Investigating of Interactions of Mono and Multi-functional Acids with Asphaltene by Using UV-vis Spectroscopy

Asphaltene deposition is one of the main problems in crude oil production. Using of asphaltene dispersants and inhibitors are one of the effective methods for preventing deposition of asphaltene particles. Acids are an important class of chemical compounds that could reduce asphaltene problems, regarding to the polarity of asphaltenes and acid molecules. Their efficiency is related to the amount of asphaltene-acid interaction. In this study, the amount of the interaction of acids and their binary mixtures was studied with extracted asphaltene from Iran crude oil by using UV-vis spectroscopy. Different acids were examined that included mono and multi-functional acids. In this method, decreasing the UV absorbance was assisted as index for the amount of the interaction of acids with asphaltene in the asphaltene-toluene solution with the presence of aqueous solution of acids and their binary mixtures. Solubility performance of acids and their binary mixtures was compared for reducing the amount of asphaltene precipitation by changing their mole volume. Experimental results show that the interaction of asphaltene-acids increases with increasing the amount of acid. Among the all studied acids, Interactions of adipic acid and oxalic acid with asphaltene are more than of other acids. The effect of acids binary mixture also investigated on asphaltene precipitation. Results of experiments show that the binary mixtures which is containing para-toluene sulfonic acid has the most interaction with asphaltene particles to reduce amount of precipitation.