Twelve International Conference on Thermal Engineering: Theory and Applications February 23-26, 2019, Gandhinagar, India

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Biodiesel Production from Castor Seeds (Ricinus communis) oil using Hydrodynamic Cavitation

1,3Utkarsh Mistry,

1,3Kartikkumar Thakkar,

2,3Pravin Kodgire,

1,3Surendra Singh Kachhawaha

1Mechanical Engineering Department, Pandit Deendayal Petroleum University, Gandhinagar-382007, Gujarat, India 2Chemical Engineering Department, Pandit Deendayal Petroleum University, Gandhinagar-382007, Gujarat, India

3Center of Biofuel & Bioenergy Studies, Pandit Deendayal Petroleum University, Gandhinagar-382007, Gujarat, India

Abstract

In India, annual production of castor seed is 1.43 million tonnes and can be considered as useful source for methyl ester production. The present work demonstrate the application of hydrodynamic cavitation method for the production of biodiesel by using castor oil as feedstock in the presence of potassium hydroxide (KOH) as a catalyst. Three main factors with respective ranges (three levels) considered for the present study are: (i) methanol to oil molar ratio (1:6 to 1:10) (ii) potassium hydroxide concentration (0.6% to 1.4%) (iii) Temperature (30 ℃ to 60 ℃). The preliminary experiments, show

maximum biodiesel yield of 80.40% obtained in 100 minutes of reaction time. Keywords: Hydrodynamic Cavitation, castor oil, Biodiesel, Transesterification

1. Introduction

Nowadays, the world community is facing different

challenges like ozone layer depletion, rapid reduction of fossil fuel, and global warming. Biodiesel is one of the alternatives to fossil fuel and a solution to environmental problems. India produced 1.43 Million tonnes of castor seeds in 2018-19 [1] and approximately 45-50% of oil can be extracted from castor seeds. There are many methods available for the biodiesel production like mechanical stirring, hydrodynamic cavitation, microwave, supercritical reactor, and ultrasonic cavitation. Ultrasonic intensification has limitations for scale up possibilities moreover, higher ultrasound power may result in soap formation which reduces the biodiesel yield. Microwave is also an effective intensification technique, however higher microwave power may cause damage to organic molecules and has risk with safety aspects [2]. Hydrodynamic cavitation is an energy effective process as the reaction occurs around atmospheric conditions [3]. With increase in pressure cavitation phenomena accelerate due to which biodiesel yield is increases [4]. During the cavitation process small bubbles form, grow and collapse rapidly. As a result, high local pressure is generated which is used for the acceleration of the transesterification reaction.

The effect of operating parameters (methanol to oil molar ratio, catalyst amount and reaction temperature) is important to study for optimization of reaction through hydrodynamic cavitation [5]. Dhyaneshwar Ghayal et. al [4] studied geometric parameters for optimization of the cavitation yield. Different numbers and size of orifice plates were used to optimize reaction conditions to obtain more than 95% of FAME conversion in 10 min. The Hydrodynamic cavitation process is simple, efficient, time saving, eco-friendly and industrially viable process due to its scale up possibilities [6]. Different edible and non-

edible oils [7] have been used by the researchers to produce biodiesel using different techniques. However only few studies are available for biodiesel production from non-edible oil using hydrodynamic cavitation [8,9].

Therefore, principle objectives of the present study are to develop an experimental setup based on hydrodynamic cavitation and by applying suitable design of experimental technique, collection of experimental data to determine optimum reaction conditions. .

2. Experimental

2.1. Materials

Castor oil used in the present experiment was

purchased from the local castor oil manufacturer “Laxmi Castor Oil”, Rajesh Sales Corporation situated in Saraspur, Ahmedabad, India. Methanol with more than 99.5% Assay was purchased from “Finar Limited” which is situated at Sanand, Ahmedabad, India. Catalyst (potassium hydroxide flakes) was used in the experiment and was acquired from “Merck Specialities Private Limited”, Mumbai, India.

Gas chromatography (GC) analysis was carried out with n-Heptane as a solvent (purity 99.0%) which was acquired from “Finar Limited”, Sanand, Ahmedabad, India.

2.2. Experimental Setup

Hydrodynamic cavitation reactor of maximum 5 L

capacity (approximate 1.5 L sample used for an experiment) was connected with two separate tanks (one for oil and other for methanol and catalyst). Main storage tank was provided with the electric heater to control temperature and was connected with a pressure pump with the maximum pressure capacity of 5 bar in the downstream side. Pump is attached with nozzle (throat dia- 1.2mm) through flow meter. There are pressure

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gauge, thermocouple, and rotameter provided for the measurement of upstream pressure, flow temperature and flow rate of reactant mixture respectively. One more tank was provided to carry exit jet of a nozzle. At the bottom of the tank, a sample collection ball valve is provided for taking samples as shown in Fig 1.

Fig.1. Hydrodynamic Cavitation Setup

Energy meter is attached with the setup for

measurement of energy consumption during each experiment.

2.3. Sample Preparation and Collection

The sample was prepared by using 1.5 L of castor

oil. Methanol was added in the sample according to oil to methanol ratio of 1:6 to 1:10 and the catalyst was added 0.6% to 1.4% (%w/w) of the oil. Oil was preheated up to sample temperature outside of cavitation reactor and then added in the mixer tank. Methoxide solution (methanol with dissolved KOH) was added in the raw oil. The mixer temperature was maintained constant in the cavitation reactor with the help of electric heater.

During the experiment, approximately 5 ml Sample was collected at 5, 10, 15, 20, 30, 40, 50, 60, 80, 100, and 120 min. Each collected sample was stored at -20 ℃

temperature in freezer. Initial experiment was taken by considering 1:6 oil to methanol molar ratio, 1% catalyst and 30℃ temperature. The remaining experiments will be

performed by using Box-Behnkan Design as show in Table 1 and the results will be presented in the conference.

Table.1. Experiments based on Box-Behnkan design

Run Order Temperature(℃) Molar Ratio Catalyst (%)

1 30 1:8 1.4

2 60 1:6 1

3 60 1:8 1.4

4 45 1:10 1.4

5 60 1:10 1

6 45 1:8 1

7 45 1:6 0.6

8 30 1:6 1

9 45 1:10 0.6

10 30 1:10 1

11 45 1:6 1.4

12 45 1:8 1

13 60 1:8 0.6

14 30 1:8 0.6

15 45 1:8 1

2.4. Analysis

Methyl ester conversion in sample was analyzed

using Agilent GC 7890 equipped with HP-5MS Capillary column (length- 30 m, diameter- 0.25 mm, and film thickness- 0.25 μm).

Following Method is adopted for the GC analysis: Initial temperature was set at 45 °C and held for 1 minute. First ramp was given as 10 °C/minute before reaching to 100 °C. From 100 °C to 200 °C, ramp of 5 °C/min was set and held at the same for 1 minute. Last ramp was given as 3 °C/min before reaching to 250 °C oven temperature where it was held for 10 minutes.

2.5. Yield Calculation

Yield of COME (castor oil methyl ester) is calculated by using following Eq. 1 [10]

(1)

Methyl ester production per unit kWh of energy input is calculated by,

(2)

3. RESULTS

3.1. Physical and chemical characteristics of raw Castor oil

Physical properties of raw castor oil is measured and

shown in Table 2 Table.2. Physical Properties of raw castor Oil

Properties Value

Density (kg/m3) 960

Kinematic Viscosity (mm2/s) 205 ± 0.05

Pour Point (℃) < -25

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The lipid profile of castor oil was analyzed by GCMS

and details are shown in Table 3 Table.3. Fatty Acid Profile of Raw Castor Oil

Fatty Acid name % composition

Ricinoleic Acid 83.84

Linoleic Acid 6.08

Oleic Acid 5.71

Palmitic Acid 2.09

Stearic Acid 2.09

3.2. Product Yield Analysis

Fig. 2. % Conversion of methyl ester with time (molar ratio-

1:6, Catalyst amount- 1%, and Temperature- 30℃)

Percentage conversion of fatty acid methyl ester (FAME) in collected samples at different time intervals are shown in Fig 2. After performing initial set of experiments, Maximum percentage conversion of FAME was 91.82% in 100 min. Energy consumption was measured during this experiment and was found to be 0.134 kWh for an oil batch of 1.5 liter at 30 °C reaction

temperature. Yield measured was 80.40% and Methyl ester production per unit kWh energy input is 8.64 L/kWh. The collection of yield data based on suggested design of experiments are under progress and will be presented during conference.

4. CONCLUSION

The Present study shows that the Hydrodynamic cavitation is the effective and energy efficient method for biodiesel production from castor seeds oil. During primary run, yield was measured 80.40% (molar ratio- 1:6, Catalyst amount- 1%, and Temperature- 30℃). The

present method is easy for scale up and produce higher production as compared to conventional methods.

Acknowledgments Authors would like to thank Gujarat Energy

development Agency (GEDA) for providing an economic support for preparing the following study. Authors like to thank center of Bio-fuel and Bio-Energy Studies lab, PDPU, Ahmedabad for providing lab facilities.

References

[1] Agriwatch, Castor Seed & Oil Monthly Research

Report, n.d.

[2] A. Talebian-Kiakalaieh, N.A.S. Amin, H. Mazaheri, A review on novel processes of biodiesel production from waste cooking oil, Appl. Energy. 104 (2013) 683–710.

[3] V.L. Gole, K.R. Naveen, P.R. Gogate, Hydrodynamic cavitation as an efficient approach for intensification of synthesis of methyl esters from sustainable feedstock, Chem. Eng. Process. Process Intensif. 71 (2013) 70–76.

[4] D. Ghayal, A.B. Pandit, V.K. Rathod, Optimization of biodiesel production in a hydrodynamic cavitation reactor using used frying oil, Ultrason. Sonochem. 20 (2013) 322–328.

[5] L.F. Chuah, S. Yusup, A.R.A. Aziz, A. Bokhari, J.J. Klemeš, M.Z. Abdullah, Intensification of biodiesel synthesis from waste cooking oil (Palm Olein) in a hydrodynamic cavitation reactor: effect of operating parameters on methyl ester conversion, Chem. Eng. Process. Process Intensif. 95 (2015) 235–240.

[6] A. Pal, A. Verma, S.S. Kachhwaha, S. Maji, Biodiesel production through hydrodynamic cavitation and performance testing, Renew. Energy. 35 (2010) 619–624.

[7] M.M. Gui, K.T. Lee, S. Bhatia, Feasibility of edible oil vs. non-edible oil vs. waste edible oil as biodiesel feedstock, Energy. 33 (2008) 1646–1653.

[8] M. Franke, B. Ondruschka, P. Braeutigam, Hydrodynamic-acoustic-cavitation for biodiesel synthesis, in: 3rd Int. Conf. Environ. Chem. Biol., 2014: pp. 23–30.

[9] M.A. Kelkar, P.R. Gogate, A.B. Pandit, Intensification of esterification of acids for synthesis of biodiesel using acoustic and hydrodynamic cavitation, Ultrason. Sonochem. 15 (2008) 188–194.

[10] K. Thakkar, K. Shah, P. Kodgire, S.S. Kachhwaha, In-situ reactive extraction of castor seeds for biodiesel production using the coordinated ultrasound – microwave irradiation: Process optimization and kinetic modeling, Ultrason. Sonochem. (2018). doi:10.1016/j.ultsonch.2018.08.007.

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