(364d) Production Of Activated Carbon For Mercury Control Using Hot Oxygen Technology

Authors: 
Bool, III, L., Praxair Inc


Activated carbon injection (ACI) represents a promising method reduce mercury emissions from coal-fired plants. In recent years Praxair has developed a flexible process to produce powder activated carbon (PAC) on-site using the plant's pulverized coal. Extreme processing conditions allow PAC to be produced in compact equipment with very short residence times. The flexible nature of the process allows both undoped and doped carbons to be easily produced from the same equipment. Third party test results from slipstream tests from utilities firing PRB fuels have shown mercury removals of 90% or greater at low (2 lb/MMacf) injection rates. Praxair has developed designs for full-scale production systems. Recent experiments have confirmed the scaling methods. Fabric filter testing has shown excellent mercury capture with Praxair produced sorbents. This paper will describe the process used to produce activated carbon, some of the slipstream results, and the scaling challenges.