Wet oxidizing process of waste soda

In the wet oxidation of an alkali waste liquid obtained by contacting an aqueous alkali and a hydrocarbon fluid containing acidic substances mainly comprising hydrogen sulfide and carbon dioxide, a process comprising:

• bringing an alkali waste liquid into contact with excess molecular oxygen so as to oxidize said alkali waste liquid at a temperature of from 150.degree. C. to 350.degree. C. and at a pressure of from 15 atmospheres to 100 atmospheres under conditions in which said alkali waste liquid can exist in liquid phase, said alkali waste liquid being obtained by contacting an aqueous alkali and a hydrocarbon fluid containing acidic substances mainly comprising hydrogen sulfide and carbon dioxide so as to absorb said acidic substances;
• reducing the pressure of a mixture of the oxidized alkali waste liquid and surplus gas resulting from the oxidation of said alkali waste liquid, to a value in the range from 0.1 atm to 5 atm by means of a pressure reducing valve;
• separating said mixture of the oxidized alkali waste liquid and surplus gas into a gas phase portion and a liquid phase portion in a gas-liquid separation tank after reducing the pressure;
• cooling at least a part of said separated liquid phase portion to a temperature in the range from 10.degree. C. to 80.degree. C. to form a cooled liquid phase portion;
• and
• contacting at least a part of said cooled liquid phase portion with said gas phase portion so as to cool said gas phase portion.

In the wet oxidation of an alkali waste liquid obtained by contacting an aqueous alkali and a hydrocarbon fluid containing acidic substances mainly comprising hydrogen sulfide and carbon dioxide, a process comprising:

• bringing an alkali waste liquid into contact with excess molecular oxygen so as to oxidize said alkali waste liquid at a temperature of from 150.degree. C. to 350.degree. C. and at a pressure of from 15 atmospheres to 100 atmospheres under conditions in which said alkali waste liquid can exist in liquid phase, said alkali waste liquid being obtained by contacting an aqueous alkali and a hydrocarbon fluid containing acidic substances mainly comprising hydrogen sulfide and carbon dioxide so as to absorb said acidic substances;
• reducing the pressure of a mixture of the oxidized alkali waste liquid and surplus gas resulting from the oxidation of said alkali waste liquid, to a value in the range from 0.1 atm to 5 atm by means of a pressure reducing valve;
• separating said mixture of the oxidized alkali waste liquid and surplus gas into a gas phase portion and a liquid phase portion in a gas-liquid separation tank after reducing the pressure;
• cooling at least a part of said separated liquid phase to a temperature in the range from 10.degree. C. to 80.degree. C. to form a cooled liquid phase portion;
• and
• recycling at least a part of said cooled liquid phase portion into said gas-liquid separation tank and, in the same tank, bringing the at least part of the cooled liquid phase portion into gas-liquid contact with the gas phase portion so as to cool said gas phase portion.

In the wet oxidation of an alkali waste liquid obtained by contacting an aqueous alkali and a hydrocarbon fluid containing acidic substances mainly comprising hydrogen sulfide and carbon dioxide, a process comprising:

• bringing an alkali waste liquid into contact with excess molecular oxygen so as to oxidize said alkali waste liquid at a temperature of from 150.degree. C. to 350.degree. C. and at a pressure of from 15 atmospheres to 100 atmospheres under conditions in which said alkali waste liquid can exist in liquid phase, said alkali waste liquid being obtained by contacting an aqueous alkali and a hydrocarbon fluid containing acidic substances mainly comprising hydrogen sulfide and carbon dioxide so as to absorb said acidic substances;
• reducing the pressure of a mixture of the oxidized alkali waste liquid and surplus gas resulting from the oxidation of said alkali waste liquid, to a value in the range from 0.1 atm to 5 atm by means of a pressure reducing valve;
• separating said mixture of the oxidized alkali waste liquid and the surplus gas into a gas phase portion and a liquid phase portion in a gas-liquid separation tank after reducing the pressure;
• and
• cooling at least a part of said separated liquid phase portion to a temperature in the range from 10.degree. C. to 80.degree. C. to form a cooled liquid phase portion, wherein said reducing the pressure provides a pressure-reduced mixture having a temperature of from about 100.degree. C. to about 130.degree. C., and said gas phase portion and said liquid phase portion are separated without substantial cooling of the pressure-reduced mixture after pressure reduction and before separation of the gas and liquid phase portions.