Monday, June 23, 2008

Military Garbage as an Energy Resource

A U.S. Army News Service piece on June 19, 2008 had an exiting title: Army Turning Trash into Energy in Iraq.

It gives information about two prototypes of the Tactical Garbage to Energy Refinery (or TGER) sent to Camp Victory in Iraq at the end of April to be tested for 3 months. See, also ECBC to Deploy New Waste to Energy Technology to Iraq.

At any forward operating base fuel is the biggest logistics pain. But waste created at bases has also become a big pain thanks to idiotistic packaging mania. Everything has to be packaged. This is in fact a daily problem for everybody in the western world. Just compare the volume of garbage you are throwing out today with 20 years ago. Getting rid of garbage is a problem. See what’s happening in Napoli, Italy. The classic way to get rid of trash is to burn it in incinerators which also require energy to run. And you get nothing useful out.

Dr. James Valdes, scientific advisor for biotechnology with the U.S. Army Research, Development and Engineering Command (RDECOM), explained in a DoD blogger roundtable in June 2008 how TGER works and how it could be used in the future.

The idea behind this small-scale waste to energy is simple: Garbage in, energy out

Garbage in: any waste created such as paper, plastics, cardboard, ammunition papers, food-slop etc.

Energy out: electricity or synthetic gas or ethanol

The TGER hybrid system was developed by defense contractor Defense Life Sciences, Purdue University and the Army's Edgewood Chemical Biological Center in Maryland. It weighs 4 ton and fits into International Standards Organization containers.

Source: US Army

How TGER works:

First, all the garbage, whether it's wet waste or dry waste, is put into a chute. Then there's a wash step where food waste is separated from the rest, and goes into the fermenter tank where you add yeast and enzymes. The solid waste like cardboard, plastic, and other dry trash are crushed into small pieces and pelletized. Those pellets, that are about an inch long and about a quarter of an inch thick, are then put into a gasifier. The gasifier then heats the pellets, and breaks them down into a synthetic gas composed of simple hydrocarbons that resembles low-grade propane. The wet-waste, meanwhile, is turned into a form of ethanol (a mix of 85 percent pure ethanol and 15% water, or what to so-called hydrous ethanol) by advanced fermentation. Then hydrous ethanol coming out of the wet-waste and synthetic gas coming out of the solid waste are blended. End output in fact is a blend of the syngas with the hydrous ethanol that powers generators. In other words, this hybrid technology gets all garbage in one hole, then splits them into two streams, then fuel coming out of those two streams get blended and then put into the generator.

When it is first started off, the generator runs primarily on diesel. It takes TGER six hours to fully power up, during which time the amount of diesel fed into the machine slowly drops, until the generator is powered by less than one gallon of fuel per hour, as compared to five per hour without TGER. When TGER is running at steady state, about 95 percent of the energy that it produces in fact is coming from garbage, and only 5 percent is coming from diesel.

Note that a standard 60 kW generator is built into TGER.

A TGER unit can handle about a ton of garbage a day.

The first TGER unit cost about $800,000 to develop, with phase two of the research, which includes the development of the second unit plus the deployment to Iraq, cost $2.3 million.

The TGER produces some CO2 but maybe in the future a way will be found out to capture and store it. Other byproducts are ash and water.


Post a Comment

Links to this post:

Create a Link

<< Home