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ENGINEERING ASPECTS OF BIODIESEL PRODUCTION PROCESS Nurhan Turgut Dunford Oklahoma State University Department of Biosy

ENGINEERING ASPECTS OF BIODIESEL PRODUCTION PROCESS Nurhan Turgut Dunford Oklahoma State University Department of Biosystems and Agricultural Engineering. Outline. Introduction Transesterification Esterification Homogeneous catalysis Heterogeneous catalysis Enzymatic conversion

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ENGINEERING ASPECTS OF BIODIESEL PRODUCTION PROCESS Nurhan Turgut Dunford Oklahoma State University Department of Biosy

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  1. ENGINEERING ASPECTS OF BIODIESEL PRODUCTION PROCESS Nurhan Turgut Dunford Oklahoma State University Department of Biosystems and Agricultural Engineering

  2. Outline • Introduction • Transesterification • Esterification • Homogeneous catalysis • Heterogeneous catalysis • Enzymatic conversion • Conversion without a catalyst • Lipid hydrotreating • Planning for production • Site selection

  3. Petroleum • A naturally occurring oil that contains mainly hydrocarbons with some other elements such as sulphur, oxygen and nitrogen • Gasoline: A mixture of hydrocarbons containing 5-8 carbon atoms, boiling point 40-180oC • Kerosine (paraffin oil): A mixture of hydrocarbons containing 11-12 carbon atoms, boiling point 160-250oC • Diesel oil: A mixture of hydrocarbons containing 13-25 carbon atoms, boiling point 220-350oC

  4. Petroleum Diesel • A fuel derived from the distillation  of crude oil • It is heavier than gasoline but lighter than engine oil and heavy  oils.   • Diesel fuel is generally  separated into two fuels: diesel number 1 and diesel number 2.  Diesel number 1 is similar to kerosene  and is lighter than diesel number 2.   While diesel number 2 is sold most of the time, diesel number 1 is sold  during winter in very cold climates because it doesn’t cloud or gel as easily  as diesel number 2. • Diesel fuel is ignited in an internal combustion engine cylinder by the heat of air under high compression in contrast to motor gasoline, which is ignited by electrical spark.

  5. Definition of Biodiesel “A fuel comprised of mono-alkyl-ester of long chain fatty acids derived from vegetable oils or animal fat designated B100” Biodiesel safety: http://www.biodieselcommunity.org/safety/ http://www.biodiesel.org/pdf_files/fuelfactsheets/MSDS.pdf

  6. Why Biodiesel? • Can be used in existing diesel engines without modification. • Can be blended in at any ratio with petroleum diesel. • Similar Btu/gal as petroleum diesel. • Also eliminates the huge cost of revamping the nationwide fuel distribution infrastructure. • Reduces CO2 emission. Average Density and Heating Value of Biodiesel and Diesel Fuel Fuel Density, g/cm3 Net Heating Value Avg., Btu/gal. % Difference vs. No. 2 Diesel Avg. No. 2 Diesel 0.850 129,500 Biodiesel (B100) 0.880 118,296 8.65 % B20 Blend (B20) 0.856* 127,259* 1.73 %* B2 Blend (B2) 0.851* 129,276* 0.17 %* * Calculated Values from those of No. 2 Diesel and Biodiesel (B100)

  7. H H OH C H HOOCR + H C OH 3H O + H 2 HOOCR’ OH H H C HOOCR” H TRIGLYCERIDES FATTY ACIDS WATER GLYCEROL Triacylglyceride

  8. Fatty Acid Molecular Structure

  9. Saturated Fatty Acids

  10. Monounsaturated Fatty Acids

  11. Polyunsaturated Fatty Acids

  12. Esterification R - COOH + R1- OH R – COO - R1 + H2O Fatty Acid Alcohol Catalyst Ester/biodiesel Water Methanol safety: http://www.biodiesel.org/resources/reportsdatabase/reports/gen/20060401_GEN-370.pdf

  13. Transesterification Triacylglyceride Alcohol Esters/Biodiesel Glycerine R1, R2, R3 are hydrocarbon chains on fatty acids and R’ is the alkyl group on an alcohol molecule

  14. Homogeneous Catalysis Acid or Base Catalysis Dryer Biodiesel Oil/fat Reactor Biodiesel Alcohol/ catalyst Separator Wash Column Glycerine + Alcohol Water Alcohol Glycerine Recovery Glycerine + Water +Alcohol Alcohol Recovery Glycerine Glycerine + Water

  15. Homogeneous Catalyst Options • Base Catalysts: NaOH, KOH, Na/K-Methoxide • Acid Catalysts: H2SO4, H3PO4, CaCO3 • Lipase Enzymes

  16. Base Catalyzed Conversions • Base catalyzed processes dominate current commercial production • Sensitive to water and free fatty acids • Typical alcohol to oil ratio varies between 6:1 and 10:1 (mole ratio) • Typical catalyst concentrations (w/w, %) • NaOH/KOH 0.3-1.4% • Na-Methoxide 0.5% or less

  17. Acid Catalyzed Conversions • Direct esterification, oils with high free fatty acid content or for making esters from soap stock • Requires water removal • Requires high alcohol:free fatty acid ratio, i.e. 40:1 • Requires large amount of catalyst (5-25%)

  18. Homogeneous Catalysis Two-Step Process Dryer Biodiesel Alcohol + Catalyst Alcohol + Base Catalyst Oil/fat Biodiesel Acid Reactor Alcohol/ Acid catalyst Base Reactor Separator Wash Column Glycerine + Alcohol Water Alcohol Glycerine Recovery Glycerine + Alcohol + Water Alcohol Recovery Glycerine Glycerine + Water

  19. Heterogeneous Catalysis Biodiesel Alcohol Glycerine Glycerine Alcohol Oil/fat Glycerine

  20. Heteregeneous Catalysts Sulfated zirconia and tungstated zirconia are typical examples of superacids Sulfonic resins such as Nafion® NR50, sulphated zirconia (SZ), and tungstated zirconia (WZ), have sufficient acid site strength to catalyze biodiesel-forming transesterification reactions as efficiently as sulfuric acid. Many types of heterogeneous catalysts, such as alkaline earth metal oxides, various alkaline metal compounds supported on alumina or zeolite can catalyze transesterification reactions. The order of activity among alkaline earth oxide catalysts is BaO > SrO > CaO > MgO

  21. Heterogeneous Esterfip-H Process Highlights • http://www.Axens.net • Continuous technology based on solid catalyst • High glycerol purity >98% • Very high ester yield: close to 100% • No waste production of low-value fatty acids • No waste saline streams that require disposal • Much lower catalyst requirements (per ton of FAME) compared with other processes

  22. Enzymatic Conversion • Lipases are used as catalyst • Immobilized or free enzymes Reactor Enzyme Biodiesel Oil + Alcohol Separator Glycerine

  23. Comparison of Enzyme and Base Catalysis Catalyst Base Enzyme Reaction temperature 60-70°C 30-4OoC Free fatty acids Saponified products Methyl esters in raw materials (soap formation) Water in raw materials Interference with No influence the reaction Yield of methyl esters Normal Higher Recovery of glycerol Difficult Easy Purification of methyl esters Repeated washing None Catalyst cost Cheap Relatively expensive

  24. Batch vs Continuous System • Batch process is better suited to smaller plants (<1 million gallons/year) • Batch process provides operation flexibility • Continuous process allows use of high volume separation systems hence increases throughput

  25. Transesterification Time At ambient temperature (70F and 21oC) reaction takes 4-8 h to reach completion Higher temperature will decrease reaction times but this requires pressure vessel because boiling point of methanol is 148F (65oC) High shear mixing and co-solvent use accelerates reaction rates

  26. Non-Catalytic Conversions • Supercritical fluids • Co-solvent systems

  27. Non-Catalytic ConversionSupercritical Methanol Biodiesel Alcohol Oil/fat High pressure & temperature reactor Separator Alcohol Separator Glycerine 350-400oC, 85-100 atm (1200-1500 psi), alcohol:oil 42:1 3-5 min reaction time

  28. Non-Catalytic ConversionCo-Solvent Process Biox Process • Uses an inert co-solvents (tetrahydrofuran, MTBE-methyl tert-butyl ether, ) that generate an oil-rich one-phase system. • This reaction is 95% complete in ten minutes at ambient temperatures. • No catalyst is required. Alcohol Oil

  29. Phase Separation Required density difference for phase separation 0.1 Specific Gravity Methanol 0.79 Biodiesel 0.88 Soybean oil 0.92 Catalyst 0.97 Glycerine 1.28 “Good reaction” as much methanol as possible “Good phase separation” min. methanol

  30. SuperCetane Several reactions occur in the process, including: hydrocracking (breaking apart of large triglyceride molecules), hydrotreating (removal of oxygen), and hydrogenation (saturation of double bonds). A conventional commercial refinery hydrotreating catalyst is used in the process and hydrogen is the only other input. Feedstocks: canola oil, soya oil, yellow grease, animal tallow and tall oil (a by-product of the kraft pulping process). Cetane number (a measure of ignition quality) of around 100 – which is comparable to commercial cetane additives. The specific gravity of SuperCetane is similar to regular diesel while its viscosity is similar to biodiesel. It is 97% biodegradable as compared to 45% for regular diesel. http://www.nrcan.gc.ca/es/etb/cetc/cetc01/htmldocs/pdfs/supercetane_e.pdf

  31. AVRO Diesel TM Process (http://www.nrcan.gc.ca/es/etb/cetc/cetc01/htmldocs/pdfs/avro_diesel_e.pdf) combines mild thermal cracking with esterification. This process is being patented by the CANMET Energy Technology Centre – Ottawa. Feedstock: waste animal fats, cooking greases, and trap grease that are 'too contaminated' for a conventional trans-esterification process, and produces clean diesel fuel. The process yields 65 to 75 wt% hydrocarbons/methyl-esters mixtures suitable for diesel fuel blending.

  32. ConocoPhillips/Tyson Renewable Diesel • The production technology for renewable diesel uses a thermal depolymerization process to co-process animal fat with hydrocarbon feedstock. • The fuel is chemically equivalent to the diesel produced from hydrocarbon feedstocks and can be transported directly through existing pipelines to distribution terminals.

  33. Biodiesel DryWashTM Adsorbent purification Magnesium Silicate (Magnesol D-Sol) Removes both particles and soluble impurities Excess methanol flash evaporated http://www.dallasgrp.com/biodiesel.pdf

  34. Ion Exchange Dry Wash • Ion exchange resin is used for biodiesel cleaning. • Greenline & Rohm-Haas Corporation collaboration: Ion-exchange resin known as Amberlite. • Amberlite looks very much like coffee grounds and functions much like coffee grounds in a percolator. The biodiesel fuel enters the top of the percolator and trickles down through the cylinder of Amberlite. • The final product is pure and dry. • The resin needs replacing at the rate of about 1 metric ton for every 250,000 gallons of biodiesel processed. http://www.greenlineindustries.com/ProcessDesc_1.htm

  35. Technology Providers • Desmet Ballestra North America • Westfalia Separator, Inc. • Crown Irons Works • Lurgi PSI 

  36. Reading Material http://www.southeastdiesel.org/Photos/Library/Ag/Eng_AspectsCh1.pdf http://www.fapc.okstate.edu/factsheets/fapc149.pdf http://www.fapc.okstate.edu/factsheets/fapc150.pdf http://www.uidaho.edu/bioenergy/biodieselED/publication/01.pdf University of Idaho-Questions http://www.uidaho.edu/bioenergy/top10q_s.htm

  37. Questions • Define biodiesel • What are the three components that are required for making biodiesel? • What are the advantages and disadvantages of using ethanol instead of methanol for biodiesel production? • What are the most common catalysts (acid and base) used for biodiesel production? • Name two reactions that are used for biodiesel production and highlight differences • Compare energy contents of biodisel and petroleum diesel • Name two biodiesel production techniques which do not require a catalyst

  38. Biodiesel Production Facilities in the US Smallest capacity: 50,000 gallons/year, recycled cooking oil Largest capacity: 37.5 Million gallons/year, soybean Earth Biofuels Inc, Durant, OK, 10 Million gallons/year, multifeed stock Green Country Biodiesel Inc., Chelsea, OK, 2.5 Million gallons/year, soybean

  39. Biodiesel Industry Expansion Largest Capacity:100 Million gallons/year Smallest Capacity: 250,000 gallons/year ADM, 85 Million gallons/year, canola oil Best Energy Solutions LLC, Tulsa, OK, 1 Million gallons/year

  40. Planning* • Location • Biodiesel Marketing • Feedstock Sourcing • Glycerine Outlet • Process Plant Size * Chris Mitchell – Biodiesel Product ManagerDesmet Ballestra North America

  41. Location* • Minimizing the freight cost for feedstock and biodiesel will be critical to survive. • How much biodiesel can be sold in a 200 mile radius? • How much competition or potential competition exists in a 200 mile radius? * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

  42. Feedstock Sourcing* • Do you have control of your own feedstock supply (as an oilseed crusher or animal fats renderer)? • If you are dependent on an external supply, how many potential suppliers are within a 200 mile radius? • Can you sign a long-term contract with one of these suppliers to insure adequate feedstock? • Will the feedstock suppliers in the area deliver by truck or rail, and at what frequency? * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

  43. Glycerin Outlet* • Where are the closest potential buyers of glycerin? • What quality of crude glycerin (H2O, MeOH, soap, FFA, salt etc) will they purchase, and at what price relative to USP grade refined glycerin? • Will the glycerin refiners in the area want delivery by truck or rail, and at what frequency? • Do you need to install your own glycerin refinery? * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

  44. Process Plant Size* • What plant size will meet the short and long term needs of the local biodiesel market? • How does local feedstock availability limit plant size? • What minimum plant size is required to provide a competitive conversion cost in the long-term? • How much equity and debt financing is available to build the plant, and how much capacity can that buy? * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

  45. Plant Site Selection* Transportation Proximity Utility Connections Specific Parcel of Land Shared Infrastructure * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

  46. Transportation Proximity* • Is the site adjacent to an active freight rail system? • Does the site, or can the site, have a rail siding installed with sufficient length of track? • At what frequency are rail switches possible, and how will the rail cars be moved for loading/unloading? • Is the site in close proximity to a highway? * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

  47. Utility Connections* • Does the site have sufficient power supply available? • Does the site have sufficient water supply available (to meet fire protection demand)? • Does the site have a sewer connection that can take the plant waste water? • Does the plant have natural gas supply available? * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

  48. Land* • Does the site have sufficient space for the process plant (with surrounding safe area), tank farm, utility building, office building, rail siding and truck route? • Does the site have sufficient extra space for a future biodiesel plant expansion or glycerine refinery? • Is the site long enough for the rail siding to hold a sufficient number of cars? • Any environmental & construction permitting issues? * Chris Mitchell – Biodiesel Product Manager Desmet Ballestra North America

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