高含硫天然气净化厂管线腐蚀监测方法的优选与应用——以普光气田为例

普光气田高含硫净化厂的原料气高含H2S(约15%)、含CO2约10%,管线的腐蚀监测和腐蚀控制对保证净化厂的安全、高效运行具有重要意义。为此,对目前常用的腐蚀监测方法在该净化厂各工艺管线腐蚀监测中的适应性进行了分析和比较,并根据生产管线的服役特点优选出了适宜的腐蚀监测方法。现场应用结果表明:电感探针监测和失重挂片监测是管线监测的良好手段,能够满足高含硫净化厂管线各种服役工况,且其投资较低;电感探针在线腐蚀监测结果与失重挂片腐蚀速率基本一致,表明监测数据可信;该净化厂第二级硫冷凝器酸性气入口管线,急冷水泵出口管线,酸水汽提塔顶和东、西区高空放空总管为腐蚀薄弱环节,其他监测单元腐蚀速率都很低。该分析结果可为高含硫净化厂管线腐蚀监测提供指导,为净化厂的安全高效运行提供保障。

Selection and application of corrosion monitoring methods in high sulfur natural gas purification plants in the Puguang Gas Field

The feed gas in a natural gas purification plant of the Puguang Gas Field contains about 15% H₂S and 10% CO₂, so corrosion monitoring and control are significant to ensure safety and high efficiency of the plant. In view of this, we analyzed and compared the advantages and disadvantages of the commonly used corrosion monitoring methods and recommended appropriate methods according to the service characters of production lines in the plant. The field application demonstrated that inductance probe monitoring and weight loss hanging slice methods are better for corrosion monitoring of pipelines in this plant. These two methods are of good adaptability, low cost and convenience and present roughly identical corrosion rates to their respective monitoring results. The on line monitoring results also show that the inlet pipe of the secondary stage sulfur condenser, the outlet pipe of chilling water pump, the top pipe of sour water stripping tower and the vent main pipes in eastern and western flanks are more susceptible to corrosion. However, other monitoring points have rather lower corrosion rates. This study provides guidance and reference for the corrosion monitoring of pipelines and thereby to guarantee the safe and high efficiency operation of high sulfur purification plants.