An investigation of mass transfer-reaction kinetics of NO absorption by wet scrubbing using an electrolyzed seawater solution

Abstract

The mass transfer-reaction kinetics of NO absorption by wet scrubbing using electrolyzed seawater was studied in a bench-scale bubbling reactor. The effects of active chlorine concentration, solution pH, absorbent temperature, NO and SO₂ inlet concentrations on NO absorption rate were investigated. The results showed that the NO absorption rate significantly increased from 0.41 × 10⁻⁵ to 1.91 × 10⁻⁵ mol m⁻² s⁻¹ with the active chlorine concentration increasing from 500 to 3100 mg L⁻¹ [Cl₂]. The NO absorption rate greatly increased from 0.25 × 10⁻⁵ to 1.58 × 10⁻⁵ mol m⁻² s⁻¹ with NO concentration increasing from 250 to 1250 ppm. When SO₂ inlet concentration increased from 250 to 1250 ppm, the NO absorption rate slightly increased from 1.09 × 10⁻⁵ to 1.17 × 10⁻⁵ mol m⁻² s⁻¹. When the solution pH was in the range of 4–6, the NO absorption rate was about 1.5 × 10⁻⁵ mol m⁻² s⁻¹. The change of the NO absorption rate was insignificant with the absorbent temperature increasing from 20 to 50 °C. The influential mechanism of the NO absorption rate was also discussed preliminarily. Furthermore, the NO absorption process by electrolyzed seawater was pseudo-first-order reaction with respect to NO concentration. A simplified equation of NO absorption rate was also obtained. The comparison results indicated that the calculated values agreed well with the experimental values.