INFLUENCE OF THE TEMPERATURE OF STEAM INJECTION INTO THE COMBUSTION CHAMBER OF A GAS-STEAM PLANT ON ITS ENERGY CHARACTERISTICS

Abstract

The relevance the work is caused by the need to improve thermal schemes and optimization of the parameters of gas-steam plants for reducing the consumption of such an energy resource as natural gas in electricity generation, which will also reduce the amount of harmful emissions into the environment. Purpose: to carry out, according to the developed methodology, a versatile parametric analysis with the choice of the optimal parameters of the operating modes of the proposed thermal schemes of gas-steam plants to improve their energy efficiency. Objects: gas-steam plants with the release of electricity based on gas turbines with steam injection into the combustion chamber. Methods: numerical methods of research based on material and energy balances of systems, as well as elements of gas-steam plants. Results. Based on the calculation of the thermal scheme of a gas-steam plant with electricity generation, the authors compared the effect on its energy characteristics of a constant and variable temperature of steam injection into the combustion chamber of a gas turbine plant. It was determined that the temperature of the injected steam into the combustion chamber significantly affects the range of parameters of the gas-steam plant. Increasing the compression ratio in the compressor and the temperature of the gases at the outlet of the combustion chamber lead to decrease in the range of parameters in comparison with the operation of a gas-steam plant with a constant temperature of the injected steam into the combustion chamber. In this case, the range of change in the temperature of the injected vapor with an increase in the degree of compression in the compressor and the temperature of the gases at the outlet of the combustion chamber is significantly reduced. It was established that the growth in the temperature of the injected steam compared to its constant temperature at the same gas temperature at the outlet of the combustion chamber and the minimum compression ratio in the compressor for this temperature increases the net electrical efficiency from 1 % at gas temperature of 1600 °С to 3 % at gas temperature of 1100 °C.