Int. J. Engg. Res. & Sci. & Tech. 2014

S R Satpute et al., 2014 ISSN 2319-5991 www.ijerst.com Vol. 3, No. 3, August, 2014 © 2014 IJERST. All Rights Reserved

Research Paper

ACID VALUE REDUCTION OF JATROPHA OIL FOR HIGH QUALITY BIODIESEL Rupali Bhole1, P V Chavan1 and S R Satpute1*

*Corresponding Author: S R Satpute,
[email protected]

Biodiesel as fuel is crucial for future energy sustainability. Feedstock selection is an important consideration for biodiesel preparation because of high amounts of free fatty acid content that hinders conversion. In present work, Jatropha oil was used as a feedstock for producing biodiesel. Jatropha oil was esterified using acid catalyst (sulphuric acid) by esterification process and reduces the free fatty acid content of Jatropha oil. Important variables are studied that affect acid value during esterification such as free fatty acid to methanol ratio, catalyst concentration and reaction time on were studied. Initial acid value of Jatropha oil was found 17 mg-KOH/g-oil and it reduces below 8.1 mg-KOH/g-oil in 1h under the conditions of 1:50 molar ratio of FFA: methanol, 20 wt% H2SO4 of oil at 63-64°C. Alkaline catalyst (Sodium Methoxide) was used for transesterification process to produce biodiesel using Jatropha oil as source material (reduced acid value). Keywords:

Acid value, Jatropha oil, Esterification, Transesterification

INTRODUCTION

terification is the important process for production of biodiesel. It is the chemical reaction of fat or oil with an alcohol in a presence of a catalyst to form esters and glycerin. Methanol is used for production of biodiesel because of its physical properties and lower cost. Different types of homogeneous catalyst are sodium hydroxide, potassium hydroxide and sodium methoxide for transesterification. Methyl ester is the main product of transesterification and the by product is glycerol. The reaction of triglycerides with alcohol is represented by the general equation:

Biodiesel is renewable, biodegradable, non-toxic and free of sulfur and aromatics. Biodiesel has better properties than petrodiesel fuel. Biodiesel is a monoalkyl esters of long-chain fatty acids derived from vegetables oils or animal fats. Alternative fuels for diesel engines has drawn considerable attention and is increasingly important to control air pollution (Demirbas A, 2008; Demirbas A, 2009). Four ways to prepare biodiesel: Direct use and blending, micro emulsions, thermal cracking and transesterification (Ma and Hanna, 1999). Transes1

where R1, R2, R3 are fatty acid chains. Five

College of Engineering, Bharati Vidyapeeth Deemed University, Satara Road, Pune-411 043.

This article can be downloaded from http://www.ijerst.com/currentissue.php 228

Int. J. Engg. Res. & Sci. & Tech. 2014

CH2-O-CO-R1

S R Satpute et al., 2014

(CATALYST)

| CH-O-CO-R2

| + 3ROH

CH2-OH +

|

|

CH2-O-CO-R3 Triglycerides

CH2-OH

Alcohol

R-O-CO-R1 | R-O-CO-R2

(1)

|

CH2-OH

R-O-CO-R3

Glycerol

Biodiesel

transesterification reaction to produce fuel-grade biodiesel. Anya et al., (2012) carried work on the effect of various methanol and sulphuric acid concentrations on acid value in neem seed oil during esterification, indicating the almost effective combinations at a fixed reaction time of 1hr, temperature of 60°C, agitation rate of 150rpm and separation time of 1hr and optimization of methanol and acid concentration during its pretreatment for making biodiesel. After pretreatment of neem seed oil, the esterified oil was subjected to transesterification process to ascertain the yield of it methyl ester.

main types of chains in biological sources are palmitic, stearic, oleic, linoleic and linolenic. In this work, pre-esterification factors were investigated. The acid value was lowered after the preesterification process. If Jatropha oil was directly used in transesterification process, it results in formation of soap and hinders separation of methyl ester from mixture (Dennis et al., 2010). Bobade et al., (2012) studied the feedstock contain less amount of free fatty acid (<5%), do not require pretreatment. Biodiesel was prepared by using alkali catalyst. If high content free fatty acid of feedstock (>5%), then oil catalyzed by alkaline catalyst and that makes soap formation. The separation of the two phases such as methyl ester and glycerol will be more difficult. Houfang et al., (2009) developed a two-step process for preparation of Methyl ester (Biodiesel) from J. curcas L. oil. Using esterification, biodiesel was produced by acid catalyst (Sulphuric acid) before transesterification and maintain its acid value below 1.0 mg-KOH/g-oil at specified condition. In esterification, FFA conversion was greater than 97%. During transesterification, the methyl ester yield was greater than 98%. Canakci et al., (2001) did work on the study of methyl ester production from feedstocks with high amount of free fatty acid. A process was explained to reduce the FFAs (<1%) contains in raw oils using pretreatment with an acid catalyst. Alkaline catalyst was used for

Study of the optimization conditions of Biodiesel/Mahua Oil Methyl Ester (MOME) preparation from Mahua oil was done by Padhi et al., (2010). This paper presents. Using acid catalyst, the FFA of Mahua oil was reduced 30% to lower than 1%. The results show that optimum conditions for esterification: 4% H2SO4, 0.33% v/ v alcohol/oil ratio, 1 hr reaction time and 65°C temperature. Optimum conditions for transesterification: 8% Sodium Methoxide, 0.33%v/v alcohol/oil ratio, 1 hr reaction time, 65°C reaction temperature and 150% v/v excess alcohol. Jatropha oil content reduction by esterification was not sufficiently studied in detail. Acid value relates to FFA content in oil which is bottleneck for biodiesel production. Hence, present study

This article can be downloaded from http://www.ijerst.com/currentissue.php 229

Int. J. Engg. Res. & Sci. & Tech. 2014

S R Satpute et al., 2014

focuses on systematically study effect of FFA to methanol ratio, sulphuric acid concentration and reaction time etc. on acid value during esterification.

Transesterification

The chemicals used to carry this experiment such as methanol (99.5%), sulfuric acid (98%) and sodium methoxide were of analytical grade. Magnetic stirrer used for production of Biodiesel. Hence, it was determined that about 17% of free fatty acid makes Jatropha oil inappropriate for biodiesel production. Two-step method was used to produce biodiesel from Jatropha oil.

In 250ml conical flask a solution of sodium methoxide (1% by wt) and methanol was prepared. We took 1:6 mole ratio of FFA to methanol. The solution was stirred continuously until the sodium methoxide was completely dissolved in methanol. The sodium methoxide solution was then added to the warm jatropha oil and stirred continuously for one hour at a temperature of 63-64°C using a magnetic stirrer. The reaction mixture was analyzed 20 minutes in interval that for FFA. Reaction completion results, the glycerin and Jatropha oil methyl esters that form two insoluble phases mixture. The reaction mixture was allowed to separate by gravity with the help of separating funnel. The biodiesel phase is further purified into biodiesel by rinses with warm distilled water washing.

Esterification

RESULTS AND DISCUSSION

The free fatty acid content of the Jatropha oil was lowered by a significant level using esterification. The sulfuric acid based esterification was intended to convert the free fatty acid in the Jatropha oil to esters to reduce acid value upto 8.1 mg-KOH/g-oil and FFA content below 4%. The Jatropha oil was heated to 100°C for the removal of moisture. Then Jatropha oil was cooled to 65°C. We took 1:50 molar ratio of FFA: methanol. The acid catalyst such as sulfuric acid (20% by wt) and methanol was added to oil and stirred continuously using magnetic stirrer. The temperature was controlled at 63-64°C for 1 hr with regular analysis of acid value after 25-30 min. When the acid value is reduced upto 8.1 mg-KOH/g-oil, the reaction was stopped. After the confirmation of completion of reaction, the mixtures were allowed to settle down for 1hr. By removing methanol from the top layer, the esterified oil was fed to the transesterification process.

Important variables affecting the acid value in the esterification process were the FFA to methanol ratio, sulphuric acid concentration and reaction time etc. Initial acid value of Jatropha oil: 17.0 mg-KOH/g-oil.

MATERIAL AND METHOD Jatropha oil was selected as feedstock for production of biodiesel. Jatropha oil was collected from local markets, all chemicals obtained from Sharad agencies, Pune.

Effect of FFA to Methanol Ratio The effect of FFA to methanol ratio on acid value is shown in Figure 1. The figure indicates that the acid value was affected by the amount of methanol. Increase in FFA to methanol ratio, decreases acid value. It is clear from graph, using different amounts of FFA to methanol ratio could reduce the acid value of the Jatropha oil. It is observed from Figure 1, using different amounts of FFA to methanol ratio at 63-64°C, catalyst concentration 10%, acid value of oil was reduced from 17.0 mg-KOH/g-oil to below 8.1 mg-KOH/ g-oil in 1hr. If the feedstock has higher acid value, then esterification process demands addition of excess methanol.

This article can be downloaded from http://www.ijerst.com/currentissue.php 230

Int. J. Engg. Res. & Sci. & Tech. 2014

S R Satpute et al., 2014

Reaction Time

Acid Value (mg-KOH/g-oil)

Figure 1: Effect of FFA to Methanol Ratio on Acid Value During Esterification Process (catalyst Concentration 10%, Reaction Time 1hr)

The effect of reaction time on acid value is shown in Figure 4. Increasing reaction time was no effect to acid value (acid value remain constant) gives straight line as shown in figure. Using different amounts of reaction time, catalyst concentration 20%, FFA to methanol ratio 1:50 at 63-64°C, it results no effect on acid value of Jatropha oil.

18 16 14 12 10 8 6 4 2 0

Figure 3: Effect of Reaction Time on Acid Value During Esterification Process (FFA to Methanol Ratio (1:50), Catalyst Concentration 20%)

(1:40)

(1:50)

(1:60)

(1:70)

FFA to Methanol Ratio

Effect of Sulphuric Acid Concentration The effect of sulphuric acid concentration on acid value is shown in Figure 2. The figure indicates that as the catalyst concentration increases, gradually decreases acid value of Jatropha oil. Using different amounts of catalyst concentration, FFA to methanol ratio 1:50 at 63-64°C, the acid value of Jatropha oil was reduced from 17.0 mgKOH/g-oil to below 8.1 mg-KOH/g-oil in 1hr.

The yield of the methyl esters by using sodium methoxide (1% by wt) and having mole ratio of FFA to methanol (1:6) at 63-64°C during transesterification, it was found 92%.

CONCLUSION

Acid Value (mg-KOH/g-oil)

Figure 2: Effect of Catalyst Concentration on Acid Value During Esterification Process (FFA to Methanol Ratio (1:50), Reaction Time 1hr)

From above results we can predict that acid value play an important role for preparation of biodiesel by reducing free fatty acid significantly. The esterification process was applied for reducing FFA level. The first stage was esterification process, which could reduce acid value of Jatropha oil and was maintained below 8.1 mgKOH/g-oil and corresponds to 4% FFA level in Jatropha oil. The esterified oil was then used in the transesterification reaction using alkaline catalyst (Sodium methoxide) to produce biodiesel or Jatropha Oil Methyl Ester (JOME) was found 92%.

12 10 8 6 4 2 0 10%

15%

20%

25%

Catalyst Concentration

This article can be downloaded from http://www.ijerst.com/currentissue.php 231

Int. J. Engg. Res. & Sci. & Tech. 2014

S R Satpute et al., 2014

REFERENCES

Conversion and Management, Vol. 50, pp. 14-34.

1. Anya Uzo Anya, Nwobia Noelle Chioma and Ofoegbu Obinna (2012), “Optimized Reduction of Free Fatty Acid Content on Neem Seed Oil for Biodiesel Production”, Journal of Basic and Applied Chemistry, Vol. 2, No. 4, pp. 21-28.

6. Dennis Y C Leung, Xuan Wu and Leung M K H (2010), “A Review on Biodiesel Production Using Catalyzed Transesterification”, Applied Energy, Vol. 87, pp. 1083-1095. 7. Houfang Lu, Yingying L, Hui Z, Yang Y, M Chen and B Liang, (2009), “Production of Biodiesel from Jatropha Curcas L. oil”, Computers and Chemical Engineering, Vol. 33, pp. 1091-1096.

2. Bobade S N and Khyade V B (2012), “Preparation of Methyl Ester (Biodiesel) from Karanja (Pongamia Pinnata) Oil”, Research Journal of Chemical Sciences, Vol. 2, No. 8, pp. 43-50.

8. Ma F R & Hanna M A (1999), “Biodiesel Production: A Review”, Bioresource Technology, Vol. 70, pp. 1-15.

3. Canakci M, Gerpen J V (2001), “Biodiesel Production from Oils and Fats with High Free Fatty Acids”, American Society of Agricultural Engineers, Vol. 44, No. 6, pp. 1429-1436.

9. Padhi S K and 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, No. 5, pp. 599-608.

4. Demirbas A (2008), “Biodiesel: a Realistic Fuel Alternative for Diesel Engines”, Springers. 5. Demirbas A (2009), “Progress and Recent Trends in Biodiesel Fuels”, Energy

This article can be downloaded from http://www.ijerst.com/currentissue.php 232