OXIDATIVE ABSORPTION OF HYDROGEN-SULFIDE BY A SOLUTION OF FERRIC NITRILOTRIACETIC ACID COMPLEX IN A COCURRENT DOWN FLOW COLUMN PACKED WITH SMV-4 STATIC MIXERS

The reactive absorption of hydrogen sulfide into a solution of the fer ric chelate of nitrilotriacetic acid (NTA) was studied at 13 degrees C in a cocurrent down flow column packed with stainless steel Sulzer SM V-4 static mixers. The concentration of ferric chelate varied from 200 to 30 mol/m(3); the pH ranged from 8.3 to 6.7. Volumetric liquid-phas e mass transfer coefficients for H2S (k(L) alpha) could be measured an d were correlated by k(L) alpha = 0.0572E(L)(0.55) for 0.060 less than or equal to U-L less than or equal to 0.156 [m/s], 0.59 less than or equal to U-G less than or equal to 2.95 [m/s], and 1.4 x 10(2) less th an or equal to E(L) less than or equal to 3 X 10(3) [N/m(2)s], in whic h E(L) is the liquid energy dissipation factor and U-L and U-G are the superficial liquid and gas velocity, respectively. The k(L) alpha val ues observed with H2S under reactive conditions appeared to be approxi mately a factor of 4 higher than those observed for oxygen absorption in the same liquid over the same packing. The cause of the extra volum etric mass transfer obtained with H2S under similar conditions is not well understood yet. The reaction kinetics of hydrogen sulfide with th e ferric chelate of NTA was found to be first order in both ferric NTA and H2S for 0.40 < p(A) < 0.8 kPa, 0 < C-Fe(III) < 200 mol/m(3), and 6.7 < pH < 8.2.