Why do circulating fluidized bed boilers have a large heat storage capacity?
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Why do circulating fluidized bed boilers have a large heat storage capacity?
Within a circulating fluidized bed, the vertical height can be divided into a dense phase bed layer and a dilute phase region; the dense phase bed layer operates in either a bubbling bed or a turbulent bed state. The bulk of the material in a circulating fluidized bed consists of hot inert gas along with bed material; combustible substances make up only a very small fraction of this mixture. This hot bed material serves as a heat source for the coal particles. During the heating process, the heat absorbed by it accounts for only a few thousandths of the total heat capacity of the bed layer. Coal particles can burn in about 10 seconds, so this has little impact on the bed temperature. In other words, circulating fluidized bed boilers possess a high heat storage capacity.