Bioenergi

• Energy can exist in different forms
• Energy conservation law: Total energy remains constant
• A country's economy is dictated by its per capita energy consumption
• Energy perspective - basic needs

  • Clean - Air - pollution free
  • Abundant - Food- Agriculture
  • Eco-friendy - Shelter - construction materials
  • Sustainable - clothing - fiber production
  • Drinking - water - purification
• production of ammonia

  • Haber-Bosch process:
  • Steam reforming
  • CO shift.
  • hater (500 degrees) CO₂ removal
  • NH₃ synthesis
  • NH₃ separation cooler
• Haber-Bosch process (1905)


  3H₂+N₂→2NH₃
• Global energy consumption 2009

  • Fossil fuels, 84%
• Today's energy scenario is characterized with:

  Population increase, Tightness of resources, Climate change, Hazardous disposal
• Biomass formation (2 types)

  • Photo-synthesis - from sun on the surface of the ocean and land
  • Chemo-synthesis - Transition metal sulfides/H2 S (Dark environment) in Deep sea hydrothermal vents
• Photo-synthesis

  1. Chlorophyl traps the solar energy

  2. Chlorophyl creates a charge gradient across a chloroplast membrane

  3. Drives a chemical synthesis

  4. Energy rich molecules- Biomass
• Efficiency of photosynthesis is directly co-related with biomass formation
• Photosynthesis reaction

  The simple reaction: H2O (Splitting of water minus e^-, to become O2) +CO2 -> CH2O (is a carbohydrat) + O2. This happens is the chloroplast, and is conducted by a series of proteins and small molecules
• Two parts of photosyntesis

  Light reaction: in the thylakoid membranes of the chloroplasts, requires light, where they convert light energy into chemical energy (ATP and NADPH)

  Dark reaction: (Calvin cycle) in the stroma of the chloroplast, does not Require light directly, used for the chemical energy (ATP and NADPH) produced in the light reaction to synthesize glucose and other carbohydrates from carbon dioxide
• Corn has the highest starch content, compared to sweet potato and cassava
• dedicated energy crops


  switchgrass, miscanthus, poplar tree, sorghum, Napier grass, energy cane
• Forest biomass


  Wood chips, bark, sawdust, logging residues, softwood, hardwood, hybrid popular, eucalyptus
• Crop residues


  Corn stover, wheat straw, rice straw, sugarcane begasse
• Algae based feedsocks

  Cyanobacteria (located in the cytoplasm, is Unicellular), microalgae (located in the chloroplast, is unicellular), macroalgae (located in the chloroplast, is multicellular)
• Alga growth conditions – light

  Low light intensity rate of photosynthesis synthesis increases with increasing Light irradiance

  (CO2 concentration, temperature – pH and salinity, nutrients)
• Algal growth conditions – reactor type

  Close type reactors: tubular, bags, flat plates

  Open type reactors: raceway pond
• Algal bio diesel production step

  • algae cultivation
  • harvesting
  • drying
  • lipid extraction,
  • bio diesel production
  • bio diesel
• Factors deciding biomass growth

  • yield with respect to time
  • energy input – fertilizer land, water, pesticide
  • cost
  • Composition of biomass (cellulose, hemi-cellulose, Lignin)
  • Composition with least contaminants
  • low Nutritional requirements
• Factors deciding biomass conversion

  • water/moisture content
  • Calorific/heating value
  • Proportional fixed carbon(FC) vs volatiles
  • Ash/residue content
  • Alkali metal content
  • Cellulose to lignin ratio
  • Other factors (physical)
• water/moisture content

  intrinsic: does not depend on surrounding whether, extrinsic: depends on surrounding weather, high moisture content biomass is generally generally suitable for biochemical conversion or fermentation, low moisture content biomass is general suitable for thermochemical conversion
• Calorific/heating value

  higher heating value or gross, colorific value, lower, heating value or net calorific value, HHV is the total heat, including Latin, and heat that it's obtained after fuel is burned in the air, LHV is HHV minus fuel Latent heat
• Proportional fixed carbon(FC) vs volatiles

  volatile matter: the amount of gases and liquids that are lost during combustion, fixed carbon: the amount of carbon in solids that is left after combustion
• Ash/residue content

  thermal chemical route – ash, biochemical route - residue
• Alkali metal content

  The medals on the first row of the periodic table
• Cellulose to lignin ratio

  cellulose has a higher biodegradability compared to lignin, Constitutes ratio plot can give a prediction of certain conversion processes such as Pyrolysis
• Other factors (physical)

  • density, Energy density
• Why pre-treatment

  • To enhance the accessibility of cellulose to hydrolytic enzymes
  • To modify the Lignin structure to reduce negative impact on enzymes
  • to break the crystalline structure of cellulose
• Physical, biomass, pre-treatment

  • Reduce the particle size that results in the increase in surface area and decrease in degree of polymerization and crystallinity
  • physical pre-treatment is energy intensive

  Impact -> attrition ->shear -> compression
• Thermochemical pre-treatment

  • Removes hemi cellulose/lignin de crystallization of cellulose
  • -> acid pre-treatment: 1:dilute acid pre-treatment, 2: liquid hot water pre-treatment, 3:steam explosion pre-treatment
  • Alkaline pre-treatment: 1: soaking in Aquespus ammonia, 2: ammonia recycle percolation, 3: low moisture anhydrous ammonia, 4: ammonia fiber expansion
  • Organosolv pretreatment: different organics with or Without catalyst, is expensive , creates higher water Pressure then water
• Biological pre-treatment

  • Employs microorganisms, such as white, brown and soft- rot, fungi, and bacteria to treat biomass
  • longer time reaction
• Other pre-treatments

  • Ionic liquid pre-treatment: Cellulose content is recovered by adding anti-solvent like acetone and water
  • Ultrasonic pre-treatment: creates pressure waves, causing the formation of cavity bubbles to collapse at solid walls, forming micro jet, is energy Intensive and expensive
  • Microwave, assisted pre-treatment: electromagnetic waves, reflected by metals, absorbed by some dielectric metals and transmitted through other materials
• Biomass combustion phases

  • drying: evolution of moisture
  • pyrolysis: causes evaporation of condensaband non-consensable gases
  • flaming combustion: causes the oxidation of violations and char by flaming combustion to produce CO2 and H2O as well as heat (flame front)
  • Char combustion: causes the breakdown of char into CO, CO2 , and release heat (shrinking core)
• What does gasification mean?

  • Conversion of biomass into combustible gas mixture by a partial oxidation of biomass at high temperature and in gasification medium
• Gasific process steps

  1: drying

  2: devolatilization —> volatiles

  3: char reactions —> char

  4: gas phase reactions —> gas products
• Bioethanol production pathways

  • bioethanol from sugary crops (1st generation biomass): fermentation + distillation & dehydration
  • bioethanol from starchy crops. (1st generation biomass): saccharifaction + fermentation + distillation & dehydration
  • bioethanol from lignocellulosic crops. (2nd generation biomass): saccharifaction + fermentation + distillation & dehydration
• Flowchart from sweet sorghum to bioethanol production

  1: plant to harvest-> 2: clean and crush tree stalks -> 3: extracting sweet sorghum juice -> 4: filtering juice & adjusting sugar content -> 5: Inoculation with yeast -> 6: fermentation and ethanol recovery