Single-Tower Oxidation-Regeneration and Dual-Tower Oxidation-Regeneration, allowing optimal selection based on specific project requirements. It is widely applied across natural gas, petrochemical, and biogas upgrading industries.

Our H₂S Treatment Solution List

Liquid Redox

Single-Tower Oxidation Regeneration Process

Dual-Tower Oxidation Regeneration Process

Catalysis and Adsorption

Skid-mounted System

Chelated Iron Solutions

Catalysis and Adsorption Solutions

Chemical

DEFINITION

What is Liquid Redox?

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.

PRINCIPLE

Working Principle of Liquid Redox

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.

Reaction Mechanism & Process Flow

1. Absorption & Oxidation

H₂S in the gas is absorbed into the chelated iron solution and oxidized to elemental sulfur by ferric ions:

H₂S+2Fe3+→S↓+2Fe2++2H+

2. Regeneration of Catalyst

Ferrous ions are oxidized back to ferric ions by air (oxygen), realizing catalyst regeneration:

4Fe2++O₂+2H₂O→4Fe3++4OH−

3. Overall Reaction

2H₂S+O₂→2S↓+2H₂O

FEATURES

Technical Features of Liquid Redox

Easy Separation:

The produced sulfur particles are large and with clear solid-liquid separation, resulting in high separation efficiency and low solution loss.

No Exhaust Emissions:

The regeneration system off-gas contains only air, with no H2S or other pollutant emissions.

High Sulfur Capacity:

The working sulfur capacity can reach above 0.3%, while that of conventional catalyst is typically less than 0.1%.

Zero Liquid Discharge:

No waste liquid or other by-products are generated during operation except elemental sulfur.

Stable Foam Performance:

High-quality sulfur foam with high sulfur loading, no light/empty foam issues.

APPLICATIONS

Applications of Liquid Redox

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

FAQs of Liquid Redox

Q

What after-sales support can you provide?

A

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.

Q

What is the core principle?

A

It adopts the Liquid Redox method. Chelated iron act as catalysts: H₂S is oxidized to elemental sulfur (S) in alkaline absorption solution.

Q

Which gases can be treated by liquid redox?

A

It is widely compatible with natural gas, biogas, petroleum gas, syngas and acid tail gas.

Q

What is the H₂S removal efficiency?

A

The outlet H₂S can be stably controlled below 10ppm, and even below 5mg/Nm³ with high-quality processes, meeting ultra-low emission requirements.

Can the existing HPF/ADA unit be transformed into Liquid Redox?

A

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.

Q

What material is suitable for the equipment?

A

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.

What are the main operating costs?

A

The main operating costs include catalyst consumption (core cost), alkali consumption, power consumption (solution circulating pump, regeneration fan), and waste water treatment.

Q

What is the difference between liquid redox and scavengers?

A

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.

Minor competitive side reactions may occur to some extent. KOH Solution is added to maintain a relatively stable solution pH and ensure excellent H₂S absorption performance.

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In the Liquid Redox process, iron is solubilized in solution by a blended chelating agent system, where the chelating agent uses include stabilizing iron across a wide range of pH conditions, thereby reducing overall operating costs.

If you want to know more about h2s treatment solutions, please visit our website.