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Biodiesel Production via Continuous Supercritical Catalytic Packed Bed Reactor. Oregon State University ◦ School of Chemical, Biological and Environmental Engineering Team Members: Staci Van Norman, Mike Knapp, Malachi Bunn
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Biodiesel Production via Continuous Supercritical Catalytic Packed Bed Reactor Oregon State University ◦ School of Chemical, Biological and Environmental Engineering Team Members: Staci Van Norman, Mike Knapp, Malachi Bunn Project Sponsors: Dr. Nick Wannenmacher, Dr. Brian Reed, Kevin Harris M.S., M.B.A. Chevron, Beaver Biodiesel, Willamette Biodiesel, Encore Fuels, ONAMI, MBI WhyBiodiesel?1 Our Production Technology – Continuous, Supercritical, Catalytic Packed Bed Transesterification Gas Chromatography Data Analysis 2 • Reduces dependency on imported petroleum • Little or no modification to existing diesel engines • Reduced emissions such as (CO2, CO, etc.), non-toxic and degrades 4 TIMES faster than petrodiesel • Oxygen content in biodiesel (BD) improves combustion efficiency and also has a flash point of 302°F (150°C) compared to petrodiesel of 147°F (64°C) Camelina Oil Chromatogram Overlay • Gas Chromatography (GC) with a Flame Ionization Detector (FID), used to detect electric current (Response) of eluting compounds, for determining sample composition • Two internal standards used for mass determination • Certified standards used for ethyl and methyl ester calibrations • In the supercritical state the miscibility (how well components mix) is greatly increased • Water content in the oil does not effect the conversion and has been shown to assist with the formation of esters. Additionally, glycerol is more soluble in water which makes product separation easier9 • Product quality is more consistent than batch methods • Free fatty acids (FFA) are converted to esters • Glycerol purity (> 96%) can be sold for cosmetic and pharmaceutical uses9 Response [mV] Project Objectives • Establish optimal operating conditions for different feedstock oils to obtain the highest production at the lowest operating cost (low energy input and separation cost) • Determine feasibility of unrefined natural oil feedstocks obtained from national and local suppliers • Develop kinetic model of transesterification reaction under supercritical heterogeneous catalytic continuous flow conditions • Conduct economic comparison to classical batch processes WhatisBiodiesel? • Monoalkyl esters of long chain fatty acids derived from renewable lipid feedstocks3 • Produced from renewable vegetable oils, waste cooking oil, animal fat and non-edible oils Yellow Grease Time [min] Operating Parameters Molar Ester Percent Howis Biodiesel Produced? • Reactor temperature (290°C & 305°C) • Alcohol to oil molar ratio (20:1 & 30:1) • Residence time within reactor based on standard flow conditions (4, 6 & 8 minutes) • Pressure of reactor (constant at 2500 psi) • Molar amount of esters present in product stream ignoring unreacted feedstock alcohol - this excess alcohol is recycled back into the alcohol feedstock storage tank Canola Castor 4 • Reaction of one large multi-ester molecule with three alcohols to make three esters and one glycerol4 • Catalyst Material • Homogeneous (i.e. liquid-liquid phase) • Heterogeneous (i.e. solid-liquid phase) Soy Bean Camelina Jatropha Ester Percent of Reactor Products Catalyst Tin catalyst applied to 50-250 μm 304 stainless steel plasma powder (OSU Patented Technologies) Limitations of Current BD Technology • Homogeneous catalysts require refined oils • Free fatty acid content over 0.5 wt% and water bearing oils cause soap and froth formation which reduces productivity and makes separation of products difficult1 • Reaction can take an hour or longer • Pretreatment required to prevent soap formation before combining with liquid catalyst and alcohol 304 Stainless Powder Treated 304 Stainless Powder High Pressure Pumps Electrical & Control Housing Reactor & Preheater Housing Cooling Loop & Pressure Regulation Domestic Biodiesel Production FeedstockOils 5 • Analysis completed on classical batch method using soybean, methanol and base catalysts • $2.15/gal • For a 60 million gallon production facility, when considering only raw material, utility and fuels costs from an economic analysis completed at Iowa State University6 • Need for a shift to more efficient, cost effective reaction methods to meet increasing demand • Food Grade Canola • Commercial Yellow Grease • Unrefined Jatropha • Expeller Pressed (MT) Camelina • Industrial Castor • Expeller Pressed (OR) Soybean • Expeller Pressed (OR) Camelina • 305°C – 20:1 • 4 minute • 6 minute • 8 minute KineticModel First Order Rate at 290˚C Second Order Rate at 305˚C Slope = k/Xe Slope = 2k(1/Xe -1)CA0 • Reaction kinetics modeling of canola and soy bean oil conversion data • Reaction rate kinetics change from first to second order with increasing reactor temperature for canola oil • Soybean oil continues to be first order with increasing temperature Variability of Crude Oil Price Economic Comparison Experimental Setup • At the beginning of this project (March 2009) crude oil was $45/bbl • As of June 8th, 2009 crude oil • was $68.7/bbl8 7 • This estimation does not include capital costs which would decrease with increasing production output • Analysis completed on raw material costs for ethanol and soybean oil including transportation costs $0.98-$0.99/gal $68.7/bbl Additional Motivation for Biofuels Dollar/barrel ($/bbl) Conclusions • Decrease dependence on petroleum based fuels • Build local economies • Reduce distribution costs • Minimal variation in % molar ester content using different oils • No significant benefit to increasing temperature or reactant ratio within the tested operating conditions • Initial economic analysis comparison, to classical batch production, demonstrates about 50% reduction in material costs per gallon produced using this technology • High FFA content changes the reaction kinetics, making overall ester production faster • Technology is ready for pilot scale production, including implementation of separation techniques References available upon request.