Comparative Study of Biodiesel Production from Pure Sunflower oil and Waste Sunflower Oil.

P.S. Vishwe*, S.T. Deshpande, M.B. Shinde, D.G. Baheti.

SCSSS’s Sitabai Thite College of Pharmacy, Shirur.

ABSTRACT:

Comparison of the optimum conditions of alkaline-catalyzed transesterification process for biodiesel production from pure sunflower oil (PSCO) and waste sunflower oil (WSCO) through transesterification process using alkaline catalysts was studied. To obtain a high quality biodiesel fuel that comply the specification of standard methods, some important variables such as reactants and catalytic activities were selected. The highest approximately 99 % biodiesel yield acquired under optimum conditions of 5:1 volumetric oil-to-methanol ratio, 0.35% NaOH catalyst at 50ºC reaction temperature. The research demonstrated that biodiesel obtained under optimum conditions WSCO was of good quality and could be used as a diesel fuel which considered as renewable energy and environmental recycling process from waste oil after frying.

KEYWORDS: Biodiesel, Transesterification, Sunflower cooking oil, Waste cooking oil

INTRODUCTION:

Biodiesel is advised for use as an alternative fuel for conventional petroleum-based diesel chiefly because it is a renewable, domestic resource with an environmentally friendly emission profile and is readily biodegradable (Zhang et al., 2003). The amount of greenhouse gas emissions, generating energy from renewable resources is being possessed a high priority gradually to decrease both over-reliance on imported fossil fuels (Blanco-Canqui and Lal, 2007). Biodiesel refers to all kinds of alternative fuels derived from vegetable oils or animal fats. The prefix bio refers to renewable and biological nature, in contrast to the traditional diesel derived from petroleum; while the diesel fuel refers to its use on diesel engines (Carlos A 2011). The ASTM (American Society for Testing and Materials Standard) describes the biodiesel as esters monoalkyl of fatty acids of long chain that are produced from vegetable oil, animal fat or waste cooking oils in a chemical reaction known as transesterification. The most common way to produce biodiesel is by transesterification, which refers to a catalyzed chemical reaction involving vegetable oil and an alcohol to yield fatty acid alkyl esters (i.e., biodiesel) and glycerol (Fig.1). Triacylglycerols (triglycerides), as the main component of vegetable oil, consist of three long chain fatty acids esterified to a glycerol backbone. When triacylglycerols react with an alcohol (e.g., methanol), the three fatty acid chains are released from the glycerol skeleton and combine with the alcohol to yield fatty acid alkyl esters (e.g., fatty acid methyl esters or FAME). Glycerol is produced as a by-product. Methanol is the most commonly used alcohol because of its low cost and is the alcohol of choice in the processes developed in this study (Zhang et al., 2003).

The high viscosity and poor volatility are the major limitations of vegetable oils for their utilization as fuel in diesel engines. Because high viscous vegetable oils deteriorate the atomization, evaporation and air-fuel mixture formation characteristics leading to improper combustion and higher smoke emission. Moreover this high viscosity generates operational problems like difficulty in engine starting, unreliable ignition and deterioration in thermal efficiency. Converting to biodiesel is one of the options to reduce the viscosity of vegetable oils (Paugazhabadivu et al., 2005).

As an alternative fuel, biodiesel can be used in neat form or mixed with petroleum- based diesel. Biodiesel, as an alternative fuel, has many merits. It is derived from a renewable, domestic resource, thereby relieving reliance on petroleum fuel imports. It is biodegradable and non-toxic. Biodiesel has a relatively high flash point (150⁰C), which makes it less volatile and safer to transport or handle than petroleum diesel (Krawczyk, 1996). It provides lubricating properties that can reduce engine wear and extend engine life (Von Wedel, 1999). In brief, these merits of biodiesel make it a good alternative to petroleum based fuel (Zhang et al., 2003).

The first objective of this study aims to compare the optimum conditions of fatty acid methyl ester or biodiesel production from pure and waste sunflower oil through transesterification process using alkaline catalyst.

MATERIALS AND METHODS:

Materials:

Pure Sunflower cooking oil (PSCO) was purchased from local grocery shop. The waste cooking sunflower oil (WSCO) was obtained from restaurants. To remove impurities the WSCOs were filtered under vacuum.

Transesterification:

The transesterification reaction of pure sunflower oil and waste sunflower oil was carried out in 500ml conical flask, with anhydrous methanol in molar ratio methanol to oil 1:5, using sodium hydroxide as a catalyst. The reaction was carried out at 50⁰C for 60min. By the end of the experiment the reaction mixture was transferred to a decanter for glycerol and methyl ester separation, allowing glycerol to separate by gravity for 24hr. The purity level of the biodiesel has strong effects on its fuel properties. Therefore, the methyl ester was purified by washing gently with three volumes of warm distilled water to remove residual catalyst, glycerol, methanol and soap using centrifuge.

Sunflower oil methyl ester analysis:

Several parameters have been analyzed by specific methods to verify whether the products fulfill the specifications. Viscosity was measured in centipoises at room temperature using Brookfield viscometer (FungiLab). Acid value was measured using titration method.

RESULT AND DISCUSSION:

The important properties of PSCO and WSCO are compiled in Table 1. The acid values expose the low amount of free fatty acids (FFA) in both types of oils. In contrast, WSCO has significantly high viscosity than PSCO.

Table No. 1: Important properties of PSCO and WSCO.

Sr No

Name of Oil

Density (gm/ml)

Viscosity

(mm²/ s)

Acid Value

(mg of KOH/gm oil)

PSCO

0.918

44.05

0.5

WSCO

0.922

53.29

1.5

The results also show that viscosity and acid value of WSCO are significantly higher than pure one. In two recent studies (Turkan and Kalay, 2006; Oliveira and Rosa, 2006), it has been found that almost 90% of the total fatty acids of commercial sunflower oil are composed of two double bonds containing oleic acids.

Analyzing biodiesel achieved under optimum condition:

As above conferred, both pure and waste cooking sunflower oil can be consumed as fuel in diesel engines, but the main obstacle to use the oil as fuel is its high viscosity (consecutively 44.05 and 53.29 mm²/s ; Tables 1 and 2) which create problems in atomization of the fuel spray and operation of the fuel injectors. The obtained free fatty acid alcohol esters or biodiesel from both oil through transesterification process have lower viscosity of 14.09 and 4.89 mm²/s (Table 2). The biodiesel samples produced under optimum condition of 5:1 volumetric oil-to-methanol molar ratio, 0.35 % KOH catalyst and 50ºC reaction temperature were analyzed concerning some significant specifications as fuel in diesel engine. These results are shown in Table 2. Most of these properties fulfill the restrictions of biodiesel standard in ASTM D 6751 and EN 14214. In contrast biodiesel obtained from WSCO has slightly higher acid value (0.44 mg KOH/ g oil) than biodiesel produced from PSCO (0.33 mg KOH/g oil). Additionally biodiesel produced from WSCO has higher viscosity. Viscosity is the most essential property of diesel fuel because it influences the wear rate of engine components (Kalam and Madjuki, 2002).

Table No. 2: Comparison of biodiesel produced from PSCO and WSCO.

Sr. No

Property

Unit

Value according to standard method

Biodiesel

(PSCO)

Biodiesel

(WSCO)

Viscosity

mm²/ s

1.9-6.0

14.09

4.89

Acid number

mg KOH/ g oil

0.50 max

0.33

0.44

CONCLUSION:

The optimum conditions for biodiesel production from WSCO and PSCO have been studied. Result shows optimal condition of sunflower oil biodiesel productions are 5:1 volumetric oil-to-methanol molar ratio, 0.35 wt. % KOH at 50⁰C reaction temperature. This study has provided evidence that waste cooking sunflower oil may be employed as a substantial source of biodiesel as fuel in diesel engines. Because, the produced biodiesel is of good quality within the array of standard method specifications and the production yield is up to approximately 99% under optimum conditions. Moreover, this research represented that the production of biodiesel from PSCO and WSCO has significant difference with respect to its viscosity. Advance research is ongoing to reduce the production cost by developing a method to decrease the emulsification during base catalytic transesterification and aqueous-washing of the product and readily recovery of glycerin byproduct. Biodiesel from used cooking sunflower oil could be used as a diesel fuel which considered as renewable energy and environmental recycling process from waste oil after frying.

ACKNOWLEDGEMENT:

A pleasant job remains to sit back and reflect on the pleasure and pains and acknowledge the efforts of all who helped to make this successful. I would like to acknowledge and my obligation to our principal Mr. D. G. Baheti for providing the necessary facilities. I would like to thank RJPDFT to give me opportunity for presenting research article regarding my interested topic. Lastly, I would like to express my gratitude to my parents who always supported and encouraged me. Thus I have solemnized my participation in this research with dedication to make it success.

REFERENCES:

· Blanco-Canqui H and Lal R. Soil and crop response to harvesting corn residues for biofuel production. Geoderma, 141;1996:355-362.

· Carlos A, Guerrero F, Andrés Guerrero-Romero and Fabio E. Sierra. Biodiesel Production from Waste Cooking Oil, In Biodiesel - Feedstocks and Processing Technologies, Dr. Margarita Stoytcheva (Ed.), 2011.ISBN: 978- 953-307-713-0, InTech,

· Kalam MA and Madjuki HH.. Biodiesel from palm oil – an analysis of its properties and potential. Biomass and Bioenergy, 23; 2002: 471-479.

· Oliveira AC and Rosa MF. Enzymatic transesterification of sunflower oil in an aqueousoil biphasic system. J. Am. Oil Chem. Soc., 83; 2006:21-25.

· Paugazhabadivu M and Jeyachandran K. Investigations on the performance and exhaust imissions of a diesel engine using preheated waste frying oil as fuel. Renewable Energy, 30;2005: 2189- 2202.

· Turkan A and Kalay S. Monitoring lipasecatalyzed methanolyses of sunflower oil by reversed- phase high-performance liquid chromatography: Elucidation of the mechanisms of lipases. Journal of Chromatography, A 127; 2006:34-44.

^·Zhang Y, Dube MA, Mclean DD and Kates M. Biodiesel production from waste cooking oil: 1. Process design and technological assessment. Bioresource Technology, 89;2003: 1-16.

Received on 22.04.2013

Modified on 10.05.2013

Accepted on 15.05.2013

Research Journal of Pharmaceutical Dosage Forms and Technology. 5(3): May- June, 2013, 171-173