机械复合管具备良好的抗腐蚀性能和经济性能,具有广阔的应用前景。目前,在集输系统中,机械复合管选用条件主要考虑为运行温度、压力和介质特性对内衬抗高温氯离子开裂风险的影响。为保证机械复合管应用效果可靠,现行制造规范进行了基管-内衬紧密度规定。实际投产后,管道运行状态复杂,但现行设计规范尚未量化保证机械复合管紧密度的具体指标。为进一步保证高温、高压集输系统合理使用机械复合管,有必要深入探讨在运机械复合管适用工况。基于机械复合管制造阶段紧密度测试方法和指标,结合钢制管道强度理论和自然锚固规律,推导了制造和运行情况下内衬不锈钢的应力计算式,探索性地提出了机械复合管紧密度校核方法,并结合算例进行了探讨与分析。结果表明,机械复合管在制造阶段的坍塌试验产生的内衬轴向压应力较高,超过屈服极限,导致试验后机械复合管紧密度大幅降低;为保证机械复合管紧密度,运行状态下内衬轴向压应力不应超过坍塌试验工况;操作-安装温度差和弹性敷设是影响机械复合管紧密度的主要因素。研究成果为油气集输系统机械复合管的精细化设计提供了一定的参考。

Mechanical composite pipe with good corrosion resistance and economic performance has a broad application prospect.At present, the selection of composite pipe condition in gathering system shall consider the impact of operating temperature, pressure and medium on the cracking performance of lining chloride of high temperature resistance.In order to ensure the reliability of mechanical composite pipe, the basic pipe-lined tightness requirement is specified in the existing manufacturing specifications. During the real production, the pipeline running state is complex, but the current design specifications have not yet quantified to ensure the mechanical composite pipe tightness.To further ensure that the mechanical composite pipe is properly used in gathering system with high temperature and high pressure, it is necessary to further explore the mechanical composite pipe in the applicable conditions. Based on the theory and index of compactness of mechanical composite pipe at manufacturing stage, combined with the theory of steel pipe strength and natural anchorage law, the stress calculation formula of stainless steel lining under manufacturing and operation is deduced, and the tightness checking method is proposed. The results show that the axial compressive stress of the lining of the mechanical composite pipe is higher than the yield limit, which leads to the decrease of the tightness after the test. The axial compressive stress of the lining should not exceed the operating condition of collapse test; temperature difference between operation and installation and elastic laying are the main factors limiting the use of mechanical composite pipe. The results of this paper provide reference for the fine design of mechanical composite pipe for gathering system.