The Performance of a Spray Tower in Scrubbing H2S from Air

Hydrogen sulfide is a hazardous gas which is fatal at high concentrations. The application of a spray tower to remove H2S from air is the simplest and cheapest method but its performance is under question. In this study, the performance of a spray tower in removing H2S from air as well as its pressure loss across the bed were investigated. In this study a spray tower was used to remove H2S from air. H2S was injected to the tower at the range of 0-30 ppm. The volumetric flow rate of water as the scrubbing liquid was 2 lit/min and spraying was carried out by a pump with 21-35 Kg/cm2 head. The volumetric flow rate of air was supplied through a fan in the range of 2400-3000 lit/min. The pressure loss across the bed was monitored by an inclined manometer. H2S concentrations in air were measured using direct reading device. The results were analyzed using SPSS version 16. The minimum pressure loss, 73.81±0.2887 Pa, was obtained at 1200 lit/min air flow rate without scrubbing liquid injected to the tower. The maximum pressure loss, 292.84±2.448 Pa, was experienced at 3000 lit/min air flow rate with 2 lit/min of water flow injected to the tower. The maximum removal efficiency, 70.53±1.5415%, was experienced at 1800 lit/min of air flow rate along with 15 ppm of H2S injected to the tower. Minimum removal efficiency, 47.74±0.9295%, was gained at 3000 lit/min of air flow rate and 30 ppm of H2S injected to the tower. Statistical t-test revealed that there is a significant difference between H2S removal efficiency with air flow rate and inlet concentration, also between pressure drop with air flow rate and the presence of water (p<0.001). The removal efficiency of spray tower decreases by increasing the input flow rate and input concentration of H2S. The performance of water as a scrubbing liquid in spray tower is not satisfactory thus, the application of water plus chemical scrubbing liquids is strongly recommended to be studied.