渣油中铁的形态分析方法研究

摘要

建立了电感耦合等离子体发射光谱法(ICP-OES)测定渣油中不同形态铁含量的分析方法;采用三氯化铁、环烷酸铁、2乙基己酸铁、四苯基卟啉氯化铁作为模型化合物,考察萃取方法的可行性及优化萃取条件.结果表明:纯水对三氯化铁的萃取率可达到100％;采用稀酸作为萃取剂进行萃取后,可将渣油中的铁分为酸提出铁、油中残留铁及其它铁,其中酸提出铁包含水溶性铁、绝大部分石油酸铁以及少量的卟啉铁类化合物;质量分数为5％的盐酸溶液对石油酸铁的萃取效果最好,对环烷酸铁和2-乙基己酸铁的萃取率分别为100.5％和93.2％;适宜的萃取时间为3h.采用所建方法分析实际渣油加氢原料和产物中铁的组成分布,发现其它铁在加氢后大部分消失了,说明这部分铁极易通过加氢反应脱除;而油中残留铁的脱除率远低于总铁脱除率.%A method was established for the determination of iron species in residue by inductively coupled plasma optical emission spectrometry(ICP-OES).Four representative iron compounds:ferric chloride,iron naphthenate,iron 2-ethlhexannoate,and iron meso-tetraphenylporphine chloride were employed as model chemicals to investigate the extraction efficiency and conditions.The results showed that the extraction rate of ferric chloride reaches 100％ by pure water.In the case of dilute acid is used as the extraction agent,the irons in residue can be divided into acid extracted iron,residual iron in oil and other iron compounds.The acid extracted iron includes water soluble iron,majority of oil acid iron and a small amount of ferroporphyrins.Hydrochloric acid solution(5 ％) was found to be the best extraction solvent for iron naphthenates.The spiked recoveries of iron naphthenates and iron 2-ethlhexannoate in residue are 100.5％ and 93.2％,respectively after extraction for 3h with the HCL solution.It is found that the other iron compounds disappear after hydrogenation,indicating they are easy to remove by hydrogenation.However,the removal rate of the residue iron in oil is far lower than the total iron removal rate.