天然气长输管道压气站最大操作压力研究

Research on MOP for compressor station of long-distance pipeline

中国天然气长输管道系统站场的压力设计通常与线路管道一致,遵循GB 50251《输气管道工程设计规范》,规范规定了最大允许操作压力(MAOP)等于或小于设计压力(DP),但管道的最大操作压力(MOP)与MAOP之间的裕量,并未强制要求。多年来,国内长输管道系统一般在压气站压缩机出口MOP与DP之间留出0.15 MPa裕量,但裕量是否合理并未得到论证。通过研究国内外长输管道系统设计规范,找出限制MOP的依据主要是事故工况下瞬变压力的超压值应不大于MAOP的10%,利用SPS模拟分析事故工况,对DP为10 MPa的长输管道常规做法进行了验证。结合现场实际运行压力的波动情况,给出了合理确定MOP的建议,对保证长输管道系统的安全、经济运行具有重要意义。

In China,for the long-distance pipeline system,usually both the design pressure for compressor station and pipeline comply with GB 50251:Code for Design of Gas Transmission Pipeline Engineering,which specifies the Maximum Allowable Operating Pressure(MAOP)shall be equal to or less than the Design Pressure(DP).However,the margin between the Maximum Operating Pressure(MOP)and MAOP is not mandatory in this Code.For many years,domestic long-distance pipeline system generally leaves a margin of 0.15 MPa between the MOP(at compressor discharge line in compressor station)and design pressure.But whether this margin is appropriate has not been demonstrated.By studying the standards of long-distance pipeline systems at home and abroad,it is found that the basis for limiting MOP is that the overpressure value of transient pressure under accident conditions shall not be greater than 10%of MAOP.The conventional practice of long-distance pipeline with 10 MPa design pressure has been verified using SPS software to simulate and analyze accident conditions.Moreover,considering the actual operating pressure fluctuations on site,recommendation is given for determining optimal MOP,which is of great significance to ensure the safe and economic operation of the long-distance pipeline system.