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Khakimov Farrukh, assistant teacher in TCTI, Tashkent Chemical Technological Institute, Uzbekistan
Tulkin Radjabo, Scientific worker, Tashkent Institute of Design, Construction & Maintenance of Automotive Roads, Uzbekistan
Maksumova Oytura,
professor, Tashkent Chemical Technological Institute, Uzbekistan
E-mail: xakimov_farrux@list.ru
EVALUATION OF DIFFERENT VISCOSITY INDEX IMPROVERS IN LOCAL LUBE OIL BASE STOCK BY MEANS OF SONIC OSCILLATOR
Abstract: In this paper the VIIs' (polymers') stabilities to the destruction in local base oil are compared, it covers the evaluation of the shear stability of engine oils in terms of the final viscosity that results from irradiating a sample of the engine oil in a sonic oscillator. The correlation has been presented between the shear degradation that results from sonic oscillation and that in engine. PVL (permanent viscosity loss) and PSSI (permanent shear stability index) of oils prepared with different viscosity modifier were evaluated. As a result, the effectiveness of each additive for lube oils was evaluated.
Keywords: VII, lubricant, sonic oscillator, engine oil, permanent viscosity loss, permanent shear stability index.
Untroduction
Modern high-performance lubricants are specifically formulated with a carefully selected balance of performance additives and base stocks to match the lubrication requirements of the equipment in which they are used. Lubricants are often designed to provide a viscosity that is low enough for good cold weather starting and high enough to provide adequate film thickness and lubricity in hot, high-severity service [1]. Viscosity index (VI) represents the effect of temperature on the kinematic viscosity of lubricant oils, and was initially proposed by Dean and Davis in 1929. It measures the stability of the kinematic viscosity with temperature [2]. The higher the VI, the more stable the kinematic viscosity with temperature. For petroleum lubricant oils, a VI slightly above 100 is almost the maximum limit attainable by economical refining processes. Any additional increase in the VI can only be achieved with the addition of polymers known as Viscosity Index Improvers (VIIs) [3].
In the following work we have made several engine oils by adding several types of VIIs to our local mineral base oil. Furthermore, we checked their PVL and PSSI by means of sonic oscillator in order to compare their properties during their functioning period. The results of this work and conclusions are given at the end.
2. Experimental Part
2.1. Apparatus
Disperser ultrasonic low-frequency UZDN-2T, which includes an ultrasonic generator, magnetostrictive radiators at 22
kHz with exponential concentrators. Cooling Bath or Ice Bath, to maintain a jacket temperature of 0 °C, with a rubber cover to fit a reaction tube. Test tube as a reaction vessel. Chronometer. Thermostats to keep the temperature at 40 o C and 100 o C. Viscometer, any viscometer and bath meeting the requirements of Test Method D445 or GOST 33-2000. Mercury glass laboratory thermometers in accordance with GOST 28498 with a scale division price of 0.5 °C.
2.2. Materials
Solvents for washing the reaction vessel; gasoline aviation grade B-70 according to GOST 1012, toluene according to GOST 5789, acetone according to GOST 2603. AMG-10 oil that meets the requirements and norms specified in GOST 6794-75. K-61: Thickening additive for oils and greases. J0050 ethylene propylene rubber copolymer lubricant additive. High viscosity modifier Infineum SV261. PAO-150. An additive (a prototype sample) that we have produced in a laboratory condition. Local mineral base oil.
2.3. Procedures
We conducted an experiment according to some standard Interstate Test Methods [4-6]. By combining these methods, we could achieve our aim, to compare our VII, which we have synthesized in laboratory condition, to other VIIs present in local market. This experiment was carried out in laboratory "PetroTestAvto" LLC.
2.3.1. First of all, we prepared engine oils with the same kinematic viscosity (the deviation is 0.3 mm2/sec, which is allowable) at the temperature of373 K. Kinematic viscosities of the lubricants were determined [6].
Section 10. Technical sciences
Figure 1 Ultrasonic low-frequency disperser UZDN-2T
2.3.2. Generator UZDN-2T is included in the electric network, water is supplied to the radiator j acket and the lamps are heated for at least 1 minute. The system is adjusted to resonance for the maximum noise of the test oil. The power setting is determined according to ASTM D2603.
2.3.3. 15 mL of the engine oil sample is introduced to be tested into a clean reaction tube and immersed in the constant temperature bath at 0 °C. The reaction tube is kept in a vertical position. The sample is allowed to equilibrate for 12.5 min. The horn is immersed in the fluid. The sample is irradiated for 40 min at exactly the same power setting determined. Upon completion of irradiation, the sample is removed and the sonic horn is cleaned in preparation for the next test.
2.3.4. 15 mL sample from engine oil is irradiated in a sonic oscillator for a period of time and the changes in viscosity are determined by ASTM Test Method D445 or GOST 33-2000.
Table 1.- The data
Viscosity indices of these engine oils have been determined as recited in GOST 25371-97 (ISO 2909-81). PVL and PSSI of the engine oils have been calculated. The data, which was taken before sonic shearing test by means of UZDT-2T, has been reported in Table 1 and the results after the test have been given in (Table 2).
3. Measurements
3.1. Viscometric Measurements were carried out according to ASTM Test Method D445 or GOST 33-2000.
3.2. Permanent shear stability index of each lubricant is calculated via the formula below:
PSSI = -
KV,
fresh
KV
KVfresh - KVba
-*100
3.3. Thickening power of each VII is calculated using the following equation:
KV — KV
fresh sheared , -, „„
TP = —--*100
KVbase *C %
3.4. The stability of the viscosity of the oil or PVL - the relative decrease in viscosity after the radiation on the unit UZDN-2T in percent calculated by the formula:
KV0 - KVT PVL =-i-*100
kv0
Where, KV° is the kinematic viscosity of the test oil at 100 °C, mm2/s; KVTt kinematic viscosity at 100 °C after radiation, mm2/s.
3.5. Viscosity indices were calculated according to GOST 25371-97 (ISO 2909-81).
4. Results and Discussion
before sonic shearing
Name of an additive VII% Wt. KV at 100 C KV at 40 C VI Increase in viscosity Thickening power
Base Oil 0 9.15 82.92 81 - -
J0050 0.42 13.26 120.13 106 4.11 106.9
K-61 0.51 13.03 111.73 111 3.88 83.1
Infineum SV261 6.65 13.29 115.99 111 4.14 6.8
PAO 150 9.7 13.14 115.34 109 3.99 4.5
Prototype sample 10.1 13.03 103.18 123 3.88 4.2
Table 2.- The data after sonic shearing
Name of an additive KV at 100 C KV at 40 C VI Increase in viscosity at 100 C Thickening power PVL PSSI
Base Oil 9.15 82.92 81 - - - -
J0050 10.93 102.47 89 1.71 46.3 17.6 56.7
K-61 10.86 91.67 103 1.66 36.6 16.7 55.9
Infineum SV261 12.49 117.1 98 3.34 5.5 6.0 19.3
PAO 150 12.59 112.81 103 3.44 3.9 4.2 13.8
Prototype sample 12.62 106.36 112 3.47 3.8 3.1 10.6
By this experiment we evaluated the shear stability with minimum interference from thermal and oxidative factors that may be present in engine. The essence of the method is to determine the relative decrease in the viscosity of the oil after scoring on an ultrasonic unit due to mechanical destruction (degradation) of polymer additives. By this way, we can predict any VII's functioning period in engine oil. Although, other than polymer degradation many factors, such as fuel dilution and oxidation may effect the viscosity index of used engine oil, GOST 23175-78 [7] can be used to evaluate thermal and oxidative stability beforehand. Moreover, in engines, which run with gas, the dilution of oil does not happen.
5. Conclusions
5.1. By this work we compared the VIIs' (polymers') stabilities to the destruction in local base oil, it covers the evaluation of the shear stability of engine oils in terms of the final
viscosity that results from irradiating a sample of the engine oil in a sonic oscillator.
5.2. Evidence has been presented that a good correlation exists between the shear degradation that results from sonic oscillation and that in engine. Although, the process in engine is so complicated and simulation it in laboratory condition is so arduous, we can at least predict how the VIIs will perform their function in there.
5.3. PVLs, TPs, PSSIs and viscosity indices of lube oils with different viscosity modifiers were evaluated. As a result, the most effective additive for lube oils, concerning PVL and PSSI, has been evaluated the additive (prototype sample) produced in laboratory condition from local raw materials, while it comes to thickening power this is valued the lowest one. Moreover, viscosity index of the lube oil prepared adding the prototype sample has been the highest, before and after the shearing process.
References:
1. Speight James G., Exall Douglas I., Refining Used Lubricating Oils, International Standard Book Number-13: 978-14665-5150-3 (eBook - PDF), by Taylor & Francis Group, LLC, 2014.
2. Sylvain Verdier and others. A critical approach to viscosity index, Denmark, Fuel 88 (2009) - P. 2199-2206.
3. Liu Yinong, Fan Lichuang, Duan Qinghua. Synthesis of Polymethacrylates Used as Multifunctional Lubricating Oil Additives, China Petroleum Processing
4. ASTM D2603, the Standard Test Method for Sonic Shear Stability of Polymer - Containing Oils.
5. GOST 25371-97 (ISO 2909-81). The Interstate Standard of Petroleum Products, Calculation of The Viscosity Index by Kinematic Viscosity
6. ASTM Test Method D445 or GOST 33-2000. The Test Methods for Kinematic Viscosity of Transparent and Opaque Liquids (the Calculation of Dynamic Viscosity).
7. GOST 23175-78 Lubricating oils. Method for assessing motor properties and determining thermal and oxidative stability.
