Research On Safe Pigging Scheme For Pipelines In China-Myanmar Natural Gas

China-Burma natural gas pipeline through the area of high mountain,steep terrain,the pipeline in the construction process often built by the terrain,which formed a lot of large gap pipe.For safety reasons,the China-Burma natural gas pipeline has not been implemented since the commissioning of the operation,because in the downhill pipeline downhill,pig and liquid bombs will be under gravity and pressure to accelerate the downward flow,when the arrival at the bottom of the pipe,due to changes in the direction of flow,the pig and the liquid bomb will form an intermittent impact stress on the bottom of the pipe and accompanied by strong vibration,strong load on its great harm,lightly caused serious pipeline structure deformation,and then lead to structural instability,destruction,a serious threat to the safe operation of natural gas pipeline.In view of this problem,this paper takes the two typical large drop pipes between Longling gas station and Midu gas station as the research object,and uses the combination of theory and numerical simulation to study the effect of the large clearance pipeline.The specific research contents are as follows:(1)In order to obtain the basic parameters of the pig,the liquid bomb and the pipeline,the simulation model of the multiphase flow is established based on the OLGA software.The simulation results are compared with the field data to verify the accuracy of the model.The range of the key parameters involved in the calculation of the purge load is obtained,which includes the following:the size and distribution of the fluid volume,the operation of the pig and the liquid bomb speed,liquid holding capacity.(2)The theoretical analysis of the force of the large drop pipe is a prerequisite for load loading.According to the characteristics of the buried state of the large drop pipe,and the calculation model of the tanker,the impact of the liquid bomb,the pressure of the pipeline,the temperature and the soil load is established,criteria for failure judgment of large drop pipe.(3)According to the OLGA software simulation of the volume distribution of the premise of the premise,for the purging process is included in the case of liquid bombs,the large drop pipe is divided into non-fluid section and the liquid section,using ABAQUS,CAESARII two finite element software.Under the action of the pipeline stress,strain size,and security checks,screening safe cleaning conditions.(4)Aiming at the safety problem of the China-Burma natural gas large gap pipeline in the process of purging the pipeline,this paper puts forward the measures to reduce the risk of the clearance of the large clean up program for the China-Burma natural gas large gap in the pipeline under the conditions of safe operation to provide some technical support.This study can not only provide scientific suggestions for the safe operation of China-Burrma pipeline,but also provide ideas and reference for other large-scale mountainous pipeline.