摘要
在石油加工过程中,氯化物腐蚀已成为制约装置长周期安全稳定运行的关键问题,常减压蒸馏装置主要面临H_(2)S-HCl-H_(2)O腐蚀和NH_(4)Cl腐蚀。在H_(2)S-HCl-H_(2)O腐蚀环境中,介质腐蚀性随温度升高而增强,随pH值升高而减弱,在酸性环境下腐蚀主要由HCl控制,H_(2)S对腐蚀有促进作用但影响较小。因此对于HCl-H_(2)S-H_(2)O腐蚀,应重点关注初凝区即露点部位的盐酸腐蚀,通过控制塔顶温度和实施“一脱三注”进行工艺防腐。NH_(4)Cl溶液的腐蚀性随温度和浓度的升高而增强,特别是碳钢在一定流速下的腐蚀速率高达90mm/a,在NH4Cl垢下腐蚀环境下,20号钢出现明显的均匀减薄和局部腐蚀倾向,316L整体腐蚀轻微,发生明显点蚀。为了控制NH_(4)Cl腐蚀,应尽量使用低浓度溶液冲洗,并建议在常压塔顶循部位增设除盐设施。
Chloride corrosion has emerged as a pivotal issue constraining the long-term safe and stable operation of equipment in petroleum processing.Atmospheric and vacuum distillation units primarily confront H_(2)S-HCl-H_(2)O corrosion and NH_(4)Cl corrosion.In the H_(2)S-HCl-H_(2)O corrosive environment,the corrosivity of the medium intensifies with increasing temperature and diminishes with rising pH value.In acidic environment,corrosion is primarily controlled by HCl,while H_(2)S promotes corrosion but has a lesser impact.Therefore,for HCl-H_(2)S-H_(2)O corrosion,emphasis should be placed on hydrochloric acid corrosion in the initial condensation zone,that is the dew point area.The process anti-corrosion should be carried out by controlling the overhead temperature of the tower and implementing the“one desalination and three injections”process.The corrosivity of NH_(4)Cl solution intensifies with the increase of temperature and concentration,particularly for carbon steel with a corrosion rate of up to 90 mm/a at a certain flow rate.In under-deposit corrosion environment with NH_(4)Cl,20#steel exhibits significant uniform thinning and localized corrosion tendency,while 316L experiences mild overall corrosion and notable pitting corrosion.To mitigate NH_(4)Cl corrosion,the use of low concentration solution flushing is recommended,and the addition of desalting facilities at the overhead of atmospheric tower is suggested.
作者
张红良
夏永生
朱琬莹
于凤昌
ZHANG Hongliang;XIA Yongsheng;ZHU Wanying;YU Fengchang(SINOPEC Refining Department,Beijing 100027,China;SEG Luoyang R&D Center of Technology,Luoyang 471003,China)
出处
《石油化工腐蚀与防护》
2025年第2期11-19,共9页
Corrosion & Protection In Petrochemical Industry
基金
中国石化集团有限公司科技开发项目(CLY24061)。
关键词
常减压蒸馏装置
氯化物腐蚀
腐蚀分析
腐蚀控制
atmospheric and vacuum distillation units
chloride corrosion
corrosion analysis
corrosion control
