CONTEXT

Hydrothermal treatments have been largely studied to destroy wastes. One limitation which is generally observed is the energy balance (especially for bacth reaction) because initiating the reaction implies  a high energy input. Thus reducing energy consumption is an aim to reduce exploitation costs.

TECHNICAL DESCRIPTION

This invention relates to a process for starting up a system intended for the oxidation of organic bodies present in an aqueous effluent and a start-up unit intended for implementation of the said method.

The said system comprises a tubular body divided in three zones:

– A first zone (16) after the inlet (12) where the aqueous effluent can be injected at a pressure P1 (>= the critical pressure of the said aqueous effluent)

– a second zone into which an oxidising composition is capable of being injected,

– an outlet;

A feature of the start-up method lies in the manner of producing the preheating thermal energy necessary for degradation of the organic bodies in the aqueous effluent through a combustible mixture which is capable of easily reacting at an intermediate temperature T1.

The process takes place following: a first quantity of thermal energy Q1, capable of raising the temperature of the fluid passing through the said tubular body from an initial temperature to a higher intermediate temperature T1, is provided to the first zone and it is injected into the said tubular body at the said pressure P1, between the said inlet and the said first zone, a definite quantity of a combustible mixture capable of reacting at a temperature lower than the oxidation temperature of the organic bodies and of which at least a first part is capable of reacting at the said intermediate temperature T1 to provide a second quantity of thermal energy Q2 raising the temperature of the said fluid to a reaction temperature T2 in such a way that injection of the said oxidising composition into the said second zone brings about at least the reaction of a second part of the said combustible mixture providing a third quantity of energy Q3 at the said outlet of the said tubular body, a fraction of the said third quantity of energy Q3 being capable of being applied to the said first zone of the said tubular body to raise the temperature of the fluid passing through it at least from the said initial temperature to the said intermediate temperature T1. When Q3 equals Q1 the preheating operation is stopped.

INNOVATIVE ASPECTS -BENEFITS

– no longer necessary to use major associated preheating means to raise the temperature of the aqueous effluent to the said temperature T2,

– preheating means size may be advantageously reduced if Q2= 40 to 80% ( Q1 +Q2),

– reduced exploitation costs  and competitive with state of the technologies,

– low cost changes in conventional equipment.

INDUSTRIAL APPLICATIONS

Any hydrothermal treatment

DEVELOPMENT STAGE

Pilot scale 100kg/h Examples of applications may be provided on demand.

For further information, please contact us (Ref 84873-01)