INTRODUCTIONINTRODUCTIONBiodiesel was synthesized under catalyst-free supercritical

methanol reactions using a variety of oils at 250 to 325oC in a 1-liter high-pressure batch reactor. Multiple experiments were performed at 6 to 80 molar ratios of methanol to oil; product samples were then analyzed by titration, and a Gas Chromatograph which monitored conversion of triglyceride by measuring total glycerine. At 300oC and 27 molar ratios, 97% conversion was attained. Following the experiment samples were placed in separatory funnel and the crude biodiesel layer was treated further to remove free glycerine by centrifugation and also with an Amberlite BD10dry which was more effective.

Soybean Oil transesterifcation ResultsSoybean Oil transesterifcation Results• Transesterification reaction at high temperature, pressure

and variable molar ratio resulted to two distinct phase after separation.

• At 27 Molar ratio, 325oC and 5500 psi, conversion dropped to 73%

• Amberlite BD10dry was more effective in reducing free glycerine compared to centrifugation

Esterifation results at high temperature and pressureEsterifation results at high temperature and pressure• Oleic acid esterification conversion rates decreased (91 to 83%) from 300

to 350 oC, due to accumulation of reaction water.

• Direct esterification at 300 oC and 8 Molar ratio, on oleic acid, restaurant grease, crude corn oil resulted into methyl esters at varying conversion rates. Two layers separated with the top consisting of water, methanol and about & 5 wt% crude biodiesel, whereas the bottom layer was about 90% methyl esters methanol and water.

• There was no effect on conversion rates when adding a modifier and/or pumping methanol at 300 oC compared to simultaneously adding oil and methanol at 25 oC

ACKNOWLEDGMENTSACKNOWLEDGMENTSIowa Energy Center and DOE Fund: DE-FG36-06GO86014

Catalyst-free biodiesel reactions and post treatment using commercial polymeric resinsSipho C. Ndlela, Norman K. Olson

Iowa Energy Center, Iowa State University, BECON Facility, 1521 West F Avenue, Nevada, IA  50201, USA

MATERIALS & METHODSMATERIALS & METHODSMaterials:• RBD Soybean oil• Oleic Acid (100% FFA)• Crude corn oil (16% FFA)• Restaurant grease (10% FFA)• MethanolReactor conditions:• 1 Liter Batch reactor, 200 to 350 oC• Molar ratios of methanol to oil: 6 to 80 (Molar ratio)Analysis:• Titration using 0.1 N KOH (FFA analysis)• ASTM D 6584 biodiesel GC methodPost treatment methods:• Amberlite BD10 DRY (10% and 25%)• HERMLE Z200 A centrifuge 6000 RPM, 15 minutes

Fig. 2 Crude soy biodiesel sample taken after reaction at 300oC, 8000 psi, 6 Molar ratio

High Pressure Batch Reactor system

Fig.1 Image from left to right: RBD soybean oil, crude corn oil, restaurant grease

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Fig.3 Soy biodiesel conversion rates at 300oC and increasing molar ratio, analyzed using a Varian CP 3800 GC-FID

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Fig.5 Crude biodiesel post treatment using a HERMLE Z200 A centrifuge and Amberlite BD10 DRY

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Fig.4 Soy biodiesel transesterification: Temperature effect at 27 Molar ratio, analyzed using a Varian CP 3800 GC-FID

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Fig.6 Oleic Acid esterification at 8 Molar ratio

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Fig.7 Reaction water during oleic acid esterification reaction

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Fig.5 Effect of adding a modifier: A: Methanol added at 25oC , B: Methanol added at 300 oC, C: Methanol and CO2 added at 300 oC.

Two phases separated:Two phases separated:

•Top layer: Mostly methanol, 7 wt% methyl esters and glycerine

•Bottom layer: About 90 % Crude biodiesel, glycerine, methanol