Method for starting up a system for treating waste by hydrothermal oxidation

Process for starting up a system intended for the oxidation of organic bodies present in an aqueous effluent, said system comprising a tubular body (10) into the inlet (12) of which said aqueous effluent can be injected at a pressure P1 corresponding to at least the critical pressure of said aqueous effluent, said tubular body (10) having a first zone (16) extending said inlet (12), a second zone (4) into which an oxidising composition can be injected, and an outlet (14),

• said process comprising the steps of:
• providing to said first zone (16) of said tubular body (10), a first quantity of thermal energy Q1 capable of raising the temperature of a aqueous effuent passing through the tubular body (10) from an initial temperature to a higher intermediate temperature T1;
• providing a definite quantity of a combustible mixture capable of reacting at a temperature lower than an oxidation temperature of the organic bodies and of which at least a first part can react at said intermediate temperature T1 to provide a second quantity of thermal energy Q2 raising the temperature of said fluid to a reaction temperature T2 and is injected into said tubular body (10) at said pressure P1 between said inlet (12) and said zone (16) of said tubular body (10) in such a way that injection of said oxidising composition into said second zone (18) brings about reaction of at least a second part of said combustible mixture providing a third quantity of energy Q3 at said outlet (14) from said tubular body (10), a fraction of said third quantity of energy Q3 being applied to said first zone (16) of said tubular body (10) to raise the temperature of the fluid passing through it at least from said initial temperature to said intermediate temperature T1;
• stopping providing of said first quantity of energy Q1 to said first zone (16) of said tubular body (10) when said fraction of said third quantity of energy Q3 is equal to at least Q1;
• and
• stopping an injection of said combustible mixture and injecting said aqueous effluent at the inlet (12) to said tubular body (10) when said fraction of said third quantity of energy Q3 is equal to at least the sum of Q1 and Q2 such as to raise the temperature of the fluid passing through said tubular body (10) from said initial temperature to said reaction temperature T2.