Supercritical CO2 (sc‐CO2) was widely used in CO2 flooding projects to enhance the recovery efficiency recently owing to its amazing dissolving capability and permeability. Fiber reinforced pipe (FRP) has exceptional properties that may be widely used in the petrochemical sector for transportation of corrosive fluid in CO2 flooding projects. In this research, a system was designed to simulate the transport behavior of fluids containing CO2 which can reaches the supercritical state by the adjustment of pressure and temperature. The fluid penetrates into the resin interior through the pores and gathers in the cavities at 65°C and 8 MPa. When the temperature and pressure are below the critical point, the CO2 volume expands dramatically, causing inter‐layered micro‐crack. When the environmental conditions repeatedly change above and below the critical point, these cracks will continue to propagate along the fiber arrangement direction, resulting in the fracture progressively grow into the delamination. At the same time, the fluid corrodes the resin in some areas of the surface, generating pitting and a 0.66% loss in resin content. The composition of elements and groups altered after corrosion revealed that a chemical interaction occurred between fluid and epoxy resin. Finally, due to physical and chemical processes produced by penetration, expansion, and dissolution, the stiffness of FRP fell by 3.53% during treatment.Highlights
In the present work, a reactor coated with polytetrafluoroethylene (PTFE) was built to model the corrosion of FRP in delivery fluids containing sc‐CO2. The corrosion mechanism was shown as a combination action by chemical react and physical behavior comprising penetration, expansion and dissolution.
The physical corrosion mechanism of fluid containing sc‐CO2 was investigated. The fluid containing sc‐CO2 penetrated the FRP via pores and accumulated in cavities. The quick expansion of sc‐CO2 causes delamination while the ambient circumstances remain below the critical threshold. The pitting and resin loss can be linked to the epoxy resin solution in supercritical CO2.
The chemical process, known as hydrolysis, took place on the interior surface of epoxy resin and a fluid containing supercritical CO2. This finally resulted in molecular structural modification.
