Optimization of schemes and ways to expand the adjustment range for the power supply of combined heat and power plants

Abstract

The article assesses the possibility of using low-flow operating modes at steam turbine with an additional boiler and steam and combined-cycle cogeneration plants for heat supply schemes, taking into account the storage properties of heat networks and buildings. It is shown that the use of low-flow operation modes of the turbine plant during the night period allows the combined heat and power plant to participate more effectively in covering the variable part of the electric load schedule. The dependence of the share of participation of an additional boiler in covering the heat load on the prices for fuel and electricity is determined. Comparison of the performance indicators of the steam turbine CHPP in low-flow modes with the release of the thermal energy necessary to the consumer from an additional boiler with the mode of its complete shutdown and the release of thermal energy from the peak hot water boiler made it possible, taking into account the accumulating properties of heat networks and buildings, to recommend a low-flow operation mode at night. For a combined-cycle cogeneration plant it is shown that it is advisable to reduce the electric power at night, while ensuring the nominal heat supply, by unloading the gas turbines with the transfer of the steam turbine to the motor mode.