Study On The Key Technology Of CO₂ Pipeline Transportation Based On CCUS

With global warming,CO2 emission reduction has gradually become an important issue for governments of all countries,At present,CCUS(Carbon Capture,Utilization and Storage)technology uses pipelines to transport CO2 to crude oil fields for oil displacement,or to seal them up.This is an effective method to solve the greenhouse effect.The elbow pipe is an indispensable pipe in the process of CO2 transport in the pipeline,and is easily damaged by-corrosive fluids.According to the relevant literature research,the cause of erosion failure at the elbow was analyzed,and the main influencing factors for the erosion at the elbow of the supercritical CO2 pipeline were determined as the pipeline operation parameters and the elbow geometry parameters.The FLUENT flow field analysis software was used.Combined with COMSOL multiphysics coupling software,combined with experimental research,based on the process parameters of the 4 million tons/year CCUS project in northern Shaanxi,the erosion behavior of the supercritical CO2 pipe at the elbow was simulated,and the supercritical CO2 pipe was obtained.The erosion corrosion mechanism at the pipe is provided and corresponding corrosion protection recommendations are put forward.FLUENT flow field analysis software was used to simulate the erosive energy and the wall surface with the change of the inlet flow velocity,curvature radius and bending angle of the elbow,the change of the turbulent kinetic energy and the wall shear force of the elbow to the erosion at the elbow.The location where the shear force has the greatest effect on the bend.When CO2 solid hydrate is contained in the bend,the CO2 solid hydrate erosion of the bend is simulated under different inlet flow velocities,curvature radii,and bending angles,and the maximum erosion rate and maximum erosion at the bend are obtained.The location of the rate.Numerical simulations of the cavitation at the bends of supercritical CO2 pipelines with different inlet flow velocities and radii of curvature were carried out,and the position change rules of the cavities at the elbow were obtained as the inlet flow velocity and curvature radius changed.Using COMSOL multiphysics coupling software combined with experimental research,the corrosion rate of the supercritical CO2 transport pipeline containing large water content was simulated to obtain electrochemical corrosion under the condition of supercritical CO2 fluid flow in the elbow.The location of the maxinuim corrosion rate Through the above four simulation results,the location and main influencing factors of the easy erosion damage at the elbow of the supercritical CO2 pipeline were analyzed.When the water content is relatively small,the damage of the supercritical CO2 pipe bend is mainly erosion,which occurs on the outer side of the inner wall of the pipe.When the water content reaches a certain level,the elbow is mainly destroyed by electrochemical corrosion.,Occurs on the inside inner wall of the elbow.According to the numerical simulation combined with the experimental study,the curve curvature radius 1.5D,the bending angle 110°,the inlet flow rate 2m/s,and the controlled water content less than 21000ppmv are set to avoid CO2 solid hydrate generation and to reduce the supercritical CO2 transport.The best anti-corrosion scheme for erosion damage at pipe bends.