Evolution of oil organic acids using a laboratorial distillation unit

摘要

The presence of organic acids in petroleum and their effects are clearly described in the relevant literature, mainly by the term "naphthenic acid corrosion". Naphthenic acid content is usually represented by total acid number (TAN), which is reported in mgKOH·g~(-1) of sample. Studies suggest that corrosion rate is not directly related to TAN values, but depends on the structure of acid species present in the oil, the operating temperature, and sulfur content, among others. These acids exist in relatively low concentrations in oil. Depending on the boiling point of these compounds, these acids can be concentrated in certain cuts during the distillation process and can cause non-aqueous corrosion under high temperatures. Short-chain acids - mainly from one to four carbon atoms - are concentrated in the system at the top of refining towers, worsening corrosion of aqueous solutions in these systems. Thus, this study aims at quantifying and specifying acids from one to four carbon atoms which reach the top of the distillation column during the distillation of Brazilian crude oils.