Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
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bridges the gap between the two electrodes. The arc generates temperatures of up to
30,000°F. The transferred torch directly contacts the arc with the material, or a
conductor, in the reactor. The non-transferred torch blows a stream of air across the arc
inside the torch to produce superheated gas, approximately 5,000°F. This gas provides
the thermal input to the reactor that is required to decompose the material. The
temperature in the reactor itself is generally around 2,000°F. Plasma arc torches require
large amounts of electricity. Depending on the fuel being processed, the facility may not
generate net electricity output.
Figure 3-8. Plasma Arc Torch Operating (Source:
http://www.zeusgroup.org/applications.html).
Applications
The extreme temperatures produced by plasma torches makes them well-suited
for waste remediation applications because the inorganic constituents in the waste that
might normally be hazardous are literally melted to form a glassy slag which can be
captured in a solid form. This encapsulation of hazardous waste requires significant
amounts of energy and has very specialized economical niche markets. Currently, some
industry leaders feel that plasma arc disposal of MSW is not economic. An alternate
approach to strictly disposing of the MSW with plasma torches is to gasify the MSW and
recover the combustible syngas that results from the thermal reaction. There are very few
21 March 2005 3-39 Black & Veatch