Waste-to-Biofuels plant to make gas from garbage
By Ben Coxworth
March 3, 2010
If you’re a fan of the original Back to the Future movie, then you probably liked the scene at the end where Doc Brown used some random household waste to fuel his time-traveling DeLorean. Well, we’re now getting a little bit closer to that being a reality... sort of. While practical flying cars, time travel and cold fusion are still a ways off, the ability to power your car with garbage isn’t. Canadian biofuels firm Enerkem is currently working with the city of Edmonton, Alberta, to convert that city’s municipal waste into ethanol. This will lower the city’s greenhouse gas output, keep much of its waste out of the landfill, and produce a “clean” fuel Doc Brown would be proud of.
The City of Edmonton already diverts 60% of its municipal waste from the landfill. This is done through an extensive home blue-bagging recycling system, along with a waste-sorting facility. At the facility, recyclable materials that missed the blue bags are extracted from household garbage, while organic materials continue into the enormous Edmonton Composting Facility. The 40% that’s left over is what will be used in Enerkem’s Waste-to-Biofuels complex.
The thermo-chemical process will begin with shredded waste being fed into a gasifier, where its chemical bonds will be broken and its carbon content will become a synthetic gas. That gas will then be cleaned, conditioned, then catalytically-converted into liquid, market-ready ethanol and methanol. Much of the inert material that’s left over will be used as aggregate for construction materials, or even used to power the system itself.
Enerkem claims it will be an energy-positive process, meaning it will create more power than it uses. It should also require minimal water usage, and could even be a net producer of water, as it will be extracting moisture from the waste.
The Waste-to-Biofuels complex is currently under construction, and is scheduled to be complete and operational by 2011. It is expected to initially produce 36 million liters (9.5 million gallons) of ethanol, from 100,000 tonnes (110,231 US tons) of sorted waste, per year. If it works as planned, only 10% of Edmonton’s municipal waste will end up in the landfill.