Preparation & Handling of Alternative Fuels (AF)
Waste for Cement Kiln Firing – Examples
Alternative Fuel Preparation – Why?
- Alternative fuel preparation is required to change the waste’s physical properties.
- A homogeneous alternative fuel allows a higher substitution rate.
Alternative Fuel Preparation – How?
Solid Waste – Example Waste Tyres
Solid Waste – Cost of Shredding
Solid Alternative Fuel Installation – General Flowsheet
Size Classification of Solid AFs
Storage & Extraction of Alternative Fuels
Storage & Extraction – Fine Solids
Storage & Extraction – Lump Fuel
Pneumatic Kiln Feeding
-Separation of oversizes & metals
-Introduction to pneumatic transport through a rotary valve
-Pneumatic transport as short and straight as possible.
-Injection through a pipe, parallel and on top of the main burner, or a central channel if available.
Gravimetric Kiln Feeding
- Actuated double or tripple pendulum flap gate
- Actuated shut-off gate(s)
-Protection of AFR feeding system during upset kiln operation.
-De-coupling of AFR feeding system.
Liquid AF Installation – General Flowsheet
- Discharge filter is mandatory
(for pump protection and to avoid atomizer blockage)
- Standard solution: Double basket filter (manual cleaning)
- Screen size depends on fuel specification:
Recommended 1.5 mm, max. 5 mm (for good atomization)
Storage & Mixing of Alternative Fuel in Cement industry
- Minimum 2 tanks (one for kiln feed, one for new deliveries)
- Vertical installation
- Conical or rounded bottom
- Continuous mixing with mechanical agitator (circulating flow only second choice)
- Retention wall
- Fire protection (water and foam)
Kiln Feeding Pumps for Liquid AF
- 2 Pumps in parallel (one stand by)
- Spec.: Particles (wear), continuous flow (no pulsations) and high pressure
- Standard pumps for liquid AF:
Screw Pole Pump
-not suited for very abrasive solids and solvents
-suited for solvents
Flow Measurement & Injection
Coriolis Type Flow Meter
- no wear parts, no flow restrictions
- simultaneous measurement:
-flow rate [m3/h]
-Density [kg/m3]- correlation to water content
- atomization with pressurized air or steam
- design of atomizer depends on max. particle size
for more information please contact us