November/14/2006
10 tips on Waste and RDF usage in Cement Kilns

The Brazilian residue co-processing market is currently undergoing a great expansion. Cement groups are investing great sums of money to take advantage of this growth and, still, reduce significantly the operational costs.

Nevertheless the use of waste fuels on cement kilns requires some additional cares. Here are some tips:

1. Residues, in general, are not homogeneous. It’s necessary to get used to it.



2. The amount and kind of residue can change along with the market. Long term contracts are rare. The handling and combustion systems should be flexible enough to absorb such changes.



3. Usually wastes have a great amount of ashes (that affect the clinker saturation) and/or great amount of water (that affects the flame temperature and the exhaust capacity).



4. Be aware of contaminants (specially chlorine, sulfur and fluoride) that can harm the kiln operation.



5. Dangerous wastes (that require incineration) should be injected through the main burner. Hard to handle residues should be introduced preferable either through the smoke chamber or calciner.



6. Pay attention to the pneumatic conveying: oil and moisture can cause clogging on the transport line. The compatibility with the conveying must be verified.



7. Bucket elevators can cost less on the implementation, but can cause more headaches during kiln operation.



8. For the injection of solid waste fuels trough the main burner, one must give preference for the use of residues with less than 10 mm in length, given the low availability of space for the pneumatic conveying and short residence time.



9. Waste handling systems rarely operate without some kind of supervision. Periodic inspections are more frequent than one can imagine.



10. Finally one must plan before using residues. Visit to plants that already use your kind of waste as alternative fuel is highly recommended, as well as reading our article about the use of waste fuel in the cement industry.

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Industrial combustion program

Cement and Lime

10 tips on Waste usage in Cement Kilns

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