Microwave-Enhanced In Situ Transesterification of Algal Biomass to Biodiesel (original) (raw)
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Bioresource Technology, 2011
The effect of microwave irradiation on the simultaneous extraction and transesterification (in situ transesterifcation) of dry algal biomass to biodiesel was investigated. A high degree of oil/lipid extraction from dry algal biomass and an efficient conversion of the oils/lipids to biodiesel were demonstrated in a set of well-designed experimental runs. A response surface methodology (RSM) was used to analyze the influence of the process variables (dry algae to methanol (wt/vol) ratio, catalyst concentration, and reaction time) on the fatty acid methyl ester conversion. Based on the experimental results and RSM analysis, the optimal conditions for this process were determined as: dry algae to methanol (wt/vol) ratio of around 1:12, catalyst concentration about 2 wt.%, and reaction time of 4 min. The algal biodiesel samples were analyzed with GC-MS and thin layer chromatography (TLC) methods. Transmission electron microscopy (TEM) images of the algal biomass samples before and after the extraction/transesterification reaction are also presented.
Microwave-Enhanced Methods for Biodiesel Production and Other Environmental Applications
Sanghi/Green, 2011
Microwave-enhanced organic/inorganic synthesis is considered as green chemistry and a preferred method due to several advantages such as lower energy consumption, substantial reduction in reaction times and solvent requirements, enhanced selectivity, and improved conversions with less by-product formation. In this book chapter, an emphasis on microwaveenhanced methods for biodiesel production is presented. A preliminary understanding of the microwave heating mechanism in achieving fast and easy synthesis of biodiesel is discussed. Biodiesel production using different feedstock (vegetable oils to algae), catalysts applied, and energy requirements of the processes are presented. Advantages of microwaveenhanced biodiesel synthesis such as non-catalytic, solvent-free transesterifi cations, higher fatty acid methyl ester (FAME) yields, lower energy requirements, and product separation times are discussed. Analyses of algal feedstock and algal biodiesel properties are also presented. In addition, microwave applications in other important organic/inorganic chemical reactions and environmental remediation are presented.
Fuel, 2012
In this comparative study, direct conversion of algal biomass into biodiesel using supercritical methanol (SCM) and microwave-assisted (MW) transesterification methods was investigated. Wet algal biomass was used as feedstock in the supercritical methanol process and dry algal biomass for the microwaveassisted transesterification. Experimental runs were designed using a response surface methodology and the process parameters such as wet/dry algae to methanol ratio, reaction temperature, reaction time and catalyst concentrations were optimized for both processes. The microwave-assisted approach improves extractions of algae significantly, with a higher efficiency, reduced extractive-transesterification time and increased yield. While the non-catalytic supercritical methanol method produces highly purified extracts (free of harmful solvents and catalyst residues), and reduces energy consumption in separation and purification steps. The algal biodiesel samples from SCM and MW processes were compared using FT-IR and TGA analysis methods to identify the functional group attributions and thermal stability of the biofuel samples, respectively. The transmission electron microscopy (TEM) analysis of algal biomass and lipid extracted algae (LEA) and energy requirements for the two processes are also presented.
Molecules
Biodiesels and biolubricants are synthetic esters produced mainly via a transesterification of other esters from bio-based resources, such as plant-based oils or animal fats. Microwave heating has been used to enhance transesterification reaction by converting an electrical energy into a radiation, becoming part of the internal energy acquired by reactant molecules. This method leads to major energy savings and reduces the reaction time by at least 60% compared to a conventional heating via conduction and convection. However, the application of microwave heating technology alone still suffers from non-homogeneous electromagnetic field distribution, thermally unstable rising temperatures, and insufficient depth of microwave penetration, which reduces the mass transfer efficiency. The strategy of integrating multiple technologies for biodiesel and biolubricant production has gained a great deal of interest in applied chemistry. This review presents an advanced transesterification proc...
Biodiesel Production from Dry Microalga Biomass by Microwave-Assisted In-Situ Transesterification
MATEC Web of Conferences, 2018
Microalga is one of the potential feedstocks in the manufacture of biodiesel because it contains high oil content. In this study, Chlorella sp. was selected because its high oil content about 28-32% of oil (based on its dry weight) and its presence is abundant among other green algae. In situ transesterification was carried out in round neck flask under microwave irradiation. Microwave irradiation can facilitate the in situ transesterification by extracted the lipid of microalga and simultaneous convert to FAME. The purposes of this study are to investigate the effect of acid catalyst concentration, microwave power, reaction time and the addition of co-solvent (n-hexane) on the yield of biodiesel, to get optimum operating conditions and to know the fatty acid compounds of biodiesel from Chlorella sp. The results of oil extraction and biodiesel were analyzed by GC-MS analysis. Based on the experiment, the yield of microalga oil was 11.37%. The optimum yield of biodiesel by in-situ tr...
International Journal of Renewable Energy Development
Aim of this research are to study and develop research related to the potential of Chlorella sp. into biodiesel with the help of microwaves in-situ transesterification by characterizing parameters such as microwave power (300; 450; 600 W) and reaction time (10; 30; 50 minutes) with catalyst concentration of KOH and molar ratio of microalga : methanol are 2% and 1:12 respectively and optimized by response surface methodology with Face Centered Central Composite Design (FCCCD). The study was carried out by dissolving the catalyst into methanol according to the variable which was then put into a reactor containing microalgae powder in the microwave and turned on according to the predetermined variable. After the reaction process is complete, the mixture is filtered and resuspended with methanol for 10 minutes to remove the remaining FAME and then the obtained filtrate is cooled. Water is added to the filtrate solution to facilitate the separation of hydrophilic components before being ...
IOP Conference Series: Materials Science and Engineering
Microalgae is one of the potential raw materials in producing the third generation biodiesel thanks to its high lipid contents and the fact that it requires relatively small space for cultivation. Microalgae in the form of Chlorella sp. was used as a raw material in this study due to its high oil content, i.e. up to 30% of the dry algae weight. The use of microwave irradiation in this process would accelerate the in-situ trans-esterification reaction by extracting microalgae lipids and simultaneously converting them into Methyl-Esters. This study aims to investigate the methyl ester production through the in-situ trans-esterification process by studying the effect of acid catalyst concentration (0.2-0.5 mol/L), microwave power (300-600 W) and reaction time (30-90 minutes). The experiment was carried out in a 500 ml flat bottom flask made of pyrex, under the influence of microwave irradiation in which homogeneous sulfuric acid (H2SO4) was introduced as a catalyst. The experiment was carried out in atmospheric pressure with the following operating variables: catalyst concentration, microwave power and reaction time, respectively. Prior to running the experiment, the response surface methodology using Box Behnken Design (3 factors and 2 levels) was conducted beforehand in order to minimize the number of runs. It is suggested from the analysis that the optimum conditions for the in-situ microwave-assisted trans-esterification of Chlorella sp. with sulfuric acid catalyst are as follows: microwave power (370 W), concentration of catalyst (0.2 mol/L), and trans-esterification time (82.7 min) with yield of 63.36 %. The predicted yield values generated from the response surface methodology with Box-Behnken design exhibit a high degree of confirmation with the actual yield from the experiment, suggesting that the optimization methodology carried out has made the experiment more effective and efficient by focusing only on certain specific parameters in order to get the best results, in terms of both quality and quantity.
American Journal of Chemical Engineering, 2018
Biodiesel, an alternative diesel fuel made from renewable sources such as vegetable oils and animal fats, is becoming prominent among alternatives to conventional petro-diesel due to economic, environmental and social factors. Transesterification is the most preferred method of biodiesel production. Knowledge of transesterification reaction kinetic enables prediction of the extent of the chemical reaction at any time under particular conditions. It is also essential in the design of reactors for biodiesel production in industrial scale, determination of kinetic model and optimization of operation conditions. In this study, a mathematical model for the microwave assisted trans-esterification reaction of microalgae and methanol has been developed to study the effect of the operating parameters on the process kinetics. A well-mixed microwave reactor was used to express the laboratory scale microwave reactor at stirring speed 500 rpm. Mass transfer controlled state was assumed to be minimal using the stirring condition. The model developed was based on experimental data described in a previous study. The experimental works were designed to study the effect of reaction time between 1-5 min; power of microwave of 100-400 W, and an amount of CaO catalyst of 1 and 3%. The use of a solid catalyst effectively reduces the purification cost of biodiesel due to ease of separation and potential for reuse. The molar ratio of microalgae oil and methanol was constant at the ratio of 1: 6. The validation of model indicated that the reaction have second order reaction in terms of triglycerides. A very good correlation between model and experiment data was observed by correlation coefficient (R 2) and least square curve fit. In addition, the experiment shows that the best conditions for reaction time were 5 min, power of microwave was 400 W and amount of CaO catalyst was 3%. The maximum yield of biodiesel in the best conditions was 93.23%.
In Situ Transesterification of Spirulina Microalgae to Produce Biodiesel Using Microwave Irradiation
Journal of Energy
The present technology of transesterification of vegetable oils to produce biodiesel, which is suited to replace petrodiesel, has economic challenges, and therefore, alternative sources are being explored. Microalgae, a renewable, third-generation biofuel resource, have the potential to become a viable feedstock due to their high oil content and environmentally friendly nature. The present study investigates the effect of microwave irradiation on the simultaneous extraction and transesterification of algae lipids to produce fatty acid methyl ester (FAME), in a batch reaction system using sulphuric acid catalyst. In situ transesterification combines the two steps of lipid extraction and transesterification into a single step. The microwave synthesis unit comprised of a 3-neck round bottom flask inside a 1300-Watt microwave oven, fitted with a quick-fit condenser and having an external stirrer. Response surface methodology (RSM) was used to analyse the influence of process variables, ...