Tactical Biorefinery

Tactical Bio Refinery Prototype


Purdue Agricultural Communication photo/Tom Campbell
Purdue researchers have developed a portable power plant that 1) can run on JP8 (the ubiquitous military fuel that is a combination of diesel fuel and gasoline) or bio-diesel produced from garbage, 2) is compact enough to fit inside a military jet or large truck and 3) could be dismantled and re-assembled elsewhere. Since the bio-refinery first produces bio-diesel before running a diesel generator, it also provides the increased versatility of producing electricity or liquid fuel.

TreeHugger1 reports on a new tactic for defending the American Empire. Developed for the U.S. Army, but deployable anywhere in U.S. farmlands, the government is funding the development of tactical generators able to convert garbage to energy.

For any readers surprised (Sorry, Mom) by the cynicism, only recently this blog had commented on a plan to build modular micro-refineries with federal dollars poured into the trough — either 1) from the $1.6 billion in new funding proposed a focus on bio-energy research and production as part of the Administration’s 2007 farm bill proposals or 2) redirected from clean energy research.

Two Main Types of Biomass Conversion


The Purdue researchers are using the two main types of biomass conversion: fermenting sugars path and a thermo-chemical path (gasification).

The appeal, of course, is the ability to turn waste to energy. When garbage is dumped into the hopper, “the tactical biorefinery first separates organic food material from residual trash.” Different processes then occur to the two separate waste streams before the products are combined to produce diesel fuel.

  1. “The food waste goes to a bioreactor where industrial yeast ferments it into ethanol, a ‘green’ fuel.” There is considerable research into converting biomass into ethanol using enhanced yeasts or other such bio-technology that more quickly breaks down the organic material into fermenting sugars. Such technology so far has proved too expensive for the production of ethanol as a transportation fuel.
  2. The residual material, the article uses paper, plastic, Styrofoam, cardboard, or wood chips as examples — basically the equivalent of municipal solid waste — goes into a gasifier. The hydrogen and carbon monoxide produced under low-oxygen conditions are combined to produce low-grade propane gas and methane.

“The gas and ethanol are then combusted in a modified diesel engine that powers a generator to produce electricity.”

A further appeal is that satellite bio-refineries could work anywhere. A diesel generator that can suck up all kinds of garbage promise applications for various off-grid situations. Two quick examples: APUs (Auxiliary Power Units) and forestry.

NextGen Auxiliary Power Unit


To gain general acceptance, APUs (Auxiliary Power Units) need to be lightweight, quiet, and low maintenance.

Michael Ladisch, a Purdue professor of agricultural and biological engineering, leads the project. He suggested that the tactical refinery could become a supplementary power source, e.g., micro-generation, for factories, restaurants, stores… “any place with a fair amount of food and scrap waste” could reduce electricity costs and “might even be able to produce some surplus energy to put back on the electrical grid.”

Jerry Warner agrees. Warner is founder of Defense Life Sciences LLC, a private company working with Purdue researchers to develop a functional prototype, which then the Army will consider for future development. The system is designed to run on diesel oil for several hours until the gasifier and the bio-reactor begin to produce fuel, researchers said. The researchers claim that their prototype produces 90% more energy than it consumes.

“In a very short time, it should be ready for use in the military, and I think it could be used outside the military,” said Warner, who envisions that tactical bio-reactors could be deployed in disaster situations, similar to Hurricane Katrina, where there is sufficient damage that repair / recovery crews are faced with significant waste disposal task. As previously noted, it might make sense to have portable production facilities that could make energy from biomass. It almost could warrant having mobile systems that could be dispatched to a location where sufficient waste has occurred, rather than having to dismantle and re-assemble production elsewhere. Emergency crews could then turn debris such as wood chips into much-needed electricity at crisis locations where people are stranded without power.

University of Florida researchers, again for the U.S. Army, have been working on a combined cooling and power experiment, compact enough to fit inside a military jet or large truck that could provide three essentials top at the top of the list of must-haves when hurricanes, wars or other emergencies force authorities to respond: water, electricity and refrigeration. Their experiment has increased efficiency because of hybrid micro-generation.

Nonetheless, since it uses a turbine for power generation, the efficiency is less than claimed by Purdue researchers. Another advantage of the Purdue prototype — it includes a bio-reactor for ethanol production from anaerobic fermentation of organic material. Like the bio-gas powered, Stirling engine prototype developed by Dean Kamen that not only generated heat and power, but also fertilizer and purified water, the Purdue prototype can make use of organic material.

An appealing feature would be if most of the char extracted when the gases pass into a cyclone is safe enough to return to the soil hastening the natural cycle where damaged trees decompose and return nutrients to the soil. (An analogy would be slash and burn agriculture.) When interviewed by Douglas Main2 writing for the Purdue University New, Warner said, the prototype produces a very small amount of its own waste,

Mostly (it is) in the form of ash that the Environmental Protection Agency has designated as “benign,” or non-hazardous. Any leftover materials from the bioreactor are put into the gasifier, which has to be emptied every two to three days. “It’s about enough to fill a regular sized trash bag, and it represents about a 30-to-1 volume reduction,” Warner said.

Warner and Ladisch also say that such tactical bio-refineries could pollutes less than traditional diesel powered generators. A Treehugger commentator challenged such a claim, reading the press announcement “as though they are making some claims about this being better than a straight diesel-fueled generator because the fuel itself is renewable. Gasification can produce some pretty serious pollution, both from the stack and in the form of the highly toxic partially-combusted sludge that’s left over at the end. I’m sure this is tactically valuable to the military, but I don’t think the environment is any better off necessarily.”

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