Ace Furnace Consulting Ltd
INCINERATION | COMBUSTION | HEAT TREATMENT |ENERGY CONVERSION
CFD Example 1 Add-On Incinerator Secondary Combustion Furnace
The furnace unit comprises a vertical cylinder in two parts:
The lower part is a cyclonic mixing section; fumes from the primary incinerator chamber enter the rectangular port. Two tangential oil burners are fitted to the round ports creating powerful mixing and heating of the incoming gases.
Cold air is premixed with the incoming gases on ports in the connecting duct (not shown) to ensure a minimum of 6% residual oxygen in the final mixed gas at the exhaust.
The lower part of the chamber is lined with castable refractory backed by insulation board.
The upper part of the furnace (the residence chamber) is designed as a double skinned metal construction with a stainless steel inner liner and outer case. The intervening space is packed with low thermal mass ceramic fibre insulation.
Not shown in the picture is an upward facing air blown ejector nozzle to create an upward flow at all times and low pressure at the inlet.
The CFD modelling was intended to test:
1. That the chosen dimensions would give 2s or more
residence time at the defined gas flow rates.
2. That gas mixing would be effective giving an even
3. That the burner output selection was adequate for the
predicted exhaust flow and temperature from the primary
4. That gas buoyancy and the action of the ejector would
maintain a negative pressure with respect to atmosphere
at the dirty gas inlet.