Study On Splitting Characteristics Of Gas-liquid Two-phase Flowing From Single Pipe To Parallel Separators

In the petrochemical industry,when the manifold is used to split the gas-liquid two-phase flow into parallel separators,mal-distribution usually occurs.Severe mal-distribution could make some separators operate in poor efficiency.Therefore,it is of importance to carry out research on gas-liquid splitting characteristics in parallel separators.In this paper,the gas-liquid splitting characteristics from single pipe to two separators are studied with experiments,and the gas-liquid splitting model for upward-inclined parallel pipelines is established.The main research contents and conclusions are as follows:The impacting T junction is used as the basic splitter,and gas-liquid splitting pipeline of two geometry are designed,single horizontal pipe-dual horizontal pipe and horizontal pipe-dual riser.For the single horizontal pipe-dual horizontal pipe,the single-phase flow rates splitting into the two separators are equal and there is no mal-distribution of gas and liquid.When the liquid slug flows across the T junction,its speed decreases and the liquid slug splits into two liquid slugs of approximately equal length,which flow into the two branches respectively.For single horizontal pipe-dual riser,the splittig characteristics of the gas-liquid two-phase flow are related to the gas-liquid flow state in the two risers.Three states are observed,Slug/Churn-Slug/Churn(SC-SC),Churn-Churn(C-C)and Churn-Slug/Churn(C-SC).SC-SC is an asymmetrical flow,generally occurring when the gas-liquid flow rate is low.C-C is a symmetrical flow,and the gas and liquid generally split equally.C-SC is an asymmetric flow,which is between the state SC-SC and the state C-C,and the state is not stable and easy to convert to C-C.Based on the principle of minimum potential energy,the gas-liquid splitting model for upward-inclined parallel pipelines is established.The influences of the inner diameter of the pipeline,the system pressure and the inclination of the pipeline on the range of the asymmetric flow region are analyzed.The practicability of the model is verified by the experimental data and previous data of other researchers.The experiments under the condition of asymmetry of pipelines are also carried out.The results show that the gas-liquid two phases split unevenly and the liquid phase tends to split more evenly than the gas phase.