جستجوی مقالات مرتبط با کلیدواژه « total acid number » در نشریات گروه « شیمی »

In this study, re-refining of used insulating oil by mesoporous silicate material (MCM-41) and metallic sodium was investigated. Also, the effect of silicate absorbents which was synthesized and functionalized with aluminum (Al-MCM-41) was studied (18 wt% and 36 wt%). The physical and structural properties of Al-MCM-41 were characterized by FT-IR, BET, XRD, FESEM and the obtained results illustrated a successful synthesis of the mesoporous material. The refined oil was treated by MCM41 adsorbent. After that, total acid number (TAN) of used insulating oil was effectively reduced by metallic sodium. The effect of some parameters such as contact time, temperature and the dosage (sodium and adsorbent to oil ratio) was designed and optimized by response surface method (RSM). The results showed that the acid number incredibly decreased at 150, 60 min and 2% of sodium to oil. The color of the re-refined oil was significantly reduced. The factors such as, time, temperature and dosage was statistically studied by ANOVA. The adsorption of MCM-41 was also studied by this way. Based on proposed procedure, the modeling was carried out. Treating of oil with MCM-41 after using metallic sodium causes lower color of oil.

The aim of this study is to explore the capability of subcritical methanol to reduce the acidity of naphthenic acids and to determine reaction kinetics for large-scale reactor design.The experiments were carried out in a 25 mL autoclave reactor (China) at temperatures of 70-120oC, Methanol Partial Pressures (MPPs) of 0.1-1.5 MPa, and reaction times of 0-60 min. The total acid number content of the samples was analyzed using ASTM D 974 techniques. Experimental results reveal that total acid number reduction of naphthenic acids increased with increasing reaction temperature, MPP, and reaction time. Approximately 74.20% total acid number was reduced at a temperature of 120oC, a MPP of 1 MPa, and a reaction time of 60 min. Experimental data revealed that total acid number removal reaction kinetics followed second-order kinetics with an activation energy of 11.27 kcal/mol. Therefore, subcritical methanol is able to reduce the total acid number of naphthenic acids without the addition of any catalyst.

Naphthenic acids and TAN are one of the ever-increasing crucial problems in oil, shale oil and sand oil industry and also environment protection. Furtherer, they increases the corrosion of some parts of a refinery and transport pipelines and also can create nanoemulsions and make complicated the refining process especially in desalters. To prevent these problems it is important to first obtain a basic knowledge about the distribution/structure of Naphthenic acids and their relationship with TAN. This might be useful for troubleshooting of probable problems when the feed of refinery changes. In the present work, two fractions of Soroush-Norowz blend crude oil were analyzed to obtain their naphthenic acids concentration and TAN. At the second step, these two fractions were physically to sub-fractions by 25 °C intervals. After that, their naphthenic acids concentration and TAN was determined to obtain a detailed view about the distribution of naphthenic acids and TAN of each sub-fraction. In addition, the obtained results gave us a view point about the overall molecular structure of naphthenic acids presents in the Soroush-Norowz blend crude oil and can guide us toward better understanding of chemical structure of mentioned crude oil and consequently better designing of oil refinery in order to minimize the corrosion and also upper the performance of some special units such as desalters.