Experimental Optimization of Sodium Sulfide Production by H2S Reactive Absorption via Genetic Algorithm

In this study, sodium sulfide (Na2S) solution was produced by reactive absorption of hydrogen sulfide (H2S) from off-gas streams into sodiumhydroxide (NaOH) solution in a spray column. The optimization of H2S absorption into NaOH solution to produce Na2S solution was performed by genetic algorithm (GA). GA determined the values of operating variables to obtain the maximum weight percent of the produced Na2S. In order to investigate the individual and interactive effects of three independent operating variables on the weight percent of the produced Na2S, response surface methodology (RSM) was applied. In this work, three independent operating variables of initial NaOH concentration, scrubbing solution temperature and liquid-to-gas volumetric ratio were considered in the ranges of 10-20% w/w, 40- 60°C and 15×10-3-25×10-3 v/v. The optimum operating variables specified by GA within the mentioned ranges resulted in the weight percent of the produced Na2S of 15.71% at initial NaOH concentration of 20% w/w, scrubbing solution temperature of 40 °C and liquid-to-gas volumetric ratio of 24.9×10-3 v/v.