Selection of venting method for long-distance natural gas pipeline

As required for the reconstruction or maintenance of long-distance gas pipeline during its operation, it is an important link to vent the main pipeline for reconstruction, maintenance and repair during its service life. Through the comparison of the 3 depressurization methods of gas pipeline home and abroad by venting, as well as the verification by the practice of centralized hot processing of Lines 2 and 3 of West-to-East Gas Pipeline Project, a venting method through continuous depressurization of multiple pipeline sections with a compressor specialized for gas pipeline was put forward. As shown in the practice, the stepwise depressurization method, compared with the traditional direct venting method and the venting method by depressurization with an external compressor, can greatly reduce the gas loss, the venting time and the effect of venting noise to surrounding production and economic activities. Additionally, the method, characterized by high-efficiency, economy, safety and environment protection, is particularly applicable to the long-distance gas pipeline with continuous and central maintenance required for multiple sections.