A novel chemical engineering system design for synergistic SO₂ reduction and CH₄/CO₂ reforming

The SO₂ reduction to elemental sulfur by CH₄ is an essential method for industrial SO₂ treatment and resource utilization, however, its application has been limited by high temperature requirement and CO₂ emissions. Herein, we propose a novel chemical engineering design integrating SO₂ reduction and CH₄/CO₂ reforming. By partial reflux of syngas and H₂S, SO₂ can be reduced into H₂S below 450 °C, which is 400 °C lower than direct reduction by CH₄. The H₂S serves as the promoter for CH₄/CO₂ reforming to produce syngas, making CH₄ conversion increase from 32% to 89% at 900 °C. The integrating process proves its feasibility that SO₂ and CH₄ are converted into H₂, CO and elemental sulfur, with desirable sulfur recovery and carbon emission management at various operation modes. The modeling and simulation results show that this system has remarkable thermodynamic advantages due to the heat exchange between SO₂ reduction and CH₄/CO₂ reforming, making the heat loads decrease by one-third to half. The chemical engineering system provides a novel strategy for synergistic SO₂ and CO₂ utilization, with potential for syngas and sulfur co-production.