Waste Gas Static Incinerator
Although waste gas can be incinerated both in horizontal or vertical chambers, typical configuration is the vertical one.
The vertical chamber, sized for a 2 seconds flue gas retention and a temperature of around 850 – 950 °C, is internally lined with refractory bricks and insulating castable and is provided with burner connection on the bottom. Peepholes are provided to see burner operation with platforms and ladder for access to them and to the thermocouples.
Outside a personnel protection is provided and consists of annular air space and a perforated plate covered with mineral wool and a stainless steel sheet.
A self supporting stack internally lined with insulating castable is installed above the combustion chamber with air intakes at base for quenching gases coming from incinerator.
A burner of special design consists of a fuel gas start-up burner and a waste gas burner concentric to it.
The fuel gas burner is operating at high pressure with forced combustion air supplied by a fan. Excess air requested to keep operating temperature when burning waste gas is supplied by centrifugal fan with a thoroidal channel and multiple nozzles.
The combustion air is supplied with a centrifugal fan.
For safety, depending on the characteristics of waste gas, a flame arrestors can be installed on waste gas line to avoid any risk of backfire from the burner.
In case waste gas is containing significant amounts of water, a K.O. Drum can be provided to remove from the gas the excess of water in order to reduce fuel gas consumption.
A burner management system governs the automatic ignition of the burner, the flame supervision during operation with valves shut-off in the event of flame failure.
At start-up the chamber is heated to the minimum operating temperature with fuel gas. When the temperature is over the minimum set the waste gas can flow.
A temperature controller governs fuel-gas to minimum flame and opens secondary air to keep operating temperature in the chamber.
If the temperature increase over the set value a second controller opens dilution air damper to keep the requested value. Any variation in the composition or in flow of waste gas does not affect operation.
The flue gas at stack base is quenched with air flowing by natural draft.
Heat recovery from hot flue gases, installed in place of air quenching, can be supplied on demand as well as suitable flue gas treatment.
Liquid Waste Static Incinerator
Liquid Waste Static Incinerator consist of a horizontal cylindrical chamber equipped with a fuel burner auto modulating type with regulation according to the flue gas temperature at the chamber outlet.
The burner ignition occurs by means of a gas pilot burner with electrical ignition.
The protection equipment assures the fuel isolation in all the cases of flame extinction.
The liquid wastes can be only fed when the minimum temperature inside the chamber has been achieved and if the burner is ignited.
The inlet of liquid waste occurs by means of a lance located over the main burner.
The lance is atomized by means of compressed air or steam with nozzles of wide section in order to limit clogging possibility.
The chamber is normally sized for a 2 seconds flue gas retention and a temperature of around 850 – 950 °C.
As soon as minimum operating temperature has been achieved, a temperature switch allows the liquid waste inlet, while another temperature switch stops the burner and the waste feeding if temperature should exceed the foreseen limit.
A typical application, as the one shown in the next figures, is treatment of liquid waste coming from painting industry, in that case two recovery systems are provided.
The first system allows to heat thermal oil, which is used directly inside the factory, by means of a flue gas/oil heat exchanger coil.
The second system allows to heat combustion air by means of a heat exchanger flue gas/air, reducing the fuel gas consumption.
At the exit from combustion air heat exchanger flue gases are directly discharged to atmosphere and a suitable flue gas treatment can be provided, depending on the characteristics of liquid wastes.
