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CHAPTER I INTRODUCTION
Background of the Research
Biodiesel has become more attractive recently because it has been shown to be the best supplement to fossil-based fuels due to environmental advantages,
renewable resource availability, and the ability to lessen dependence on imported oils. Additionally, it is well suited for immediate substitution of petro-diesel in
system utilizing existing diesel engines and in fuel distribution infrastructure. Technically, biodiesel is a better fuel than petro-diesel in terms of engine
performance, emissions reduction, lubricity, and biodegradability [1, 2]. In Indonesia, research and development activities on biodiesel research, production
and utilization have advanced to such a stage that its application as diesel supplement. Answering the need, the Indonesian government has shown its
seriousness in developing bio-fuel. Various policies which are supporting the development of this energy have been made. Among them are the Presidential
Regulation No. 52006 regarding the National Energy Policy [3], and Presidential Instruction No. 12006 regarding the utilization of bio-fuel which was released
formally on 25 January 2006 [4]. Referring to the National Energy Policy, the Minister of Energy and
Mineral Resources has issued the National Energy Management Blueprint [5]. Blueprint covers the national strategy in managing and utilizing various energy
resources including the roadmap of biodiesel. Detail of biodiesel road map is presented in Appendix 1. The estimated target of biodiesel utilization is set by 1.5
million kilo litre in 2010 10 of diesel oil consumption in the transportation sector and will be increased up to 6.4 million kilo litre in 2025 20 of diesel oil
consumption in the transportation sector or 5 of total national diesel oil [5]. The biodiesel standard – so called SNI 04-7182-2006 has been approved by the
National Standardization Agency BSN through a decree No. 73KEPBSN2006 on 22 February 2006. The detail SNI 04-7182-2006 is shown in Appendix 2.
2 Biodiesel can be made from transesterification of vegetable oils or animal
fats with short-chain alcohols, mainly methanol MeOH. The major component of vegetable oils and animal fats are triacyglycerols or triglycerides TG. In the
transesterification process, TG are first reduced to diglycerides DG, and then to monoglycerides MG. Lastly, the monoglycerides are reduced to fatty acid
methyl esters FAME; also called biodiesel and glycerol GL [6, 7, 8]. Most of the currently known methods for biodiesel production use an
alkaline andor acid catalyst. However, there are at least two problems associated with this process. The first problem due to the two phase nature of vegetable
oilMeOH mixture requires vigorous stirring to proceed in the transesterification reaction. The second problem is products purification because the reaction product
contains residual catalyst, unreacted MeOH and saponified products [9]. The disadvantages resulting from the use of a catalyst could be eliminated if the non-
catalytic transesterification can be realized. The non-catalytic transesterification has several advantages. The removal of
free fatty acids FFA from oil by refining or preesterification is not required. In the non-catalytic process, two types of reaction exist in this method for methyl
esters formation, transesterification of TG and methyl esterification of fatty acids. Thus, a higher yield can be obtained than that produced by the alkaline-catalyzed
method [10, 11]. In addition, because of a catalyst free process, separation and purification become much simpler and environmentally friendly. The
disadvantages of the non-catalytic process are the necessity of the large molar excess of MeOH the molar ratio of MeOHoil was 24 – 42 and higher operating
temperature 240-350
o
C than the catalytic process [9, 12, 13]. The optimum temperature of the catalytic transesterification was 60
o
C when molar ratio of MeOHoil was 6 [8]. Additionally, most of the non-catalytic transesterification
were conducted under pressurized conditions, i.e., supercritical or sub-crtical of MeOH, which are not viable in practice in industry.
Yamazaki et al., [14] studied the non-catalytic alcoholysis of sunflower oil for biodiesel fuel production in a bubble column reactor BCR. Effects of
reaction temperature, MeOH feed flow rate, operating pressure, stirring rate and initial oil volume on out flow rate of FAME were investigated. Based on the
3 maximum out flow rate of FAME, the optimum condition is 290
o
C and 0.1 MPa. Increase in MeOH feed flow rate and initial oil volume, and decrease in stirring
rate all increased the outflow rate of FAME. Increase in outflow rate of FAME with MeOH feed flow rate indicates the large effect of product inhibition in this
reaction. Decrease in outflow rate and total production rate of FAME with increase in stirring rate shows the effect of MeOH bubble residence time in the
liquid phase. Effect of initial oil volume on reaction also indicates the same effect. From these results, not the interface between top surface of liquid phase and
bottom of gas phase but the interface between MeOH bubbles and the surrounding liquid phase seemed to affect the reaction. It is predicted that increasing this
interface area and prolonging the residence time of MeOH bubble in the liquid phase leads to an improvement in reaction rate. However, kinetic study of
transesteerification reaction, the bubble interface, performance of BCR for methyl esterification of FFA, and the continuous-flow BCR have not yet been
investigated. The dissertation begins with giving background of the research by
reviewing available biodiesel production technologies Chapter I. Current status of biodiesel production process was described in Chapter II. The advantages and
disadvantages of each production technology were described in this chapter. In the Chapter III, The kinetics study of the non-catalytic transesterification of palm oil
was studied in the BCR by semi-batch process. Performance of the BCR for the non-catalytic of methyl esterification of fatty acids was described in Chapter IV.
This chapter presented the comparison of methyl esterification and tranesterification results. In addition, reactivity of palm fatty acids myristic,
palmitic, stearic, oleic and linoleic acids was investigated in this chapter. Chapter V described the continuous flow BCR for non-catalytic transesterification of palm
oil. In this chapter, effects of the reaction temperature and methanol feed flow rate on the productivity and the purity methyl esters content of biodiesel. The final
evaluation and discussions were presented in Chapter 6 and the conclusion of the research is shown in Chapter VII.
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Objective of the Research
a. To study the kinetics of the non-catalytic transestrification of palm oil at atmospheric pressure by semi-batch process. The effects of reaction
temperature on the rate constant, conversion, yield of ME and composition of the reaction product in the transestrification are investigated.
b. To study the performance of a bubble column reactor for the non-catalytic methyl esterification of FFA at atmospheric pressure by semi-batch
process. Five fatty acids which are commonly found in palm oil were chosen as substrates.
c. To develop a process for the continuous non-catalytic transesterification of palm oil in a BCR. This study is focused on determining the optimal
reaction time for maximum production of biodiesel from palm oil with the best quality.
Benefits of the Research
a. To give contribution in the development of science and technology,
specifically for bio-diesel production by non-catalytic process in a BCR. b.
To provide basic information of biodiesel production by non-catalytic process in a BCR such as the reaction temperatures for transesterification
and esterification, effect of MeOH feed flow rate on the productivity and quality of bio-diesel.
c. The ultimate benefit of this research is to provide essential data for
developing scale up model of biodiesel production system by non-catalytic process using BCR for industrial application.
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CHAPTER II CURRENT STATUS OF BIODIESEL PRODUCTION
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