Control of industrial boiler nitrogen oxide emissions using hydrogen peroxide treatment-phase II chemical analysis and phase III preliminary results

Keywords

Hydrogen peroxide, Nitric oxide

Abstract

NOx is a major air pollutant in industrialized nations. It has recently been under examination due to its link _to-. acid rain and photochemical smog. Several mechanisms govern NOx production, the most important of which is the hightemperature dissociation of 02 and N2 and subsequent recombination as NO. NOx is produced from any combustion source such as power plants or automobiles. The EPA has instituted new regulations for all stationary combustion sources in order to limit pollution. Current technology for NOx control focuses on modification of combustion sources in order to reduce NOx formation. Tpese technologies take advantage of recent research into the thermal and fuel NOx formation mechanisms. By controlling variables such as·flame temperature and the air:fuel ratio, lower levels of NOx are formed. However, these modifications do not eliminate all of the NOx emissions. Currently, two technologies have been developed to remove NOx emissions from combustion flue gas. Both selective catalytic reduction (SCR) and selective noncatalytic reduction (SNCR) reduce NOx to molecular nitrogen.

This pro6ess carries a high capital cost as well as a complex operating procedure. For the past decade, Drs. Clausen and Cooper at the University of Central Florida have been research~ng a new technology to oxidize NOx to more soluble species so that wet scrubbing can be implemented for removal. Previous phases of the project have developed a high temperature pilot scale system that uses hydrogen peroxide as the oxidizing agent. At high temperatures, the hydrogen peroxide dissociates into hydroxyl radicals. These radicals then undergo a chain reaction with NOx resulting in the formation of HN02 and HN03 . These acid species can then be removed by wet scrubbing. It is the purpose of this thesis to present the chemical analysis of Phase II and the preliminary results of Phase III. These phases ha~e an objective to produce hydroxyl radicals at low temperatures. Phase II focused on a pilot scale·ultraviolet reactor, where the ultraviol~t light source was focused into the reactor containing the _NOx. This system had limited success. It was believed that other species were competing for the UV radiation and thus complete photolysis did not occur. Phase III studied microwave radiation as a possible method to generate hydroxyl radicals. Lab experiments showed some success, but the hydroxyl radicals that were formed may have been due to a thermal· mechanism. The second part of Phas.e III deals with UV radical formation external to the NOx stream. Lab experiments show that for this methodology to be effective; the speed of delivery of the radicals to the NOx system is critical.

Notes

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Graduation Date

2001

Advisor

Clausen, Christian

Degree

Master of Science (M.S.)

College

College of Arts and Sciences

Department

Chemistry

Format

PDF

Pages

96 p.

Language

English

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

Identifier

DP0028711

Subjects

Arts and Sciences -- Dissertations, Academic; Dissertations, Academic -- Arts and Sciences

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