Pressurized Fluidizedbed Combustion

Mixing an adsorbent (e.g, limestone) directly into the flu-idized bed in which coal is burned achieves direct sulfur dioxide control (see Figure 5.19.7). Fluidization is achieved via the combustion air that enters the base of the bed (Halstead 1992). Environmental engineers can apply this basic concept in several ways to meet the needs of chemical industries as well as power generation plants.

The potential advantages of fluidized-bed combustion are as follows:

Lower combustion temperature resulting in less fouling and corrosion and reduced NOx formations Fuel versatility including range of low-grade fuels, such as char from synthetic fuel processing

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- Water Steam

FIG. 5.19.7 Pressurized fluidized-bed combustion system.

- Water Steam

FIG. 5.19.7 Pressurized fluidized-bed combustion system.

Higher thermal efficiency including high heat release and heat transfer Waste solids in dry form

The potential disadvantages are as follows:

Large particulate loading in the flue gas Potentially large amounts of solid waste, which are SO2 absorbent.

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