AECOM Process Technologies provides cost-effective removal of sulfur in the mid-size range from 0.2 to 25 tons per day with CrystaSulf®.

Removing sulfur from gas streams that contain 0.2 to 25 long tons per day of sulfur has historically been problematic. In this size range, the operating cost of once-through chemicals for hydrogen sulfide (H2S) scavenging is high, while traditional amine/Claus units suffer from prohibitively high capital costs and operating problems.

CrystaSulf® can remove sulfur economically without the operating issues of aqueous-iron systems and with significantly lower pumping costs for most applications. Using SO2 as an oxidant, CrystaSulf® converts inlet H2S to elemental sulfur through a modified liquid-phase Claus reaction. Elemental sulfur is soluble in CrystaSulf® solution, which eliminates circulating solids in high-pressure equipment. The sulfur is crystallized and separated in equipment designed to handle solids, while the rest of the process remains solids-free.

The CrystaSulf® process can achieve pipeline H2S specifications of less than 4 parts per million by volume (ppmv) at pressures above 150 psig. CO2 has been shown to have no effect on the process.  Inlet hydrocarbons also have little or no effect.

CrystaSulf Advantages

Lower cost

  • Lower overall treatment cost, especially in high-CO2 applications
  • Lower maintenance and clean-out cost
  • Greater on-stream factor

Direct Treatment of high-pressure streams

  • Easy to pump solids-free solution
  • Low circulation rate

Solvent with high solubility for elemental sulfur

  • No sulfur settling additives or surfactants
  • No foaming or plugging problems typically found in aqueous systems

Common industrial equipment

  • No special design requirements for slurry handling
  • No sulfur solids in circulating solution

Production of large sulfur particles

  • Easy handling, separation, and filtration of sulfur
  • Less disposal cost associated with drier sulfur

Easy control of H2S removal

  • Increased buffering capacity (changes happen slowly)
  • Easily monitored compound removal

Adjustable footprint

  • Modules can be designed for vertical placement (smaller footprint)
  • Easy access to all equipment afforded by low-profile design
  • Ideal for retrofit in congested plants with space constraint

Expedited project schedule

  • Standardized and modular design
  • Fast-track schedule to engineer, procure, and construct
  • Readily available equipment

Multiple applications well suited for CrystaSulf

  • Sour high-pressure natural gas (including shale gas)
  • Hydrogen recycle streams in refinery HDS units
  • Refinery fuel gas
  • Claus tail gas streams
  • Gasification syngas
  • Off-gas from heavy oil upgrading
  • Gas associated with in-situ oil sands operations