Increasing the Operation Efficiency of Low Pressure Cylinders of Cogeneration Turbines

Abstract

An increase in the operation efficiency of cogeneration turbines used by big heat and power plants is conditioned by the need of a maximum use of the fuel heat, mainly that of natural gas. The generation of two types of energy, in particular electric and thermal by cogeneration turbines for outside consumers is closely related to turbine operation modes and first of all to those for low pressure section in which the permanent heat loss occurs. The purpose of this research was to analyze the operation of low pressure cylinders used by operating cogeneration turbines of Т-100/120-130 and Т-250/300-240 types in a wide range of changes in electric and thermal loads. At high heat consumption according to the thermal schedule and low steam rate in the LPC the cascades of it operate consuming power at high ventilation losses. The joint operation of supply line heaters and low pressure cylinders was analyzed using the method of mathematical simulation of the turbine unit, experimental investigation of the models of LPC cascades and full-scale test data of cogeneration turbines built by different organizations. The relationships for the determination of power losses by LPC cascades when operating in low rate modes and additional generation of electric power by the turbine with the rational distribution of thermal load between the supply-line heaters have been given. It has been shown that the choice of heat release mode by the turbine unit can be defined by the optimization problem that requires the comparative estimation of power losses in the LPC and a gain in electric power due to the rational distribution of thermal load between the supply-line heaters.