Joseph S. Maresca says:

Biofuels Engineering Process Technology by Drapcho et al.

A McGraw Hill Publication 2008

Reviewed by: Dr. Joseph S. Maresca

The authors begin by explaining the justification for

alternative energy.

The reasons set forth are:

o diminishing oil reserves and the increasing difficulty

and cost of extraction

o global climate change considerations

o increasing fuel prices

o the need for energy independence

The largest oil reserves are in Saudi Arabia, Canada,

Iran, Iraq, Kuwait, UAE and Venezuela.

Geothermal and solar energy have less than 20% efficiency

at the current technological learning curve but zero emissions.

Biofuels are substantially carbon neutral according

to the authors. There was a considerable presentation on

fuels derived from fermentations;

such as, ethanol, hydrogen, microbial oils and methane.

The strategy for a bioreactor design is based upon the

maximum rate of production formation, biomass production

or substrate utilization. Fuel treatments to reduce fire

hazards can contribute 54 MT ( million tons) of bio mass yearly.

Muni solid waste has the potential for biofuel production.

Vegetable based fuels capture solar energy through plants

and photosynthetic pigments. These veggie based fuels

sequester CO2 from the atmosphere as a primary carbon source.

The carbon is biologically converted to greater energy

starches, celluloses, proteins and oils as storage

and structural compounds. Some algae can convert

CO2 to 60% – 70% of their dry weight in the form of storage

oils.

Microalgae have very versatile growing conditions

dating back to the earliest eukaryotic organisms

on the earth. Algae can inhabit many different environments

as long as water and micronutrients exist alongside.

Algae have been shown to accumulate a high level of

lipids consisting of over 80% of their dry weight .

The microbial fuel cell or MFC is a specialized biological

reactor where the electrons processed during microbial

metabolic activity are intercepted to provide useful electric

power. In an MFC, the oxidation of the electron donor

compound is physically separated from the terminal electron

acceptor. The microbes are grown in the anode chamber where

the electron donor compound is oxidized, with the electrons

transferred to the anode instead of oxygen or an external

electron acceptor. MFCs convert chemical to electrical energy.

Emissions from biodiesel in combustion engines are greatly

reduced compared to the petroleum diesel. Nonetheless,

nitrogen oxide emissions constitute a drawback.

Decreases in NO emissions are possible with corrections

in injection timing and combustion temperatures. These

incremental costs may add more steps to the process and

(by implication) more costs.

The thermodynamic properties with respect to temperature

of biodiesel fuels compared to diesel are higher for biodiesel.

Higher flash points result in a safer fuel for handling.

Density and viscosity of biodiesel is higher than for

petroleum fuels and alcohols. Electricity from

gasification of biomass has a low production cost at

5 cents per KWH. Simultaneous esterification of free

fatty acids to alkyl esters will occur due to increased

biodiesel yields from lower quality feedstocks.

Esterification involves two reactants (alcohol+ acid)

to form an ester product. Esters are common in organic

chemistry and may smell like fruit.

This characteristic leads to the application of esters

in fragrances. Ester bonds may be found in polymers.

The yield of the product in esterification

may be improved by using Le Chatelier’s principle.

Esterification is a reversible reaction as opposed to an

irreversible one. Hydrolysis or “water splitting” is the

addition of water and a catalyst like NaOH

to an ester to arrive at the sodium salt of the

carboxylic acid and alcohol. As a result of this reversibility,

many esterification reactions are equilibrium reactions.

These reactions go to completion by Le Chatelier’s

principle.

An irreversible process is a process that cannot return

both the system and the surroundings to the original state(s)

assuming a reversal of the original process .

Most processes, of course, are irreversible processes

(or nonequilibrium processes).

Letting air from a balloon released into a room is an

irreversible process.

Overall, these irreversible processes are a consequence

of the second law of thermodynamics,

which is frequently defined in terms of the entropy or

disorder of a system.

There are several ways to phrase the second law of

thermodynamics. There is a limit on how efficient any

transfer of heat can be. According to the second

law of thermodynamics, some heat will be lost in the

process. This loss explains why it is not possible to

have a completely reversible process in everyday life.

For example, a car engine doesn’t give back the fuel it

took to drive up a hill even if the

car coasts down a mile long hill thereafter.

The authors concentrate efforts substantially on biofuels.

Ultimately, the “Artificial Sun” may prove to be the

game changer. Shortly , a scientific team will begin

attempts to ignite a tiny manufactured star inside a

lab and trigger a thermonuclear reaction.

Its goal is to generate temperatures of more than

100 million degrees Celsius and pressures billions

of times higher than those found anywhere on earth,

from a tiny speck of fuel.

The National Ignition Facility (NIF) in Livermore

will utilize a laser that concentrates 1,000 times

the electric generating power of the United States

into a billionth of a second. The result should be an

explosion in the reaction chamber which will produce

10 times the amount of energy used to create it.

Until now, such fusion has only been possible inside

nuclear weapons and highly unstable plasmas created

in incredibly strong magnetic fields. The work at

Livermore could change the historical applications mix.

Source: NIF, Livermore

Overall, the authors provide a very thorough rendition

of biofuels engineering with excellent reference

materials at the end of each chapter. Readers who are

conversant in organic chemistry, materials science

structure of matter and thermodynamics will appreciate

the superior technical presentation embodied in this

text . There is an extensive scientific presentation of

conversion factors and constants at the end of the book.

Rating: 5 / 5