Date of Award

Fall 1997

Document Type

Thesis

Degree Name

Master of Science in Chemical Engineering - (M.S.)

Department

Chemical Engineering, Chemistry and Environmental Science

First Advisor

Henry Shaw

Second Advisor

Howard David Perlmutter

Third Advisor

Angelo J. Perna

Abstract

The use of sodium chlorite (NaClO2) and alkaline aqueous cumene hydroperoxide (CHP) as oxidizing agents to promote the absorption of nitric oxide from flue gases was investigated in a semicontinuous bubbling scrubber. The efficiency of the scrubbing solutions to remove nitric oxide was evaluated as a function of operating conditions such as pH, concentration of the oxidants, residence time, temperature, flue gas compositions.

Under acid conditions, sodium chlorite can stoichiometrically react and absorb 99.5% NO and 80% SO2 in the same scrubber with 0,672 M NaClO2 in buffered solution at pH 6, and 0.3 M NaOH. During the reaction, nitric oxide was oxidized to nitrates and nitrites and sulfur dioxide to sulfates. Consequently, sodium chlorite can be used to control NO as well as SO2. However, the parasitic effect Of SO2 in consuming the reactant results in a relatively high operating cost. On the other hand, organic cumene hydroperoxide scrubbing solution has been found to operate under high alkalinity to control nitric oxide. The hydroperoxide used in this study was less expensive than sodium chlorite system and commercially available. The removal of 92% nitric oxide was achieved at 94º C, 1.531 min residence time (scrubber contains 1.49 dm3 solution and flue gas is bubbled at 0.94 dm3 /min), with 0.12 M cumene hydroperoxide and 0.1 M potassium hydroxide. The major products obtained from the NO oxidation by alkaline cumene hyddroperoxide are NO2- and NO3- and cumyl alcohol. Other products such as acetophenone and cc-methyl styrene are observed as a result of the decomposition of the reactant and intermediates.

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