Limitations of GFRP wrapping revealed by Erosion–Corrosion and sulfide stress cracking in Sour-Gas Environments: Experimental and numerical simulation perspectives

This study examines the failure of a U-shaped heat exchanger outlet pipe internally wrapped with eight layers of glass fiber reinforced polymer (GFRP), which leaked after only four months of operation at 120–140 °C. A multi-approach investigation was conducted through visual, metallurgical, mechanical, and computational fluid dynamics (CFD) analyses. Visual inspection identified deposit buildup that caused turbulent multiphase flow and wall thinning to below 1 mm, producing high hoop stress and rupture. Metallurgical analysis revealed intergranular corrosion and cracking. Based on Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) observation results from three observation locations, the failure location and Heat Affected Zone (HAZ) have the highest sulfur content, approximately 1.6 at% and 2.18 at%. This data reveals that the pipe absorbed H2S gas, and the presence of sulfur allows for sulfide stress corrosion cracking (SSCC). Additionally, SEM-EDX results from all three locations also showed the presence of chlorine (Cl), which can lead to pitting corrosion. Fourier-Transform Infrared spectroscopy (FTIR) spectra showed acidic compounds such as amine salts, carboxylic acids, and anhydrides, indicating corrosion–deposit interaction. Mechanical tests demonstrated hardness in the weld area of 212–245 HV compared to < 180 HV in the base metal, indicating higher brittleness. Tensile strength reached 444.2 MPa in the HAZ, 437.2 MPa in the weld, and 407.3 MPa in the base metal. Compression strength decreased from 294.15 MPa (base metal) to 268.81 MPa (HAZ). Flexural resistance declined by 30 % near the leakage (2.55 kN vs. 8.49 kN for new GFRP). Impact energy absorption also dropped from 79 J (base metal) to 55 J (HAZ), marking a ductile-to-brittle transition. CFD confirmed turbulent flow and high wall shear at the sockolet, intensifying erosion–corrosion synergy. These results demonstrate the combined effects of SSCC, deposit-induced erosion, and turbulent flow as primary causes of failure. The findings highlight the limitations of GFRP wrapping in sour-gas environments and point toward future applications of high temperature adhesive, flow-conditioning design, and CFD-based predictive maintenance to extend service life in pipelines and refinery heat exchangers.