Renewable Chemicals From Biomass Flashcards
What does biomass consist of?
- Agricultural residues
- Food processing wastes
- Livestock production wastes
- Wood waste
- Algae
What does biomass consist of?
- Cellulose (sugars / starches)
- Hemicellulose
- Lignin
What is the reaction of the energy released on burning biomass?
(CH2O)n + nO2 -> nCO2 + nH2O
What is the amount of energy released during burning biomass, oil & gas?
biomass: 15 kJ/g
Oil: 48 kJ/g
Natural Gas: 55 kJ/g
Is burning biomass carbon neutral? Give an example.
Biomass accounts for 12% of UK’s electricity.
An example: Saw Mills
1. Saw dust generated -> pressed into wood pellets => use in heating applications.
2. Used in energy generating plants => generating electricity.
3. Companies that generate it receive subsidies (from ukgov), supposed to be “carbon neutral”.
4. Wood pellets harvested from forests, replaced at a slower rate than their growth.
Answer: No, it increases CO2 emissions, and air pollution.
What are alternative ways to generate energy from biomass?
- Thermal Transformation (thermal treatment of biomass)
- Transformation using microorganisms
What processes are involved in Thermal transformation?
- Thermolysis (450 - 800 dC) => charcoal, fuel, gases
- Pyrolysis (1500 dC) => C2H2, charcoal
- Gasification (650 - 1200 dC) => CO, H2, CH4, CO2
- Hydrothermolysis (250 - 600 dC) => charcoal, fuel, CO2
What processes are involved in transformation using micrroorganisms?
- Fermentation => ethanol, CO2
- Anaerobic digestion => CH4, H2O
What are biodiesels and what is their reaction?
- They are mainly obtained from trans-esterification of vegetable oils (triglycerides) with MeOH.
[O2CR]x3 + 3MeOH <=> [OH]x3 + 3RCO2Me
In equilibrium: using catalyst.
What do palm oil based triglycerides contain? Mention 3 alternative oils.
- Palmitic acid - 42.8%
- Oleic acid - 40.5%
- Linoleic acid - 10.1%
- Stearic acid - 4.5%
- Linoleic acid - 0.2%
Alternative oils include:
a) soybean
b) rapeseed
c) sunflower seed
State an alternative to produce biodiesel, as well as the chain of its production.
- Algal biomass is an alternative to producing biomass.
- Microalgae is a more efficient way of removing CO2.
- Photosynthetic microorganisms better efficiency for biomass conversion.
(All that compared to plants)
Sun, CO2, Waste Water (C, N, P, Mn, Mg, K)
|
Algal Cell => O, H exit
|
1. Biomass => food & feed, bioremedation, biogas
2. Carbohydrate => biofuels, bioplastics
3. Pigments => Therapeutics
4. Lipid => Biodiesel, Nutraceuticals
5. Bioactive compound & protein => nutraceuticals & therapeutics
What is biodiesel generated from and how is it used?
- Through engineering algae - augmented neutral lipid contents ~ 60-70%
- Lipids trans-esterified to biodiesel and residual biomass
Also, generated from:
- waste oils and fats
- waste oil through recycling
Used as animal nutrient or fermented.
What is bioethanol produced from?
The fermentation of corn or sugarcane.
- 60% corn
- 25% sugarcane
- 3% wheat
- 2% molasses
The rest: grains, cassava & sugar beets.
State two other ways of producing bioethanol.
- Lignocellulosic feedstocks (forest and wood residues)
- Cellulose and hemicellulose (agricultural residues)
What is the pre-treatment process done prior to fermentation?
Rigid structure of biomass requires opening up, creating amorphous regions, therefore:
=> cellulose and hemicellulose are pre-treated
=> hydrolysis to sugars enabled prior the fermentation step.
Pre-treatment could be done:
1. Upon hydrolysis by enzymes.
2. By treatment with acids or bases.
