Kinetics of NOxAbsorption into (NH4)2SO3Solution in an Ammonia-Based Wet Flue Gas Desulfurization Process

The mass transfer and kinetics of NO x absorption into (NH 4 ) 2 SO 3 solution, the main compound of an ammonia-based wet flue gas desulfurization process, have been investigated in a double-stirred reactor. Under the experimental conditions, the gas−liquid reaction between NO x and the (NH 4 ) 2 SO 3 solution without O 2 coexisting is controlled mainly by the gas film because the (NH 4 ) 2 SO 3 concentration is higher than 0.05 mol/L. In this case, the absorption rate of NO x is found to be zero-order with respect to the (NH 4 ) 2 SO 3 concentration. The inlet partial pressure and the oxidation degree (Φ = NO 2 /NO x ) have an apparent effect on the absorption rate of NO x . In this research, a simplified mathematical calculated model is applied to the simulation of the absorption process. The experimental results demonstrate that the orders of the reaction with respect to the concentration of NO x (NO 2 * or NO*) in the gas phase and the reaction rate constants of NO x (NO 2 * or NO*) with (NH 4 ) 2 SO 3 are all a function of the oxidation degree. A kinetic equation for total NO x absorption as a function of the oxidation degree can be obtained, and the calculated value fits the experimental data well.