Rotary Kiln Emissions Control: Key Design Factors
Can a Rotary Kiln Help Meet Emissions Requirements?
A rotary kiln can form the primary thermal-treatment stage of a system designed to meet project-specific emissions limits, but the kiln alone does not guarantee compliance. Performance depends on feed characterization, combustion temperature, residence time, mixing, oxygen control, secondary combustion, gas cooling, air-pollution-control equipment, monitoring and source testing.
Where Rotary Kiln Systems Are Used
Rotary kilns may be configured for selected municipal, industrial or sludge waste streams after their composition, heating value, moisture, ash and hazardous constituents are evaluated. HiTemp also designs other equipment for solvent-bearing exhaust and soil-vapor-extraction applications, but those gas streams are generally treated using purpose-selected catalytic oxidizers or thermal oxidizers.
Rotary Kiln Design Features
Depending on the application, HiTemp rotary kiln systems can incorporate:
- Modular components selected for transport and site installation
- Controls designed for integration with project-specific computer or plant-control systems
- Access for routine inspection, maintenance and component replacement
- Secondary combustion and air-pollution-control equipment selected for the expected pollutants
- Optional heat recovery for steam, hot water or electricity when included in the complete plant design
Customers with preferred component suppliers can ask those suppliers to coordinate with HiTemp during development of the complete system.
Combustion and Emissions-Control Conditions
The design described on this page uses a nominal kiln operating temperature of 800°C, refractory rated up to 1,400°C and a secondary-chamber design temperature of 1,000°C. These figures are not universal operating requirements. Final temperatures, residence times and control setpoints must be established for the actual feed material, required destruction efficiency and permit conditions.
Secondary combustion can support further oxidation of carbon monoxide and organic compounds remaining in the kiln exhaust. Actual emissions performance must be confirmed through properly designed monitoring and source testing; temperature alone does not demonstrate complete combustion or regulatory compliance.
Information Needed for System Selection
- Representative feed composition and physical form
- Hourly and daily throughput range
- Moisture, ash and heating value
- Target destruction efficiency and applicable emissions limits
- Available utilities, site conditions and heat-recovery goals
- Required monitoring, testing and residue-management provisions
Review HiTemp's industrial rotary kiln systems or use the contact form to discuss project-specific requirements.