Treatment of feed gas streams containing hydrogen sulphide

摘要

Part of a hydrogen sulfide containing feed gas is burnt in a furnace 6 in the presence of oxygen or oxygen-enriched air. Sulfur dioxide is formed and reacts with remaining hydrogen sulfide to form sulfur vapor which is extracted by means of a condenser 16. The resulting sulfur vapor depleted gas stream is reduced to hydrogen sulfide in a reactor 22. Water vapor is removed from the gas mixture condensation in a quench tower 32. A part of the resulting water-depleted gas stream is recycled to the furnace 6. Another part is sent for further treatment to form a purge stream. The pH in the quench tower 32 is maintained in the range 9 to 12 at least during chosen periods. For this purpose a gas containing ammonia, for example a feed stream to the furnace 6, is introduced into the quench tower 32.