Incinerators
Incineration in Modern Waste Management
Incineration plays a vital role in integrated waste management strategies. It significantly reduces the volume of waste sent to landfill, enables the recovery and reuse of metals and other valuable materials, and supplies heat that can be converted into electricity in waste-to-energy (WtE) plants.
Components and Function of Incinerators
All incinerators include at least one combustion chamber, a controlled air supply system, and a flue gas treatment unit to minimise the release of hazardous emissions. While the basic components are shared, incinerator designs vary in how waste is introduced and how it moves through the combustion system. The ideal design depends on the waste's physical state, chemical composition and volume.
Static Hearth Incinerators
Static hearth incinerators are typically used for small waste volumes. These units feature a single opening for both waste insertion and ash removal. They are simple, compact and well-suited for batch operations.
Moving Grate Incinerators
For larger volumes, moving grate incinerators are more efficient. These incorporate mechanical systems-such as rollers, rockers, or conveyor belts-that agitate and advance the waste through the furnace. Grates also allow ash and non-combustible residues to fall into collection chambers below, facilitating continuous operation and improved combustion.
Rotary Kiln Incinerators
Rotary kilns provide a dynamic solution by rotating the combustion chamber itself. These units consist of a refractory-lined, slightly inclined drum. Waste enters at the higher end and is gradually burned as it moves downward. The rotation ensures uniform heat distribution and effective processing of solid, liquid and sludge waste, including hazardous and medical materials. Rotary kilns are designed for continuous, high-capacity operation.
Fluidised Bed Incinerators
A fluidised bed incinerator features no moving mechanical parts. It uses a vertical refractory-lined chamber filled with fine sand. Preheated air is blown from below, suspending the sand particles in a fluid-like state. Waste is introduced from above and combusts efficiently at lower temperatures. This system is suitable for low-density, homogeneous waste and can also support alternative thermal treatments like gasification and pyrolysis.