Study Guide. Biofuel vs Petroleum-based fuel Exam questions will relate the lectures to each other

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1 Study Guide Biofuel vs Petroleum-based fuel Exam questions will relate the lectures to each other Advantages and disadvantages of the different fuels (methanol, ethanol, bioethanol, and biodiesel) and compared to petroleum How are they similar and different from each other? Make a table to compare EXAM # 2 IS ON TUESDAY NOVEMBER 30 TH : Endophyte-Assisted Phytoremediation plus the three bioenergy lectures so far

2 Bioenergy Lectures Th Nov 16- Overview Tu Nov 18- Biodiesel Th Nov 23- Bioethanol and methanol Tu Nov 25- Holiday Nov 30- EXAM #2 (Phyto( with endophytes; first 3 bioenergy lectures) Dec 2-Ways 2 to improve the efficiency of biofuel production Dec 7-7 (cont.) Dec 9-9 Environmental applications of trees; paper assignment given Dec 13- Final exam (75 pts) on last 3 lectures (in class for both ESRM and CFR); Paper (50 pts) is due

3 Bioethanol (Many of the following slides are from Prof. Renata Bura)

4 Overview What is bioconversion? Why bioconversion? Biomass composition Bioconversion to ethanol process Pretreatment Hydrolysis Fermentation Pros and cons of bioethanol Comparison to other biofuels

5 What is bioconversion? General: a process which uses biological agents (microorganisms or protein) to transform a feedstock into desirable products. Bioethanol A chemical/biochemical process by which lignocellulosic materials are converted to ethanol and other co-products.

6 Bioconversion Pretreatment Biomass Hydrolysis Ethanol Fermentation Distillation

7 Ethanol (CH 3 CH 2 OH) Ethyl alcohol, grain alcohol Clear, colorless liquid Ethanol made from cellulosic biomass instead of starch crops-bioethanol Advantages of bioethanol Domestic renewable fuel sources Reduces reliance on foreign oil Cleaner fuel sources Easily produced and stored Increases fuel octane number for little cost

8 Energy content Gasoline Ethanol Biodiesel 100% 67% 86%

9 Henry Ford We can get fuel from apples, weeds, sawdust, almost anything.. And it remains for someone to find how this fuel can be produced commercially- better fuel at a better price than we now know. Henry Ford

10 Why bioconversion? Energy An alternative source of energy for the transportation sector produced locally Air pollution Reduction in greenhouse gas emission Waste elimination Elimination of problems with field burning/incineration, stockpiling, etc. Socio/economical benefits Creation of new jobs, rural development

11 Possible feedstocks Agricultural residues (corn stover, corn fibre, wheat straw, rice straw) Wood residues: Hardwood (poplar, willow) Softwood (Douglas-fir, lodgepole pine) Paper waste Municipal solids waste

13 Biomass composition

14 Cellulose

15 Hemicellulose

16 Lignin

17 Lignin A major barrier to accessing the cellulose Provides strength and rigidity

19 Bioconversion of biomass to ethanol (pretreatment) Pretreatment Liquid phase Sugars Ethanol Fermentation Biomass Solid phase Lignin Recovery Cellulose Hydrolysis Fermentation Sugars Ethanol

20 Pretreatment Helps in separation of main biomass components (cellulose, hemicellulose and lignin) Increase available surface area Reduce particle size Ideally pretreatment: Solubilizes hemicellulose Increases enzymatic hydrolysibility of cellulose

21 Pretreatment disruption Possible methods: Mechanical (milling) Chemical (acid and base) Biological Combination

22 Steam explosion Treatment of biomass with high-pressure steam for a short period of time followed by sudden decompression Acid (H 2 SO 4, SO 2 ) impregnation of biomass increases SE efficiency Typical conditions: Temperature: o C, F Time: 10sec-10min 10min

23 Steam gun Fill valve Karin Receiving vessel Receiving vessel Blow valve Steam valve Pretreated corn stover

25 Bioconversion of biomass to ethanol (hydrolysis) Pretreatment Liquid phase Sugars Ethanol Fermentation Biomass Solid phase Lignin Cellulose Recovery Hydrolysis Fermentation Sugars Ethanol

26 Cellulose The goal of the hydrolysis step is to break the cellulose into simple sugars prior to fermentation

27 Must be able to break cellulose to get the energy Cows, deer, sheep Rumen is a fermentation vat Microbes break down the cellulose using the enzyme, cellulase

28 Fungi can break down cellulose too Cellulases are enzymes that break down cellulose White rot fungi: good source of enzymes

29 What are cellulases? Enzymes made by many strains of bacteria and fungi Catalyzes the depolymerization of cellulose chains (details in Renata Bura s s class)

31 Bioconversion of biomass to ethanol (fermentation) Pretreatment Liquid phase Sugars Ethanol Fermentation Biomass Solid phase Lignin Cellulose Recovery Hydrolysis Fermentation Sugars Ethanol

32 Fermentation Defined as: Cellular metabolism under anaerobic conditions (absence of oxygen) for the production of energy and metabolic intermediates Many organisms can ferment Not all produce ethanol as an end-product

33 Strain selection Traditionally been a Yeast Yeast: Single cell microorganism Fungi Facultative anaerobe Most common industrial fermenter is Saccharomyces cerevisiae (baker s or brewer s yeast) Why?

34 Why S. cerevisiae? Has been selected over thousands of years High ethanol yield and productivity Relatively simple to culture

35 Fermentation (Glycolysis first)

36 FERMENTATION If electron acceptor (such as oxygen) is present Cellular respiration GLYCOLYSIS PYRUVATE PROCESSING KREBS CYCLE ELECTRON TRANSPORT AND OXIDATIVE PHOSPHORYLATION Glucose Pyruvate FERMENTATION If electron acceptor (such as oxygen) is NOT present

37 Fermentation Regenerates NAD + Fermentation pathways allow cells to regenerate NAD + for glycolysis. Fermentation by-product Intermediate accepts electrons from NADH GENERAL PATHWAY

38 Alcohol fermentation occurs in yeast. 2 Pyruvate 2 Ethanol 2 Acetylaldehyde

39 Fermentation Conversion factor g/L of glucose: 0.51g/L ethanol (maximum)

41 Challenges (Cons) Feedstock diversity Economical feasibility of the process Cost of biomass Cost of enzymes Ethanol as a final product = very cheap

42 Pros (again) Energy An alternative source of energy for the transportation sector produced locally Air pollution Reduction in greenhouse gas emission Waste elimination Elimination of problems with field burning/incineration, stockpiling, etc. Socio/economical benefits Creation of new jobs, rural development

43 Sugar cane & sugar cane bagasse Sugar cane bagasse Processing Ethanol

44 Corn plant

45 Biofuels-comparisons Corn grain ethanol Production (billion gallons) 4.86 Production cost ($) 1.09 Energy balance 1.3 GHE reduction (%) 22 Cane ethanol Lignocellulosic ethanol NA NA Biodiesel 0.50 NA

46 Part 2. Methanol Casio Toshiba

47 Biomass to Liquid Fuel Crude Syngas Clean Syngas Gasifier Scrubber Methanol Reactor Wood Biomass (Syngas = CO 2 + H 2 ) + CO Bio-Methanol (Wood Alcohol)

48 How is biomethanol made? All the woody biomass is used NOT FROM FERMENTATION Wood chips gasifier at high temp scrubbers biomethanol Wood to bioethanol yields gal Wood to biomethanol yields gal BECAUSE IT USES ALL THE BIOMASS, NOT JUST THE SUGAR

49 2. Principle of methanol synthesis by the gasification method CO + 2H 2 Carbon Hydrates: Mixture of Gases: Biomethanol (CH 2 O)n + Oxygen+ water 1000 C Hydrogen, carbon monoxide, carbon dioxide, water Pressure atm CH 3 OH Slide adapted from H. Nakagawa

50 Typical test questions How is bioethanol and biomethanol different in terms of how they are made? How is biodiesel different from both bioethanol and biomethanol in terms of the plant material used?

51 Some conversion efficiencies to alcohols Material Sugar cane gar_production_from_cane.pdf,, K Vogt estimate Corner stover Kheshgi et al. 2000, Wood Kheshgi et al. 2000, K Vogt estimate Ethanol (gallons / 1 Mg biomass) gallons (6-9%) gallons gallons Methanol (gallons/ 1 Mg biomass) Chemistry determines how much liquid byproduct produced gallons NOTE: Ethanol cannot be made from lignin, a major component of waste biomass Starch or Cellulose being converted Cellulose and lignin being converted

52 Then why the focus on bioethanol instead of biomethanol? Plants contain a lot of nitrogen (not just carbon hydrates ) Gasification of nitrogen in the presence of oxygen makes toxic NO gases Toxic byproducts Lower energy Smaller market (but maybe changing)

53 SFR biofuels research agenda Vision: Cost effective cellulosic transportation fuels Use mixed biomass sources With good process yields Profitable at moderate economies of scale Co-produce fuels and high value products Commodity Chemicals Polymers Pulp Fibers

54 Review Ethanol from fermentation of starch from grain or sucrose from sugarcane Bioethanol from fermentation of any cellulosic biomass- can be produced sustainably; can be mixed with gasoline Biodiesel from plant oils- high energy fuel; not compatible with most US cars (yes-bus) Biomethanol- lower energy; smaller market; but efficient production; can be used in power cells

55 Study Guide Biofuel vs Petroleum-based fuel Exam questions will relate the lectures to each other Advantages and disadvantages of the different fuels (methanol, ethanol, bioethanol, and biodiesel) and compared to petroleum How are they similar and different from each other? Make a table to compare EXAM # 2 IS ON TUESDAY NOVEMBER 30 TH : Endophyte-Assisted Phytoremediation plus the three bioenergy lectures so far

56 Comparing Fuels Structure Diesel: saturated hydrocarbons, C10-C15 C15 Biodiesel: Ethanol/Bioethanol: Methanol: Energy content Diesel: High energy content Biodiesel: Ethanol/Bioethanol: Methanol Air pollution Diesel: High Biodiesel: Ethanol/Bioethanol: Methanol:

57 Fuel Comparisons (cont.) What is it? Sources? Microbes needed? How is each different from petroleum or diesel? Benefits of the biofuel?

58 References