| This paper selected about868.821km pipeline from Yulin to Qihe station to launch the research on basic theory, gas flow formula selection, gas transmission efficiency and pigging Based on analysis and solution of Yu-Ji throttle problems which stem from Hydrate blockage and the existence of free water, corrosion products, coagulation effusion in pipeline.Based on the operation parameters of Yu-Ji gas transportation pipeline, the Peng-Pobinson Equation was selected during calculation based on the Aspen Hysys software. Furthermore, it was also achieved that the establishment of a hydraulic model for one-dimentional steady-state non-isothermal flow, as well as its solution procedure. According to the field data of Yu-Ji gas transportation pipeline running at the early stage, under the assumption that the transmission efficiency of gas was0.95, combining with the TGNET software, this paper got flow calculation formula applying for Yu-Ji pipeline and it was Colebrook formula.During the research of gas transmission efficiency, a calculation model was explored as well as the solving steps combining with the actual situation of Yu-Ji pipeline. According to the flow calculation formula applying for Yu-Ji pipeline, this paper using operation data (March to May,2011) calculated theoretical gas flow under that condition of yu-ji pipeline to get the efficiency of gas transmission pipeline. In the range of project allowed, if the gas transmission rate was less than90%, it suggested pigging for pipeline. This paper got the relationship of Yu-Ji pipeline between gas transmission efficiency, gas transmission and pressure drop. It was based on the pipeline pressure drop whether the pipeline need for pigging. This paper combining with the reality analyzed the impact of temperament components, pipe diameter and wall roughness on the trunk gas efficiency and proposed to strengthen the natural gas pretreatment, add the corresponding drag reduction agent, reasonably select filter and so on to improve the gas efficiency.In the aspect of pigging, this paper used the actually operational data of the pipeline to check the environmental parameters and input data of Yu-Ji pipeline model basing on OLGA software. This paper analyzed the operation of pipeline before pig and predicted the pig velocity, pipeline inlet pressure, pipeline outlet pressure and so on during pigging process. The Yu-Ji pipeline pigging operation procedures and pigging operation process was established based on the standard SY/T6383-1999——the regulation of pigging for transmission natural gas pipeline. This paper verified the feasibility of the proposed scheme according to the situation after the pipeline pigging.Through this research, a further theory research was recommended for unusual circumstances in pigging. Advice was proposed for long-distance trunk pipeline pigging process as follows:①pigging operation control and monitoring,②the installation of separators in route pipelines,③the maintenance of station equipment. |
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