New Biotechnological Method for H2S Removal from Biogas, 1993 Environmental Conference Proceedings

A new biotechnological method for H2S removal from gasses was developed in order to recover the H2S as elemental sulfur without the excessive use of chemicals. A scrubber integrated with a bioreactor proved to be a very effective and inexpensive way to remove the H2S. A pilot plant on a 20 m3/h scale showed that a high removal efficiency was possible (I-W in clean gas less than 40 ppm) at a low NaOH use. Important parameters for the system were the pH and the flow of the washing liquid for scrubbing efficiency and the sulfide loading rate for the ulfate formation. At approximately 6 kg H2S per day, a removal efficiency of 99% is achievable. At this loading rate, it can be expected that 70% of the H2S is converted to sulfur and 30% to sulfate and thiosulfate. The NaOH use in this case is approximately 3 litre NaOH (20%)/kg H2S. Using a conventional scrubber this value would be 22.5 litre NaOH (20%)/kg H2S. The produced sulfur slurry consisted for 50% sulfur with ash content <1 %.="" the="" slurry="" can="" be="" reused="" relatively="">