New Hardware and System Designs for Lime Recovery Kiln Chain Systems to Increase Efficiency and Reduce Maintenance, 2004 International Chemical Recovery Conference

Although many lime recovery kiln systems are equipped with external drying systems, the chain system remains the workhorse of the industry. With recent findings indicating higher fuel efficiency obtained with conventional chain system equipped kilns, the introduction of partial chain systems into external dryer equipped kilns to better control heat profile and transfer; new chain system hardware and chain system designs have evolved to increase overall heat transfer efficiency, control dust losses functioning with longer life and reduced maintenance.

In the past chain system maintenance including problems associated with chain hardware failure led to short term gains with sometimes long term headaches for both mill operations and maintenance personnel. If parts of a chain system fail and/or is not maintained over time, it continually loses efficiency. Chain system hardware suppliers realized these problems in the cement industry as long as 20 years ago and began efforts to bring innovative designs to that industry for longer life with less maintenance. With a proven record in cement, lime recovery kiln OEM’s and other system suppliers have begun to incorporate the new hardware into their designs. To accommodate the new styles while increasing efficiency, overall chain system designs have been modified as well. The most obvious change has been the utilization of insulated metallic lining plates in areas that were formerly lined with castable refractory. Other innovations include combination hanger/shackles for chain attachment and new chain link geometry to gain increased heat transfer surface area.

This paper will present an overview of these new chain system hardware designs and the use by chain system suppliers. General information from completed chain system retrofit projects at Kraft mills will be presented to document the application and results of this technology.