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.

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.

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.

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.

COSWEET™

COSWEET™ is a process for carbonyl sulfide (COS) removal from sour natural gas streams associated with amine-based sweetening processes that allow for the simultaneous removal of COS, H₂S and/or CO₂.

By combining amine absorption with catalytic COS hydrolysis, COSWEET™ allows gas sweetening, either total (removal of both H₂S & CO₂) or selective (removal of H₂S mainly), with complete COS removal. This process is applicable to any type of absorption solvent.

The natural stream to be treated is sent to the acid gas removal unit (AGRU), where H₂S and/or CO₂ are removed by the amine solvent. COS is then decomposed into CO₂ and H₂S on the COSWEET™ reactor, using an Axens proprietary catalyst. Different options can be foreseen for H₂S polishing:

• Gas is contacted in an amine absorber with the regenerated solvent from AGRU to achieve the required treated gas specifications in the outlet stream, or
• Gas is sent to a polishing reactor filled with Axens AxTrap™ catalyst for complete H₂S removal in the outlet stream.

SPREX®

SPREX® is a process developed for bulk H₂S removal from highly sour gas. SPREX® offers economic alternatives for the development of highly sour gas reserves with acid gas reinjection, which allows CAPEX and energy consumption reduction and limits sulfur production.

SPREX® has been developed to meet the challenges of the development of very sour (> 10% acid gases) natural gases.

The process principle is as follow: highly sour gases are split in a cryogenic distillation, producing partially sweetened gas at the overhead and liquid acid gas mixture at the bottom, which is suitable for reinjection.

AdvAmine™

AdvAmine™ solutions rely on a unique and long-term cooperation between:

• TotalEnergies, the initial developer of the AdvAmine™ technology portfolio
• IFP Energies nouvelles, an innovative R&I center
• Axens, a recognized licensor.

The Advamine™ series of processes, designed to be suitable for all applications: gas plants, LNG plants, refineries, shale gas, syngas, etc.., enables to treat any type of feed gas composition and to achieve the most stringent specifications. Process configurations are adapted to operator specific cases with tailor-made solvent composition formulation, using open market chemicals in order to reduce solvent costs.

HySWEET™

HySWEET™ has been developed based on the selection of the most suitable physical solvent for blending with a variety of amines (DEA, MDEA, formulated MDEA).

It enables to maximize mercaptan removal together with the absorption of the acidic species while minimizing the usual drawback of hybrid solvents: an increased hydrocarbon co-adsorption potentially harmful for the downstream Claus unit, treating the recovered acid gas stream.

AdvaMEG®

History:
Originally developed by CCR Ltd, now exclusively licensed by Axens. AdvaMEG® is a pioneer technology with the 1^st worldwide reference (1999, Gulf of Mexico, offshore).

Highlights:
AdvaMEG® benefits are supported by:

• The experience of Axens as a process licensor as well as an engineering company delivering complete skid-mounted processing units, for both onshore and offshore applications.
• Continuous improvement of its current know-how based on operating feedback results from its long-term R&D with IFPEN and close collaboration with key partners.
• Selection of equipment and materials which have proven their reliability and high efficiency and are suitable for motions on floating support.

Onshore and Offshore Project Approach:

• Feasibility Stage
  Analysis of flow assurance study outputs, feasibility, scheme definition and conceptual study to optimize MEG regeneration and reclamation sizing.
• Project Execution
  License supply, basic design, process engineering, detailed engineering, revamping studies, procurement, supply of complete processing units/modular turn-key units.
• Start-up
  Assistance in pre-com/commissioning and start-up phases to secure unit performances. Experts on site to allow smooth transition from licensor to operators.
• Operation
  After sales services and continuous end user support such as training, supply of spare parts, analysis and technical assistance.

Cyclohexane Process

The Axens Cyclohexane process is the industry’s benchmark for the production of high purity Cyclohexane by benzene hydrogenation.

The process is combining two steps:

• A liquid phase hydrogenation, for an optimal control of exothermicity and selectivity at the lowest investment;
• A fixed catalyst bed reactor to meet the most severe Cyclohexane product specifications.