Pressurized Fluidized Bed Combustion Low Temperature Cycle Demonstration Plant

The merits of the turbocharged PFBC cycle are well known. Brown Boveri have been working in the past on a concept to commercialize this technology. As the leader of a team, with Foster Wheeler, Burns & Roe and Research Cottrell, Brown Boveri have conceived a turbocharged PFBC retrofit demonstration plant (20 MWe/40 MWe, net heat rate 11,000 BTU/kWh) which is discussed below. Several old power stations in the USA have small coal-fired electric generating units which are inactive. The boilers are usually unreliable and their overhauling is uneconomical. The balance of the systems is quite often in a relatively good condition. In this retrofit concept the existing conventional boiler is replaced by a field-assembled PFBC steam generator with pneumatic feed system. It is considered that the steam turbogenerator with its complete condensing plant, together with the coal handling and the storage system can be used. The estimated total construction cost for the retrofit installation amounts to $28,000,000 for the 20 MWe and to $40,200,000 for the 40 MWe plant. This price is accurate to within plus/minus 20%. An extrapolation of these costs for a 80 MWe retrofit unit using barge transport for shop-fabricated and assembled components and applying coal-water slurry feed system result in an investment cost of $600/kW approximately. The cost of a retrofit plant looks attractive and indicates that the PFBC turbocharged cycle is economical compared to the conventional plant with FGD, as has been reported before. Improved cost prediction for a 80 MWe unit is only possible if a conceptual design is carried out.