Combustion of Halogenated Pollutants

Liquid and/or gaseous halogenated organic pollutants are oxidised in an adiabatic combustion chamber at high temperatures, with formation of the corresponding halogen acids. The hot flue gases are cooled in a steam generator and then quenched to saturation temperature.

In a subsequent absorption level, the halogen hydrogens contained in the flow of flue gas are rinsed with water and recovered as product acid. The flue gases undergo fine purification to reach the corresponding emission limit values in a caustic treatment following the absorption stage.

The almost complete, highly turbulent combustion at high temperatures, with the appropriate residence time, means that the level of destruction of the pollutants is very high. Both horizontal and vertical adiabatic combustion chambers are used.
The incombustible lining is specially selected to take into account the aggressive flue gas atmosphere and possible dewpoint corrosion of the combustion chamber sheet metal wall.

If possible in terms of process technology and if economically viable, waste heat utilisation is also included, through steam generation in a waste heat boiler, for example. After this, the hot flue gases are quenched immediately within milliseconds, which suppresses the back formation of dioxins and furans.

Because the control of the combustion process has been optimised, there is a high rate of conversion of the halogenated hydrocarbons to the corresponding halogen hydrogens, which minimises free halogens. Product acids can be recovered in very high concentrations.

Example 1

ICI Wilhelmshaven

Thermal output:

12.3 MW

Capacity:

7,962 kg/h liquid and gaseous chlorinated hydrocarbons

Use of heat:

12.3 t/h saturated steam

Flue gas purification:

2-stage treatment

Product recovery:

1,600 kg/h hydrochloric acid (10%)

Emissions:

in line with TA Luft regulations

Scope of delivery:

Engineering, material delivery, commissioning monitoring

Example 2

3M, Antwerp

Thermal output:

2 MW

Capacity:

288 kg/h waste gas containing fluorine
356 Nm³/h exhaust air

Flue gas purification:

Immersion quenching and subsequent 3-stage treatment

Product recovery:

1,060 kg/h hydrofluoric acid (15%)

Scope of delivery:

Engineering, material delivery, commissioning monitoring