Combustion of Salted Waste Waters

The Sub-X® technology developed by SELAS-LINDE / T-THERMAL itself is used to treat salted waste waters.
Combustible pollutants are forward, if necessary with support fuel, over the downward firing main burner and burnt together with air.
The non-combustible, salted waste waters are injected underneath the main burner into the vertically structured adiabatic combustion chamber using atomiser nozzles.

The high combustion temperatures create a molten salt mass which flows downwards on the incombustible lining of the combustion chamber. This molten salt mass, is quenched in the quench tank, which is positioned directly underneath the combustion chamber. The hot flue gases are forwarded through an immersion pipe into the quench tank, where they are cooled to saturation temperature. The quench tank is also, at the same time, the pre-washing stage for the removal of acid flue gas components and solids such as salted dusts, for example. A salted waste water is discharged here.
The flue gases undergo fine purification to reach the corresponding emission limit values in subsequent scrubbing or filter stages.

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.
The adiabatic combustion chamber is positioned vertically and fired from the top down so that the molten salt mass can flow down freely. 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. In the Sub-X® quench tank the hot flue gases are quenched 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. The quench tank has an additional safety function to prevent the overheating of downstream plant parts if the water supply fails.

Example 1

HOVIONE, Loures

Thermal output:

7 MW

Capacity:

1,000 kg/h organic liquid residues with up to 2.5% sodium and potassium salts and up to 2% compounds containing iodine and chlorine

Use of heat:

5 t/h saturated steam (10 bar)

Flue gas purification:

2-stage treatment to remove dust

Product recovery:

155 kg/h NaI solution (8%-ig)

Emissions:

in line with EC Directive 94/67/EC

Scope of delivery:

Engineering, material delivery, commissioning monitoring

Example 2

UCB, Shanghai

Thermal output:

5.3 MW

Capacity:

3,000 kg/h aqueous residues with up to 5% sodium salts and sulphur
compounds 500 Nm³/h explosive waste gases (Zone 0)

Use of heat:

6 t/h saturated steam (10 bar)

Flue gas purification:

Dry absorption for dust separation

Scope of delivery:

Engineering, material delivery, commissioning monitoring

Example 3

CHEMINOVA, Lemvig

Thermal output:

3.5 MW

Capacity:

1,000 kg/h liquid residues with up to 30% inorganic salts, plus chlorine, phosphorus and nitrogen compounds
5,000 Nm³/h waste gases

Flue gas purification:

2-stage treatment to remove dust

Scope of delivery:

Engineering, material delivery, commissioning monitoring

Example 4

GUERBET, Lanester

Thermal output:

7 MW

Capacity:

2,000 kg/h liquid residues with up to 3% sodium salts plus iodine compounds

Flue gas purification:

2-stage treatment to remove dust

Scope of delivery:

turnkey