Bài giảng - Biofuels

BIOFUELS


Outlines
General Introduction
 Biodiesel production
 Ethanol production
 Acetone-Butanol-Ethanol (ABE)
 Hydrogen Production



Biofuels
Fossil Fuel: a hydrocarbon fuel, such as petroleum,
derived from living matter of a previous geologic time.
• Coal, Oil, Natural Gas
Biofuel: Any fuel that derives from biomass – recently
living organisms or their metabolic byproducts
• Biodiesel, Butanol, Ethanol, Hydrogen


Why Biofuels?





Reduce dependency on fossil-fuels
Reduce GHG emissions (reduce impact on
health, environment)
Improve energy security

Contribute to rural development through
domestic production


BIODIESEL


What is Biodiesel
Mono-alkyl esters of fatty acids (i.e. methyl or ethyl
esters) which are produced by transesterification of
triglyceride


Biodiesel Production

• Physical properties very similar to
conventional diesel
• Must meet the quality requirements of
ASTM D6751
• Biodiesel Blend: mixture of biodiesel and petroleum diesel
• BXX = volume XX% biodiesel
• Most common blends are B5, B20


Sources of Lipids for Biodiesel
Production
Animals
 Plants
 Oleaginous microorganisms
 Algae




What are Algae?


Algae
 Most live in water
 Photosynthetic
 Capture light energy
 Convert inorganic to organic matter
 Nonvascular
 Use lipids and oils to help float in water
 Range from small, single-celled species
to complex multicellular species, such
as the giant kelps


Why Algae?
Photosynthetic organisms are capable of
efficiently using solar energy and CO2 to
create biomass.
Algae, like terrestrial plants, produce
storage lipids in the form of triglycerides.
Capable of utilizing high nutrients in waste
water streams
Incredible growth rates (much faster than
plants)

Why Algae?


As the use of biofuels expands globally,
traditional food crops such as corn and soy
beans are increasingly being used as feedstocks
for the most popular liquid biofuels, ethanol and
biodiesel, rather than as foods.
This raises price competition between fuels and
food commodities- not a sustainable practice.



Algae can be grown on non-arable land, where
food crops simply cannot grow.



Oil Yield
Gallons of Oil per Acre per Year


Corn . . . . . . . 15



Soybeans . . . .48



Safflower. . . . . 83



Sunflower . . . 102



Rapeseed. . . 127



Oil Palm . . . . 635



Micro Algae . .1850 [based on actual biomass yields]



Micro Algae . .5000-15000 [theoretical laboratory yield]

Cultivating Algae for Liquid Fuel Production ( 2005


Fig1. Procedure of algal biodiesel
production


Open vs closed Algal production system

Closed system
Open system
Advantages: low cost and energy
consumption
Disadvantages: poor productivity;
contamination

Advantages: high productivity;
control culture conditions, no
contamination
Disadvantages: expensive,
difficult to scale up, energy
intensive


The use of a fuel containing Chlorella
vulgaris in a diesel engine
Some microalgae such as Chlorella vulgaris are
unicellular (5–10 μm) and has a high lipid
content, which is suitable for combining in an
emulsion fuel. An emulsion consisting of
transesterified rapeseed oil, a surfactant and a
slurry of C. vulgaris was used as a fuel in an
unmodified single cylinder diesel engine.
 The fuel consumption and emissions of this
fuel was determined and although the carbon
monoxide levels were higher the Nox emission
was lower than that of diesel.


Fig. 2. The formation of an emulsion of biodiesel and algae: (1)
biodiesel with surfactant (0.5% Triton X-100); (2) biodiesel with 20%
algal slurry; (3) biodiesel with surfactant with 20% algal slurry. The
components were mixed vigorously and the photograph taken after 24
h.




WANT TO PROPOSE SOME NEW
MICROBE FOR BIODISEL
PRODUCTION? READ THE PROVIDED
ARTICLE TO FIND OUT HOW.


Ethanol Production


Ethanol Production

Glycolytic Pathway for
Ethanol Production by
Saccharomyces cerevisiae




CO2 is commonly captured and purified with a

scrubber so it can be marketed to the food processing
industry for use in carbonated beverages and flashfreezing applications.
Dried distillers grain (DDG) is commonly used as a
high-protein ingredient in cattle, swine, poultry, and
fish diets