Black Powder Deposition Characterization In Natural Gas Pipeline

One of the major challenges gas industries are facing is contaminants called Black Powder.It causes erosion,lowers performance of equipment,compromises gas quality and even leads to incidents by its nature and its entrainment or deposition.It is difficult but required to determine the severity of black powder contaminants inside pipeline,which is necessary to guide pigging and normal operations.This work aims to numerically investigate particle deposition mechanism in an air pipe by FLUENT code to study gas-solid flow.The major scopes are as follows:(1)Euler-Lagrangian approach is chosen to track solid phase in pipe gas flow by studying the theory of gas-solid two-phase flow in detail.(2)A 2D model is built to compare and select turbulence models.Reynolds Stress Model captures the anisotropic properties for the turbulence especially at wall adjacent area.The model coupled with turbulence model and discrete phase model is validated by a benchmark experiment.(3)A 3D model is established to investigate the black powder deposition mechanism in a horizontal circular pipe,which gives the relationship between the deposition velocity and the particle size.The deposition curve reaches a good agreement with experimental and empirical results.(4)An experimental setup and a 2D asymmetric model are built to predict particle flow free-flight length after injecting radially from the top of the horizontal pipe.The varying regime of particle free-flight length with the air velocity depends on the compensating of the re-entrainment and deposition effects as well as particle interactions.The results match the experimental data,which is valuable for engineering calculation and guides pigging operations.