With a record of 150 sulphur recovery plants, most of which are based on our own technologies, we can provide our customers with tailored solutions, either air-Claus or air oxygen-enriched Claus, tail gas treatment (trade marked as HCR) and our own sulphur degassing process. Our plants are able to deliver a sulphur recovery efficiency as much as 99.9+%.

There is a wide family of process technologies for sulphur bearing compounds removal from the gas phase and their potential recovery as a sellable liquid sulphur product. Historically the most used sulphur recovery process has been the Claus process, in which the H2S in gas phase is burnt with sub-stoichiometric air to produce SO2 and subsequently make it react with the remaining H2S to form sulphur.

Claus processes may have different implementations depending on the concentration of H2S in the gas and the type of contaminants to be dealt with. Additionally, stricter environmental regulations, which call for constantly improving removal and recovery efficiencies, practically define the design of the process line-up, with the most appropriate selection of solvents being another critical degree of freedom.

Our expertise includes the following process technologies: 

  • Modified Claus technology, with H2S concentrations ranging from 15% vol. to 100% vol., capacities from few tons/day to more than 2000 tons/day per train and recoveries up to 98.5%
  • Ammonia and advanced Ammonia Claus technology, to treat acid gases with concentrations of ammonia higher than 25% vol. overall
  • Oxygen-enriched Claus technology, with low, mid and high enrichments
  • Integrated Claus Process from energy point of view
  • Direct Oxidation technology integration, for treatment of acid gases with H2S concentrations below 10% vol.
  • Selective Oxidation technology integration, for recoveries from 99.0% to 99.5% with minimal investment cost
  • Sub Dew-point Processes technology integration.

The recovery of the sulphur is only one part of the business. Gas pre-treatment, gas post-treatment and liquid sulphur treatment and management, are key aspects to complete the sulphur recovery panorama.

Our expertise includes the following process technologies:

  • Acid gas enrichment and its integration with upstream Acid Gas Sweetening and downstream Tail Gas Treating units
  • Reductive tail gas treating (Siirtec Nigi HCR) for raising the sulphur recovery efficiency up to 99.9+%
  • Oxidative tail gas treating integration
  • Caustic scrubbing
  • Selective SO2 adsorption and conversion to sulphur
  • Siirtec Nigi proprietary sulphur degassing technology (H2S residue <10 ppmw)
  • Thermal and catalytic oxidizers (Claus tail gas incineration) and stacks
  • One and two stage sour water stripping technology
  • Sulphur forming technology integration (slating/flaking, water and air prilling, granulation, pastillation).

In addition, our expertise in the design and supply of proprietary equipment places us in a unique position offering a wealth of experience in some of the most demanding aspects of sulphur plants.

Our expertise includes:

  • Siirtec Nigi proprietary Acid Gas Burners for Claus reaction furnaces
  • Claus Reaction Furnaces and Waste Heat Boilers
  • Sulphur Condensers
  • Incinerator and stack packages
  • Modularized low-footprint sulphur plants

Finally, we are at the cutting edge of the process simulation in the world of sulphur through continuous involvement in alfa and beta-testing programs with main world leading sulphur process simulators and with constant tuning using real world plant data feedback.

Via Algardi 2 - 20148 Milan
+39 02 392231
+39 02 39223010
Mon - Fri: 8.30 am - 6 pm