| 摘要 |
<p>PURPOSE:To enhance the purity of recovered sulfur by preventing the lowering in the removal ratio of H2S and suppressing side-reaction, by holding pH of an iron chelate absorbing solution to a specific range and holding the mol ratio of trivalent chelate iron to the total chelate iron in the absorbing solution after absorption to a specific range. CONSTITUTION:The pH of an absorbing solution containing an iron ion, EDTA and triethanolamine is held to 7-9 and H2S-containing exhaust gas is introduced into an absorbing tower 1 to be subjected to the gas-liquid contact treatment with the absorbing solution from a spray nozzle 8. At this time, the mol ratio of trivalent chelate iron to the total chelate iron in the absorbing solution directly after gas-liquid contact treatment is set to 0.60-0.90. The absorbing solution containing elemental sulfur obtained through the oxidation of H2S in exhaust gas is sent to an oxidizing tower 2 through a liquid chember 9 and the catalyst in the absorbing solution is oxidized while the treated absorbing solution is sent to a recirculation tank 3. Subsequently, the absorbing solution is supplied to a filter press 5 through a sulfur bubbling tank 4 to separate and recover solid sulfur.</p> |
