Extraction of Jatropha Bio-base Oil for Two-Stroke Engines

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Extraction of Jatropha Bio-base Oil for Two-Stroke Engines

Hunaida Abd Elbage Abazar Ahmed, Kamal Eldin Eltayeb Yassin

Chemical Engineering Department, University of Khartoum, Sudan

Abstract:- Bio-lubricant based oil was developed from Jatropha oil; it is considered the best alternative to traditional lubricants based on mineral oils and synthesis esters. This study intended ameliorating the environmental control measures of air pollutants by preparing base oil from local ingredients for two-stroke engines lubrication in Sudan. American Society for Testing and Materials has applied for analyzing the physiochemical characteristics of oil based on Jatropha. Based on the experiment conducted, we found that oil based on Jatropha as bio-lubricant has high flash point (266oC), viscosity index (354),American Petroleum Institute of 17, an acid number of

0.457 mg KOH/mg, carbon residue (0.001 w/w%), and low pour point of -13 0C. By comparing the obtained results with those of commercially used oils for two-stroke engines, the proposed alternative is far better in its quality and it meets the minimum requirements of international and local standards. Finally, it was recommended to use oil based on Jatropha oil for two-stroke engines to improve the environmental conditions by mitigating emissions from point sources. In addition, more research is needed to study future production and its quantities for the manufacture of bio-lubricants from local ingredients. One day, lubricants based on mineral oils will replaced with biologically based products in environmentally sensitive applications.

Keywords: Jatropha oil, Bio-lubricant, Two-stroke engines, Trans-esterification, Aryl-alkylation

1 INTRODUCTION

Two-stroke engines are considered total-loss type lubricating systems therefore the oil is mixed with fuel [1]. Emissions from 2- stroke engines can be reduced by rigorous inspection and maintenance programs and used of lubricating oil of correct quality and quantity [2, 3, 4]. Bio-lubricant oils are perceived as alternatives to mineral oils because they possess certain natural technical properties and they are biodegradable [5, 6].

Jatropha is small evergreen tree and grows in the wildness [7]. The oil is not fit for human consumption or animals therefore it could be used to produce bio-fuel that burns without hazardous emissions to the environment [8].

2 MATERIALS AND METHODS

    1. Materials

      Jatropha seeds were acquired from National Center for Agricultural and Forests Researches. Jatropha oil was extracted mechanically using cold pressing method to avoid water added during extraction process. It was analyzed for free fatty composition using gas chromatography analyzer in the central laboratory at Khartoum University (Table 2-1). Bio-lubricant base oil is extracted from Jatropha oil using acetic anhydride, 2-Ethyl-1- hexanol, sodium, Toluene, aluminum chloride and hydrochloric acid.

      Table 2-1: Fatty acid composition of Jatropha oil

      Fatty acid

      Composition %

      Unsaturated

      Palmitoleic (C16:1)

      0.8

      cis-10-Heptadcanoic (C17:1)

      0.2

      Oleic (C18:1)

      36.5

      Linoleic (C18:2)

      41.3

      cis-11-Eicosenoic (C20:1)

      0.2

      cis-13,16-Docosadienoic (C22:2)

      0.8

      Saturated

      Palmitic (C16:0)

      10.0

      Heptadcanoic (C17:0)

      0.1

      Stearic (C18:0)

      8.8

      Tricosanoic (C23:0)

      1.3

    2. Preparation of base oil

      1. Acetylation

        Acetylation was needed to provide the hydrocarbon solubility of Jatropha oil [9]. 250g of Jatropha oil was reacted with 80g of acetic anhydride under constant stirring. Acetic anhydride was added dropwise during a period of 45 min at 40-50oC. Then, the temperature was slowly raised to 120oC during the next 160 min while the contents were stirred constantly. The mixture was washed with distilled water from excess acetic anhydride until pH 6-7 (Figure 2-1).

        230g of acetylated Jatropha oil was mixed with 57.5g of toluene (25% of acetylated J. oil) and heated to 70oC, then the mixture was heated under vacuum (-0.6 bar, 66oC) in vacuum pan connected with distillation column to separate the water and toluene.

        Figure 2-1: Acetylation of Jatropha oil

      2. Trans-esterification

        200g of 2-ethyl-1-hexanol was heated with 1g of sodium in magnetic heater with constant stirring. The temperature of mixture was slowly raised until all sodium dissolved to give clear solution at 90oC. This sodium ethyl hexanoate was added to 218g of acetylated Jatropha oil in magnetic heater at 80-110oC with continuous stirring. Then the temperature of reaction was raised to 163-172oC for 22 hrs. (Figure 2-2) [10, 6].

        Figure 2-2: Trans-esterification of Jatropha oil

        Steam with 1.2 bar and 100oC was passed through the mixture until sodium ethyl hexanoate hydrolyzed. After 20hrs at room temperature, two layers were totally separated that were glycerol and ester. The ester was dissolved in toluene to remove the traces of water in vacuum pan at 66oC and -0.6 bar.

      3. Aryl-alkylation

        174g of ester was dissolved in 430g of toluene and cooled to -11oC in a freezer. 10g of AlCl3 was slowly added over a period of 55 min. During the addition, the temperature was allowed to rise to 3oC and the reaction mixture was maintained at 0oC for 12 and half hrs. with constant stirring. After that, the contents were poured into water with 10% hydrochloric acid and kept for 9 hrs. The upper layer was washed rapidly to remove the acidity. Then the upper layer was heated under vacuum (66oC and -0.6 bar) in vacuum pan to remove the washed water and the excess of toluene. The product was tolyl ethyl hexyl ester of Jatropha fatty acid (herein referred to JT) (Figure 2-3).

        Figure 2-3: Alkylation of Ethyl hexyl ester of Jatropha oil fatty acid

        2.3 Characterization of the base oil: laboratory analysis

        For characterization of JT oil, standard methods were used that were given in Table 2-2 and the experimental values are reported in

        Table 3-2. All tests were conducted in the professional laboratories of faculty of Engineering, Khartoum University.

        Table 2-2: Standard methods used for JT oil analysis

        Analysis

        Methods

        Kinematic viscosity

        ASTM D445

        Viscosity index

        ASTM D2270

        Density

        ASTM D4052

        API gravity

        ASTM for density, relative density or API gravity of crude oil.

        Pour point

        ASTM D97

        Flash point by Cleveland open cup

        ASTM D92

        Carbon residue

        ASTM D4530

        Water content

        ASTM D6304

        Copper corrosion

        ASTM D130

        Acid number and strong acid

        ASTM D644

  1. RESULTS AND DISCUSSION

    1. Materials balance

      In this study, lubricant based oil was prepared from Jatropha oil through three phases had been discussed in 2.2). The amount of chemicals that are required for those reactions had been calculated based on the stoichiometric equations Figure 2-1, Figure 2-2 and Figure 2-3 and was shown in Table 3-1.

      Table 3-1: The amount of chemicals was reacted to prepare JT oil

      The material

      Mole required for reaction

      Stoichiometric mass (g)

      Amount reacted (g)

      Jatropha oil

      1

      827.59

      250

      Acetic anhydride

      1

      102.09

      80

      Acetylated J. triglyceride

      1

      911.68

      218.19

      2-Ethyl-1-hexanol

      3

      390.69

      200

      Ethyl hexyl ester of J. fatty acid

      1

      1210.28

      174

      Toluene

      1

      92.14

      430

      Catalyst

      Sodium

      1

      Aluminum chloride

      10

    2. Physio-chemical characteristics of JT oil

      Jatropha oil is high rich in oleic oil (C18:1) and Linoleic (C18:2), having around 77% of C18:1 and C18:2 (Table 2-1). Oleic is considered more stable than other un-saturated fatty acids [11]. However, hydroxyl group makes it insoluble in gasoline. Pour point and viscosity index below 95 also was not desirable therefore; raw Jatropha oil could not be used for 2T oil as such. Flash point was suitable for its application as lubricants. Considering all properties, it was needed to be converted to aryl-alkylated ethyl-hexyl ester [12]. After the conversion, its viscosity index of 354 (

      Table 3-2) was met the minimum requirement of 90 and kinematic viscosities at100oC was 26.12 cSt. JT oil had a flash point of above 250oC as measured, which it is considered safe product for storage and transportation. Pour point of it was 13oC as

      determined that means there is no trouble to use in Sudan during summer and winter without the addition of polymer or pour point depressant as due to metrological conditions of Sudan.

      For Copper strip corrosion, JT oil was classified as 1a after the copper strip was heated at120oC for 3 hrs. according to ASTM D130, which is met the minimum requirement of standard. The TAN- should not be more than 0.5 mg KOH/g as is prescribed by standard specifications for petroleum turbine lubricating oils stability, which was possible due to chemical modification of Jatropha oil (

      Table 3-2). Fatty acid monoesters are more stable than vegetable oils.

      The developed base-stock (JT oil) of two-stroke engines from Jatropha oil was in conformity with specifications, which was a significant achievement.

      Table 3-2: Physio-chemical characteristics of JT oil

      Characteristic

      Method of test

      Actual specification

      Targeted specs.

      Density @ 30oC (g/ml)

      ASTM D4052

      0.943

      To be reported

      Density @ 15oC (g/ml)

      ASTM D4052

      0.953

      To be reported

      API

      17.0

      > 10

      Kinematic viscosity @40oC (cSt)

      ASTM D445

      79.06

      45 min

      Kinematic viscosity @100oC (cSt)

      ASTM D445

      26.12

      6.5 min

      Viscosity index

      ASTM D2270

      354

      90 min

      Flash point (oC)

      ASTM D92

      266

      70 min

      Pour point (oC)

      ASTM D97

      -13

      -6 max

      Carbon residue (w/w %)

      ASTM D4530

      0.001

      0.6 max

      Water content (vol. %)

      ASTM D6304

      0

      0.03 max

      Copper strip corrosion (3h/120oC)

      ASTM D130

      1a

      1 max

      Total acid number (mg KOH/g)

      ASTM D664

      0.457

      0.5 max

      Strong acid number

      ASTM D664

      Nil

      Nil

  1. CONCULUSION

    The bush "Jatropha represents the most important trees, on which interest began to a large extent, within the framework of a new concept called the project of cultivating energy that can be an alternative to mineral oils, petroleum based oils and petroleum- derived fuel.

    In response to reducing the amount of air pollutants, automobile fuels and lubricants offer the most plausible solution to obtaining renewable and eco-friendly lubricants. Renewable, biodegradable and environmentally friendly base oil was prepared from local an ingredient that is Jatropha oil. Jatropha based oil has high flash point (266oC), viscosity index (354), carbon residue (0.001wt%), an acid value of 0.457 mg KOH/g, density @15oC of 0.953 g/ml and low pour point of -13oC. Jatropha based oil is more viscous than the standard engine super 20w/50 and has lower acid values than the mineral lubricant, which makes it of higher yield or quality.

  2. REFERENCES

  1. AMSOIL, "Two-cycle Engine Applications and Lubrication Needs," AMSOIL Action News, July 2001.

  2. K. E. Yassin, Pollution by 2-Stroke Engines, Khartoum: Sudanese Standard and Metrology Organization, 2017.

  3. M. Islam, "STRATEGIES TO PHASE OUT LEADED GASOLINE AND TWO STROKE ENGINES IN BANGLADESH: TECHNICAL, ECONOMIC, AND PUBLIC HEALTH CONSIDERATIONS.," Environmental Protection Agency, US, 1999.

  4. Jsong, "Emission Control of Two- and Three-Wheel Vehicles," Manufacturers of Emission Controls Association, 2014.

  5. A. K. Jain and A. Suhane, "Capability of Bio-lubricants as alternative Lubricant in Industrial and Maintenace Applications," International Journal of Current Engineering and Technology, vol. 3, no. 2277- 4106, pp. 179-183, 2013.

  6. P. S. Chauhan and V. K. Chhibber, "Non-Edible Oil as a Source of Bio-Lubricant for Industrial Applications," International Journal of Engineering Science and Innovative Technology (IJESIT), vol. 2, no. 1, pp. 299-305, January 2013.

  7. R. Misra and M. Murthy, "Jatropha the future fuel of india," Renewable and Sustainable Energy Reviews, vol. 15, pp. 1350-1359, 2011.

  8. A. Alhaj, "Jatropha tree to help produce fuel," Sudan Now Magazine, Khartoum, 2011.

  9. G. O and F. H, "Acetylated castor oil," Ind. Eng. Chem, vol. 37, no. 5, pp. 485-491, 1945.

  10. C. Y. May, "Transesterification of Palm Oil: effect of reaction parameters," Oil Palm Research, vol. 16, no. 2, pp. 1-11, 2004.

  11. E. S.Z., S. B.K. and P. J.M., "Oxidation and low temperature stability of vegetable oil-based lubricants," Ind. Crop. Prod., vol. 24, pp. 292-299, 2006.

  12. S. A.K., "Mono-ester of high viscosity from vegetable oils," in 10th lubricating Grease Conference Proceeding (NLGI), Aurangabad, 2008.

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