Government Technology - January 2009 - (Page 46)

emerging tech j j Synopsis: An explanation of plasma gasification and why Sacramento may build a plasma gasification plant. S TAT E | L O C A L | F E D E R A L Jurisdiction: Sacramento, Calif. Fact of Matter B Y C H A D V A N D E R V E E N | A S S O C I AT E E D I T O R Technology: Plasma gasification. Contact: Jim Rinehart, economic development manager, Sacramento, jrinehart@ cityofsacramento.org. ILLUSTRATION BY TOM McKEITH A plasma gasifier uses superheated plasma arcs to convert solid waste into a synthesis gas and slag. The slag can be used in construction, while the gas can be used to make alternative fuels or drive steam turbines. Sacramento, Calif., investigates how plasma gasification might revolutionize waste management. W JAN_09 hy don’t they just fill a rocket full of garbage and shoot it at the sun?” Many who want to reduce pollution but have a flimsy grasp on rocket science and economics have asked this question. But what if such a feat could be accomplished without a rocket? That’s essentially what plasma gasification is designed to do. Plasma gasification is the process of breaking down matter at the atomic level by exposing it to high temperatures. Gasification isn’t combustion or incineration. Those processes result in unpleasant, toxic byproducts. Gasification uses extreme heat, in the form of plasma arcs, to reduce matter to its basic elements. Superheated plasma is nothing new. For decades, plasma arcs, which reach temperatures of up to 8,000 degrees Fahrenheit, have been used in foundries to melt metals. However, a few years ago several waste disposal startups in the United States and Japan took notice of a plasma arc technology developed by NASA that produced an arc at temperatures exceeding those on the sun’s surface. Any solid matter that came into contact with such an arc would be reduced to nothing more than synthesis gas — or syngas, which is generally carbon monoxide and hydrogen — and an inert slag. It turns out the syngas can be used to produce useful products like diesel and methanol or separated and sold to industries that use hydrogen and carbon monoxide in manufacturing. The slag also has several applications, such as asphalt and tile production. In addition, syngas must be cooled before it’s stored. The cooling process results in considerable amounts of steam, which can run the turbine that powers the plasma arc to begin with. Sacramento, Calif., is considering constructing a plasma gasification plant in which to dump garbage. In addition to its own landfills, Sacramento currently sends tens of thousands of tons of waste to landfills in Nevada, a costly process that’s neither sustainable nor environmentally friendly. In February 2008, the city began negotiations with Sacramentobased U.S. Science and Technology (USST) to 36 http://www.govtech.com

Table of Contents Feed for the Digital Edition of Government Technology - January 2009

Government Technology - January 2009 Contents Point of View On the Scene Big Picture Four Questions for... Stemming the Retirement Tide Getting the Picture Fact of Matter Money Trail Rays the Roof Trick or Tweet? The Modern Way to Vote Products signal:noise

Government Technology - January 2009

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