Biodiesel production from jatropha seeds: Solvent extraction and in situ transesterification in a single step

The objective of this study was to investigate solvent extraction and in situ transesterification in a single step to allow direct production of biodiesel from jatropha seeds. Experiments were conducted using milled jatropha seeds, and n-hexane as extracting solvent. The influence of methanol to seed ratio (2:1–6:1), amount of alkali (KOH) catalyst (0.05–0.1 mol/L in methanol), stirring speed (700–900 rpm), temperature (40–60 °C) and reaction time (3–5 h) was examined to define optimum biodiesel yield and biodiesel quality after water washing and drying. When stirring speed, temperature and reaction time were fixed at 700 rpm, 60 °C and 4 h respectively, highest biodiesel yield (80% with a fatty acid methyl ester purity of 99.9%) and optimum biodiesel quality were obtained with a methanol to seed ratio of 6:1 and 0.075 mol/L KOH in methanol. Subsequently, the influence of stirring speed, temperature and reaction time on biodiesel yield and biodiesel quality was studied, by applying the randomized factorial experimental design with ANOVA (F-test at p = 0.05), and using the optimum values previously found for methanol to seed ratio and KOH catalyst level. Most experimental runs conducted at 50 °C resulted to high biodiesel yields, while stirring speed and reaction time did not give significantly effect. The highest biodiesel yield (87% with a fatty acid methyl ester purity of 99.7%) was obtained with a methanol to seed ratio of 6:1, KOH catalyst of 0.075 mol/L in methanol, a stirring speed of 800 rpm, a temperature of 50 °C, and a reaction time of 5 h. The effects of stirring speed, temperature and reaction time on biodiesel quality were not significant. Most of the biodiesel quality obtained in this study conformed to the Indonesian Biodiesel Standard

Studies on design of heterogeneous catalysts for biodiesel production

The production of biodiesel is gaining momentum with the ever increasing demand of the fuel. Presently, limited literature is available with respect to well designed solid heterogeneous catalyst for biodiesel production considering all the characteristics, process and operation parameters. Hence, a study was conducted to design effective heterogeneous catalyst for biodiesel production. Further, the significant impact of different catalysts, different feed stock, various reaction conditions such as temperature, methanol oil molar ratio, catalyst concentrations and stability/inactivation of the catalysts, are detailed out for transesterification process of biodiesel production. Based on the studies it can be concluded that well designed heterogeneous catalyst can yield high throughput of biodiesel

Καινοτόμες μέθοδοι παραγωγής βιοντήζελ από ελληνικά γεωργικά παραπροϊόντα

The objective of the present thesis was the production of biodiesel from Greek agricultural by-products (waste frying oils, sunflower seed and cotton seed). Biodiesel production was achieved by using both homogeneous and heterogeneous catalysis. Moreover two different stirring methods were used: mechanical stirring and ultrasonication. Finally, for the production of biodiesel from oil seeds conventional and in situ transesterification were carried out. The main conclusions of the present thesis are as follows: • The transesterification of two different frying oils (soybean oil and a mixture of soybean and cotton seed oil) with methanol, in the presence of an alkaline-catalyst (NaOH), by means of low frequency ultrasonication (24 KHz, 200W) and mechanical stirring (600rpm) for the production of biodiesel fuel was studied. The two different frying oils gave similar yields of isolated methyl esters both under mechanical stirring and ultrasonication. Also the physical and chemical properties of the two biodiesel fuels produced were investigated. The fuels produced, were characterized by determining their density, viscosity, flash point, boiling point, cetane number, sulphur content, cloud point, pour point, cold filter plugging point, ash content, water content, acid value, iodine value, and saponification value. From the physical and chemical properties of the two biodiesel fuels it is concluded that these fuels have very similar properties to those of conventional diesel, except for the cetane number which is higher and the sulphur content of the biodiesel which is negligible. Thus experimental biodiesel fuels are environmentally friendly and attractive alternatives to conventional diesel. • Also both conventional and in situ transesterification of sunflower seed oil with both methanol and ethanol using mechanical stirring and ultrasonication was investigated. It was shown that ultrasonication in most cases led to similar yields of alkyl esters as compared to mechanical stirring. Regarding in situ transesterification, ultrasonication and mechanical stirring are both equally efficient in the case of production of methyl esters. However, in the case of production of ethyl esters, ultrasonication was substantially more efficient in triglycerides’ conversion. Furthermore, a considerable increase in yield of esters is obtained in a remarkably short time span (the ultrasonication assisted reaction is completed in 20 min with methanol and in 40 min with ethanol) achieved by the use of alkali-catalyzed in situ transesterification. Methanol gave shorter reaction times and higher yields of alkyl esters than ethanol. Finally, acid in situ transesterification gave lower yield of methyl esters than alkaline transesterification reaction. The same parameters were studied for cotton seed oil and the results were similar to those of sunflower seed oil. Finally, the heterogeneous catalysis of the transesterification reaction was studied. It was concluded that the most appropriate catalyst for this reaction was the MgAl. Also the use of ultrasonication accelerated significantly the reaction as compared to mechanical stirring (5h versus 24h).Το βιοντήζελ είναι μια γενική ονομασία για τους μεθυλεστέρες ή αιθυλεστέρες λιπαρών οξέων από οργανική πρώτη ύλη. Μπορεί να παραχθεί από μεγάλη γκάμα σπορέλαιων, όπως αυτό από ελαιοκράμβη, από ηλιοτρόπια, από σόγια και το λάδι από κοκκοφοίνικα. Επίσης μπορεί να παραχθεί από ζωικά λίπη και γράσα. Το λάδι περνάει από μια χημική διεργασία (μετεστεροποίηση) και μετατρέπεται σε αλκυλεστέρες, οι οποίοι έχουν παρόμοιες προδιαγραφές καυσίμου με αυτές του πετρελαίου κίνησης. Λόγω του μεγάλου ιξώδους του, χρησιμοποιείται ύστερα από ανάμειξή του με το συμβατικό πετρέλαιο. Οι κατασκευαστές κινητήρων συνήθως συμφωνούν στη διατήρηση της εγγύησης όταν χρησιμοποιείται μίγμα βιοντήζελ έως 5%. Στην παρούσα διατριβή η παραγωγή βιοντήζελ πραγματοποιήθηκε από ελληνικά γεωργικά παραπροϊόντα και συγκεκριμένα από τηγανισμένα λάδια, ηλιόσπορο και βαμβακόσπορο. Η παραγωγή βιοντήζελ πραγματοποιήθηκε τόσο με ομογενή όσο και με ετερογενή κατάλυση. Επιπλέον χρησιμοποιήθηκαν δύο μέθοδοι ανάδευσης: η μηχανική και οι υπέρηχοι. Τέλος, για την παραγωγή του βιοντήζελ από τους ελαιούχους σπόρους χρησιμοποιήθηκε η συμβατική μέθοδος μετεστεροποίησης, κατά την οποία η λιπαρή ύλη εξήχθη από τον σπόρο με τη μέθοδο Sohxlet κι έπειτα ακολούθησε η αντίδραση μετεστεροποίησης, αλλά και η in situ μετεστεροποίηση, κατά την οποία τόσο η εκχύλιση της λιπαρής ύλης όσο και η αντίδραση μετεστεροποίησης πραγματοποιήθηκαν σε ένα στάδιο

Waste Lard Methanolysis Catalyzed by KOH at Moderate Temperatures

The KOH-catalyzed methanolysis of waste lard from piglet roasting in a moderate temperature range was investigated in order to establish the reaction kinetics. For comparison, lard and thermally treated lard were also included in the study. All three reactions occurred via a pseudo-homogeneous regime where the chemical reaction controlled the overall process kinetics. A simple kinetic model comprising the irreversible pseudo-first-order reaction was demonstrated for all three fatty feedstocks. The reaction rate constant increases with raising the fatty acid unsaturation degree. The final products satisfied the EN 14214 biodiesel standard specifications