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Show 2 - initially fuels will be coal and natural gas, with coal providing at least 65% of heat input and ultimately 95% - the commercial plant will have a 65% annual capacity factor and generate electricity at a 10% lower cost. The initial designs will be based on a V84.4 gas turbine with a nominal output of 150 MY; however, our designs are also compatible with the large aeroderivative machines. In combined cycle systems the total design output is 270 MV. The design of the HITAF system is complicated by the close coupling between the operating conditions of the combustor and the integrated air heater combined with the need to control the flow and disposition of the ash. Our approach has been to design the components with a "top down" methodology. That is, we first select an available turbine, in our case the V84.4, and then match the component designs with realistic operating conditions. This is a more efficient approach than broad-based concept-screening for "generic" conditions even though our designs are applicable to aeroderivative gas turbines as well. In the concept definition/system optimization analysis, the characteristics of the HITAF and gas turbine-based combined-cycle power system will be refined into an overall plant design through systems integration and optimization studies. These studies are using verified computer programs to synthesize a well-integrated power plant taking into account performance, environmental acceptance, reliability, and cost-of-electricity. Preliminary studies have identified a baseline plant concept, shown schematically in Figure 1, consisting of two HITAF units, one gas turbine, and a single steam turbine producing an overall plant output of about 268MY at a projected heat rate of 6867 Btu/kYh. The characteristics of the major streams are given in Table 1. Studies by UTC's Turbo Power and Marine Division and Bechtel have indicated that this size plant is in the range that the utility industry is investigating for coal-fired combined-cycle plants (250MY-400 MY). Also, highly reliable and efficient steam turbine and heat recovery equipment can be obtained commercially at reasonable $/kY in this size range thereby reducing the risk and cost of commercial implementation. HITAF Combustor/Air Heater Based on an analysis of all options, a preliminary conceptual HITAF combustor design has been defined. The system, Figure 2, has as its primary design goal the formation of ash that will not foul the air heater, therefore, it should not adhere to the walls. This established a maximum gas temperature at the entry to the air heater and defines the range of coals that can be burned . Our approach uses a controlled fuel distribution/long flame primary combustor. Heat release is stretched out gi ving progressive heat removal. The flame is naturally staged because it has a fuel rich core. The air recycled from the turbine is divided into three streams: primary combustion air, burnout or overfire air, and dilution air. The segmented air heater provides a cavity at the optimum |