Features of a choice of technical design parameters of combined steam-cycle power unit high-temperature sets

The new high-efficient coal-fired technology based on combinations of Field-Baranovsky and Rankine cycles is proposed. Efficiency of such power units can achieve 48-50 %. Design procedure of CSCPU is developed and the mathematical model taking into account calculation features of high-temperature sets is created. A number of calculations for the power generating units of 25-65 MW are executed. Technical design parameters and estimations of capital investments for the coal-fired low-pressure boilers with high-temperature heating surfaces and the high-temperature turbines are received.The dimensions of coal-fired boiler of CSCPU are approximately in 2 times larger than ones of conventional boilers of the same steam capacity, and the HT-turbines are commensurable with low-pressure cylinders of conventional steam turbines. High temperatures and low pressures of a working medium allow using the composite ceramics as a material of furnace tubes and high-temperature nickel and nickel-cobalt alloys for turbine blades. Capital investments in high-temperature sets (the boiler and the high- temperature steam turbine) per the rated kilowatt of CSCPU are 280-310 dollar/kW.