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Pressurized pipelines are the most reliable and cost-effective option for the long-distance transportation of CO2 from an emitter to an onshore storage site. Propagating or unstable factures are considered catastrophic pipeline failures, resulting in a massive escape of inventory within a short period of time. The decompression curve for CO2 exhibits a large drop in decompression wave speed at the phase transition pressure, leading to a higher driving force for crack propagation. The study of fracture control plans is very important for assessing the possibility of fracture propagation and preventing unstable fracturing along CO2 pipelines. Three full-bore rupture (FBR) experiments were performed using an industrial-scale (258 m long, 233 mm inner diameter) CO2 pipeline with initial CO2 states of gaseous, dense and supercritical phases, respectively. The relation between the decompression velocity and the pipeline fracture propagation velocity was analyzed during the process of buried CO2 pipeline release. A fracture propagation criterion was established for the buried CO2 pipeline. For the gaseous CO2 leakage, the pressure plateau corresponding to the decompression wave velocity only appeared near the closed end of the pipeline. For the dense CO2 leakage, the pressure plateau corresponding to the decompression wave velocity was observed near the saturation pressure after rapid decompression. For the supercritical CO2 leakage, the pressure plateau corresponding to the decompression wave velocity was observed in the stage when the supercritical CO2 transformed into the two phases of gas and liquid. Compared with the gaseous and dense CO2, for the supercritical CO2, the initial decompression wave velocity was the smallest, and the requirement of the pipeline safety factor was the highest. 相似文献
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Ezra S Feinstein S Yakirevich A Adar E Bilkis I 《Journal of contaminant hydrology》2006,86(3-4):195-214
This study investigates the mechanisms controlling the distribution of 3-bromo-2,2-bis(bromomethyl)propanol (TBNPA) and 2,2-bis(bromomethyl)propan-1,3-diol (DBNPG) in a fractured chalk aquitard. An extensive monitoring program showed a systematic decrease in the TBNPA/DBNPG ratio with distance from the contamination source. Sorption of TBNPA on the white and/or gray chalks comprising the aquitard is approximately one order of magnitude greater than that of DBNPG. This results in more efficient removal of TBNPA from the fracture into the porous matrix and thus decreases the TBNPA/DBNPG ratio in the fracture water. Mathematical modeling of solute transport in the fracture domain illustrates the probable importance of sorption in controlling the spatial variation in TBNPA and DBNPG ratio. 相似文献
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The coal and gas outburst results from plenty of factors, while vibration is the most important factor among them. Therefore, the influences of vibration acting on gas desorption and coal structure had been conducted. And the mechanism of coal and gas outburst induced by vibration was illustrated through examples. The results showed that the gas desorption accelerates under the action of vibration, and then the gas gradient increases. Meanwhile, vibration would increase and expand fractures in the internal coal body, which aggravates the risk of coal and gas outburst greatly. In conclusion, vibration is a more important factor attributable to coal and gas outburst compared with other coal mining method, mining technology and construction method. 相似文献