This paper proposes a novel reactor–separator network in the Bunsen process for high hydrogen production thermal efficiency. Six case studies were conducted to investigate the effect of reactants on the Bunsen reaction. The key classification of the case studies was the location of the SO₂–O₂ stream to avoid oxygen contact in the Bunsen reaction and the use of an HI_X purifier instead of the SO₂ absorber to reduce iodine. The thermal efficiency in the best case was 48.91%. The main criteria for high efficiency were low iodine flow, high HI flow, and higher amount of SO₂ recycling to avoid hindrance and maintain low iodine flow.