326 Separator Components

Other applications requiring excellent toughness and erosion resistance include internal components of cyclones that separate solids.

Engineers in a major U.S. city evaluated CFCCs vortex finders in a waste separating cyclone (Fig. 3.11). The cyclone separates combustible from noncom-bustable trash. A downstream incinerator converts the combustable trash to steam for plant use and generation of electricity. Trash, mixed with sand to facilitate separation, is fed at high-speed into the heated cyclone. The cyclone has a centrally located hollow tube, called a vortex finder. Sand and trash rapidly wear the metal superalloy vortex finder. Panels of CFCC are being evaluated to replace the metal because of their superior erosion and high-temperature resistance. They also resist the corrosive atmosphere that contains various acids, chlorides, sulfides, trash, and sand.

City engineers, teamed with Honeywell and Foster Wheeler engineers, tested CFCCs in this rigorous application. CFCCs retained 100% of their original properties after 2500 h of operation. This included a 300-h startup followed by 2200 h of operation at 900°C (1650°F). The erosion rate of the 4 x 8 ft CFCC panels is ^ that of the superalloy metal panels.

The reduced maintenance and downtime saves money as well as enabling increased operating temperatures, more complete combustion, and less landfilling

Particle

Separator

Schematic

FIGURE 3.11 Erosion resistance of CFCCs improve durability of this cyclone separator.

CFCC Resists Erosion

Particle

Separator

Schematic

CFCC Resists Erosion

FIGURE 3.11 Erosion resistance of CFCCs improve durability of this cyclone separator.

of trash. Maintenance is particularly costly because the cyclone is located 60 ft above ground, requiring scaffolding, adding to downtime. The lighter panels of CFCC ease handling and installation. CFCCs enable reduced maintenance, a higher operating temperature, increased efficiency, reduced energy use, and produce less pollution. Higher operating temperatures also allow hotter air to reach the heat exchanger, increasing steam and energy production.

Other solid-solid separation processes also need erosion-resistant parts. Using industries include chemical processing, power generation, and others. The successful use of CFCCs in municipal waste incinerators make them candidates for applications in these other industries.

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