Study On Design Method Of Ventilation Tube For Natural Gas Transmission

To ensure the safety of gas production and use, gas vent pipeline system plays an important role in security facilities for natural gas pipelines and gathering station in relieving pressure and reducing the accident consequences. At present, the gas station and pipeline vent pipe design method of China refer to API RP521vent pipe design method, but Chinese basic situation have a big differences with the American, nor China give an explanation of it. The paper consider two factors:natural gas pipeline vent pipe design investment and vent risk, and it also put forward the design method of the vent pipeline. The method has certain reference significance in perfecting China vent pipe design standard in the furture.The mainly work of the paper is the following aspects:(1) The research situation of the vent pipe design method at home and abroad is investigated, and the influence factors of the vent pipe design are analyzed. Both provide a theoretical basis for the paper.(2) Based on the theory of fluid mechanics,the paper carry out hydraulic analysis on the vent pipe, and get the vent gas flow hydraulic characteristics in the vent pipe.Moreover, the emptying volume and emptying time of the gas station and pipeline emptying system has been determined, which can provide a scientific basis for vent pipe design theoretically.(3) Through the considerations the risk of the vent pipe vents the gas into the economic, the paper unifies the risk of the vent pipe and cost-benefit analysis in together and establish calculation model for gas pipeline vent pipe design, based on the risk of vent pipe and cost-benefit. Then the optimal height design formula for different regional level has been solved.Compared with the existing vent pipe design method, the analysis shows that the vent pipe height is lower and less investment according to this research method.(4) For the sour natural gas pipeline, the design method of the vent pipe is the same as the purifying gas pipe vent pipe. First, the way to vent for sour natural gas pipeline must be judged through comparing two empty ways of risk analysis, the results showed that sour natural gas pipeline is suitable to use flare stack to vent gas.Then, by determining the related coefficient of sour natural gas,the optimal height design formula of sour natural gas pipeline has been get for different regional level.