Tactical Garbage to Energy Refinery (TGER) - Sustainable Biotechnology: Sources of Renewable Energy - page 88

The Tactical Garbage to Energy Refinery (TGER) design is a “hybrid” that uti-
lizes both biocatalytic (fermentation) and thermochemical (gasification) subsystems
in a complementary manner to optimize overall system performance and to address
the broadest possible military waste stream. The hybrid design is based on detailed
analysis of the waste stream combined with a modeling and simulation program
unique to the TGER. Given the objective waste stream which includes both food
and dry material wastes, a system which included a biocatalytic format for organic
wastes such as food and juice materials, and a thermochemical format for solid
wastes such as paper, plastic and Styrofoam, would have significant advantages over
unitary approaches.
The Energy and Material Balance mathematical model showed that conversion of
materials and kitchen wastes to syngas and ethanol would provide sufficient energy
to drive a diesel engine and generate electricity. A downdraft gasifier was selected
to produce syngas via thermal decomposition of solid wastes, and a bioreactor con-
sisting of advanced fermentation and distillation was used to produce ethanol from
liquid waste and the carbohydrates and starches found in food waste.
Both dry and wet field wastes (with the exception of metal and glass) are intro-
duced into a single material reduction device which reduces both the wet and dry
waste into a slurry. This slurry is then subjected to a “rapid pass” fermentation run
which converts approximately 25% of the carbohydrates, sugars, starches and some
cellulosic material into 85% hydrous ethanol. The remaining bioreactor mass is
then processed into gasifier pellets which are then converted into producer gas, also
known as “syngas”. The hydrous ethanol and syngas are then blended and fumigated
into the diesel engine, gradually displacing the diesel fuel to an estimated 2% pilot
drip. The design process model is shown in Fig. 2.

HYBRID TECHNOLOGY
IN- LINE BIOREFINERY DESIGN PROCESS MODEL

INPUT BIOREFINERY OUTPUT

BIOCATALYTIC THERMOCHEMICAL

Dry Waste
- Fiberboard
- Paper
- Plastic
- Wood
Wet Waste
Food Waste
Slop Food
Raw Agri
Liquid Waste

Residual
Prep

Gasifier

Feedstock
Prep

Fermenter

Electricity
Heat
Water or:

PRODUCER GAS

Residues

Diesel
Gen Set

Water
Source

Ethanol
Recovery

ETHANOL

Ethanol
Syn-Diesel

BioPlastics

Heat Exchanger

Power Takeoff

- Thermal component provides heat and power to run biocatalytic
- Residues from Bioreactor path are channeled to gasifier
- System starts on diesel fuel; then create/introduces Producer Gas and
Vaporous Ethanol to displace diesel to minimum drip for pilot ignition

- Petroleum based plastics recalcitrant until gasifier
- Bioplastics can degrade immediately

Fig. 2 In-line biorefinery design process model