We wish to know about oxygen enrichment in the cement kilns/precalciners. Please brief us about the expected merits and demerits. Are there any cement plants using this technique? If yes, then why is it not used commercially on regular basis in most of the cement plants.

This is a big question! The merit is that the output of the kiln can be boosted by up to 15 per cent, the demerit is that the oxygen is expensive and therefore the costs of producing the additional clinker are higher. If market demand exists with good prices for cement then oxygen enrichment can be a good option. There are a number of kilns in the USA using oxygen enrichment of either the main burner or the precalciner. It is worth noting that CEMEX USA consider oxygen enrichment of precalciner firing to be their technology for which they have lodged a patent. You can find papers on oxygen enrichment in the proceedings of the IEEE conference in Vancouver 2001.

How can we solve the nose ring formation at the kiln? Any help much appreciated.

The most likely solution will be to adjust the main burner of the kiln either by changing the position in the kiln by pushing the burner in or pulling it out a little. Alternatively adjustment of the axial and radial air settings might solve the problem. All these adjustments should be done cautiously and one at a time at sufficient intervals to fully evaluate the effects of the adjustments. There is potential to adversely affect the clinker quality or damage the refractory lining therefore only make small changes before evaluating the effects.