光纤监测埋地二氧化碳管道泄漏实验研究

【摘要】 以DN250、长260 m的工业规模管道作为容器，开展DN100埋地超临界二氧化碳管道在不同口径、不同方向的泄漏实验，通过在泄漏口周向设置热电偶及感温光纤、在管道顶部轴向设置感温光纤，分析感温光纤监测超临界二氧化碳泄漏的可靠性及有效性。结果表明，超临界二氧化碳泄漏时，在泄漏口附近的土壤会降温至-78℃生成干冰区。泄漏口径为3 mm时，干冰区会覆盖泄漏口所在的管道截面圆周方向。泄漏口径为1 mm时，干冰区仅处于泄漏侧。与热电偶与土壤的热传导机制相比，因土壤与光纤硅芯管热传导及硅芯管与光纤芯之间空气层热对流，导致光纤测温时存在延迟或温降数值偏小等情况，但作为泄漏监测技术仍具有较好可靠性。当光纤布置在干冰生成区域的土壤内时，能够监测到超临界二氧化碳泄漏导致的显著温降，监测具有较好有效性。当光纤布置在干冰生成区域外部土壤时，监测到的温降幅度较小。更多还原

【Abstract】 Using a DN250 industrial-scale pipeline with a length of 260 meters as a container, leakage experiments on the DN100 buried supercritical carbon dioxide pipeline in different diameters and directions were carried out. By arranging thermocouples and temperature-sensitive optical fibers around the leak port and axially arranging temperature-sensitive optical fibers at the top of the pipeline, the reliability and effectiveness of the temperature-sensitive optical fibers in monitoring supercritical carbon dioxide leakage were analyzed. The results show that when supercritical carbon dioxide leaks, the soil near the leak will cool to-78 ℃ to form a dry ice area. When the leak diameter is 3 mm, the dry ice area will cover the circumferential direction of the pipe section where the leak port is located. When the leak diameter is 1 mm, the dry ice area is only on the leak side. Compared with the heat conduction mechanism between the thermocouple and soil, due to the heat conduction between the soil and the optical fiber silicon core tube and the air layer thermal convection between the silicon core tube and the optical fiber core, there are delays or small temperature drop values in optical fiber temperature measurement. However, it still has good reliability as a leak monitoring technology. When the optical fiber is arranged in the soil in the dry ice generation area, it can detect significant temperature drop caused by supercritical carbon dioxide leakage, and the monitoring is effective. When optical fibers were placed in the soil outside the dry ice generation area, the temperature drop detected was small.更多还原