增强热塑性复合管在酸性环境下的耐蚀性能

增强塑料复合管被认为是解决酸性气田地面集输管道腐蚀问题的有效手段之一，内衬层、增强层与金属连接接头的耐蚀性能是增强热塑性复合管整体防腐性能的决定性因素。为此，采用高温高压釜、材料试验机、维卡软化温度测定仪和红外光谱仪等设备，测试了一种玻纤增强热塑性复合管内衬层、增强层与金属连接接头在模拟酸性环境（总压为10 MPa，H₂S分压为0.6 MPa，CO₂分压为0.25 MPa，温度为80 ℃）下的耐腐蚀性能。结果表明：经高温高压环境浸泡试验后，内衬层材料PVDF及玻纤增强树脂层均发生了溶胀增重（增重率小于1％），PVDF拉伸强度下降了3.15％，维卡软化温度下降了3.4 ℃，PVDF结构成分未发生明显变化，玻纤树脂增强层拉伸强度下降了13.11％，PVDF和玻纤增强树脂适合作为酸性环境下应用的复合管机构材料；3种金属接头材质在模拟环境中腐蚀速率高低次序为：L360NS＞316L＞Alloy825，镍基合金825和316L属于轻度腐蚀，适合作为连接接头材料

Corrosion resistance of reinforced thermoplastic pipes in a sour environment

The use of reinforced thermoplastic pipe (RTP) is considered to be one of the most effective solutions to corrosion problems of surface gathering and transmission pipelines in sour gas fields. The corrosion resistance of the lining layers, reinforced structural layers and the metal end fittings are the three decisive factors for anti-corrosion performance of RTP. In this paper, an autoclave, a material testing system, a VST testing instrument and a FTIR spectrometer are used to determine the corrosion performances of the lining layers, reinforced structural layers and metal end fittings of a newly developed RTP in a simulated sour environment (p_tota=10 MPa, p_H2S=0.6 MPa, p_CO2=0.25 MPa, T=80 ℃). The research results show that, after HTHP immersion tests, both PVDF and glass fiber reinforced resin layers swelled and gained weights (with weight gain rates less than 1%), whereas tensile strength of PVDF decreased by 3.15%; VST dropped 3.4 ℃ and the compositions of PVDF displayed no obvious changes; tensile strength of fiber-reinforced resin decreased by 13.11%. The results suggest that PVDF and glass fiber reinforced resin are suitable as a lining layer and a reinforced structural layer of RTP respectively to be used in a sour environment. Corrosion rates of three metallic end fittings in the simulated sour environment can be organized in the following order: L360NS＞316L＞Alloy825. With slight corrosion, nickel-based Alloy 825 and 316L are suitable materials for fabrication of end fittings.