A study on mass transfer–reaction kinetics of NO absorption by using UV/H2O2/NaOH process

Abstract

Based on two-film theory, the mass transfer–reaction kinetics of NO absorption from flue gas by using UV/H2O2/NaOH process was investigated in a photochemical reactor. The effects of several operating parameters on NO absorption rate were studied. The mass transfer-reaction process of NO absorption was analyzed. A simple NO absorption rate equation is also established and tested. The results indicate that when H2O2 concentration increases from 0 to 1.0mol/L, NO absorption rate increases from 0 to 1.55×10−5mol/m2s. NO absorption rate increases from 0.92×10−5 to 1.76×10−5mol/m2s when NaOH concentration increases from 0 to 0.01mol/L. As NO concentration increases from 200 to 1000ppm, NO absorption rate increases from 0.82×10−5 to 3.23×10−5mol/m2s. However, NO absorption rate decreases from 1.61×10−5 to 1.54×10−5mol/m2s as SO2 concentration increases from 0 to 2000ppm. The absorption process of NO from flue gas by using UV/H2O2/NaOH process is a pseudo-first-order fast reaction with respect to NO. The relationship between NO absorption rate, mass transfer and chemical reaction can be described by the following equation: NNO=pNO,G·1kNO,G+1HNO,Lkov1·DNO,L1/2-1. The tested results of kinetic model indicate that the calculated values are in good agreement with the experimental values.