Acidity removal of Iranian heavy crude oils by nanofluid demulsifier: An experimental investigation

Document Type: Original Research Paper


1 Department of Chemistry, K.N. Toosi University of Technology, Tehran-Iran

2 Refining Technology Development Division, Research Institute of Petroleum Industry, Tehran, Iran

3 Research Institute of Petroleum Industry, Tehran-Iran

4 Department of Biology, Faculty of Science, Payam Nour University, Tehran, Iran


The scope of this study is to propose a new and convenient method for reduction of acidity of heavy crude oils to less than 1 mg KOH/g of sample. For this purpose, acidity of several Iranian heavy crude oils has been investigated. Is this research, two precise methods were developed and the results compared for the acidity reduction of samples based on using nanofluid demulsifiers. In the first technique, after separating the formation water and salt of the samples, the acidity was determined potentiometrically on the treated samples by using trace quantities of a commercial polymer-based nanofluid demulsifier. In the second technique, distillation of crude samples was performed according to ASTM standard procedures and the related fractions were subsequently evaluated for acidity measurements. The results obtained from both separation techniques revealed that the formation water of crude samples is responsible for the presence of salt and some organic acids such as naphthenic acid and its derivatives. Here, the acidity removal techniques are ideally suited for heavy Iranian crude oils with water content between 0.05-20 vol.% and salt between 10-10000 pounds per thousand barrels (ptb).