Objective Determine the technical and economic adaptability of desulfurization and purification by complex iron desulfurization process in sour gas wells.

Methods The principle, flow and characteristics of complex iron desulfurization process were analyzed. According to the industrial application examples of sour gas wells, the technical and economic adaptability conditions of complex iron desulfurization process were studied and put forward.

Results In terms of technology, the complex iron desulfurization process was applicable to the desulfurization of natural gas with any hydrogen sulfide content. The hydrogen sulfide removal rate could reach more than 99.9%, and the removal effect was stable. It would not be affected by the fluctuation of hydrogen sulfide content in the short term. The CO₂ removal rate was determined by the operating pressure of the absorber and the CO₂ content in feed gas. The removal rates of methyl mercaptan and ethyl mercaptan with different concentrations could reach more than 97% and 92%, respectively, and the removal rate of carbonyl sulfur was about 6.51%-35.02%. The reasonable sulfur capacity should be the value when the comprehensive cost of reagent and power consumption was the lowest. The reasonable sulfur capacity was also different under different operating conditions. At present, the elemental sulfur produced by the process was mainly removed and treated in the form of sulfur paste. The economic and environmental recovery of sulfur was a difficulty in the complex iron desulfurization process. In terms of economy, the complete cost analysis of the process was carried out, and the calculation formulas of the process economic limit H₂S content and economic limit treatment capacity under the condition of 12.35 t/d latent sulfur capacity were put forward.

Conclusion The above research results have certain reference for the technical optimal selection and optimization of complex iron desulfurization process as well as the demonstration and analysis of economic benefits.