Research on the technology of vacuum extraction desulfurization and harmless treatment of gas field high-sulfur wastewater

Aiming at the low desulfurization rate of high-sulfur wastewater in Puguang gas field, the technology of "aeration + vacuum extraction + catalytic oxidation of tail gas" was adopted and orthogonal experiment optimization was designed. The optimized operating conditions are shown as follows: sewage pH value of 4.0, temperature of 20 ℃, gas stripping vacuum degree of -0.02 MPa, aeration gas-liquid ratio of 20:1, and sewage desulfurization ratio is as high as 94%. The influence of vacuum desulfurization operation conditions on the desulfurization rate from strong to weak in the order is air aeration gas-liquid ratio, sewage pH value, gas extraction vacuum degree and sewage temperature. Iron-base ionic liquids was optimized as exhaust gas desulfurization catalyst in the test. The results show that Fe³⁺ oxidized H₂S at a very fast rate in iron-based ionic liquids, the concentration of H₂S in tail gas is 0 mg/m³, and the oxidation products is elemental sulfur. Meanwhile, Fe²⁺ in ionic liquids can be oxidized to Fe³⁺ by air. The application of iron-based ionic liquids not only realizes the low cost reuse of the desulfurization liquid, but also completely eliminates the SO₂ emission problem caused by the combustion of the tail gas containing sulfur.