Modeling of NO mass transfer characteristics absorbed in sodium persulfate solution with a bubble reactor

Abstract

Sodium persulfate solution is considered as an effective wet denitrification medium, however, it is unclear that the influence of the operating conditions on mass transfer characteristics parameters during the absorption of NO with sodium persulfate solution. To determine the key mass transfer characteristics parameters, the specific interfacial area $a$ and the mass transfer coefficients $k_L,$ $k_G,$ were determined based on the Danckwerts method during CO₂ absorption in a bubble column. $k_L,$ $k_G$ and $a$ were calculated by correlations between the mass transfer coefficients of NO and CO₂. Results showed that the specific interfacial area increased 77.64 m^-1, the liquid phase mass transfer coefficient increased 2.49 × 10^-4 m·s^-1, and the gas phase mass transfer coefficient increased 0.71 × 10^-5 mol·Pa^-1·s^-1·m^-2 with superficial gas velocity increasing from 0.6 to 1.4 L·min^-1. With the temperature of sodium persulfate solution increasing from 293 to 333 K, the specific interfacial area decreased 42.66 m^-1, while the liquid phase mass transfer coefficient and the gas phase mass transfer coefficient increased 3.89 × 10^-4 m·s^-1 and 1.18 × 10^-5 mol·Pa^-1·s^-1·m^-2, respectively. The experiments results determined the correlations of $a,$ $k_L,$ and $k_G$ with the temperature of the absorption phase and the superficial velocity of the gas. It can serve as a guide to the enhancement of the sodium persulfate wet denitrification process.

Keywords: Mass transfer coefficient; bubble column reactor; gas absorption; gas–liquid specific interfacial area.