碳钢在液/固双相管流中的磨损腐蚀机理研究

文中利用自行研制的管流动态模拟试验装置 ,研究了碳钢在液/固双相流中的磨损腐蚀。结果表明碳钢在流动 5%河砂的双相 3.5 %NaCl溶液中 ,磨损腐蚀速度随流速的增加而显著地增大 ,没有出现像单相流中磨损腐蚀速度显著降低的流速区段 ,其磨损腐蚀过程仍主要受阴极氧扩散控制。在液/固双相流中 ,碳钢阻抗谱为双容抗半圆弧 ,且都出现低频收缩现象。对碳钢施加阴极电流 ,由于抑制了电化学因素 ,大幅度削弱了与流体力学因素的协同效应 ,使碳钢腐蚀大大减轻。证明了在双相管流中 ,碳钢磨损腐蚀过程仍主要受电化学因素控制。

Erosion-corrosion of carbon steel in liquid/solid two phase flow through pipe

The erosion-corrosion of carbon steel in flowing liquid-solid two-phase 3.5% NaCl solution was studied with self-made pipe simulating apparatus. The experimental results show that the erosion-corrosion rate of carbon steel in flowing two-phase 3.5% NaCl solution containing 5% sands increases with increase in flow velocity. But there is no reduction region where the corrosion rate decreases in flowing single phase solution. Erosion-corrosion process of carbon steel in flowing liquid-solid two-phase solution is still controlled by cathodic oxygen diffusion process. The Nyquist plots for carbon steel electrode are double capacitive loops in flowing liquid-solid two-phase 3.5% NaCl solution, and the contraction phenomenon of Nyquist plots in low-frequency region is noticed. The erosion-corrosion rate of carbon steel decreases abruptly when the cathodic current is impressed on carbon steel. This is due to that the electrochemistry factor is restrained and that the synergism between electrochemical factor and hydrodynamic factor is weakened. It is verified that the electrochemical factor plays a key role in erosion-corrosion of carbon steel in flowing two-phase solution.