SmartSulf™ (formerly known as ClinSulf™ or DegSulf™) is a breakthrough sulphur recovery process, especially adapted to the treatment of very lean acid gases which enable sulphur recovery yields up to 99.5% in a two catalytic stages Claus process configuration, using proprietary isothermal reactors.

Process Scheme


Process Principle

  • Thermal stage: acid gases are burnt with air to produce sulphur at high temperature thanks to Claus reaction.
  • COS and CS2 hydrolysis: COS and CS2 from the process gases are hydrolyzed at high temperature in the first zone of the SmartSulf™ reactor operating in hot mode.
  • Claus reaction: Claus reaction occurs in the second zone of the hot mode SmartSulf™ reactor where heat of reaction is continuously removed by thermoplates internals, thus increasing sulphur conversion.
  • Subdewpoint Claus reaction: Claus reaction is performed in the cold mode SmartSulf™ reactor operating below sulphur dewpoint and producing liquid sulphur which is trapped on catalyst.
  • Cycle switch: when cold mode SmartSulf™ reactor is saturated with liquid sulphur, a switch between hot and cold mode is performed automatically by rotating the two coupled 4 way valves, enabling the beginning of a new cycle.    

Key Benefits

  • Performance above 99.5% sulphur recovery
  • Complete COS and CS2 destruction at high temperature
  • Proven technology, successfully operating in commercial plants since 1995
  • Very low capital cost
  • Low operation cost: process is fully automatic and nearly needs no follow-up
  • Use of conventional open market Claus catalysts
  • Easy retrofit to upgrade existing Claus units into SmartSulf™

Industrial references

There are currently 13 references using SmartSulf™ technology among which 4 are under design/construction.

80 TPD SmartSulf™ unit at RIAMA Refinery, Salamanca - Mexico