Sulfur Recovery

Sulfur Recovery

Axens Offer

AdvaSulf™ portfolio provides reliable, flexible and low-cost solutions for Sulfur Recovery to meet the most stringent environmental standards, at minimized capital and operating costs. The portfolio covers a complete range of processes for any applications: gas plants, refineries, upgraders, biogas, shale gas, etc., in a wide range of single train capacities, from a few tons per day to more than 2,200 tons per day of sulfur produced.

When Sulfur Block is required, Axens has the internal knowhow to include in the Process Design Package (PDP) the following additional units: Sour Water Stripper (SWS), Amine Regeneration Unit (ARU) and Acid Gas Enrichment (AGE). In addition, the sulfur block can be completed by developing a duty specification for the sulfur forming unit.

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The traditional Claus-based process is composed of two steps, a first thermal stage and a second catalytic stage. In sub-dewpointing Claus, the latter stage differentiates from the conventional Claus process as it has 2 permutable catalytic stages (Hot & Cold reactors), where the second stage works at sub-dewpoint condition.

Process Technologies

SmartSulf® - AdvaSulf™ Suite

SmartSulf® fundamental principle consists in removing the heat produced by the exothermic Claus reaction directly in the catalyst bed, by means of proprietary cooled reactors, rather than being removed by condensation in a downstream heat exchanger.

This technology relies on two important features:

Increased thermodynamic conversion of the Claus reactions thanks to the embedded heat exchanger.
Sub-dewpoint Claus process that improves the overall Sulfur Removal by absorbing liquid elemental sulfur on the catalyst.

This technology uses a combination of Axens titanium-based and alumina catalysts, in order to deal with residual COS and CS₂ species and at the same time reach outstanding H₂S conversion performances.

The CAPEX/OPEX of this technology is comparable to that of a conventional Claus unit and offers an easy operability and potential for: retrofit in a small footprint, increase of conversion capacity and efficiency of existing sulfur recovery units.

More than 99.5%+ Sulfur Recovery without TGT Unit

Very low capital cost & footprint thanks to the use of just 2 permutable catalytic reactors

Successfully operating in commercial plants for 25 years

Commercial Bulletin

Related Offer

Modular Unit

SmartSulf® + Polishing

SmartSulf® process can be also adapted to 99.9+% sulfur removal when more stringent emission regulations are required. This solution consists in adding a Polishing Section downstream of the Thermal Oxidizer (Incinerator).

This upgrade allows to achieve Word Bank Specifications (150 mg/Nm³ SO₂ emission) with a fraction of the capital investment and plot plan area needed by the conventional Amine based TGTU.

Water Treatment Package can be integrated depending on on-site facilities for treatment of effluent with dissolved salts from polishing.

Maximized performance up to 99.9+% of sulfur removal with low involvement of capital and operating costs

Minimum chemical consumption with easily disposable effluent

World Bank atmospheric emissions specification are achievable

Commercial Bulletin

SmartSulf® Direct Oxydation / DO

SmartSulf® process could be adapted, by removing the Reaction Furnace, in order to treat lean acid gas (0.5<H₂S<15% vol.). This process is called SmartSulf® Direct Oxidation (DO) and it allows to produce, by means of air injection and catalytic reactions, a commercial grade liquid sulfur without having any effluent to be disposed of.

SmartSulf® DO can be designed in order to deal with a wide range of lean acid gas composition and with an overall Sulfur Recovery from 90% up to 99%.

Typical applications are desulfurization of lean acid gases, Light Hydrocarbon streams, Biogas, Shale gas, Gasification.

Very lean acid gases at low or high pressure can be processed

Simple scheme with low capex and low maintenance and operating costs

Production of commercial grade liquid sulfur

Commercial Bulletin

Catalysts & Grading Materials

Catalysts

Claus Active Bed Support Catalysts

Claus productivity can be boosted if the bed support material also acts as catalyst.

Catalysts

Claus Catalysts

Promoting the Claus reaction kinetic while avoiding pore blockage in the catalyst is key to sulfur recovery maximization.

Consulting, Studies & Audits

Axens offers a customized approach, including tailored studies, audits and consulting services, covering technical and operational challenges.

Unit Revamps & Retrofits

You face many challenges, which include operating in a safe, reliable and environmentally sound manner while responding to changing markets dynamics.

Customer Training

Designed for all Axens technologies, dedicated to operators & engineers, Axens offers customized training solutions to all our licensees, covering the whole range of Axens technologies.

Technical Support & Performance Management

Axens is fully committed to be your partner and provide assistance and support during your project lifecycle, from conception to start-up & running operations.

Digital Services & Applications

Axens' digital platform combines real-time data and digital solutions to optimize operations, reduce environmental impact, and lower costs while maximizing profitability. By delivering actionable insights and detailed performance reports, it enhances asset operation and performance for smarter, more efficient outcomes.

The Claus and other advanced process solutions for sulfur recovery involve using thermal and catalytic reactions. Sulfur recovery can range from 95% up to 98% depending on the feed and number of reactors used.

Promoting the Claus reaction kinetic while avoiding pore blockage in the catalyst is key to sulfur recovery maximization. Axens aluminas provide first-class performance thanks to their optimized properties. When dealing with residual COS and CS₂ species, titanium-based catalysts, used alone or in combination with aluminas, is the solution of choice to reach outstanding performances.

Process Technologies

Claus

The Claus conventional process allows a sulfur recovery between 95 and 98% by converting H₂S present in feed gas streams and recover it as elemental liquid Sulfur. The process is based on the Claus reaction that is composed of two steps, a first thermal stage and a second catalytic stage.

The thermal stage, carried out in the Reaction Furnace, consists in the partial oxidation of H₂S to generate Sulfur dioxide (SO₂), which will then react with the remaining hydrogen sulfide (H₂S) to produce Sulfur in the catalytic stages.

Alumina is the main catalyst used in the Claus process, where the formation of sulfur occurs at the surface of heterogeneous (solid) catalysts. In addition, TiO₂ based catalyst is largely used in the bottom of the first Claus reactor to better convert COS and CS₂ and further reduce sulfur emissions out of stack. The most suitable catalyst configuration to match the required performances and Catalyst Life Span is selected from Axens large SRU Catalyst Portfolio, on a case by case basis.

More than 60 years of expertise and know how in Claus process with single train capacity from a few TS/d up to 2,200 TS/d

Most widely recognized Claus catalysts on the market

Large experience on Claus unit operation and troubleshooting thanks to several industrial feedbacks

Related Offer

Modular Unit

Catalysts & Grading Materials

Catalysts

Claus Active Bed Support Catalysts

Claus productivity can be boosted if the bed support material also acts as catalyst.

Catalysts

Claus Catalysts

Promoting the Claus reaction kinetic while avoiding pore blockage in the catalyst is key to sulfur recovery maximization.

Consulting, Studies & Audits

Axens offers a customized approach, including tailored studies, audits and consulting services, covering technical and operational challenges.

Unit Revamps & Retrofits

You face many challenges, which include operating in a safe, reliable and environmentally sound manner while responding to changing markets dynamics.

Customer Training

Designed for all Axens technologies, dedicated to operators & engineers, Axens offers customized training solutions to all our licensees, covering the whole range of Axens technologies.

Technical Support & Performance Management

Axens is fully committed to be your partner and provide assistance and support during your project lifecycle, from conception to start-up & running operations.

Digital Services & Applications

Tail Gas from the Claus section still contains unrecovered sulfur species: H₂S and SO₂, residual COS and CS₂, traces of vapor and liquid elemental sulfur.

To further increase recovery yields, tail gas leaving the Claus section can be treated using different processes. Axens proposes dedicated technologies and products for sub-dewpoint applications or hydrogenation plus amine process (Sultimate™) where sulfur species are reduced back to H₂S and recycled to the Claus section inlet. These optimized catalysts help reaching the ever-increasing stringent specification on sulfur emissions.

Process Technologies

Sultimate™ - AdvaSulf™ Suite

Axens offers Sultimate™, a Tail Gas Treatment (TGT) technology in sulfur recovery processing that uses conventional or proprietary amine based solvent, featuring the highest sulfur recovery achievable: typically 99.9+%.

The catalyst filled within the TGT Hydrogenation (Reduction) Reactor is one of its best feature. Axens CoMo catalyst has the best performance available on the market at low temperature, allowing drastic OPEX reduction while maintaining high activity during long run duration.

Sulfur Recovery up to 99.9+% with conventional MDEA

Over 150 sulfur recovery technology references including many references with Sultimate™ TGT units

Axens TGT low temperature catalyst features major energy and cost savings

Commercial Bulletin

Related Offer

Modular Unit

Catalysts & Grading Materials

Catalysts

Tail Gas Treatment Catalysts

To further increase recovery yields, tail gas leaving the Claus section can be treated using different processes. Axens offers dedicated products for sub-dewpoint applications or hydrogenation processes where sulfur species are reduced back to H₂S and recycled to the Claus section inlet.

Consulting, Studies & Audits

Axens offers a customized approach, including tailored studies, audits and consulting services, covering technical and operational challenges.

Unit Revamps & Retrofits

You face many challenges, which include operating in a safe, reliable and environmentally sound manner while responding to changing markets dynamics.

Modular Units

A modularization strategy offers superior benefits versus on-site manufacturing. During the last 40 years, Axens has supplied over 500 modular units, both onshore and offshore, providing tailor-made designs according to client project specifications.

Customer Training

Designed for all Axens technologies, dedicated to operators & engineers, Axens offers customized training solutions to all our licensees, covering the whole range of Axens technologies.

Technical Support & Performance Management

Axens is fully committed to be your partner and provide assistance and support during your project lifecycle, from conception to start-up & running operations.

Digital Services & Applications

SweetSulf™

SweetSulf™ is a redox process developed for high-pressure natural gas, medium pressure fuel gas or low-pressure acid gas applications. Its specific solid sulfur removal technology overcomes the foaming/plugging problems experienced with other types of redox processes.

Reaction: Sour Gas is contacted with an aqueous redox solution which extracts the H₂S and converts it into solid elemental sulfur.
Gas separation: Treated gas, free of H₂S (H₂S specification down to < 1 ppmv is achievable), is separated from the redox solution.
Solid separation: Solid sulfur is filtered under pressure on a cartridge filter which can be regenerated on stream.
Re-Oxidation: The redox solution is depressurized and re-oxidized by contact with air.

Selective H2S removal with direct conversion into solid elemental sulfur

Pipeline gas or LNG specification as well as World bank SO2 emission specifications are achievable

Ambient temperature operation without thermal regeneration

Related Offer

Modular Unit

Consulting, Supply & Support

Consulting, Studies & Audits

Axens offers a customized approach, including tailored studies, audits and consulting services, covering technical and operational challenges.

Unit Revamps & Retrofits

You face many challenges, which include operating in a safe, reliable and environmentally sound manner while responding to changing markets dynamics.

Technical Support & Performance Management

Axens is fully committed to be your partner and provide assistance and support during your project lifecycle, from conception to start-up & running operations.

Digital Services & Applications

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Sulphur + Sulphuric Acid 2025 Conference & Exhibition

Sulphur + Sulphuric Acid continues to be an essential annual forum for the global sulphur and acid community to learn, connect and do business. Knowledge sharing is at the event's core: via the respected dual-streamed technical programme, and the connections made with industry experts and solution providers attending.

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Resources

Technical article 24 September 2024

Technical Article - New low-density titanium dioxide catalyst for improved sulphur recovery

Video 3 October 2024

Video - Axens Sulshine® CRS 41 - Introducing the Newest Addition to the Sulfur Recovery Catalysts Family

Case Study 3 January 2023

Case Study - Successful start-up of a Sub-dewpointing Sulfur Removal Technology

Video 3 January 2023

Video - Axens SmartSulf®️ Technology - Up to 99.7% Sulfur Recovery without TGTU

More resources

Insight 1 June 2020

Sulfur Recovery, Recommended Route to Meet Environmental Specifications

See all Insights

Natural Gas

Case Study

Case Study - Successful start-up of a Sub-dewpointing Sulfur Removal Technology

See all Case studies

Technical article 24 September 2024

Technical Article - New low-density titanium dioxide catalyst for improved sulphur recovery

Technical article 27 April 2021

Technical Article - SMARTSULF™ Process In Direct Oxydation Mode For Very Lean Acid Gas Application

Technical article 27 April 2021

Technical Article - Boosting Sulphur Recovery With Sub-Dewpoint Processes

Technical article 27 April 2021

Technical Article - Advantages Of Modular Construction For Small Scale SRU In Harsh Climates

See all Technical articles

FAQ 6 May 2021

What steps do we need to take to keep our sour water stripper at peak performance following a shutdown?

FAQ 5 May 2021

Our tail gas unit is performing below spec. We are experiencing high levels of heat stable salts in the solvent. How do we deal with this?

See all FAQ

Press release 11 May 2023

Axens to provide technologies for the complete gas treatment chain at CSV Albright Sour Gas Processing Plant in Canada

Press release 8 April 2019

Axens’ Technologies for HPCL Rajasthan Refinery in India

See all Press releases

Natural Gas

Video

Video - Axens Sulshine® CRS 41 - Introducing the Newest Addition to the Sulfur Recovery Catalysts Family

Natural Gas

Video

Video - Axens SmartSulf®️ Technology - Up to 99.7% Sulfur Recovery without TGTU

See all Videos

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