The influence of petroleum resins and ultrasonic treatment on the structural and mechanical properties of petroleum wax solution in decane

The influence of ultrasonic processing, additives of petroleum resins, and a complex method that includes treatment of petroleum wax in decane solution in an ultrasonic field, followed by introducing 0.3% by weight petroleum resin on the rheological parameters of the test solution, a paraffin crystallization process, and a sedimentation process, was investigated in present work. The structure of petroleum resins that participate in the process of inhibiting sedimentation was studied by IR spectroscopy. The object of study is a 6% by weight solution of petroleum wax in decane. Petroleum resins, which are natural depressants of viscosity and pour point and inhibitors of sedimentation, were used as the modifying agent. Ultrasound treatment of the samples was performed by a UZDN sonifier at 22±1.65 kHz. The solution was treated in an ultrasonic field for 10 min at 25 °C. The rheological parameters of the solutions were determined using a rotary viscometer, HAAKE Viscotester iQ. The process of crystallization of paraffin from solutions of petroleum wax in decane was investigated by optical microscopy using the AXIO LAB.A1 CarlZeiss microscope in transmitted light. The deposition process was quantitatively estimated by a device designed based on the "cold finger" test method. The experiment was conducted for 1 h at +30 °С for the solution and +8 °С for the finger. The sample weight was 40 g. The mass of sediment formed in the rod was determined gravimetrically, and the values obtained were calculated to 100 g of solution. Infrared spectra of resins were obtained in a thin layer on an FTIR spectrometer Nicolet-5700 at 400-4000 cm-1. The test sample was applied as a film onto KBr glass. Adding 0.3% by weight resins to the solutions of petroleum wax in decane helped to reduce structural-mechanical and energy parameters of the system. Joint sonication and addition of resins resulted in additional reduction in the viscosity- temperature characteristics: there was a significant reduction in viscosity below 16 °C and in the temperature for sol-gel transition. Complex treatment reduced the energy parameters of the system: the activation energy of viscous flow was reduced by 2.5 times (60%), the specific energy fracture by 6 times (83%) compared to the values of the energy of the viscous flow and the specific energy fracture for a stock solution of petroleum wax in decane. Decreasing values of energy parameters indicated a change in the structure formed during crystallization of paraffinic hydrocarbons of petroleum wax in decane solution. The introduction of 0.3% resins after ultrasonic treatment resulted in less structured formation at low temperatures, and the crystal structures formed required less energy consumption for their destruction. According to the data obtained, the inhibition of sedimentation processes was performed by fragments of aliphatic petroleum resins that were adsorbed on the high molecular weight hydrocarbons of normal structure and prevented their aggregation.

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