Development of a high-performance coal-fired power generating system with pyrolysis gas and char-fired high-temperature furnace (HITAF): Volume 4. Final report

An outgrowth of our studies of the FWDC coal-fired high performance power systems (HIPPS) concept was the development of a concept for the repowering of existing boilers. The initial analysis of this concept indicates that it will be both technically and economically viable. A unique feature of our greenfields HIPPS concept is that it integrates the operation of a pressurized pyrolyzer and a pulverized fuel-fired boiler/air heater. Once this type of operation is achieved, there are a few different applications of this core technology. Two greenfields plant options are the base case plant and a plant where ceramic air heaters are used to extend the limit of air heating in the HITAF. The greenfields designs can be used for repowering in the conventional sense which involves replacing almost everything in the plant except the steam turbine and accessories. Another option is to keep the existing boiler and add a pyrolyzer and gas turbine to the plant. The study was done on an Eastern utility plant. The owner is currently considering replacing two units with atmospheric fluidized bed boilers, but is interested in a comparison with HIPPS technology. After repowering, the emissions levels need to be 0.25 lb SO{sub x}/MMBtu and 0.15 lb NO{sub x}/MMBtu