延迟焦化装置分馏塔顶循线腐蚀及防护

Corrosion and Protection of Top Circulation System in Delayed Coking Fractionator

延迟焦化是一种石油二次加工技术,可处理残炭和金属含量很高的劣质原料,提高轻质油的收率和脱碳效率;有操作连续化、处理量大、灵活性强、脱碳效率高、投资和操作费用低等优点。延迟焦化装置加工劣质原料中硫等腐蚀性杂质含量高,操作温度高,设备和管线容易产生腐蚀。为了解决焦化装置顶循线的腐蚀减薄问题,对该管线进行了宏观检查、化学成分分析和顶循线腐蚀机理分析。分析结果表明,顶循线腐蚀主要发生在管线内壁,为湿硫化氢腐蚀。从工艺、设备和腐蚀介质检测等三个方面提出了相应的防护措施。

Delayed coking is a kind of secondary oil processing technology,which can dispose of inferior raw materials with residual carbon and high metal content,improve yield of light oil and decarbonization efficiency.It has the advantages of continuous operation,large processing capacity,satisfactory flexibility,high decarbonization efficiency and low investment.Corrosion is prone to occur on equipment and pipeline,owing to high sulfur content and other corrosive impurities in inferior raw materials of the unit.Approaches such as macro inspection,chemical composition analysis and corrosion mechanism analysis were performed as a response to corrosion thinning.It was found that wet hydrogen sulfide corrosion mainly occurs on pipe inner wall of top circulation system.Corrective actions were implemented from aspects in technology,equipment and corrosion medium detection.