An investigation is made to evaluate the flue gas desulfurization (FGD) by absorption in a gas-continuous impinging stream gas-liquid reactor recently developed for systems involving fast reaction(s) in liquid. The mixture of air and SO2 was used as the pseudo-flue gas and Ca(OH)(2)-water suspension as the absorbent. By employing horizontal two-impinging streams, the reactor is simple in structure with few internal parts, while exhibits satisfied overall performance for FGD. Under moderate conditions, the content Of SO2 in the cleaned gas can achieve a level much lower than that permitted, while the pressure drop across the device is about 400Pa only. The influences of some operating and structural parameters, such as V-L/V-G, Ca/S mole ratio, SO2 concentration in flue gas, impinging distance S, and nozzle location, etc., are examined. The gas-film mass transfer coefficient, k(G), is determined based on Sauter mean diameter of spray droplets. The results show that k(G) is essentially independent of concentration of SO2 in flue gas, implying the process can be considered to be controlled by diffusion through gas film. The relationship between k(G) and impinging velocity, u(0), is fitted to be k(G) = 2.9 x 10(-4) u(0)(1.75821) with the standard deviation of SD = 2.45 x 10(-4) m s(-1), suggesting u(0) is a strong effecting variable on mass transfer, and, consequentially, important operating variable. In the range of u(0) from 5.53 to 16.62 m s(-1), the values determined for the volumetric mass transfer coefficient, k(G)a, are 0.577-1.037 s(-1), and those for k(G) are ranged from 0.00641 to 0.0416 m s(-1). (c) 2006 Elsevier Ltd. All rights reserved.