高含硫酸性湿天然气加热炉盘管腐蚀规律研究

发布时间：2018-06-30 02:23

  本文选题：高含硫天然气 + 加热炉盘管　； 参考：《中国石油大学(华东)》2015年硕士论文

【摘要】：在高含硫气田湿气输送过程中,由于存在H_2S、CO_2和水,天然气加热炉盘管处于H_2S和CO_2共存的的酸性环境中,加热炉盘管腐蚀比较严重,影响了加热炉的正常运行,降低了换热效果。本文基于H_2S/CO_2共存体系中的反应过程,对高硫酸性湿天然气加热炉盘管的腐蚀规律开展研究。通过对含硫气田常用管材L360钢进行腐蚀实验和数据分析,总结腐蚀速率的变化规律,并运用SPSS软件对腐蚀数据进行回归分析,建立了天然气加热炉盘管腐蚀预测模型。实验结果表明,对腐蚀速率影响较大的因素是H_2S分压、CO_2分压、温度和Cl-浓度。L360钢中的合金元素Cr可增强钢在酸性环境中的耐蚀性;均匀腐蚀速率随H_2S分压的升高逐渐升高;不同CO_2分压下,L360钢在H_2S/CO_2中腐蚀速率在CO_2分压为2.5MPa时高达0.6297mm/a,且随着CO_2分压的升高,腐蚀速率呈现先下降后上升规律;腐蚀速率随总压的增大而增大,先缓慢升高后趋于平缓,但增幅不多,基本稳定在同一水平;腐蚀速率随温度的变化呈现先升高后降低的趋势,在70～90℃达到最大;随着Cl-浓度的升高,L360钢的腐蚀速率逐渐升高,当Cl-浓度达到30mg/mL时,L360钢的腐蚀速率达到最大,Cl-浓度大于30mg/mL后,L360钢的腐蚀速率逐渐降低;pH4.76时,均匀腐蚀速率随着腐蚀体系pH值的增大而逐渐降低,当pH4.76时,腐蚀速率随着腐蚀体系pH值的增大而逐渐增大。腐蚀速率与H_2S分压、CO_2分压、温度和Cl-浓度间呈非线性关系,拟合了腐蚀预测模型为:V =-21.553P_(H_2S)~2 +5.875P_(H_2S) +0.065P_(CO_2)~2-0.138P_(CO_2)-0.00005561T~2 +0.009T-0.00002132 C_(Cl~-)~3 +0.001C_(Cl~-)~2-0.016C_(Cl~-)+0.116自变量P_(H_2S)~2,P_(H_2S),P_(CO_2)~2,P_(CO_2),T~2,T,C_(Cl~-)~3,C_(Cl~-)~2,C_(Cl~-)的回归系数的显著性水平在数值上均远远小于0.05,可以判定,所有的回归模型的回归系数都是显著的。拟合的腐蚀预测模型验证表明,最大误差为9.87%,平均误差为8.07%,腐蚀预测模型精度满足现场要求。研究结果对于高含硫气田天然气加热炉盘管的腐蚀预测提供实验数据及借鉴意义。
[Abstract]:In the process of wet gas transportation in high sulfur gas field, due to the existence of H2SCO2 and water, the coils of natural gas reheating furnace are in the acidic environment where H _ 2S and CO _ 2 coexist. The corrosion of reheating furnace coil is serious, which affects the normal operation of heating furnace and reduces the heat transfer effect. Based on the reaction process of H _ 2s / CO _ 2 co-existing system, the corrosion law of high sulfur acid wet natural gas heating furnace coils is studied in this paper. Through the corrosion experiment and data analysis of L360 steel, a common pipe material in sulfur-bearing gas field, the variation law of corrosion rate is summarized, and the corrosion prediction model of natural gas heating furnace coils is established by using SPSS software to carry out regression analysis of corrosion data. The experimental results show that the major factors affecting the corrosion rate are the partial pressure of H _ 2S and CO _ 2, the alloy element Cr in Cl-concentration. L360 steel can enhance the corrosion resistance of steel in acid environment, and the uniform corrosion rate increases with the increase of partial pressure of H _ 2S. Under different CO2 partial pressures, the corrosion rate of L360 steel in H2s / COS-2 is as high as 0.6297mm / a when the partial pressure is 2.5MPa, and with the increase of CO _ 2 partial pressure, the corrosion rate decreases first and then rises; the corrosion rate increases with the increase of total pressure, and then increases slowly. The corrosion rate of L360 steel increased gradually with the increase of Cl-concentration, and the corrosion rate of L360 steel increased gradually with the increase of Cl-concentration, and then decreased with the change of temperature, and the corrosion rate of L360 steel increased gradually with the increase of Cl-concentration, and the corrosion rate of L360 steel increased gradually with the increase of Cl-concentration. When the concentration of Cl- is 30 mg / mL, the corrosion rate of L360 steel reaches the maximum when the concentration of Cl- is more than 30 mg / mL, and the corrosion rate of L360 steel decreases gradually with the increase of pH value of corrosion system, and when pH value is 4.76, the corrosion rate of L360 steel decreases gradually with the increase of pH value of corrosion system, and the corrosion rate of L360 steel decreases gradually with the increase of pH value of corrosion system. The corrosion rate increases with the increase of pH value. There is a nonlinear relationship between corrosion rate and H _ 2S partial pressure, CO _ 2 partial pressure, temperature and Cl-concentration. 鎷熷悎浜嗚厫铓，

本文编号：2084434