Co-firing coal-water slurry in low-NOx burners: Experience at Penelec`s Seward Station

The electric utility industry is facing significant challenges for meeting environmental regulations for its coal fired generation units, and at the same time must stay cost competitive in an industry that is being deregulated. An emerging technology that can reduce environmental equipment costs, lower fuel costs, and help to mitigate the environmental hazard of coal fine impoundments is the recovery and use of coal fines (< 100 mesh) in the form of a coal-water slurry (CWS). The are a number of issues to be addressed in the commercialization of this technology: coal fines recovery and beneficiation; CWS formulation and transportation; and storage, handling, and firing by the combustion equipment owner. This paper deals primarily with the utilization of coal-water slurry in utility boilers. Experience on a 32MWe wall-fired boiler at the Pennsylvania Electric Company (Penelec) Seward Station indicates that CWS can be stored, handled, and co-fired with pulverized coal with only minimal modifications to the low-NOx coal burners and no modifications to the boiler. There was no degradation in combustion performance and NOx emissions were reduced approximately 20 % when firing up to 35 % of the total boiler heat input as coal-water slurry. Penelec contracted to purchase 2,500,000 gallonsmore » of CWS and are currently coming the fuel as it is produced and delivered. CWS fuel made from coal cleaning plant waste fines and from coal fines recovered from existing impoundments is expected to be available for less than $1.00/MMBtu.« less