Investigation of Tribological Characteristics of Non Edible Castor and Mahua Oils as Bio Lubricant for Maintenance Applications

Transcription

1 5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th 14 th, 2014, IIT Guwahati, Assam, India Investigation of Tribological Characteristics of Non Edible Castor and Mahua Oils as Bio Lubricant for Maintenance Applications Amit Kumar Jain 1*, Amit Suhane 2 1* Research Scholar, Department of Mechanical Engineering, M.A.N.I.T Bhopal MP India, , amitkumarjain05@gmail.com 2 Assistant Professor, Department of Mechanical Engineering, M.A.N.I.T Bhopal MP India, , amitsuhane2003@yahoo.co.in Abstract Lubricants have a very important role to play in every type of industry in reducing friction and wear between two relatively moving parts. Mainly lubricants are formulated from petroleum oil which is on the verge of extinction thus its price is also increasing at a higher rate. Furthermore these petrobased lubricants are poorly biodegradable and toxic in nature which is highly undesirable due to environmental concerns and health and safety of operator. This paper represents the investigation of tribological characteristics of non edible vegetable oils as bio lubricants. Formulated oil samples were refined castor oil and its blend with mahua oil at 10%, 20% and 30% mixing ratio. Wear and friction analysis is done using a pin on disk wear testing machine at various parameters like applied normal load, rotational speed and time. The results (wear rate, frictional force and coefficient of friction) indicate that blend of castor oil with mahua oil at 20% mixing ratio have tremendous capacity for being used in maintenance application particularly in gear applications. Keywords: Bio lubricants, Castor Oil, Mahua Oil, Tribological characteristics. 1. Introduction 1.1 Lubricant Lubricant is a substance which is applied between two relatively moving surfaces, to form a film which keeps the contacting surfaces apart. Lubricants help in reducing friction, wear and tear of machine parts due to relative motion. Lubricants can be solid, liquid, semisolid and gaseous (Denis, Briant and Hipeaux, 1997). Lubricants mainly consist of base fluid and additives to impart desirable properties. Conventional lubricants have petroleum oil as a base fluid. Petroleum based lubricants are the major cause of environmental pollution, because of their poor biodegradability and toxic nature (Aluyor et al., 2009). Due to higher environmental concerns there is a need of some alternate lubricants from non edible vegetable oils for industrial and maintenance applications. 1.2 Bio lubricants Vegetable oils are chemically triglycerides of fatty acids (Erhan and Asadauskas, 2000). Lubricants derived from edible or non edible vegetable oils are generally known as bio lubricants. It has been reported that bio lubricants have very high biodegradability in comparison with petroleum based lubricants (Ioan, 2002, Aluyor et al., 2009). The toxicity of bio lubricants is also very less or they are non toxic. Furthermore bio lubricants have almost similar performance properties that petrobased lubricants have (Masjuki et al., 2011). The objective of this paper is to show the wear and friction behavior of castor oil and its blend with mahua oil for maintenance application, and to perform comparative analysis of tribological properties with the conventional lubricant. Petroleum based lubricants used for comparison of results is () Servo Gear Oil 90 (T). These lubricants are used for extreme pressure hypoid gear oil. The performance standard of these oils meet IS: It is produced by an Indian Oil Corporation Ltd. India. Castor oil: Castor oil is a non edible vegetable oil obtained from the seeds of the castor plant. The botanical name is ricinus communis and castor plant is from euphorbiaceae family. Castor plants are available worldwide and also famous for its medicinal usage as a laxative. In India castor plants are available in abundance, and seeds from castor plants have an oil content of 40 to 60% by volume and have annual production of 271 MT (Chauhan and Chhibber, 2013). Castor oil is having high lubricity out of all the available non edible vegetable oils and also having high oxidative stability, (Singh, 2011, Politi et al., 2013) therefore it will be used as base oil

2 Investigation of Tribological Characteristics of Non Edible Castor and Mahua Oils as Bio Lubricant for Maintenance Applications Mahua oil: Mahua oil is a non edible vegetable oil obtained from the seeds of mahua plant. The botanical name is madhuca indica. It is a deciduous tree found in Uttar Pradesh, Madhya Pradesh, Gujarat, and Andhra Pradesh. Seeds from mahua plants have an oil content of 35 to 40% by volume (Jain and Suhane, 2012) and have annual production of 100 MT (Chauhan and Chhibber, 2013). In India very less work is done on mahua oil, but from the past work (Padhi and Singh, 2010) it is found that it is having the potential to be used as a bio lubricant. It will be used for blending with castor oil. Fatty acid composition and characteristics of castor and mahua oil is shown in table 1 and table 2. Table 1 Fatty acid composition of castor and mahua oil Characteristics Name Castor Oil Mahua Oil Saturated Acids C16 Palmitic C18 Stearic Unsaturated Acids C18:1 Oleic C18:2 Linoleic Ricinoleic Table 2 Characteristics of castor and mahua oil S.No Characteristics Castor oil Mahua oil 1 Colour Colourless to very pale yellow Slight Greenish yellow 2 Iodine Value Saponification Value mg KOH/g Acid Value mg <4 39 KOH/g 5 Pour Point o C Specific gravity 20 o C (g/cm3) Melting Point o C 8 Boiling Point (595 - C F) 9 Density kg/m Cloud Point o C Refractive index Seeds of the castor and mahua plant are the main source of oil production. Seeds of these plants are easily available in abundance and are very cheap (NOVODB, 2014). Seeds used for extraction of oil are rich in oil content and already pre-treated to remove any type of toxic or harmful content (Barnes et al., 2009). Oil is extracted from the seeds by using oil expeller; pure oil is available within minutes (Pradhan et al., 2011). Expeller is manually operated by a single person. Oil yield per tonne of castor seeds is 32 to 35% and of mahua seeds are 31 to 38% by this machine. The extracted oil is purified to remove any polluting compounds like gums, unwanted fatty acids etc. Oil purifying processes, which can be done, are degumming, a fatty acid separating process (neutralization), bleaching and deodorization. Blending of oil is done as per following plan shown in table 3. Table 3 Blending plan S.No Refined Castor Oil (ml) Refined Mahua Oil (ml) Mixing Ratio (%) Name RCO Blend Blend 3 2. Test Setup Pin on Disc (POD) Wear Testing Machine Tribological characteristics of a wide range of materials under conditions of various normal loads can be determined by the POD machine. A stationary pin mounted on a pin holder is brought into contact against a rotating disc at a specified speed. Pin slides in the presence of lubricating oil, introducing frictional force between the pin and disc (see, figure 1). Figure 1 Pin on disc wear testing machine 2.1 Test Specimen The typical pin specimen is cylindrical in shape. Typical cylindrical pin specimen diameter is 10 mm and length is 30 mm. The surface of the pin is finished because rough surfaces make wear measurement 416-2

3 5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th 14 th, 2014, IIT Guwahati, Assam, India difficult. Material used for making pins for testing is plain carbon steel also known as bright steel (IS: ). The disk material is mild steel on which the pin slides. 2.2 Test Parameters 1. Normal Load: Values of the force in Newton s at the wearing contact. For this experimental study the starting load was 5 N and it is varied upto 40 N. 2. Speed: The relative sliding speed between the contacting surfaces in metres per second. The test was performed at 200 and 300 RPM. 3. Time: Running time of experiment in minutes. For this experimental study the running time was 20 minutes. 4. Track Radius: The path generated is circle, so the specimen pin can be positioned over disc between 0 to 55 mm. For this experimental study the track radius was 50 mm. 5. Flow Rate: Flow of oil on the disk. A constant flow of oil is maintained for this experimental study to achieve a film between the contacting surfaces. 2.3 Output Parameters 1. Wear Rate (mm 3 /Nm): Material removal rate per unit parameter due to wear (ASTM G40, 1987, Williams, 2005]. 2. Frictional Force (N): Force exerted by a surface on a relative moving object across it (ASM, 1992). 3. Coefficient of Friction: A dimensional less quantity indicating the frictional force between the two relative bodies. 4. Sliding Distance: It is the linear distance travelled by the pin over the plate within given time interval if freed from the tool holder. Sliding distance evaluates the wear rate. Sliding distance does not vary with load, time, flow rate etc. It varies only with speed. The value of sliding distance reported at 200 RPM is m and at 300 RPM is m. 5. Sliding Velocity: Sliding velocity denotes velocity with which the pin slides over the plate. The value of sliding velocity reported at 200 RPM is m/s and at 300 RPM is m/s. 3. Analysis of Tribological Characteristics A starting load of 5 N was applied at the contact zone of a pin and disk and a constant flow of oil sample is maintained. The disk is rotated at 200 and 300 RPM and is allowed to run for duration of 20 minutes. After that wear rate, frictional force and coefficient of friction was measured for the particular load and speed. Further test was carried out at successively higher loads up to 40 N. The oil samples were RCO, Blend 1,, Blend 3 and. On the basis of the tests, curves were drawn for all the oils on a logarithmic scale, which shows the effect of load in N on the wear rate in mm 3 /Nm, frictional force in N and coefficient of friction. 3.1 Effect of Applied Normal Load on Wear Characteristics A comparative analysis with all oil samples is to be done to find the potential of formulated oil samples. Figure 2 exhibits a comparative study of the effect of normal load on the wear rate at 200 and 300 RPM for different oils. It is evident from the curve that the wear rate increased with increase in applied load for all the oils. Figure 2 Comparison of wear load curve for different oils at 200 and 300 RPM. The wear rate was found to increase with the increase in speed from 200 RPM to 300 RPM there is a slight change in the values of wear rate at the various applied normal load, this increase was slow at lower loads. It is clear from the values of Blend 1 and RCO that there is a slight reduction in the wear rate at particular load and speed. Blending with mahua oil is improving the wear resistant properties of refined castor oil about 8 to 10%. There is a drastic reduction in the values of wear rate of at particular load and speed compared to RCO. Blending with mahua 416-3

4 Investigation of Tribological Characteristics of Non Edible Castor and Mahua Oils as Bio Lubricant for Maintenance Applications oil at 20% mixing ratio is improving the wear resistant properties of refined castor oil about 13 to 15%. The values of Blend 3 show that there is a slight increase in the wear rate at particular load and speed compared to. Blending with mahua oil at 30% mixing ratio is not improving the wear resistant properties of refined castor oil as much as improved by 20% mixing ratio. The most comparative values with are of, showed almost the same value at lower load. The wear rate of Blend 1 is lesser than RCO & Blend Effect of Applied Normal Load on Frictional Force Aim of lubricant is to minimize this effect and thus it is quite important to study the behaviour of oils against friction. Figure 3 exhibits a comparative study of the effect of normal load on the frictional force at 200 and 300 RPM for different oils. and Blend 1 reveal that there is a slight reduction about 4 to 5% in the values of frictional force of Blend 1 than of the RCO. This is due to the addition of mahua oil in refined castor oil. The values of frictional force of show that there is a high reduction about 8 to 10% in the values of frictional force of the RCO. Further the values of frictional force of Blend 3 having a slight increase in the values of frictional force than of, but lower than of the RCO. It is clear from the values of frictional force of that the lowest values of frictional force than all other oil samples are of. It is quite evident from the trend shown through the figure 3 that the lowest frictional force shown by and the highest values are shown from RCO and Blend 3. The nearest values are shown by Blend 1 and the most comparable values with are shown by. 3.3 Effect of Applied Normal Load on Coefficient of Friction Lower coefficient of friction is desirable for proper functioning of equipments and reduces the energy loss. Figure 4 exhibits a comparative study of the effect of normal load on the coefficient of friction at 200 and 300 RPM for different oils. Figure 3 Comparison of frictional force for different oils at 200 and 300 RPM The figure 3 reveals the effect of applied normal load on the frictional force for RCO at 200 and 300 RPM. As usual, increasing the load caused higher frictional force. At a starting load of 5 N the frictional force was quite less, similar to the trend in wear rate, the frictional force increased steadily with increase in normal load. With the increase in speed from 200 RPM to 300 RPM there is a slight increase in the frictional force. The values of frictional force of RCO Figure 4 Comparison of coefficient of friction for different oils at 200 and 300 RPM The figure 4 reveals the effect of applied normal load on the coefficient of friction for RCO at 200 and

5 5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th 14 th, 2014, IIT Guwahati, Assam, India RPM. As usual, increasing the load caused higher coefficient of friction. With the increase in speed from 200 RPM to 300 RPM there is a slight increase in the coefficient of friction. It is clear from the values of the coefficient of friction of RCO and Blend 1, that there is a slight reduction about 7 to 10% in the values of the coefficient of friction of Blend 1 than of the RCO. This is due to the friction modifying tendency of mahua oil present in the blend. Similarly the value of the coefficient of friction of is reduced to 12 to 15% as compared to RCO. As compared to there has been a slight increase in the value for Blend 3. This could be probably due to the saturation effect. It is quite evident from the trend shown through the figure 4 that the lowest coefficient of friction shown by and the highest values are shown from RCO and Blend 3. The nearest values are shown by Blend 1 and the most comparable values with are shown by. The values of coefficient of friction of are in between 0.01 to 0.02 which is a good sign to be used as a lubricant. 3.4 Percentage Reduction for Wear Rate, Frictional Force and Coefficient of Friction The formulated oil sample was found to be giving the most comparable values of wear rate, frictional force and coefficient of friction with conventional oil. Table 4 shows the percentage reduction in the values with respect to dry condition. It is quite clear from the values of percentage reduction of is very near to the. Table 4 Percentage reduction with respect to dry condition at 200 and 300 RPM Percentage reduction in wear rate with respect to dry condition at 200 RPM Percentage reduction in wear rate with respect to dry condition at 300 RPM Percentage reduction in frictional force with respect to dry condition at 200 RPM Percentage reduction in frictional force with respect to dry condition at 300 RPM Percentage reduction in coefficient of friction with respect to dry condition at 200 RPM Percentage reduction in coefficient of friction with respect to dry condition at 300 RPM Maintenance Applications Certain findings from the above experimental work are as follows: Coefficient of friction was found to be less than 0.02, on an average 90 % reduction, thus results in lower energy losses and reduced fuel consumption. Average 45 to 63 % wear reduction, thus increase in mechanical operating efficiency, extension of application design life and a weak mechanical wear of the engine. Excellent anti wear properties increases service life of mechanisms. It also results in increased longevity and longer service intervals. 5. Cost Analysis of Bio Lubricant Servo gear oil 90 (T) used in the experimentation was procured from IOC outlet. The unit cost of this oil available in the market is Rs. 210 per liter. The castor and mahua oil used for bio lubricant preparation in the laboratory is available in the local market at bulk price of Rs. 60 per liter each. As per experimental observations, (80 % Castor oil + 20 % Mahua oil) has comparable properties to the servo grade oil. For commercial production of such blends with enhanced properties for gearing applications, including additional cost amounts to Rs. 50 to 100 then also the final user cost at the customer end would be lesser to servo grade oil. Taking into consideration the full accounting cost including operational, maintenance, environmental damage etc. bio lubricant is poised to have the upper hand than the servo grade oil. Castor oil based bio lubricants have immense potential in restoring the environmental calmness and reduced operational cost. 6. Conclusions This paper presents the assessment of tribological properties of the refined castor oil and its blend with refined mahua oil. The experimental study reveals findings which are discussed below: A major achievement of this research was the exploration of friction modifying tendency of refined mahua oil as an additive to refined castor oil. It was also observed that these blends of refined castor oil with the refined mahua oil have tremendous capacity to be used in gear applications. Coefficient of friction was found to be less than 0.02, on an average 90% reduction, thus higher reliability, better fuel economy and higher performance. Cost savings on account of less maintenance, man power, storage and disposal costs. Expected reduced maintenance costs of the machine as the decreased coefficient 416-5

6 Investigation of Tribological Characteristics of Non Edible Castor and Mahua Oils as Bio Lubricant for Maintenance Applications of friction will minimize the gradual degradation that a machine is exposed to during operation. Reduction of wear; average 45 to 63% wear reduction on metal parts, thus increase of mechanical operating efficiency and extension of application design life. The optimal mixing ratio for blend formulation is 20% beyond that the results are not effective, thus it can be effectively used in gearing applications. Refined mahua oil can be used as an environment friendly friction modifier additive. References Aluyor, E.O., Obahiagbon, K.O., Jesu, M.O. (2009), Biodegradation of vegetable oils: a review, Scientific Research and Essay, Vol. 4, pp ASM Handbook (1992), Friction, Lubrication and Wear Technology, ASM International, U.S.A., Vol.18. ASTM G40 (1987), Standard terminology relating to wear and erosion, Annual Book of Standards, Vol , pp Barnes, D.J., Baldwin, B.S., Braasch, D.A. (2009). Degradation of ricin in castor seed meal by temperature and chemical treatment, Industrial Crops and Products, Elsevier, Vol. 29, pp Chauhan, P.S., Chhibber, V.K. (2013), Non-edible oil as a source of bio-lubricant for industrial applications: a review, International Journal of Engineering Science and Innovative Technology, Vol. 2, pp testing, IEEE First Conference on Clean Energy and Technology CET, pp NOVODB (National Oilseeds and Vegetable Oils Development Board), (2014), Ministry of Agriculture, Government of India, Padhi, S.K., Singh, R.K. (2010), Optimization of esterification and transesterification of mahua (madhuca indica) oil for production of biodiesel, Journal of Chemical and Pharmaceutical Research, Vol. 2, pp Politi, J.R.S., Matos, P.R.R., Sales, M.J.A. (2013), Comparative study of the oxidative and thermal stability of vegetable oils to be used as lubricant bases, Journal of Thermal Analysis and Calorimetry, Vol. 111, pp Pradhan, R.C., Mishra, S., Naik, S.N., Bhatnagar, N., Vijay, V.K. (2011), Oil expression from jatropha seeds using a screw press Expeller, Bio Systems Engineering, Elsevier, Vol. 109, pp Singh, A. K. (2011), Castor oil-based lubricant reduces smoke emission in two-stroke engines, Industrial Crops and Products, Elsevier, Vol. 33, pp Williams, J.A. (2005), Wear and wear particles - Some fundamentals, Tribology International, Vol. 38, pp Denis, J., Briant, J. and Hipeaux, J.C. (1997), Lubricant Properties, Analysis and Testing, Editions Technip, pp Erhan, S.Z. and Asadauskas, S. (2000), Lubricant base stocks from vegetable oils, Industrial Crops Production, Vol.11, pp Ioan, S. (2002), On the future of biodegradable vegetable lubricants used for industrial tribo systems, Gal I Fascicie, VIII, Issue No Jain, A.K., Suhane, A. (2012), Research approach & prospects of non edible vegetable oil as a potential resource for bio lubricant - a review, Advanced Engineering and Applied Sciences: An International Journal, Vol. 1, pp Masjuki, H. H., Kalam, M. A., Nurul, M. F., Jayed, M. H., Liaquat, A. M., Varman, M. (2011), Environmentally friendly bio-lubricant lubricity 416-6