Feeding Systems

The waste feed system introduces refuse into the incinerator from the tipping floor or pit (or, in case of an RDF fuel plant, from the preprocessing facilities). Of the two main types of refuse feed systems, a continuous loading system contributes to more efficient combustion than batch loading because it allows a more even flow of fuel.

In batch loading, the waste is introduced by a front-end loader that shoves the garbage, in discrete batches, into the furnace. The batch method adversely affects combustion since each load pushed into the incinerator causes a temporary overload, depleting available oxygen and creating poor combustion conditions. Variations in temperature due to air leaks into the furnace have an adverse impact on refractory material and increase air emissions. In small plants with floor dumps and stored MSW, feeding is accomplished on a semibatch basis by rams which push MSW directly to the furnace at 6- to 10-min cycles.

With continuous loading, a traveling bridge crane equipped with a grapple deposits waste, a few tons at a time, into the top of an inclined chute. The garbage moves down the chute onto the drying zone of a moving grate allowing for continuous introduction of waste into the furnace. RDF is typically continuously fed into the furnace.

A basic requirement of the continuous loading system is to keep the charging hopper to the furnace fired at all times and to protect against burnbacks of fire from the combustion area through the chute to the storage pit area.

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