Environmental Engineering Reference
In-Depth Information
Jatropha Promotion (CJP) for biodiesel production, the endeavor did not succeed as
planned due the lower oil content and increased water demand. The increased cost
made the private companies to drop out from further investment. Though edible
feedstocks such as coconut, soybean, sugarcane have good oil content, these can no
longer be used because they deprive of food stock and drive up food costs. Plants
with good oil content used in cosmetic and pharmaceutical industry are not logical
candidate for energy production.
3.2.2 Production Challenges
As steady world economic growth cannot be taken for granted, cost of production
of biofuels will play a major role
in other words, these fuels need to be produced
at competitive price with conventional fuels now available. Feedstock may be
cultivated at remote places, and transportation costs to get the stock to production
sites could be excessive. Transportation of cellulosic and biowaste materials needs
extra care. Bacteria and other organism-based fuel production require extra pro-
tection from all possible harmful consequences. When cultivation of feedstock
requires a certain seasonal cycle, storage could be a challenge.
—
3.2.3 Performance Challenges
Several engine and
flight tests have demonstrated acceptable aircraft performance
with biofuels. However, consistent energy density and speci
fl
c thrust are key factors
for military applications in particular. (If these fuels are used in air crafts that take
off from
flight decks, and in those demanding strict thrust performance.) Other
challenges include the shelf life, long-term stability of the fuels, possible coating
formation on components (by combustion products), and CO
2
emissions.
fl
3.2.4 Possible Bene
t from Biofuels
Noise produced from aircraft jet engine exhaust had been an issue for the past
several decades, and engine and airplane manufacturers have invested substantially
to reduce it. Cabins in modern jet aircrafts are quieter and together with noise
canceling headphones provide a comfortable space. However, the noise produced
from military
fighter jets is extremely high, and a person exposed to these noise
levels over a short period of time can become partially or fully deaf. Figure
6
shows
a comparison of noise foot print from commercial and military aircrafts. As can be
seen, the noise footprint of a small military aircraft is much larger than the jumbo
Boeing 747 airplane.
The exhaust from the combustion of present jet fuels contains nano-size toxic
particles that can enter the cochlea through the ear canal (Fig.
7
) or by conduction
through the skin increasing the risk of ear injury and hearing loss
—
as opposed to
Search WWH ::
Custom Search