Regeneration of caustic solutions

A caustic recovery system comprising:

• an oxygen source that is fluidly coupled to an oxidizer tower and configured to provide oxygen to the oxidizer tower;
• a caustic source configured to provide spent caustic and an oxidation catalyst source configured to provide an oxidation catalyst;
• wherein the caustic source and the oxidation catalyst source are fluidly coupled to each other and the oxidizer tower via a mixing device, wherein the mixing device is configured to provide a mixture of spent caustic and oxidation catalyst to the oxidizer tower;
• wherein the oxidizer tower is configured to allow introduction of the mixture an oxygen recycle stream, and the oxygen at a lower portion of the tower to thereby provide co-current contact of the spent caustic and catalyst with the oxygen and the recycle stream and to so produce regenerated caustic,
• wherein the oxidizer tower further includes a recycling conduit that is configured to deliver the oxygen recycle stream from an upper vent opening of the oxidizer tower to a lower feed opening of the oxidizer tower, and
• wherein the oxygen recycle stream is substantially free of waste gases.