چكيده به لاتين
Bitumen is one of the resources that exists in large quantities in our country and most of its resources are in the provinces of Kermanshah, Ilam and Khuzestan. This material has various uses and due to the lack of suitable technology for processing these resources, it is exported entirely in raw form. On the other hand, due to the high amount of ash and sulfur in bitumen, this product is not suitable for export or domestic use, so reducing ash and sulfur in bitumen using a new and improved method seems necessary. Therefore, the purpose of this study is to find a suitable method for desulfurization of Iranian bitumen.
About 90% of Iranian bitumen is composed of organic compounds and the sulfur in it is of elemental, organic and inorganic types. Existing methods of desulfurization and ash desalination of coal, bitumen and similar samples are divided into two main physical and chemical categories, while physical methods are often based on the removal of mineral compounds and chemical methods are based on the removal of sulfur compounds. Organic and inorganic are effective. According to studies, three methods of spontaneous oxidation and chemical oxidation by means of ultrasonic waves and washing with molten caustic have been selected as appropriate methods.
In this research, by determining the specifications of the natural bitumen prototype, the structure of its compounds has been completely identified by performing SARA analysis. In addition, in order to perform the desired tests, the required materials and equipment are provided for each category of tests according to the selected methods.
Finally, experiments were performed according to the three main methods selected. Although the results obtained from spontaneous and chemical oxidation were not suitable, but the results obtained from the washing method with molten caustic were very suitable. By determining 12 parameters affecting the efficiency of this process, six sub-parameters were selected and the effect of six parameters of reaction temperature, reaction time, caustic to bitumen ratio, number of washing steps, reaction mixing phase and the effect of cap use were investigated. As a result, it managed to reduce the amount of sulfur from 7.97 to 1.42% and ash from 10.9 to 1% in suitable reaction conditions, which in 2 hours, at 450 C C, the ratio of caustic to bitumen 6 to 1 and from natural bitumen less than 90 microns Then four washing steps are performed with water and acidic hydrochloric acid solution with a concentration of 20% at a temperature of 80 ° C. Finally, by performing SEM, FTIR, XRD analyzes, the results are interpreted and the changes made in the final sample compared to the prototype are discussed.
