Integrated lime kilm process

Abstract

A process and system for recovering waste heat from a kiln used for lime or cement production. The system unifies the kiln, a waste heat recovery and power generation circuit and a dry scrubber for scrubbing the pollutants from the kiln offgas. Essentially, the system employs the boiler component of the waste heat recovery and power generation circuit as a heat exchanger to recover the waste heat from the kiln, which is used to drive the steam turbines. The heat absorption from the latter stage lowers the temperature of the kiln offgas sufficiently for optimum performance from the scrubber. The presence of lime particles in the offgas effectively protects the boiler tube surfaces from corrosion which would occur at optimum scrubber temperatures, and subsequently provides the lime required as a scrubbing medium for the dry scrubber. Further, the efficient scrubbing allows for the use of any fuel for firing the kiln inclusive of high sulphur content compounds. A process for effecting the technology is also provided.

1 . A system for recovery of thermal energy from a kiln for power generation, comprising:
 a kiln;   a waste heat recovery circuit including a boiler and a steam turbine, said boiler for receiving offgas from said kiln and generating steam for said turbine; and   a dry scrubber for receiving cooled offgas at a temperature from said boiler suitable for optimizing scrubber efficiency.   
   
   
       2 . The system as set forth in  claim 1 , wherein said kiln is a lime kiln. 
   
   
       3 . The system as set forth in  claim 1 , wherein said kiln is a cement kiln. 
   
   
       4 . The system as set forth in  claim 1 , wherein said system further includes a condenser and cooling tower.