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Mass transfer in the absorption of nitrogen oxides in alkaline solutions
Author(s) -
Newman Bernard L.,
Carta Giorgio
Publication year - 1988
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690340715
Subject(s) - absorption (acoustics) , mass transfer , chemistry , mass transfer coefficient , diffusion , analytical chemistry (journal) , nitrogen , nitric acid , aqueous solution , inorganic chemistry , thermodynamics , chromatography , materials science , organic chemistry , physics , composite material
The absorption of mixtures of nitrogen oxides into aqueous solutions of NaOH in the range of partial pressures of 0.004‐ to 0.05‐atm NO and 0.002‐ to 0.015‐atm NO 2 was investigated. Absorption experiments were conducted in a gas‐liquid contactor that permitted independent variation of the gas and liquid mass transfer coefficients. The results were analyzed in terms of a model which accounted for diffusion, reaction, and formation of higher oxides and oxyacids in the gas and in the liquid phases. Absorption of both HNO 2 and N 2 O 3 , formed in the bulk gas and within the gas diffusion film, were found to be significant. Using a rate coefficient of 8.8 × 10 −3 mol/s · cm 3 · atm 3 for the formation of HNO 2 in the gas phase (England and Corcoran, 1975), a value of the absorption factor, H √ Dk , for N 2 O 3 of 2.5 × 10 −3 mol/s cm 2 atm was determined at 25°C. This value was found to decrease with temperature and was 1.2 × 10 −3 at 40°C. The use of concentrated base as an absorbent solution prevented the formation of nitric acid mist, a problem encountered in many previous studies of NO x absorption.