Talking about the important of energy with the world and the future of it. Why do we
need to find another energy source?
Biofuel is a new energy.
What is biofuels? How many kinds of Biofuels? Explain the benefits and disadvantages
of those kinds. Why? Why did they against biofuel? How to solve that problem?
2nd generation is the key to answer. Microalgae is chosen to be the material because it has
The global economy runs on energy. If the governments around the world stick to current
policies, the world will need almost 60% more energy in 2030 than today. Transportation
is one of the fastest growing sectors using 27% of the primary energy. Thus, energy is
very important with our life. Nowadays, energy resources base on fossil fuel. We cannot
use fossil fuels forever, because they are finite resources, and their waste will lead to
increased green house gases : carbon dioxide (CO ), sulfur dioxide (SO ) and nitrogen
oxides (NO ). Those gases are harmful for the earth. We need to find another energy
resource which is unlimited and doesn’t have a lot bad effects.
Biofuel is the answer key for that problem. What’s is biofuel?
Biofuel can be solid, liquid, or gas fuel produced from biomass. There is 2 generation of
The 1st generation is made from feedstock. They isolates diesel, ethanol, or lipid, .... from
large amount of food crops such as sugarcane, sugar beet, maize (corn), sorghum and
wheat. This technology encounter the against of society – (called “food vs fuel”) –
because it will consume vast area of farmland and building land, increase food prices, and
result in little reduction in GHG emissions. However, the widespread availability of
inexpensive petroleum during the 20 century determined otherwise.
They said that biofuels could supply some 30% of global demand in an
environmentally responsible manner without affecting food production.
In contrast, the second generation biofuels are derived from non-food feedstock. They
are extracted from microalgae and other microbial sources, ligno-cellulosic biomass, rice
straw and bio-ethers, and are a better option for addressing the food and energy security
and environmental concerns.
Using microalgae is a best choice for producing biofuel.
Some microalgae grow heterotrophically on organic carbon source. However,
heterotrophic production is not efficient as using photosynthetic microalgae , because
the renewable organic carbon source required is ultimately produced by photosynthetic
Microalgae, use a photosynthetic process similar to higher plants and can complete
an entire growing cycle every few days.
Microalgae operate as a small biochemical factories, and appear more efficient
photosynthetically than terrestrial plants and are efficient CO2 fixers. The ability of algae
to fix CO2 has been used as a method of removing CO2 from waste gases from power
plants, and thus can be used to reduce emission of GHG. Many algae are exceedingly
rich in oil, which can be converted to biodiesel.
The oil content of some microalgae exceeds 80% of dry weight of algae biomass. The
net annual harvest of algal biomass cultivated in subtropical areas can be as high as 40
tons/ha (dry matter), even higher if CO2 is supplied.
In theory, high oil content algae could produce almost 100 times of soybean per unit
area of land.
The use of algae as energy crops has potential, due to their easy adaptability to growth
conditions, the possibility of growing either in fresh- or marine waters and avoiding the
use of land. Furthermore, two thirds of earth’s surface is covered with water, thus
algae would truly be renewable option of great potential for global energy needs.
This paper aims to analyze and promote integration approaches for sustainable microalgal
biodiesel production, with emphasis on hydrothermal technology for direct liquefaction
of algal biomass with no need to dry the feedstock.
II. Integrated Biodiesel production for Microalgae
The way to get highest profit is to grow biomass in a closed system. That system would
be the integrated biomass production conversion system (IBPCS).
The design of an IBPCS requires the combination and optimization of several
factors such as biomass culture, growth management, transport to conversion
plants, drying, product separation, recycling, waste (liquid and solid) management,
transport of saleable products and marketing. These factors can be simplified and
reduced to three main groups; culturing of microalgae, harvesting and processing of
The growth can be applied in a microalgal farm. Nutrients/ are renewed/ based on their
status /include of /sunlight, air, CO2 growth media.
The conversion plants should be located in or near the biomass growth areas.
Why? Because that could save the cost of transporting biomass to the plants.
Besides, the waste could be recycled to the growth, and we could control the environment
matter and waste disposal problems.
About 50% of the dry weight of microalgal biomass is carbon, which is received from
CO2 . Thus, an algae farm can be located next to a power plant to consume CO2 from
the burning process.
algae can remove nitrogen, phosphorus, and heavy metals such as As, Cd, and Cr
from aqueous solutions. We can use wastewater as nutrients for the algae production.
A problem associated with algal biomass is the relatively high water content. It
requires pre-treatments to reduce water content and increase the energy density.
However, this will increases the energy cost. Direct hydrothermal liquefaction in sub-
critical water conditions can be used to convert the wet biomass to liquid fuel without
reducing the water content.
Overall, we can combine some different technologies such as wastewater
treatment, nutrients and heavy metal recovery by algae culture to solve the economical
and environmental problems.