Abstract: Conventional desulfurization technologies employed for small- and medium-scale sour wellhead gas suffer from several drawbacks, including complex process flow, high energy consumption, large reagent dosage, and difficult disposal of sulfur paste. Aimed at wellhead gas with H₂S volume fraction below 1.5% and based on the irreversible and exothermic characteristic of the selective catalytic oxidation of H₂S, an automated fixed-bed selective catalytic oxidative desulfurization process (SCO-DO) was proposed and designed, and its feasibility for wellhead gas desulfurization was systematically analyzed. The SCO-DO process integrates dual-reactor switching and regeneration, waste heat recovery, and supplementary refining, thereby addressing the bottlenecks of catalyst deactivation caused by sulfur deposition, excessive energy consumption, and difficulty in meeting purification standards. In comparison with the traditional high-pressure chelated iron process and amine absorption coupled with self-circulating chelated iron process, the SCO-DO process features simpler flow path and lower operating cost. The desulfurization product is commercial-grade elemental sulfur, leading to outstanding environmental benefits and great potential for industrial application.

Key words: wellhead gas, selective catalytic oxidation, desulfurization, techno-economic performance