Process for reducing ringing in lime kilns
This application discloses exemplary processes and systems for reducing mineral ring accumulation in calcination kiln. The processes and systems comprise inserting non-condensable gases (“NCGs”) in a preheating zone of a calcination kiln, upstream of the burner end. The pre-heating zone may be characterized by temperatures ranging from 1,300° F. to 1,750° F. The system may desirably comprise a plenum for inserting the NCGs into the rotating calcination kiln at the pre-heating zone.
1. A process for reducing the accumulation of mid-kiln rings in an elongate rotary calcination kiln, the process comprising:
introducing non-condensable gases (NCGs) into an elongate rotary calcination kiln having a burner end at a first end of a kiln chamber and a feed end at a second end of the kiln chamber distally disposed from the first end, wherein the NCGs are introduced at an insertion location downstream of the burner end toward the feed end in the kiln chamber, wherein a temperature of the kiln chamber at the insertion location is in a range of 212° F. to 2,200° F., and
measuring a first temperature at a first location upstream of the insertion location toward the burner end of the kiln chamber, measuring a second temperature at a second location downstream of the insertion location toward the feed end of the kiln chamber, comparing the first temperature to the second temperature to calculate a temperature difference, adding a cooling agent with the NCGs at the insertion location when the temperature difference is less than 100° F.
2. The process of claim 1 further comprising not introducing the NCGs into the burner end of the elongate rotary calcination kiln.
3. The process of claim 1 further comprising introducing a compound at the insertion location with the NCGs, wherein the compound is selected from the group consisting of: air, ammonia, a sintering agent, urea, oxygen, re-circulated flue gas, and water vapor.
4. The process of claim 1 , wherein the temperature at the insertion location is between about 1,300° F. and about 1,750° F.
5. The process of claim 1 further comprising ceasing to add the cooling agent when the temperature difference is 100° F. or greater.
6. The process of claim 1 , wherein the insertion location comprises a pre-heating zone of the elongate rotary calcination kiln.
7. The process of claim 6 , wherein the NCGs are introduced at the insertion location via a plenum annularly disposed around the elongate rotary calcination kiln at the pre-heating zone.