Tactical Garbage to Energy Refinery (TGER) - Sustainable Biotechnology: Sources of Renewable Energy - page 89

Adding the advanced fermentation process to the design of the TGER added no
significant energy costs, as heat generated by the engine's exhaust drives the distilla-
tion, which is carried out in an 8-foot-high column packed with material over which
fractionation of ethanol and water occurs. The additions of a few small pumps used
to transport the ethanol solution from the fermentation tank to the distillation column
and finally to the ethanol storage tank, were the only additional power requirements.
The combination of the two waste-to-energy technologies allowed for the remedia-
tion of a broader spectrum waste stream, both solid and liquid, the ability to extract
much more energy from the waste, and operation of the generator at full power due
to the anti-knock properties of the hydrous ethanol.

2 Background Research

There were two key bodies of knowledge that defined our research and technology
transition plan. First, was the development of an understanding of the military con-
text in which the tactical biorefinery was to serve and, second, was the search of the
available “solution space”, that is, the match of current and future technologies to
requirements for energy generation and trash reduction.
Within the military context, a number of science and technology variables were
considered. These included the type of input biomass, the type or types of biomass
processing to be used, the output energy stream that results, and the kinds of military
applications that would be served. A graphic depicting our “solution space” is shown
in Table 1.
Table 2 illustrates the energy content of different fuels relative to diesel fuel
[3-5]. The value of converting organic waste into ethanol is clearly shown. Ethanol

Ta b l e 1 Solution space for waste to energy

Energy product ∗∗ Waste Technology Military application served

Food waste (starch) Bioprocessing Ethanol (fluid.69) Liquid fuel for

burners/generators

∗ Starch

Food waste (oil,
grease)

Methanol (fluid 0.51) (primary or fuel additive)

∗ Cellulosic

Plastics Bio-oil (fluid) Gaseous fuel for modified

generators

∗ Petroleum based

Pyrolysis to
bio-oil

Biodiesel (fluid 0.6) Fuel cells, PEMs generators

∗ Bio-based

Gasification to
energy

Methane (gas 0.97) Liquid fuel for advanced

batteries

Paper (cellulosic) Hybrid Hydrogen (gas 0.2) Direct electricity to power

grid

∗ Thermal

Fiber board
(cellulosic)

Hot water for troop use

∗ Bioprocess

Locally agriculture

∗∗ Form and energy per unit volume, Gasoline

=

1.0