engleski

Paraffin wax in petroleum industry: A review on formation, experimentation, prevention, and removal techniques

Crystallization of paraffin wax in crude oil, with subsequent deposition on the walls of pipelines and process equipment, is one of the main causes of many problems in the petroleum industry. Due to the paraffin wax deposition, there is a reduction in the actual diameter of the pipeline resulting in a higher pressure drops and the formation of gelled interlocking structures in the pipeline and process equipment, which leads to the interruption of crude oil production. There are two classes of petroleum waxes, paraffin wax and microcrystalline wax. Paraffin waxes consist of straight chain saturated hydrocarbons, with carbon atoms from C18 to C36, crystallize in large flat plates, macrocrystalline structures. Waxes composed primarily of cycloalkanes and branched hydrocarbons, with carbon atoms from C30 to C60, crystallize as small needle structures and are referred as microcrystalline waxes. There is two mechanisms of wax deposition, molecular diffusion, and shear dispersion. Molecular diffusion describes the process by which the radial temperature gradient in the line causes a concentration gradient of dissolved paraffin components in the liquid phase. Shear dispersion describes the relationship between deposition rate and shear rate. Paraffin wax deposition can be prevented or removed by several different methods. These methods fall into three main categories: thermal, mechanical, and chemical. Laboratory analyses are carried out for the purpose of determining the tendency of paraffin wax deposition from crude oil. Paraffin wax analysis can include determination of paraffin wax content, molecular weight distribution, cloud point/pour point, wax appearance temperature, deposition test etc. Based on the composition of the crude oil, it is possible to predict the type of paraffin wax that will form and the best techniques for preventing and removing paraffin deposit from crude oil production system.

paraffin wax, .crude oil

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