Fuel from Waste

Incineration is quite a good way to get rid of garbage, especially if you can extract useful energy in the process, but unfortunately it does produce pollutants. A big welcome, therefore to a new technology which vaporizes organic materials to produce a mixture of hydrogen and carbon monoxide (syngas), and from there to useful chemicals and fuels. The technique is described by Kevin Bullis.

The new system makes syngas in two stages. In the first, waste is heated in a 1,200 °C chamber into which a small amount of oxygen is added--just enough to partially oxidize carbon and free hydrogen. In this stage, not all of the organic material is converted: some becomes a charcoal-like material. This char is then gasified when researchers pass it through arcs of plasma.

Non-organic residues are oxidized and pooled with molten glass to make material useful for road-building and safe for landfill. The next stage catalyzes the gas mixture into ethanol and methanol, the former for a fuel additive or alternative, and the latter to make biodiesel.

There is enough municipal and industrial waste produced in the United States for the system to replace as much as a quarter of the gasoline used in this country, says Daniel Cohn, a cofounder of IET and a senior research scientist at the Plasma Science and Fusion Center.

It looks rather a promising way of converting unsightly and offensive waste into useful energy, and the company claims it can be done competitively, the more so if you factor in the costs of current disposal. It's almost certainly technologies like this which will reduce our environmental footprint, rather than calls for us to consume less and live more simply.

Madsen Pirie, Environment, www.adamsmith.org
http://www.technologyreview.com/
read_article.aspx?id=18084&ch=energy