High-temperature dust collection is common in furnaces, kilns, boilers, dryers, foundries and thermal processing plants. Cyclone dust collectors are well suited to these applications because they can handle hot, dust-laden gas without the temperature limitations associated with fabric or cartridge filters.

However, designing a cyclone for high-temperature service requires attention to more than airflow and dust load.

Material Selection for High-Temperature Cyclone Dust Collectors

The cyclone material must withstand the continuous operating temperature, peak temperature, corrosion and particle erosion expected in the process.

Depending on the application, the construction may use carbon steel, stainless steel, heat-resistant alloys or abrasion-resistant sections.

Refractory Lining for High-Temperature Cyclones

For very high-temperature gas streams, a refractory-lined cyclone may be required to protect the metal shell from excessive heat.

The refractory should be selected for the operating temperature and dust characteristics. Its design must also accommodate thermal expansion during repeated heating and cooling cycles.

Thermal Expansion in Cyclone Dust Collector Design

High-temperature operation causes the cyclone shell, ducts and supports to expand. If this movement is not considered, thermal stresses can develop at connections and supports.

The design should therefore include suitable expansion allowances and flexible connections wherever required.

Inlet Velocity, Efficiency and Erosion

Cyclone inlet velocity affects both particle separation and pressure drop. Excessive velocity can increase turbulence, fan power and erosion, particularly when the dust contains abrasive particles.

The design should balance collection efficiency, pressure drop and wear resistance according to the process conditions.

Dust Discharge and Hopper Design

Hot dust must be discharged reliably without excessive air leakage into the cyclone.

Rotary airlocks, flap valves or other suitable discharge arrangements may be used depending on the application. The discharge equipment should also be rated for the actual dust temperature.

Pressure Drop and Downstream Equipment

Cyclone pressure drop must be considered along with ductwork, downstream filters, fans and stacks.

If a cyclone is followed by a fabric or cartridge filter, the cyclone outlet temperature must also remain within the downstream equipment’s operating limits.

Key Design Parameters

Conclusion

A reliable high-temperature cyclone dust collector requires coordinated consideration of temperature, materials, thermal expansion, velocity, erosion and dust discharge. Proper design allows the cyclone to provide effective primary dust separation while protecting downstream filtration equipment.