Treatment of an aqueous stream containing water-soluble inorganic sulfide compounds

Abstract

Abstract AN AQUEOUS STREAM CONTAINING A WATER-SOLUBLE, INORGANIC SULFIDE COMPOUND IS TREATED BY CONTACTNG THE AQUEOUS STREAM AND OXYGEN, IN AN AMOUNT SELECTED TO REACT LESS THAN 0.5 MOLE OF O2 PER MOLE OF SULFIDE COMPOUND, WITH A FIRST OXIDIZING CATALYST AT OXIDIZING CONDITIONS, INCLUDING A RELATIVELY LOW PRESSURE AND TEMPERATURE, SELECTED TO FORM AN EFFLUENT STREAM CONTAINING A WATER-SOLUBLE POLYSULFIDE; AND THEREAFTER BY CONTACTING THE POLYSULFIDE-CONTAINING EFFLUENT STREAM AND OXYGEN IN AN AMOUNT LESS THAN THE AMOUNT UTILIZED IN THE FIRST STEP, WITH A SECOND OXIDIZING CATALYST AT OXIDIZING CONDITIONS, INCLUDING A TEMPERATURE GREATER THAN OR EQUAL TO THE MELTING POINT OF SULFUR AND A PRESSURE SUFFICIENT TO MAINTAIN AT LEAST A PORTIN OF THE EFFLUENT STREAM IN THE LIQUID PHASE, SELECTED TO PRODUCE LIQUID SULFUR AND A SUBSTANTIALLY SULFIDE-FREE TREATED WATER STREAM. KEY FEATURES OF THE DISCLOSED METHOD INVOLVE THE USE OF A FIRST CATALYTIC OXIDATION STEP WHICH IS RUN AT RELATIVELY LOW TEMPERATURES AND PRESSURES TO PRODUCE POLYSULFIDE, COUPLED WITH A SECOND CATALYTIC OXIDATION STEP WHICH IS RUN AT RELATIVELY HIGH TEMPERATURES AND PRESSURES TO SELECTIVELY OXIDIZE THE POLYSULFIDE TO ELEMENTAL SULFUR, THEREBY PREVENTING THE DEPOSITION OF ELEMENTAL SULFUR ON THE CATALYST USED DURING THESE OXIDATION STEPS, WHILE SIMULTANEOUSLY MINIMIZING THE AMOUNT OF OXYGEN WHICH MUST BE SUPPLIED AT THE RELATIVELY HIGH PRESSURES.

Inventors

• 👤 Kenneth M Brown

Bibliographic Details