Microwaves clean up stack gas pollutants
Transcript of Microwaves clean up stack gas pollutants
SCIENCE/TECHNOLOGY
Symposium honors Vanderbilf s J. C. Martin Speakers at a symposium titled "From σ Constants to σ Aromaticity" gather around Vanderbilt University professor of chemistry James Cullen Martin, in whose honor the symposium was held. The event, presented by the university's chemistry department, brought together former students, postdoctoral fellows, and
friends, who paid tribute to 40 years of publication by Martin. Martin's earlier work in free-radical chemistry gave the first evidence for neighboring-group participation in peroxide decompositions forming radicals. His more recent research has focused on synthesis of novel hypervalent main-group element species, with stability
established by use of new types of ligands. Gathered with Martin are (left to right, along wall) Peter Livant of Auburn University; Wesley Bentrude of the University of Utah; Thomas Fisher of Mississippi State University; John Verkade of Iowa State University; William McEwen of the University of Massachusetts; Yohsuke Yamamo-to of Japan's Hirosha University; Howard Har-gis of Auburn University; Peter Beak of the University of Illinois, Urbana-Champaign; (middle) Alan Cowley of the University of Texas; Gary Schuster of the University of Illinois, Urbana-
Champaign; (front) Martin; Anthony Arduengo of Du Pont Central Research Laboratory, Wilmington; and Yorke Rhodes of New York University. Speakers not pictured were James Franz of Battelle Pacific Northwest Laboratory, Richland, Wash.; and Clifford Dykstra of Indiana-Purdue University, Indianapolis.
donate a very substantial sum of money to endow this prize is testament to Hirschfelder's devotion and vision/'
The new prize honors Hirschfelder's memory by recognizing important research accomplishments in theoretical chemistry or related fields, such as physics, biophysics, and chemical engineering. Each recipient will spend one week at the University of Wisconsin and give a series of three lectures. Widom, the current winner, was selected by university scientists, but subsequent awardees are to be selected with assistance from an international advisory committee that is currently being formed.
In the past, theoretical chemistry has been a neglected area for awards, Skinner notes, and the Hirschfelder Prize will help to fill that gap. Increased recognition for physical chemists will also come from the recently established American Chemical Society Award for Theoretical Chemistry, a $5000 annual award sponsored by IBM. The first recipient, for 1993, is chemistry professor Martin Karplus of Harvard University.
Stu Borman
Microwaves clean up stack gas pollutants vide about 55% of all electricity generated in the U.S., and produce 65% of all sulfur dioxide emissions.
In the new process, Kim says, sulfur dioxide is absorbed in an activated char bed and decomposed under the microwave energy field to sulfur, whereas the nitrogen oxides are decomposed directly under the microwaves to nitrogen. The sulfur is cooled in a spray chamber and recovered as a by-product for sale. The nitrogen is released into the atmosphere.
The process doesn't require expensive sorbents or catalysts and produces no liquid or solid waste streams, Kim explains. Lab tests indicate that about 98% of the sulfur dioxide and nitrogen oxides are decomposed to sulfur and nitrogen. The initial evaluation has shown the process to be technically and economically feasible, with the potential to be highly efficient and cost-effective, he adds.
James Krieger
WASHINGTON, D.C.
Development work is proceeding on an electromagnetic technique for cleaning sulfur dioxide and nitrogen oxides from the stack gases resulting from coal combustion. The process makes use of high-frequency electromagnetic waves (microwaves).
Work on the process is being led by Chang Y. Cha, president of Cha Corp., Laramie, Wyo., who is also a chemical engineering professor at the University of Wyoming, Laramie. It is one of the programs sponsored by the Department of Energy's program for Small Business Innovation Research, DOE coal utilization division project manager Soung S. Kim told the Division of Petroleum Chemistry. Coal-fired utility plants, Kim points out, currently pro-
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