25 May 2012

Modern, Efficient Pre-heater Rotary Kilns

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We produce lime on two modern and efficient pre-heater rotary kilns. Our kiln system is fully automated and computer-operated which allows us to produce the highest quality lime in the industry. Combined with our product sizing, handling, and storage system we are able to segregate a variety of lime products in different sizes and chemistries. We can supply the specific lime you need for your application.

  • Large Pebble Lime
  • Midsize Pebble Lime
  • Granular Lime
  • Ground Lime
  • Low Sulfur Grade Lime
  • Low Carbon or AOD Grade Lime

Process Overview

Limestone is fed into the kiln stone bin by conveying equipment from our on-site quarry. Gravity feeds stone from the bin through chutes into the pre-heater. As hot gas from kiln fuel combustion is drawn through the pre-heater, heat is transferred to the stone to start the calcination process. Calcination is the process by which limestone is heated to chemically convert the stone to lime. Stone and fuel run countercurrent to each other with stone originating on one end and exiting the other end as lime. Kiln fuel is combusted on the lime discharge end of the kiln and hot gases are exhausted on the end of the kiln where the stone enters the process.

After heating and partial calcining in the pre-heater, the stone is discharged by a hydraulic ram to the pre-heater discharge opening. Gravity causes the stone to flow from the pre-heater, through the transfer chute, into the kiln. The high temperatures found in the kiln complete the calcination process that began in the pre-heater.

Through calcination the limestone has been converted to burnt lime. Lime gravity flows from the kiln into the cooler where a bed of hot lime is formed. Ambient air is blown from louvers at the bottom of the bed through the bed of hot lime. As the hot lime cools the incoming ambient air, which becomes combustion air, is heated which increases the efficiency of the process.

The benefits of the pre-heater rotary kiln are in the high recovery of heat throughout the system. Heat that would typically be wasted is used to pre-heat stone and combustion air to make a highly efficient process. Other benefits include lower SOx and NOx emissions to the environment, reduced fuel consumption, and superior product quality.

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