DAVI DOS SANTOS, STEPHEN MONTGOMERY, ANN NUNNELLEY, MD NURUDDIN BSEN 5540/6540: BIOMASS AND BIOFUELS BIODIESEL PRODUCTION FROM VEGETABLE OIL GROUP: POPLAR 13 NOVEMBER, 2015
Table of Contents Introduction 3 Materials 3 Production of Biodiesel 3 Transesterification Reaction 4 Discussion 6 Conclusion 6 References 7
1.Introduction Vegetable oil is an immense and renewable source for the production of environment friendly fuels and valuable chemicals without compromising the needs of future generations. Due to the everincreasing energy demands, vegetable oils such as Cottonseed, Soybean, and Castor Oils, have been utilized as a potential alternative to replace coal, petroleum oil and natural gas. Apart from the gradual depletion of these fossil resources, the emission of CO 2 from fossil fuel is undoubtedly the major concern since CO 2 is the major greenhouse gas responsible for global warming. In addition, other major environmental concerns arising from fossil fuels consumption are ozone layer depletion, volatile organic compounds (VOC), NOx, SOx and soot (particulate matter) emission to the atmosphere (Chan et al., 2015; Staš, Kubička, Chudoba, & Pospíšil, 2014). The increased efforts to mitigate these drawbacks of fossil fuels have led to the need for the development of new generation transportation fuels and eco-friendly chemicals. Twenty-six leading experts in the U.S proposed a Roadmap for Biomass Technologies, predicting gradual replacement of fossil fuels in different energy consumption sectors such that 20% of transportation fuel and 25% of chemicals in the U.S. could be produced from biomass by 2030 (Wang, Leitch, & Xu, 2009). Extensive research has been conducted to determine the viability of utilizingvegetable oils, wood and agricultural residues for production of biofuels. Biodieselsderived from vegetable oils or animal fats, are monoalkyl esters of long fatty acids. They have drawn wide attention due to their superior characteristics like renewability, biodegradability, emission profile and high flash points (Gurunathan & Ravi, 2015). Currently, biodiesel mixed with conventional diesel can be used in compression ignition engines without any modification (Robles- Medina et al., 2009). 2. Materials This was a relatively simple process that involved the transesterification of canola oil using methanol (CH 3 OH) and a sodium hydroxide catalyst (NaOH).An Excella E24 Incubator Shaker from New Brunswick Scientific was used to assist in the process. 3. Production of biodiesel from Canola oil using sodium hydroxide catalyst The basic transesterification reaction of Canola oil was carried out at batch mode using a glass bottle and a mechanical shaker. The set up was such that 10 ml methanol was added to 0.5g of
sodium hydroxide. The mixture was shaken thoroughly at 58 C until complete dissolution of sodium hydroxide pellets. Then 50 ml of oil was added to the mixture (oil to catalysts ratioof 0.1% wt.) and the open mouth of bottle was sealed with paraffin so that the alcohol would not evaporate out of bottle. The bottle containing oil, methanol and sodium hydroxide was placed on the mechanical shaker and allowed to agitate for one hour (Figure 1). Once the transesterification reaction was finished, the mixture was allowed to settle so that the multiple phases could be seen. The upper phase contained the desired product and the lower phase contained the glycerol (Figure 2). Figure-1. Mechanical shaker (Excella E24 Incubator Shaker, New Brunswick Scientific) 4.Transesterification Reaction Figure-2. Transesterification reaction of vegetable oil.
CH3OH+ NaOH CH3OH+ NaOH+Oil CH3OH+ NaOH+Oil (1st Stage) (2nd Stage) Biodiesel Glycerin Biodiesel+Glycerin (Final stage) Figure-3. Flow diagram of different stages of biodiesel production.
5. Discussion Initially the mixture of oil, methanol and sodium hydroxide was transparent. After a few minutes, the appearance of cloudy layer on the top of the surface (Figure 3) indicated the initiation of transesterification reaction. After 30 minutes, the whole solution became cloudy, indicating vigorous reaction. At the end of one hour, the solution was allowed to settle and two separated phases appeared. The bottom phase contained glycerin and upper phase contained biodiesel. From Figure 2, it can be seen that one mole of triglyceride reacts with 3 mole of methanol to yield 3 mole of biodiesel and one mole of glycerin. During the production of biodiesel, excess methanol is required to shift the equilibrium in the forward direction for the maximum formation of methyl esters. Gurunathanand Ravi (2015) used the optimal oil to methanol ratio of 1:10, and achieved a maximum biodiesel yield of 97.01%. The reaction vessel contained biodiesel, glycerin, unreacted methanol and catalysts (NaOH). That is why a proper separation system is needed to purify the biodiesel. Moreover, excess amount of alkali resulted soap formation by saphonification reaction. Furthermore, refined canola oil contained less than 0.05% free fatty acid (FFA). Material with this FFA content is not a suitable feedstocks for alkali-catalyzed diesel production since it leads to soap formation. The formation of soap adversely affects the reaction as well as the separation and recovery of glycerol since this soap leads to the emulsification of the ester and glycerol (Markley, 1961). Thus, production of biodiesel from vegetable oil containing high FFA requires atwo-step reaction: conversion of FFAs to fatty acid methyl esters (FAMEs) (i.e., biodiesel) using a catalyst such as sulfuric acid followed by transesterification using an alkali catalyst(singh et al, 2014). 6. Conclusion The production of sustainable fuels is a major challenge facing the world over the next generation. Producing diesel fuel from a renewable biomass source through the transesterification of oils is one alternative process that produces a renewable fuel. The experiment performed shows that the production of biodiesel from canola oil is possible, however, further studies must be completed to determine the actual sustainability of this fuel production process. This experiment was merely a laboratory scale proof of concept reaction, that shows that transesterification is possible, but does not deal with any of the separation or upgrading steps required after production to produce a usable biodiesel fuel.
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