ABSORPTION REMOVAL OF SULFUR-DIOXIDE BY FALLING WATER DROPLETS IN THEPRESENCE OF INERT SOLID PARTICLES

An experimental analysis of the absorption removal of sulfur dioxide b y the free falling water droplets containing the inert solid particles is presented. The wheat hour powder is introduced as the inert solid particles. Tests with and without the flour powder in the water drople ts are examined. The mass fluxes and mass transfer coefficients of SO2 for the cases with and without the flour powder are compared to eluci date the effects of the inert solid particles contained in the water d roplets on the gas absorption. The results indicate a significant diff erence between the two cases for the concentrations of the flour powde r in the absorbent droplets (C-S) within the ranges of the experimenta l conditions, namely 0.1 to 10 wt% flour powder in the absorbent dropl ets. In general, the inert solid particles of the flour powder as the impurities in the water droplets tend to decrease the SO2 absorption r ate for the experimental absorption system under investigation. Variou s values of C-S cause various levels of the interfacial resistance and affect the gas absorption rate. The interfacial resistance is recogni zed by introducing an interfacial mass transfer coefficient k(s) with its reciprocal being proportional to the magnitude of the interfacial resistance. The values of 1/k(s) may be computed by the use of the equ ation 1/k(s) = (1/K-OLs - 1/K-OL) where K-OLs and K-OL are the overall liquid-phase mass transfer coefficients with and without the inert so lid particles, respectively. The values of k(s) with C-S of 0.1 to 10 wt% are about 0.295-0.032 cm s(-1) for absorbing 1000-3000 ppmv SO2 wi th the water droplets. This kind of information is useful for the SO2 removal and the formation of acid rain that the impurities of the iner t solid particles contaminate the water droplets.