THE APPLICATION OF STRAIN-BASED DESIGN TO PIPELINES AND THE REQUIREMENTS ON PIPE MATERIALS

ABSTRACT With the sharply rising demand of oil and gas, the pipeline industry has been experiencing a rapid development in recent years. Pipelines in the areas of ground movement from slope instability, seismic sideslip, loess collapse, mining subsidence, frost heave and thaw settlement in discontinuous permafrost can experience displacement-controlled plastic strain. The current paper describes the application of strain-based design of pipelines and introduces relevant codes, standards, and criteria of other countries. Some major issues in strain-based design such as geologic conditions, strain limits, mechanical performance, etc., are mentioned. The prospect of strain-based design of pipelines is discussed with reference to the geologic conditions and the state of the pipeline industry. Finally the requirements on parameters of line pipe materials, including yield stress, yield and tensile strength ratio, stress ratio, weld mismatch, anisotropy etc., and their influence on strain-based design are discussed

Significant Improvement of Anticorrosion Properties of Zinc-Containing Coating Using Sodium Polystyrene Sulfonate Noncovalent Modified Graphene Dispersions

High-quality graphene zinc-containing anticorrosive coatings are highly and urgently desirable for effective, economical anticorrosion of metals and alloys in industrial products. The realization of such coatings is, however, hindered by the dispersibility and compatibility of the graphene in them. This work reports a novel direct modification of graphene using sodium polystyrene sulfonate (PSS) without reduction of graphene oxide, leading to homogeneous dispersion of graphene in water. The agglomeration of graphene is prevented thanks to the formation of π−π interaction between PSS and graphene sheets. Such graphene dispersion can effectively improve the anticorrosion performance of the zinc-containing epoxy coatings. With the addition of graphene modified by PSS into the 20% zinc-containing epoxy coating (graphene is 0.05% by weight of the coating), its anticorrosion properties revealed by both electrochemical characterization and the neutral salt spray tolerance analysis are rather close to those of 60% zinc-containing epoxy coating. These results demonstrate that direct PSS modification is an effective method for graphene dispersion and thus open a pathway to achieve graphene zinc-containing anticorrosive coatings with high performance

Enhanced Anti-Corrosion Performances of Epoxy Resin Using the Addition of Sodium Dodecylbenzene Sulfonate-Modified Graphene

The improvement of anti-corrosive property of epoxy resin is significant for the development of coatings to avoid metal corrosion and thus to reduce the economic loss in many industries. The superior properties of graphene, a two-dimensional material, make it possibly suitable to fulfill this task. However, this is hindered by the easy agglomeration of graphene layers in solvents. In the present work, we report the modification and stabilization of graphene in water using sodium dodecylbenzene sulfonate (SDBS) and the enhancement of the anti-corrosive properties of epoxy resin by mixing such SDBS-modified graphene layers. The influence of the dosage of SDBS on the modification effect of graphene was studied in detail and an optimized dosage, i.e., 50 mg SDBS for 10 mg graphene, was obtained. The SDBS modification could effectively reduce graphene thickness, and the minimum thickness of the modified graphene was 3.50 nm. The modified graphene had increased layer spacing, and the maximum layer spacing was 0.426 nm. When the modified graphene was added into the epoxy resin, the electrochemical impedance modulus value evidently increased compared to pure epoxy resin and those incorporated by pure graphene, indicating that the anti-corrosion performance was significantly improved. These results clarified that SDBS could effectively modify graphene and the SDBS-modified graphene could subsequently largely improve the anti-corrosive property of epoxy resin, which is of significance for the anti-corrosive coatings