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Biomass based energyنهائي ندوة
The document discusses biomass as a renewable source of energy and chemicals. It can be used to produce fuels like ethanol through various processes like pretreatment, hydrolysis, fermentation and distillation. Algae can also be used to produce biofuels through photosynthesis using sunlight, water and carbon dioxide in open pond systems. Biomass can undergo biological processes like fermentation and anaerobic digestion to produce fuels. It can also be converted through microbiological and thermochemical processes to generate hydrogen and other biofuels.
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Similar to Biomass based energyنهائي ندوة
Biomass based energyنهائي ندوة
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- 2. Renewable Resources: Natureand Availability We can express an equation whereby the Earth’s capacity (EC) is defined as the product of world population P, the economic activity of an individual C and a conversion factor between activity and environmental burden B: EC = P × C × B. We need to find new ways of generating the chemicals, energy and materials as well as food that a growing world population (increasing P) and growing individual expectations (increasing C) needs, while limiting environmental damage B.
- 3. biomass can beused to produce not only energy but also chemicals and materials
- 4. Biomass is arenewable energy source comprising a wide range of biological materials that can be used as fuels and as precursors for the production of other industrial chemicals. Energy generated from biomass is usually referred to as Bioenergy. In general, biomass-derived fuels may be solids (e.g. chips, pellets), liquids (e.g. ethanol, biodiesel), or gases (e.g. biogas, hydrogen). They can be classified based on the processes used in their production, which include physical upgrading, microbiological processes, thermochemical processes , and chemical processes, as described in Figure below:-
- 9. Basic Ethanol Proces Pretreatment (releaseof sugars) Hydrolysis (breakdown to fermentable sugars) Fermentation Distillation Ethanol CO2 Feed (Vinasse Distillers grain) Enzymer Feed molasses
- 10. How does algaegrow? Sunlight, Water & Carbon Dioxide
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- 14. Finding the RightAlgae Over 40,000 species of algae have been identified, likely hundreds of thousands more to be discovered
- 15. The Source ofAlgae Energy
- 16. These include low-valuehigh-volume products such as transportation fuels (e.g. biodiesel, bioethanol), commodity chemicals and materials and high-value low-volume products or specialty chemicals such as cosmetics.
- 17. • Phase Ibiorefinery (single feedstock, single process and single major product); • Phase II biorefinery (single feedstock, multiple processes and multiple major products); and • Phase III biorefinery (multiple feedstocks, multiple processes and multiple major products).
- 20. Biological Processing Fermentation Fermentation involvesthe use of microorganisms such as bacteria and fungi to transform sugars into products. Bioconversion of biomass into products through fermentation is a very flexible process which could lead to a wide range of products including biofuels, biochemicals, or biomaterials
- 21. Anaerobic Digestion Anaerobic digestion(AD) involves a mixture of bacteria including syntrophic bacteria, fermentative bacteria, acetogenic bacteria and methanogenic bacteria to decompose biomass under anaerobic conditions in order to produce biogas (methane and hydrogen) as fuel. The process is divided into four stages: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. In the hydrolysis stage, insoluble organic compounds are broken down into water-soluble monomers by hydrolases secreted by a consortium of bacteria.
- 22. The barely decomposablepolymer, which is not decomposed by hydrolases, remains solid and thus limits the efficiency of AD. The products of hydrolysis are then converted into short-chain organic acids, alcohols, aldehydes, and carbon dioxide in the acidogenesis stage and transformed into acetates, carbon dioxide, and hydrogen in the acetogenesis stage. Finally, methanogenic bacteria utilize acetic acid, hydrogen, and carbon dioxide to produce methane. About 70% of the methane is converted from acetic acid while the remaining 30% results from carbon dioxide reduction. Biogas and digestate, which is the remaining solids with the mineralized nutrient, are the final products .
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- 24. Bacteria, fungal, andyeast or some cells plant or animals used in bioreactor
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- 26. Phases of CellGrowth and Division
- 37. The Fate ofNADH and Pyruvate Aerobic or anaerobic?? Pyruvate is also energy - two possible fates: aerobic: citric acid cycle anaerobic: LDH makes lactate
- 38. Microbiological Processes ForHydrogen Production:- Various microbial processes can be exploited to utilize energy that has been stored in biomass by photosynthesis. These processes can generate useful biofuels such as hydrogen, butanol, and biogas. Moreover, biomass can be converted into ethanol; this is commonly done using fungi but can also be achieved with bacteria. Finally, certain algae can be used to produce biodiesel
- 39. The hydrogenase reactionhas the following stoichiometric formula: As indicated above, the process is reversible so hydrogen may either be produced or consumed. Four categories of hydrogen-related processes and organisms that perform them have been delineated as listed below: 1. photoautotrophic hydrogen production; 2. photoheterotrophic hydrogen production; 3. heterotrophic hydrogen production; and 4. heterotrophic hydrogen production coupled to photo-production.
- 40. There are threemicrobial groups that have been studied for biological hydrogen production as shown in Table.1. The first group consists of the cyanobacteria that are autotrophs and directly decompose water to hydrogen and oxygen in the presence of light energy by photosynthesis. Since this reaction requires only water and sunlight and generates oxygen, it is attractive from an environmental perspective. However, the cyanobacteria examined thus far show rather low rates of hydrogen production and may have difficulty overcoming large Gibb’s free energy (+237 kJ/mol hydrogen) requirements.
- 41. The second andthird groups of bacteria are heterotrophs and use organic substrates as a carbon source for hydrogen production. The heterotrophic microorganisms produce hydrogen under anaerobic conditions, both in the presence or absence of light energy. Accordingly, the process is classified as either photofermentation or dark fermentation. Phototrophic purple nonsulfur bacteria produce hydrogen through photofermentation, and nonphototrophic fermentative bacteria produce hydrogen through dark fermentation.
- 43. Thermodynamically, hydrogen production throughphotofermentation is not favorable unless light energy is supplied. In addition, only phototrophic bacteria are able to convert simple organic compounds such as organic acids to hydrogen, which thus limits the use of complex organic wastes. Dark fermentation continuously produces hydrogen from renewable sources such as carbohydrate-rich wastes without an input of external energy, a considerable advantage.
- 44. Hydrogen Production Pathwaythrough Dark Fermentation In most biological systems, hydrogen is produced by the anaerobic metabolism of pyruvate formed during the catabolism of various organic substrates. Simple sugars such as glucose are metabolized to pyruvate through various pathways that often involve the Embden–Meyerhoff–Parnas (also known as glycolysis) and the Entner– Doudoroff pathways.
- 45. Hydrogen production pathwayof enteric bacteria during dark fermentation.
- 46. Hydrogen production pathwayof clostridia during dark fermentation.
- 48. insoluble polysaccharides, suchas cellulose and hemicellulose) and subsequent conversion by primary and fermentation reactions with undefined mixed cultures. During primary fermentation of sugars, substrates are converted to pyruvate, which results in the production of NADH and H+. All equivalents must be re-oxidized via H+ reduction by: (a) NADH oxidation; or (b) NADH oxidation via reduction of pyruvate or its oxidized organic derivatives, depending upon the hydrogen partial pressure.
- 49. At increasing hydrogenpartial pressures, the flow of electrons from NADH shifts from H2, acetate and CO2 production towards formation of increasingly reduced fermentation products. CO2 and H2 are produced in the pyruvate oxidation reaction that is catalyzed by pyruvate: ferredoxin oxido reductase.
- 50. The products ofprimary fermentation can react further within undefined mixed cultures through several secondary fermentation reactions: (c) autotrophic homoacetogenesis; (d) hydrogenotrophic methanogenesis; (e) carboxylate reduction to alcohols with hydrogen or ethanol; (f) aceticlastic methanogenesis; (g) chain elongation of carboxylates with ethanol; (h) electricigenesis (i) lactate oxidation to n- butyrate (acetate and H+ as electron acceptor); and (j) lactate reduction to propionate (oxidation to acetate for energy conservation).
- 53. Chemical post-processes thatconvert carboxylates to bulk fuels or solvents with pure-culture biochemical, electrochemical, and thermochemical steps, or a combination thereof. In post-processing step 1, carboxylates are converted to esters via esterification; are reduced to carbonyls; or ketonized to carbonyls. In post-processing step 2, the carbonyl intermediates are converted to alkanes via decarbonylation; or reduced to alcohols. Finally, in post- processing step 3, the alcohol intermediates are converted to alkanes via reduction. Other conversions are possible.
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