Naphthenic acids are a diverse group of saturated mono- and polycyclic carboxylic acids that may account for as much as 10-12 weight % of crude oil. During production at several newer oil fields, there have been discoveries of oil that have very high acid and calcium content. This indicates that there are some naphthenic acids bound to calcium as calcium naphthenates present in the oil, and that these are oil-soluble. Oil-soluble calcium naphthenates can cause problems during refinery, as the calcium present can lead to fouling and catalytic deactivation. The coke and fuel quality will also be affected. The removal of calcium in the refinery can be an expensive and comprehensive process, which results in the suppliers getting a lower price on their crude oil.In this master thesis, naphthenic acids from non-soluble calcium naphthenates have been isolated by using an ion exchanger method and a Solid Phase Extraction-method. The work also consisted of neutral and acidic washing of the samples, measurements of water-content, Ca-content and total acid numbers. The different phases from the isolations have also been analyzed by using FT-IR Spectroscopy, APPI-MS and ESI-MS for characterization to see if the naphthenic acids bound to calcium differ from other acids.The naphthenic acids that are bound to calcium in the crude oil have a higher average molecular weight than the other naphthenic acids, at 875 and 580 g/mole respectively. This result was confirmed by TAN-measurements and APPI-MS of samples after isolation with the Acid-IER method. The correlation between the TAN-measurements and the results from APPI-MS suggest that the acids can be characterized as monoacids. They do not have a particular molecular weight, but have a broad distribution between 150 and 2000 g/mole. It seems that the calcium naphthenate formation is controlled by the total amount of acids in the oil, their molecular weight and pH, and not as much on structure as first were presumed.
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机译：环烷酸是各种不同的饱和单环和多环羧酸，它们可能占原油的10-12％（重量）。在几个新油田的生产过程中，发现了具有很高的酸和钙含量的石油。这表明油中存在一些环烷酸与环烷酸钙结合，而环烷酸钙是油溶性的。油溶性环烷酸钙会在精炼过程中引起问题，因为存在的钙会导致结垢和催化失活。焦炭和燃料质量也将受到影响。在炼油厂中去除钙可能是一个昂贵且全面的过程，这会导致供应商降低其原油价格。在本硕士论文中，已通过使用离子交换剂从非可溶性环烷酸钙中分离出环烷酸方法和固相萃取法。这项工作还包括样品的中性和酸性洗涤，水含量，钙含量和总酸值的测量。还通过使用FT-IR光谱，APPI-MS和ESI-MS分析了分离物中的不同相，以鉴定与钙结合的环烷酸是否与其他酸不同。原油的平均分子量比其他环烷酸高，分别为875和580 g / mol。通过酸-IER方法分离后的样品，通过TAN测量和APPI-MS证实了该结果。 TAN测量值与APPI-MS结果之间的相关性表明，酸可以表征为单酸。它们没有特定的分子量，但分布范围在150至2000 g / mol之间。看起来环烷酸钙的形成受油中酸总量，其分子量和pH值的控制，而不是像最初推测的那样多。
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