Liquid Redox is a chemical oxidation-based process used for hydrogen sulfide (H₂S) treatment in gas streams, wastewater, and industrial emissions. It removes hydrogen sulfide by converting it into elemental sulfur through a continuous liquid-phase reaction, making it an efficient and regenerable H₂S treatment technology for industrial applications.
Unlike one-time-use chemical hydrogen sulfide scavengers, the liquid redox for H₂S treating operates in a regenerative system, allowing the oxidizing solution to be continuously regenerated and reused. This makes it a cost-effective and environmentally friendly solution for large-scale hydrogen sulfide removal and sulfur recovery.
The Liquid Redox process treats H₂S by converting it into elemental sulfur in the liquid phase based on the chelated iron solutions, with simultaneous sulfur recovery. During the oxidation of H₂S to elemental sulfur, ferric ions (Fe³⁺) in the catalyst are reduced to ferrous ions (Fe²⁺). The ferrous ions are then regenerated back to ferric ions (Fe³⁺) by air, enabling continuous cyclic reuse. Elemental sulfur produced in the reaction is separated and recovered using a plate-and-frame filter press.
H₂S in the gas is absorbed into the chelated iron solution and oxidized to elemental sulfur by ferric ions:
H₂S+2Fe3+→S↓+2Fe2++2H+
Ferrous ions are oxidized back to ferric ions by air (oxygen), realizing catalyst regeneration:
4Fe2++O₂+2H₂O→4Fe3++4OH−
2H₂S+O₂→2S↓+2H₂O
The produced sulfur particles are large and with clear solid-liquid separation, resulting in high separation efficiency and low solution loss.
The regeneration system off-gas contains only air, with no H2S or other pollutant emissions.
The working sulfur capacity can reach above 0.3%, while that of conventional catalyst is typically less than 0.1%.
No waste liquid or other by-products are generated during operation except elemental sulfur.
High-quality sulfur foam with high sulfur loading, no light/empty foam issues.
H₂S removal of natural gas
H₂S removal of associated gas
Acid gas tail gas treatment and sulfur recovery
Refinery gas H₂S removal
Removal of H2S from biogas
Syngas H₂S removal
WINVO, as a professional H2S services company, provide one-stop after-sales service, including on-site installation guidance, operation training, remote guidance for troubleshooting, on-site support when necessary, and guarantee for catalyst supply.
It adopts the Liquid Redox method. Chelated iron act as catalysts: H₂S is oxidized to elemental sulfur (S) in alkaline absorption solution.
It is widely compatible with natural gas, biogas, petroleum gas, syngas and acid tail gas.
The outlet H₂S can be stably controlled below 10ppm, and even below 5mg/Nm³ with high-quality processes, meeting ultra-low emission requirements.
Yes, and the retrofit is straightforward is convenient. There is no need to rebuild the tower; only the spray, regeneration and sulfur recovery systems need to be optimized. The transformation cycle is short, the investment is low, and the shutdown time is minimized.
Absorption/regeneration towers can use carbon steel + anti-corrosion lining or 304/316 stainless steel; pipelines, pumps and tanks need internal anti-corrosion for carbon steel to avoid local corrosion.
The main operating costs include catalyst consumption (core cost), alkali consumption, power consumption (solution circulating pump, regeneration fan), and waste water treatment.
Liquid redox systems continuously regenerate a liquid solution to convert H₂S into elemental sulfur, making them suitable for large, continuous gas streams. In contrast, scavengers are typically chemical consumables that permanently react with H₂S and are not regenerated. Liquid redox is more economical for high-volume applications, while scavengers are better suited for smaller or intermittent gas flows.
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