Caustic Regeneration – GT-RENEW

GT-RENEW  Technology treats spent caustic solutions containing sodium mercaptides coming from caustic treating systems used to remove mercaptan impurities from gas and liquid hydrocarbon streams. The spent caustic solution will be heated up first in a caustic-steam heater; catalyst will be added to the spent caustic solution via an in-line catalyst addition vessel and then the caustic solution will be directed to the packed section of the oxidizer tower.

In the oxidizer, the contact of the caustic solution with the injected air is promoted by the use of a packing section within the oxidizer. Then disulfide oil can be removed from the regenerated caustic solution via gravity or by the use of a small solvent stream. The regenerated and disulfide-free caustic solution is then returned, via a circulation pump, to the mercaptan extraction treater to extract more mercaptans.

The oxidizer uses a tray at the top of the oxidizer to separate the excess air from the caustic solution before the solution is sent to the gravity or solvent wash separator. The gases separated in the tray will pass through a coalescing pad and then to the incinerator or flare system.

The sizing, circulation flow rates, air injection and solvent injection rates and required residence times are project dependent; they are based on the amount of mercaptides in the spent caustic solution and the total sulfur requirements in the treated hydrocarbon stream out of the mercaptan extraction treater.

Process Advantages

  • Guaranteed high oxidation efficiency of mercaptides to disulfide oil.
  • Guaranteed removal of disulfide oil to lower sulfur back extraction and meet the total sulfur specification of the treated hydrocarbon stream.
  • Ability to operate the oxidizer over a wide range of caustic throughputs to achieve operating and treating flexibility.
  • Excellent turndown and overdesign operating capabilities.
  • Minimal plot space required.
  • Ability to maintain 100% service factor with scheduled turnarounds every five years.
  • Simplicity of operation.
  • Low capital investment.
  • Minimum effluent production.
  • Lower operating costs than other processes where high caustic circulation is needed.