Study On The Separation Of Naphthenic Acid From High Total Acid Number Crude Oil By Extraction

As the decrease of petroleum resourse and the improvement of oil exploration technique, more and more crude oils with high TAN are extracted than before, The acid substances in crude oil are mainly composed of naphthenic acids(NA), which mainly lead to the heavy corrosive of the refinery equipment and degrade the oil product. On the other hand, naphthenic acid is a useful fine chemical material, and It widely used in many fields, such as drier, petroleum additive, wood preservative. Therefore, the process for extraction of NA directly from crude oil is high valued by oil refine industry.Up to now, the separation of oil and NA is focused on two ways. First, traditional alkali-or ammonia solute neutrlization is conducted deeply by optimizating of the process and alterating the technology. Second, the naphthenic acid separated from oil is refined by means of adsorption and extraction. The latter is feasible on the level of laboratory bench procedure theoretically. At present time it is the only the former method that can be widely used in industry. By analysing the process foracid removal from crude oil, an effective extraction technique isproposed. Consequently the purpose of removal naphthenic acid from crude oil was reached and the problem of acid corrosion in oil refinery processing was solved. The main research contents and conclusions are as follows:1.Based on the basic principle of colloidal chemistry, principle of acid removal from crude oil is proposed. By using combined solute composing of alcohol, isopropanol, ammonia, the optional process conditions are determined by experiments carefully. The key to the process of the present process is its solvent system, the solvent system contains alcohol, ammonia and water in certain critical ratios. The mass ratio of ammonia is about 8%, alcohol above 25% and isopropanol 20% by weight.2.The properties of two kinds of crude oil and corresponding NA characteristics are analyzed, naphthenic acids existing as a complex mixture of compounds and can be catalogued into proportions of isomers further characterization of the mixture into relative proportions of l-,2-,3- ringed structures is determined..The results show that naphthenic acids the molecular weight of carboxylic acids widely range from 100~1000, Carbon number is between 7~70.and the contents of mono~tetracyclic naphthenic acid dominate .