipe diameter. 7,8 Th e impact of the latter on the decompression behavior of the CO 2 stream and the appropriate pipeline fracture toughness has been the subject of a number of studies.…”