TITLE : CYCLONIC TYRE INCINERATOR SIMULATION

DETAILS :

• The flow in the tyre-burning furnace was simulated in order to predict velocity, pressure and temperature for steady-state operating conditions.
• Of particular interest was the mixing pattern, known to influence the combustion efficiency and gas composition at outlet greatly .
• Tyres are fed to the hearth at the furnace periphery and incinerated, after which the solid residue is disposed of via a quench tank at the centre of the furnace.

NOTES :

• The key feature of the gas flow is that it swirls due to the injection of air by angled jets, which are located around the refractory wall, at a level just below the sloping furnace roof.
• Cool air is drawn downward from the jets at the periphery of the furnace, and travels across the hearth, where it oxidises the tyres. Combustion products then travel upward as a swirling plume ensuring effective mixing and combustion.

DISCUSSION :

• The flow predictions matched well both quantitatively with pressure and temperature, and qualitatively with the experience of furnace operators.
• The study also provided insight into the mechanics of fluid mixing which was not available empirically.

1. Layout (half section),
   
2. Iso-surface of pressure indicating the shape of the cyclone above the quench tank,
   
3. Streamlines illustrating the path of the combustion products from the furnace hearth to the outlet at the top of the furnace,
   
4. Iso-surface of temperature giving the shape of the thermal products stream,
   
5. Iso-surface of turbulent viscosity highlighting a region of turbulence in the vicinity of the furnace roof.