الفهرس | Only 14 pages are availabe for public view |
Abstract Corrosion management is a key concern in all oil and gas assets due to the nature of fluids produced and injected throughout their life cycle. This is applicable for all asset types, regardless of their age and the level of corrosive agents’ present in the flow stream, such as CO2, H2S, water or chlorides. Accordingly, application of effective corrosion management concerning different types of mitigations like application of coating, chemical treatment and material selection are important elements. The main object of this work is to synthesize a highly water-repellent film (superhydrophobic coated film) to be used for corrosion protection of carbon steel pipelines. To achieve this purpose, polystyrene, styrene / vinyl acetate copolymer using emulsion polymerization technique, SiO2 nanoparticles and nanocomposites were prepared and evaluated as corrosion inhibitors of carbon steel. The prepared polymers and their composites were characterized using a variety of techniques, namely: (i) FT-IR, (ii) 1H-NMR spectroscopy, (iii) Gel permeation chromatography (GPC) (for molecular weight determination), (iv) Thermogravimetric analysis (TGA), (v) differential scanning calorimetry (DSC), (vi) dynamic light scattering (DLS), (vii) transmission electron microscopy (TEM), (viii) energy dispersive X-ray spectroscopy (EDX), (ix) X-ray diffraction (XRD), (x) scanning electron microscopy (SEM), (xi) contact angle measurements, (xii) atomic force microscopy (AFM). The prepared polymers and their composites were evaluated as superhydrophobic coating films to be used as corrosion resistant materials for carbon steel. Summary ii Generally, the results obtained from the present investigation reveal the following:- 1) Effect of emulsifier concentration on emulsion stability Particle size growing, polydispersion index (PDI), and ζ- potential, using four emulsifiers blends (EB) concentrations as 1, 0.75, 0.5 and 0.25 wt., % showed that the optimum concentration of EB (Emulsifier Blend), which gives the highest emulsion stability and the lowest P(St-VAc) particle size was 0.50 wt., % at monomer ratio of 1:1 for styrene:vinyl acetate monomers, respectively 2) Effect of styrene:vinyl acetate (St:VAc) monomer molar ratio on emulsion stability Particle size, film sheet morphology, the resultant molecular weights and the contact angle revealed that the best initial monomer ratio (St:VAc) was 75:25 (E3); that produce a copolymer with smallest droplet size (89.01 nm), highest morphology properties (adhesion and transparency on glass surface), and highest molecular weight (MW=13.75 x 104). 3) Corrosion inhibition test a) Evaluation of the coated surface as corrosion resistance material It was evident that the corrosion rate decreased from 1.5 to 0.3 mpy as the concentration of the coating solution increased from 100 to 300 ppm, respectively. This may be attributed to the formation of compacted inhibiting superhydrophobic film on metal surface. b) Effect of temperature and activation energy (Ea) on the corrosion rate Increasing the temperature leads to activate the coupons surface; thereby, the corrosion rate increases. Higher activation energy (Ea) indicates to higher resistance of the coated metal to corrosion. Summary iii c) Effect of contact angle on the corrosion performance It is obvious that the tendency of the coated film to roll-off the water droplets from the coated film has a direct impact on the corrosion resistance efficiency of the coated coupons. As the water contact angles of the coated coupons increased from 65.01° to 163.77°, the inhibition efficiency of the coated film by PSt-polymer and Z- composite increased from 90.66 % to 98.1 %. |