Abstract:

According to the requirements of domestic and foreign piping specifications, petrochemical piping shall be pressure tested after installation. Pressure test includes hydraulic test, pneumatic test, hydraulic and pneumatic combined test and other methods. Generally, hydraulic test is preferred. However, due to the differences of medium characteristics, working conditions, material specifications, connection forms and layout of petrochemical pipelines, as well as the limitations of conditions on-site, it is difficult to carry out hydraulic test for some pipelines. As the use of pneumatic test has great dangerous, and the relevant standards and specifications also have corresponding restrictions on the pneumatic test, so the pneumatic test of piping system may be impracticable and limited. Therefore, when formulating the piping pressure test scheme, we should consider not only the quality of the test, the safety of the piping system and the cost of the test, but also the feasibility of the pressure test. In the pressure calculation of pressure test, the design temperature, piping material, pressure bearing capacity of piping components in the piping system and other factors shall be considered to avoid the damage of piping components due to the pressure test. The selection of test temperature for pressure test shall mainly consider avoiding low-temperature brittle failure of piping.

Key words: piping, pressure test, hydraulic pressure test, pneumatic pressure test

摘要：

根据国内外现行管道规范的要求，石油化工管道在安装完成后一般要进行压力试验。压力试验有液压试验、气压试验、液压+气压结合试验等多种方式，一般情况下优先选用液压试验。但由于石油化工管道的介质特性、工况条件、材质规格、连接形式及布置方式千差万别，同时也受现场条件限制，部分管道进行液压试验存在一定困难，除此之外，采用气压试验危险性较大，相关标准规范对于气压试验也有相应的限制条件，故管道系统采用气压试验时可能存在不可实施性和局限性。因此，在制定管道压力试验方案时，既要考虑试验质量、管系安全及试验成本，也要考虑压力试验的可实施性。压力试验中的压力计算需同时考虑管道设计温度、管材属性、管道元件的承压能力等因素，避免因压力试验致使管道元件损伤。压力试验温度选择时应注意避免造成管道低温脆性破坏。

关键词: 管道, 压力试验, 液压试验, 气压试验