Abstract: Systems and methods are provided for the treatment of caustic wastewater. Specifically, systems and methods are provided for combining refinery spent caustic and ethylene spent caustic solutions and treating the combined spent caustic mixture using a wet air oxidation process.

Abstract: Systems and methods are provided for the treatment of caustic wastewater. Specifically, systems and methods are provided for combining refinery spent caustic and ethylene spent caustic solutions and treating the combined spent caustic mixture using a wet air oxidation process.

Abstract: Systems and methods are provided for the treatment of caustic wastewater. Specifically, systems and methods are provided for combining refinery spent caustic and ethylene spent caustic solutions and treating the combined spent caustic mixture using a wet air oxidation process.

Abstract: A wet oxidation process is used to control the concentration of reduced sulfur compounds from a viscose process. The wet oxidation process oxidizes the reduced sulfur compounds to convert such reduced sulfur compounds to an alkali sulfate and/or thiosulfate species. The alkali sulfate stream is recycled to the viscose process. Oxidation is performed under elevated temperature and pressure conditions such that the offgas has an oxygen concentration of between about 2% to 18% and the alkali sulfate stream has a pH of about 2 to 10.

Abstract: Systems and methods are provided for the treatment of caustic wastewater. Specifically, systems and methods are provided for combining refinery spent caustic and ethylene spent caustic solutions and treating the combined spent caustic mixture using a wet air oxidation process.

Abstract: An apparatus for mixing pressurized air with pressurized waste liquor at the inlet of a wet oxidation system heat exchanger device is disclosed. The apparatus is a T-shaped piping member with an inline first inlet and outlet and a second inlet oriented at about a right angle to said inline first inlet. The outlet is connected to an inlet tube of a tube and shell heat exchanger. A conduit supplies a pressurized waste liquor stream to the piping member through the second inlet. An oxygen-containing gas supply conduit, with circumferential sealing means, extends from exterior the T-shaped member, through the first inlet and terminates at a point beyond the intersection of the first and second inlets. The circumferential sealing means seals to the first inlet. The liquor entering the T-shaped member is heated to a selected elevated temperature prior to contacting a pressurized oxygen-containing gas supplied from the gas supply conduit.

Abstract: This is a process for wet oxidation of an ammonium salt containing waste liquor which prevents plugging of the vapor-carrying lines of the wet oxidation system. The vapor-carrying lines are maintained in an unobstructed condition by adding sufficient liquid water to dissolve condensed ammonium salt which can plug these lines. This provides for safe operation of the wet oxidation system.

Abstract: The invention is a process for starting up a wet oxidation system using essentially pure oxygen for oxidation of a concentrated wastewater. Flow of startup water and air is established through the wet oxidation system at an elevated temperature and pressure. An incremental increase in flow of oxygen and wastewater to the system commences while simultaneously an incremental decrease in flow of startup water and air occurs, raising system temperature in a controlled fashion. The incremental changes in flows are repeated until the wastewater and pure oxygen have reached about 100 percent of selected operating flows, the startup water and air flows have decreased to zero, and the system has attained the selected operating temperature, while maintaining a selected oxygen residual in the offgases.

Abstract: A process is disclosed which limits the corrosion of the materials of construction of a wet oxidation system treating wastewaters. The process is particularly useful in the wet oxidation treatment of ammonium sulfate containing wastes such as acrylonitrile wastewaters. The wastewater is mixed with an oxygen containing gas such that a substantial residual oxygen gas concentration is maintained from before the stream-gas mixture is heated for wet oxidation until after the oxidized stream-gas mixture is cooled and separated. Preferably, in the treatment of acrylonitrile waste water the shutdown procedure comprises cooling said waste stream by introducing an aqueous liquid substantially free of organic impurities and containing a basic material.

Abstract: A method for starting up and controlling the temperature of a wet oxidation process in which a heat exchanger employing superheated steam is used to initially heat a waste stream introduced into a wet oxidation reaction vessel for start up and then to subsequently adjust the temperature of the waste stream, after it is preheated by the effluent from the reaction vessel, to a level suitable to maintain steady state operation of the reaction vessel.

Abstract: A method for operating a continuous wet oxidation system for destroying cyanide in caustic cyanide and metal wastes which scale upon heating. Raw waste is introduced into the wet oxidation reactor without heating while a mixture of heated dilution water and oxygen containing gas is introduced into the reactor by a separate inlet. The reactor is fitted with a pair of valved effluent lines and corresponding valved lines for introducing dilute mineral acid into each effluent line at system pressure. Oxidized effluent and offgases exit through a first effluent line while dilute mineral acid flows through a second effluent line into the reactor to prevent scale buildup. Periodically the flows are alternated such that oxidized effluent and offgases exit through the second effluent line and dilute mineral acid flows through the first effluent line into the reactor to remove scale. The oxidized effluent and offgases are then cooled and separated.

Abstract: A process for treating thiosulfate containing liquors such as coke oven gas scrubbing liquors by first adding acid, preferably sulfuric acid, to convert thiosulfate to elemental sulfur and bisulfite, separating and removing the elemental sulfur, and subjecting the remaining liquor to wet oxidation.

Abstract: A process and apparatus for treating thiosulfate containing liquors such as coke oven gas scrubbing liquors in two stages of wet oxidation with intermediate removal of elemental sulfur. Mild oxidation conditions in the first stage results in conversion of thiosulfate sulfur to elemental sulfur, which is removed prior to second stage wet oxidation of the liquors to substantially reduce the liquor oxygen demand.