Gas Displacement Analysis Of Long Distance Natural Gas Pipeline

The natural gas industry in China has developed rapidly in recent years. We have exploited some large oilfields such as Changqing, Qinghai and Xingjiang oil field. Shannxi-Beijing line, Changhu line and West-East natural gas transmission pipeline also put into production in succession. The construction of natural gas long-distance pipeline has a great investment and cost. To ensure the pipeline’s safety, it is necessary to use inert gas instead of natural gas. After finishing the construction, it also needs to do the displacing operation of natural gas.The displacing operation of natural gas is a quite dangerous work. In case of improper replacement or misoperation, it will be a major safety accident or caused huge property losses and people casualty. The only way of controlling the displacement process is to control the technological parameter. There are no specific studies in displacing operation process at present, nor the effect of technological parameter in displacement operation process of natural gas long-distance pipeline. There is a greater blindness in displacement operation. It could not predict the amount of nitrogen, the time of displacement, and the speed of gas propelling in pipeline. Thus it is unable to detect qualified for propelling a large amount of gas into pipeline. The constructors always wait for a long time on the spot but couldn’t do construct operations. After finishing the construction, since they couldn’t control the speed of displacement, there are a large amount of natural gas emissions. The above situation are happened frequently and it wasted manpower and material resources. This thesis analyzes the flowing style of natural gas in pipeline, to ensure the changing condition of technological parameter in displacement process. The thesis also studied the effect with parameter’s changing. By studying the parameter and some related theories, optimizing the displacement process.