Effect of ultrasound on the properties of the rapeseed oil?monoethanolamine system

Abstract

The effect of an ultrasound field on the rheological properties and thermal stability of rapeseed o i l ( R O ) i n t h e p r e s e n c e o f m o n o e t h a n o l a m i n e ( M E A ) a n d t h e d i s p e r s i n g p r o p e r t i e s o fthe RO-MEA system were investigated. The extremal character of the change in the dispersing effect of RO with an increase in the concentration of MEA was established. Ultrasound vibrations cause mechanochemical transformations that decrease the thermal stability at high temperatures. The increased interest in studying the effect of functional additives on the physicochemical properties of vegetable oils -natural renewable raw material -is due to the necessity of creating new environmentally safe processes and working media with high performance properties [1-3]. When additives of different natures -oligomers, surfactants (SF) -are added to vegetable oils, rapeseed oil in particular [4], their lubricant and dispersing properties can be varied within relatively wide limits. In addition, the viscosity properties of the oil can be regulated by changing the concentration of oligomers of different nature while preserving the character of flow [5].We investigated the effect of MEA on the rheological and dispersing properties and thermal stability of industrial RO.The effect of MEA on the dispersing properties of RO was determined gravimetrically using flat samples of steel 45. A lapping disk made of ChKhZ cast iron (GOST 7769-82) was set in a tray containing 15±0.1 ml of the compound investigated and 3±0.1 g of abrasive -KZ M-28 green silicon carbide. Abrasive wear was conducted at a fixed load on the disk of 98.07 kN/m 2 for 300 sec.The rheological properties of RO and binary systems with MEA were investigated by rotational viscometry on a Rheotest-2 instrument using a system of coaxial cylinders.An ultrasound field with a frequency of 22 kHz created in a UZDN-1 unit was applied to the RO-MEA binary system to study the effect of mechanical energy on its rheological properties. The power of the ultrasound vibrations was 50 W/cm 3 and the oil system sample volume was 30 cm 3 .The rheological properties were measured every 12 h after ultrasound radiation to exclude the effect of relaxation processes on the results.