Research of the two-circuit combined-cycle cogeneration plant’s behavior according to the temperature chart

Abstract

THE PURPOSE. To consider the actual problem of determining the optimum value of the connected heat load to the cogeneration combined cycle gas turbine (CCGT) of the heat generation profile. METHHODS. Simulation modeling of operation modes using the "United Cycle" software is applied as a research method of the considered power unit operation. We studied several regimes of heat supply from the considered CCGTs during the heating period with the determination of integral annual indicators, as well as the relative fuel savings compared to the separate generation and the increase in the specific integral economic effect for different values of the cogeneration coefficient.RESULTS. We found that the optimal cogeneration coefficient for the object of study is 0.49. However, the value of the optimal cogeneration coefficient, determined by the condition of maximizing the specific integral economic effect for the object of research, is also 0.49. CONCLUSION. Determining the optimal unit commitment, which influences not only the initial investment, but also the expected operating (fuel) costs, is a pressing issue in power plant design. We present a basis for the possibility of using the indicator of relative fuel economy compared to separate generation as an optimization criterion. This parameter is widely used for optimization of combined heat and power units under conditions of planned economy. Under current economic conditions, it is possible to obtain a direct link between the incremental net discounted income from combined production and the relative fuel savings. This method can be used to analyze and optimize the mix of CCGT equipment regardless of geographical area, type of power system, energy resources cost, market conditions, as well as the characteristics of the used equipment.