针对H2S、CO2、Cl-同时存在的高温、高压腐蚀环境, 选择22Cr、25Cr双相不锈钢和028铁-镍基合金、G3镍基合金进行对比试验, 在其它条件相同的情况下(H2S/CO2分压、温度、液体流动等条件一致, 仅Cl-浓度变化), 分析Cl-含量对各种耐蚀合金管材发生均匀腐蚀与点蚀的腐蚀速率的影响。结果表明, 在温度为160 ℃, CO2分压为4.13 MPa, H2S分压为2.66 MPa, 流速为3 m/s的条件下, 随着Cl-浓度增加(25 g/L、100 g/L、120 g/L、250 g/L), UNS S32205和UNS S32750两种双相不锈钢的均匀腐蚀速率和局部腐蚀速率增加; 028和G3两种镍基合金的均匀腐蚀速率变化不大, 且无局部腐蚀发生。UNS S32205、UNS S32750双相不锈钢试样表面钝化膜的主要成分为Cr2O3和/或Cr(OH)3; 028和G3镍基合金试样表面钝化膜的主要成分为NiO、Cr2O3和/或Cr(OH)3。

Aimed high temperature high pressure at HTHP corrosive environments with simultaneous existence of H2S/CO2/Cl-, 22Cr/25Cr duplex stainless steels, i.e., (DSS) and 028 Fe-Ni-based alloy/G3 Ni-based alloy were selected to conduct comparative tests. Under the same conditions other than Cl- concentration, i.e., (H2S/CO2 partial pressure, temperature and liguid flow were the same, only Cl- concentration was different, the influence of Cl- concentration on corrosion rates of general corrosion and pitting corrosion of corrosion resistant alloys was analyzed. The experimenal results show that under the corrosive conditions of temperature 160 ℃, CO2 partial pressure 4.13 MPa, H2S partial pressure 2.66 MPa and flow rate 3 m/s, with the increase of Cl- concentration(25 g/L, 100 g/L, 120 g/L, 250 g/L), the general corrosion rates and localized corrosion rates of two kinds of duplex stainless steels(UNS S32205 and UNS S32750) increased. The general corrosion rates of 028 and G3 Ni-based alloys had a little change and localized corrosion did not happen. The main compostion of passivation film on the surface of DSS specimen(UNS S32205/UNS S32750) was Cr2O3 and/or Cr(OH)3. The main compostion of passivation film on the surface of Ni-based alloy specimen(028/G3) was NiO/Cr2O3 and/or Cr(OH)3.